HomeMy WebLinkAboutMINUTES - 06092015 - C.01RECOMMENDATION(S):
APPROVE the Byron Highway-Camino Diablo Intersection Improvements Project and AUTHORIZE the Public
Works Director, or designee, to advertise the project, Byron area. [Project No. 0662-6R4094, DCD-CP# 15-01]
(District III), and
FIND, on the basis of the Initial Study/Mitigated Negative Declaration and all comments received and staff responses
contained herein, that there is no substantial evidence the project may have significant effect on the environment, and
ADOPT the Mitigated Negative Declaration and Mitigation and Monitoring Reporting Plan in compliance with the
California Environmental Quality Act (CEQA), pursuant to Article 6, Section 15070(a), (the custodian of which is
the Department of Conservation and Development Director located at 30 Muir Road, Martinez, CA), and
DIRECT the Director of Conservation and Development to file a Notice of Determination with the County Clerk, and
AUTHORIZE the Public Works Director to arrange for payment of $2,210 for California Department of Fish and
Wildlife fees, a $50 fee to the County Clerk for filing the Notice of Determination, and a $25 fee to Department of
Conservation and Development for processing.
APPROVE OTHER
RECOMMENDATION OF CNTY
ADMINISTRATOR
RECOMMENDATION OF BOARD
COMMITTEE
Action of Board On: 06/09/2015 APPROVED AS
RECOMMENDED
OTHER
Clerks Notes:
VOTE OF SUPERVISORS
AYE:John Gioia, District I Supervisor
Candace Andersen, District II
Supervisor
Mary N. Piepho, District III Supervisor
Karen Mitchoff, District IV Supervisor
ABSENT:Federal D. Glover, District V Supervisor
Contact: L. Chavez, Environmental (925)
313-2366
I hereby certify that this is a true and correct copy of an action taken and entered on the minutes of the Board of
Supervisors on the date shown.
ATTESTED: June 9, 2015
David J. Twa, County Administrator and Clerk of the Board of Supervisors
By: June McHuen, Deputy
cc: County Administrator, Auditor-Controller, R. Perez, Dept. of Development & Conservation - Planning, Public Works Finance, P. Denison, Environmental, L. Chavez,
Transportation Engineering, N. Wein, Transportation Engineering, A. Villar, Design/Construction, K. Emigh
C. 1
To:Board of Supervisors
From:Julia R. Bueren, Public Works Director/Chief Engineer
Date:June 9, 2015
Contra
Costa
County
Subject:APPROVE the Byron Highway-Camino Diablo Intersection Improvements Project and related actions under the
California Environmental Quality Act.
FISCAL IMPACT:
Funding will be 23% Highway Safety Improvement Program Grant Funds, 17% Measure J Return to Source
Funds, 12% East County Regional Area of Benefit Funds, and 48% Local Road Funds.
BACKGROUND:
Byron Highway and Camino Diablo Road are heavily used truck and commuter routes that provide a vital
transportation link between Contra Costa and Alameda Counties as well as San Joaquin County. Both Byron
Highway and Camino Diablo Road are two-lane roads with no turning lanes and no shoulders at this intersection.
Neither road is signalized, with free-through movements on Byron Highway and stop controls on both legs of
Camino Diablo Road. The project includes installation of new traffic signal lights and road improvements to
accommodate the addition of left turn lanes on three of the four legs at the intersection.
The existing travel lanes will be widened approximately 1,300 feet along Byron Highway (500 feet north to 800
feet south of the intersection) and approximately 800 feet along Camino Diablo Road (600 feet west and 200 feet
east of the intersection). The road widening will provide 12-foot wide travel lanes, 12-foot wide left turn lanes,
and 5-foot wide paved shoulders on both roads. A majority of the pavement widening will be along the east side
of Byron Highway south of the intersection and the north side of Camino Diablo Road west of the intersection. In
addition, a railroad crossing adjacent to the intersection will be improved with the installation of new railroad
panels and crossing gates. The project will also provide pedestrian facilities along the north side of Camino Diablo
Road from the intersection of Main Street to Byron Highway, which include sidewalk, curb and ADA ramps.
Construction activities associated with the project include the acquisition of new right-of-way (ROW) and
earthwork for the roadway widening, tree removals, drainage improvements, utility and roadway signage
relocations, guard rail installation, and restriping to accommodate new travel lane configurations. One-way traffic
control on Byron Highway, and road closure on Camino Diablo Road just west of the intersection for work
around the railroad will be required for a portion of the project.
Real property transactions will be necessary in support of this project including fee titles for the ROW acquisitions
and temporary construction easements.
Project construction is planned for 2016 and will take approximately four months to complete sometime between
April and October 2016.
CONSEQUENCE OF NEGATIVE ACTION:
Delay in approving the project may result in a delay of design, construction, and may jeopardize funding.
CHILDREN'S IMPACT STATEMENT:
Not applicable.
ATTACHMENTS
Final NOD
Initial Study/Mitigated Negative Declaration & Mitigation Monitoring Reporting Plan
Response to Comments
CALIFORNIA ENVIRONMENTAL QUALITY ACT
NOTICE OF DETERMINATION
Authority cited: Sections 21083, Public Resources Code.
Reference Section 21000-21174, Public Resources Code.
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To: Office of Planning and Research From: Contra Costa County
P.O. Box 3044, Room 113 Dept. of Conservation & Development
Sacramento, CA 95812-3044 30 Muir Road
Martinez, CA 94553
County Clerk
County of: Contra Costa
State Clearinghouse Number: 2015042014
Project Title: Byron Highway-Camino Diablo Rd Intersection Improvements - CP#15-01; WO#: 0662-6R4094
Project Applicant: Contra Costa County Public Works Department
Project Location: Byron in East Contra Costa County
Project Description: Byron Highway and Camino Diablo Road are heavily used truck and commuter routes that
provide a vital transportation link between Contra Costa and Alameda Counties as well as San Joaquin County. Both
Byron Highway and Camino Diablo Road are two-lane roads with no turning lanes and no shoulders at this
intersection. Neither road is signalized, with free-through movements on Byron Highway and stop controls on both
legs of Camino Diablo Road. The project includes installation of new traffic signal lights and road improvements to
accommodate the addition of left turn lanes on three of the four legs at the intersection. The existing travel lanes will
be widened approximately 1,300 feet along Byron Highway (500 feet north to 800 feet south of the intersection) and
approximately 800 feet along Camino Diablo Road (600 feet west and 200 feet east of the intersection). The road
widening will provide 12-foot wide travel lanes, 12-foot wide left turn lanes, and 5-foot wide paved shoulders on both
roads. A majority of the pavement widening will be along the east side of Byron Highway south of the intersection and
the north side of Camino Diablo Road west of the intersection. In addition, a railroad crossing adjacent to the
intersection will be improved with the installation of new railroad panels and crossing gates. The project will also
provide pedestrian facilities along the north side of Camino Diablo Road from the intersection of Main Street to Byron
Highway which will include sidewalk, curb, and ADA ramps, and crosswalk. The project is partially funded by federal
transportation funds, High Risk Rural Road program. Project construction is planned for 2016 and will take
approximately 4 months to complete som etime between April and October 2016. Construction activities associated
with the project include the acquisition of new right-of-way (ROW) and earthwork for the roadway widening, tree
removals, drainage improvements, utility and roadway signage relocations, guard rail installation, and restriping to
accommodate new travel lane configurations. One-way traffic control on Byron Highway, and road closure on Camino
Diablo Road just west of the intersection for work around the railroad will be required for a portion of the project. Real
property transactions will be necessary in support of this project including fee titles for the ROW acquisitions and
temporary construction easements.
The project was approved on:
1. The project [ will will not] have a significant effect on the environment.
2. An Environmental Impact Report was prepared for this project pursuant to the provisions of CEQA.
A Mitigated Negative Declaration was prepared for this project pursuant to the provisions of CEQA.
3. Mitigation measures [ were were not] made a condition of the approval of the project.
4. A mitigation reporting or monitoring plan [ was was not] adopted for this project.
5. A statement of Overriding Considerations [ was was not] adopted for this project.
6. Findings [ were were not] made pursuant to the provisions of CEQA.
Notice of Determination was sent to Office of Planning and Research.*
This is to certify that the final Mitigated Negative Declaration with comments and responses and record of project
approval, or the Negative Declaration, is available to the General Public at:
Contra Costa County Public Works Department
255 Glacier Drive, Martinez, CA 94553
Signature (Contra Costa County): Title:
Date: Date Received for filing at OPR:
AFFIDAVIT OF FILING AND POSTING
I declare that on ____________________________________________ I received and posted this notice as required
by California Public Resources Code Section 21152(c). Said notice will remain posted for 30 days from the filing date.
Signature Title:
Applicant: Department of Fish and Game Fees Due
Public Works Department EIR - $3,069.75 Total Due: $ 75.00
255 Glacier Drive Neg. Dec. - $2,210.00 Total Paid $ 2,285.00
Martinez, CA 94553 DeMinimis Findings - $0
Attn: _Claudia Gemberling_____ County Clerk - $50 Receipt #: 2271668
Environmental Services Division Conservation & Development - $25
Phone: (925) 313-2192
*Notice of Determination may be sent by fax to (916) 323-3018, if followed up with a duplicate mailed copy.
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Environmental Checklist Form
1. Project Title:
Byron Highway-Camino Diablo Intersection Improvements
2. Lead Agency Name and Address:
Contra Costa County Department of Conservation and Development
30 Muir Rd., Martinez, CA 94553
3. Contact Person and Phone Number:
Claudia Gemberling, Environmental Analyst II (925) 313-2192
4. Project Location:
Byron, East Contra Costa County (Figure 1)
5. Project Sponsor's Name and Address:
Contra Costa County Public Works Department
255 Glacier Drive, Martinez CA 94553
6. General Plan Designation:
AL (Agricultural Lands), C (Commercial), LI (Light Industry), SH (Single Family Residential – High)
7. Zoning:
A-2 (General Agricultural), C (Commercial), R-B (Retail-Business), R-6 (Single Family Residential)
8. Project Description:
Byron Highway and Camino Diablo Road are heavily used truck and commuter routes that provide a
vital transportation link between Contra Costa and Alameda Counties as well as San Joaquin County.
Both Byron Highway and Camino Diablo Road are two-lane roads with no turning lanes and no
shoulders at this intersection. Neither road is signalized, with free-through movements on Byron
Highway and stop controls on both legs of Camino Diablo Road. The project includes installation of a
new traffic signal and road improvements to accommodate the addition of left turn lanes on three of the
four legs at the intersection (Figure 2).
The road improvements include widening Byron Highway and Camino Diablo Road to accommodate
the turn lanes and to provide paved shoulders. The road improvements will occur ap proximately 1,300
feet along Byron Highway (500 feet north and 800 feet south of the intersection) and approximately
800 feet along Camino Diablo Road (600 feet west and 200 feet east of the intersection). The road
widening will provide 12-foot wide left turn lanes and 5-foot wide paved shoulders on both roads; the
width of the existing travel lanes will not change. A majority of the road widening will be along the
east side of Byron Highway south of the intersection and the north side of Camino Diablo Road west of
the intersection.
Construction activities associated with the project include the acquisition of new right-of-way (ROW)
and earthwork for the roadway widening, pedestrian facility construction, railroad crossing
improvements, guard rail installation, tree removals, relocation of roadway signage, restriping to
accommodate new travel lane configurations, utility relocations, and drainage improvements.
^_
Project Location
Figure 1Project LocationPath: K:\Projects_3\County_of_Contra_Costa\00218_14_ByronHwy_CaminoDiabl\mapdoc\Fig_1_Project_Location_20140522.mxd; User: 29391; Date: 3/17/20150 105
Miles´Source: Basemap, ESRI 2013
^_
Project Location
EXISTINGIMPROVEMENTSPROPOSEDIMPROVEMENTSEXISTINGROADRIGHTOFWAY,DEDICATEDRIGHTOFWAY,ORAREAWHERECOUNTYHASRIGHTSEXISTINGRAILROADRIGHTOFWAYEXISTINGPROPERTYLINESPROPOSEDRIGHTOFWAYPROPOSEDTEMPORARYCONSTRUCTIONEASEMENTNORTHFIGURE 2: PROJECT SITE OVERVIEW MAP
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The ROW acquisitions will be of sliver portions (varying between 5 and 15 feet) along the frontages
from a number of residential properties along the east side of Byron Highway south of the intersection
and north side of Camino Diablo Road west of the intersection to accommodate which will require
removal of landscaping including trees and fences; mailboxes will be relocated. ROW acquisition will
also be necessary from the railroad property for the roadway widening at the railroad tracks.
Temporary construction easements may also be needed.
Address APN
Proposed ROW
Acquisition
(square feet)
Byron Highway
15161 002-140-002 316
15147 002-140-003 620
15125 002-140-004 1,135
15103 002-140-005 1,530
15089 002-140-006 1,489
15075 002-140-007 1,574
15057 002-140-008 810
15045 002-140-009 1,184
14800 002-260-002 3,282
N/L 002-260-003 9,293
Camino Diablo Road
3101 002-102-011 1,777
3073 002-102-015 212
The earthwork will require removal of approximately 1,300 cubic yards of roadway material and soil
that will be off-hauled from the project site and importing approximately 2,000 cubic yards of soil to
the site to build up the vertical fill around the railroad tracks to accommodate the road and shoulder
widening.
Pedestrian facilities include construction of at least a 5-foot wide sidewalk with American Disability
Act (ADA)-compliant ramps at the northeast, southeast, and northwest corners of the intersection and
crosswalks. The sidewalk will extend along the north side of Camino Diablo Road from the northwest
corner of the intersection west to Main Street.
Standard construction equipment will be used, including but not limited to: excavators, graders,
scrapers, loaders, sweepers/scrubbers, plate compactors, rollers, backhoes, and pavers. Staging will
occur within the County road ROW. Construction activities will be generally limited to the hours
between 7:00 a.m. to 5:00 p.m. One-way traffic control on Byron Highway, and road closure on
Camino Diablo Road just west of the intersection for work around the railroad will be required for a
portion of the project; detour route signs will be posted 7 days prior to start of construction in various
locations in the project vicinity; emergency vehicles will have access at all times. Disturbed areas will
be stabilized as necessary.
Construction of the project is anticipated to start sometime between April and October in 2016 and take
approximately 4 months to complete.
9. Surrounding Land Uses and Setting:
Byron is a small unincorporated community that primarily consists of residential development with
some commercial development from the early twentieth century surrounded by rural residential and
farmlands. The project area is adjoined by residences along the east side of B yron Highway and
railroad tracks along the west side. A gas station occupies the southeast corner of the intersection and a
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trucking company southwest of the intersection. Residences primarily adjoin the north and south sides
of Camino Diablo and commercial buildings fronting Main Street are located just north of Camino
Diablo (Figure 2).
10. Other public agencies whose approval is required (e.g. permits, financing, approval, or
participation agreement):
Federal Highway Administration (FHWA), California Department of Transportation (Caltrans)
The project will be partially funded through the High Risk Rural Road (HRRRL) program. Caltrans, on
behalf of the FHWA, is the lead agency for the National Environmental Policy Act (NEPA).
Therefore, the project will be reviewed by Caltrans for NEPA compliance.
East Contra Costa County Habitat Conservation Plan/Natural Community Conservation Plan
(HCP/NCCP) Federal Endangered Species Act (ESA), California Natural Community Conservation
Planning Act (NCCP)
The project is located within the HCP/NCCP inventory area and is a covered activity. The HCP/NCCP
is intended to provide an effective framework to protect natural resources and special-status species
recovery in eastern Contra Costa County while improving and streamlining the environmental
permitting process for impacts on these species and associated habitats. The HCP/NCCP complies with
Section 10(a)(1)(B) of the federal ESA and California Natural Community Conservation Planning Act
of 2003 and as such covered activities are authorized incidental take of HCP/NCCP-covered special-
status species subject to mitigation fees for both permanent and temporary impacts to species habitats
and implementation of specific conditions and conservation measures to avoid or minimize potential
effects to species and/or its habitats. The HCP/NCCP requires reporting and fee payment to the
HCP/NCCP Implementing Entity, the East Contra Costa County Habitat Conservancy, a joint exercise
of powers authority formed by the Cities of Brentwood, Clayton, Oakley and Pittsburg and Contra
Costa County (Jones & Stokes 2006).
U.S. Army Corps of Engineers (USACE) – Sacramento District
Clean Water Act, Section 404, Nationwide Permit
Section 404 of the Clean Water Act regulates discharges of dredged or fill material into jurisdictional
waters of the U. S., including wetlands. A drainage ditch and a seasonal wetland adjoin the project
area. There will be minimal temporary impacts during construction. This type of activity would be
authorized under a Regional General Permit program for HCP/NCCP-covered projects (USACE 2015).
Therefore, the USACE Sacramento District will be notified for authorization.
Regional Water Quality Control Board (RWQCB) – Central Valley Region
Clean Water Act, Section 401, Water Quality Certification
Section 401 of the Clean Water Act also regulates projects that will discharge dredged or fill material
into jurisdictional waters of the U.S., and waters of the state, including wetlands when a federal permit
or license will be issued (RWQCB 2015). As noted above, a drainage ditch and seasonal wetland
adjoin the project area. There will be minimal temporary impacts during construction. Therefore, a
Water Quality Certification will be obtained from the RWQCB.
State Water Resources Control Board (SWRCB)
National Pollution Discharge Elimination System (NPDES) General Permit for Storm Water
Discharges Associated with Construction and Land Disturbance Activities (Order 2012-0006-DWQ)
(Construction General Permit [CGP])
Projects that disturb one or more acres of soil or disturbs less than one acre but are part of a larger
development that in total disturbs one or more acres, are required to obtain coverage under this permit
(SWRCB 2015). If the project will disturb less than 5 acres, the permit allows for a waiver certification
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if the project will occur when the rainfall erosivity factor value is less than five (i.e., typically
occurring in dry seasons when rains are less frequent and less force). At this time, it is anticipated that
the project will disturb approximately 3 acres. Therefore, a waiver certification will be requested from
the SWRCB.
Contra Costa County Department of Conservation and Development (CCCDCD)
The removal and placement of soil and roadway material may require grading and truck permits.
Therefore, project contract specifications will require the contractor to obtain necessary permits from
the CCCDCD.
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EVALUATION OF ENVIRONMENTAL IMPACTS:
I. AESTHETICS
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Have a substantial adverse effect on a scenic vista?
b) Substantially damage scenic resources, including but not
limited to, trees, rock outcroppings, and historic
buildings within a state scenic highway?
c) Substantially degrade the existing visual character or
quality of the site and its surroundings?
d) Create a new source of substantial light or glare that
would adversely affect day or nighttime views in the
area?
Contra Costa County has two main scenic resources in addition to many localized scenic features: (1) scenic
ridges, hillsides, and rock outcroppings; and (2) the San Francisco Bay/Delta estuary system. Throughout
much of the County, there are significant topographic variations in the landscape. The largest and most
prominent of these are the hills that form the backdrop for much of the developed portions of the area. Views
of these major ridgelines help to reinforce the rural feeling of the County’s rapidly growing communities.
These major ridges provide an important balance to current and planned development (Contra Costa County
2005a).
The project is located within the downtown area of Byron, a small rural community in East Contra Costa
County that primarily consists of residential development with some commercial and retail development
from the early twentieth century, surrounded by rural residential and farm lands. The rolling hills and Mount
Diablo ridgelines to the west of Byron provide a rural scenic backdrop from Byron and thus Byron Highway
and Camino Diablo Road are designated as County scenic routes as they primarily provide expansive,
unobstructive views of the rolling hills and ridgelines (Contra Costa County 2005a). There are no designated
or eligible cultural, historical or natural resources that could be considered important visual resources within
the project area as reported in the technical studies prepared for this project (CardnoEntrix 2014a,b,c,
California Office of Historic Preservation 2014, ICF International 2014).
a) Would the project have a substantial adverse effect on a scenic vista?
The rolling hills and Mount Diablo ridgelines to the west provide a rural scenic backdrop from Byron.
The project will introduce a traffic signal at a main intersection in downtown Byron and remove
approximately 35 ornamental trees, primarily palm, cypress, and olive, from the frontage of residential
properties that immediately adjoin Byron Highway on the east side and the north side of Camino Diablo
Road to accommodate the road widening. Removal of the trees will not have a substantial effect on the
scenic vista. The traffic signal will not have a substantial adverse effect on a scenic vista as the location
of the traffic signal will be placed at a location where views of the hills to the west are obscured by
mature trees and buildings west of downtown Byron. Further, introduction of a traffic light would not
substantially obstruct views. Therefore, the project will have no impact.
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b) Would the project substantially damage scenic resources, including but not limited to, trees, rock
outcroppings, and historic buildings within a state scenic highway?
While Byron Highway is identified as a County Scenic Route, Byron Highway is not an officially
designated or eligible State Scenic Highway (Caltrans 2015). Further, the ornamental trees that will be
removed are not considered scenic resources as they are not native heritage trees or trees of local
significance; there are no designated or eligible cultural, historical or natural resources that could be
considered important scenic resources within the project area. Therefore, the project will have no
impact.
c) Would the project substantially degrade the existing visual character or quality of the site and its
surroundings?
The traffic light will not substantially degrade the existing visual character or quality of the site and
surrounding area as the traffic signal will be installed in the developed area of Byron that contains
similar infrastructure features such as overhead utility poles and lines and railroad crossing arms. The
vegetation removal will not be substantial considering other mature vegetation that occur on these
properties and in the area. Construction of the project will impact the visual character of this area but it
will be temporary. Therefore, project impacts will be less than significant.
d) Create a new source of substantial light or glare that would adversely affect day or nighttime views in
the area?
The traffic signal will create a permanent source of light however the light would not adversely affect
day or nighttime views in the area as it will not be substantial. Further, the glare from the lights would
not result in nuisance to nearby residences considering that the lights will be located in an area that is
primarily adjoined by commercial businesses. Construction will take place during the daylight hours
and therefore, will not create a nighttime light source. Therefore, project impacts will be less than
significant.
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II. AGRICULTURE AND FOREST RESOURCES
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Convert Prime Farmland, Unique Farmland, or
Farmland of Statewide Importance (Farmland), as
shown on the maps prepared pursuant to the Farmland
Mapping and Monitoring Program of the California
Resources Agency, to non-agricultural use?
b) Conflict with existing zoning for agricultural use, or a
Williamson Act Contract?
c) Conflict with existing zoning for, or cause rezoning of,
forest land (as defined in Public Resources Code
section 12220(g), timberland (as defined by Public
Resources Code section 4526), or timberland zoned
Timberland Production (as defined by Government
Code section 51104(g)?
d) Result in the loss of forest land or conversion of forest
land to non-forest use?
e) Involve other changes in the existing environment,
which due to their location or nature, could result in
conversion of farmland, to non-agricultural use or
conversion of forest land to non-forest use?
Regulatory Background
The Farmland Mapping and Monitoring Program (FMMP) was established in 1982 in response to a critical
need for assessing the location, quality, and quantity of agricultural lands and conversion of these lands over
time. FMMP is a non-regulatory program that provides a consistent and impartial analysis of agricultural land
use and land use changes throughout California (California Department of Conservation [CDC] 2015).
In order to be shown on FMMP’s Important Farmland Maps as Prime Farmland and Farmland of Statewide
Importance land must have been used for irrigated agricultural production at some time during the four years
prior to the Important Farmland Map date and must meet physical and chemical soil criteria as determined by
the Natural Resource Conservation Service. Prime Farmland has the best combination of physical and
chemical features able to sustain long term agricultural production. This land has the soil quality, growing
season, and moisture supply needed to produce sustained high yields. Farmland of Statewide Importance is
similar to Prime Farmland but with minor shortcomings, such as greater slopes or less ability to store soil
moisture. Unique Farmland is of lesser quality soils used for the production of the state's leading agricultural
crops; this land is usually irrigated, but may include non-irrigated orchards or vineyards as found in some
climatic zones in California (CDC 2015).
In addition, land may be enrolled under the ‘Prime Agricultural Land’ designation under the state’s
Williamson Act if it meets certain economic or production criteria. The California Land Conservation Act of
1965, commonly known as the Williamson Act (Act), created a program to help counties preserve agricultural
land and open space by offering a tax incentive to property owners. The Act provides an arrangement where
private landowners voluntarily restrict their land to agricultural and compatible open space uses under a
contract with the County. (Contra Costa County Department of Conservation and Development 2015).
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CEQA Guidelines address farmland conversion impacts directly in two ways; first, cancellation of Williamson
Act contracts for parcels exceeding 100 acres is an action considered to be of “statewide, regional, or area-
wide significance, and thus subject to CEQA review (CEQA Guidelines Section 15206(b)(3)). Second, a
project that would convert prime agricultural land to non-agricultural use or impair the agricultural
productivity would normally have a significant effect on the environment.” No set acreage of prime farmland
conversion has been determined by case law or regulatory framework which would constitute a significant
impact (California Natural Resources Agency 2015).
a) Would the project convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance
(Farmland), as shown on the maps prepared pursuant to the Farmland Mapping and Monitoring Program
of the California Resources Agency, to non-agricultural use?
The project will not convert Prime Farmland, Unique Farmland or Farmland of Statewide Importance as
no farmland with these designations occurs within or immediately adjacent to the project area as shown on
the Contra Costa County Important Farmland Map (2012). Therefore, the project will have no impact.
b) Would the project conflict with existing zoning for agricultural use, or a Williamson Act Contract?
The project will not conflict with existing zoning for agricultural use or a Williamson Act Contract as the
project will not affect farmland with an existing Williamson Act contract as shown on the Contra Costa
County Agricultural Preserve Map (2012). Therefore, the project will have no impact.
c) Would the project conflict with existing zoning for, or cause rezoning of, forest land (as defined in Public
Resources Code section 12220(g)), timberland (as defined by Public Resources Code section 4526), or
timberland zoned Timberland Production (as defined by Government Code section 51104(g)?
The project will not conflict with existing zoning for, or cause rezoning of, forest land (as defined in
Public Resources Code section 12220(g), timberland (as defined by Public Resources Code section 4526),
or timberland zoned Timberland Production (as defined by Government Code section 51104(g) because no
forest land or timberland is present within or adjacent to the project area. Therefore, the project will have
no impact.
d) Would the project result in the loss of forest land or conversion of forest land to non-forest use?
The project will not result in the loss of forest land or conversion of forest land to non-forest use because
forest land is not present within or adjacent to the project area. Therefore, the project will have no impact.
e) Would the project involve other changes in the existing environment, which due to their location or nature,
could result in conversion of farmland, to non-agricultural use or conversion of forest land to non-forest
use?
The project will not result in conversion of farmland to non-agricultural use or forest land to non-forest
use as no farmlands or forest land occur within or adjacent to the project area. Therefore, the project will
have no impact.
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III. AIR QUALITY
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Conflict with or obstruct implementation of the
applicable air quality plan?
b) Violate any air quality standard or contribute to an
existing or projected air quality violation?
c) Result in a cumulatively considerable net increase of
any criteria pollutant for which the project region is a
non-attainment under an applicable federal or state
ambient air quality standard (including releasing
emissions which exceed quantitative thresholds for
ozone precursors)?
d) Expose sensitive receptors to substantial pollutant
concentrations?
e) Create objectionable odors affecting a substantial
number of people?
Regulatory Background
The federal Clean Air Act (CAA) requires the U. S. Environmental Protection Agency (USEPA) to set
National Ambient Air Quality Standards (NAAQS) for six common criteria air pollutants: particulate
matter, ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead. Of the six
pollutants, particle pollution and ground-level ozone are the most widespread health threats. The CAA
requires the USEPA to designate areas as meeting (attainment) or not meeting (nonattainment) the
standards (USEPA 2015). In addition, the California Health and Safety Code requires the California Air
Resources Board (CARB), a division of the California EPA, to establish and periodically review area
designation criteria for state standards, which are more stringent. The project is located within the San
Francisco Bay Area Air Basin which is currently designated as nonattainment for national and state ozone
and particulate matter standards (Bay Area Air Quality Management District [BAAQMD] 2015a,b).
The CAA also requires states to develop a general plan to attain and maintain the NAAQS and a specific
plan to attain the standards for each nonattainment area. The CARB and the BAAQMD periodically
prepare and update these plans in cooperation with regional agency partners. These plans usually define
control strategies to reduce air pollutant emissions from industrial facilities, commercial processes, motor
vehicles, and other sources which are typically implemented through a combination of regulations
enforced by the BAAQMD, grant and incentive programs, public education and outreach, and partnerships
with other agencies and stakeholders. The current air quality plan is the 2010 Clean Air Plan which
includes the most recent ozone attainment plan and focuses on reduction of ozone, particulate matter, and
greenhouse gases (GHGs) (BAAQMD 2010a).
In order to address GHGs, which include criteria air pollutants (regional pollutants) and toxic air
contaminants (local pollutants), the BAAQMD adopted CEQA thresholds of significance and updated its
1999 CEQA Air Quality Guidelines in 2010 to assist lead agencies in evaluating air quality impacts to
determine if a project’s individual emissions would be cumulatively considerable. Various modeling tools
are used to estimate emissions based on the type of project (i.e., land use develo pments, linear
transportation and utility projects) (BAAQMD 2010b, 2011). However, the BAAQMD’s 2010 adopted
thresholds were challenged in a lawsuit and in March 2012 the Alameda County Superior Court issued a
judgment finding that the BAAQMD had failed to comply with CEQA when it adopted the 2010
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thresholds of significance. As such, the 2010 thresholds are not formally in place pending CEQA review
and have been pulled from the 2011 CEQA Guidelines which were updated in 2012 to omit the thresholds
to reflect this ruling (BAAQMD 2012). In the interim, while the BAAQMD has indicated that Lead
Agencies may rely on BAAQMD’s updated CEQA Guidelines for assistance in calculating air pollution
emissions, obtaining information regarding health impacts of air pollutants, and identifying potential
mitigation measures, the BAAQMD suggests that Lead Agencies determine appropriate thresholds for
each project, and consider the 1999 thresholds along with the evidence in record for the project to
determine air quality impacts. The deferral of the 2010 thresholds was based on a procedural action and
not on the scientific merits of the thresholds. For this reason, the 2010 thresholds were used to determine
the project impacts. The 1999 and 2012 CEQA Guidelines were also consulted (BAAQMD 1999, 2010b,
2012).
In addition to criteria air pollutants, naturally-occurring asbestos (NOA), a toxic air contaminant, is also an
air pollutant of concern. It can cause lung cancer and mesothelioma which is dependent upon the type of
asbestos fibers inhaled and exposure levels. NOA is typically associated with serpentinite and ultramafic
rocks formed in high-temperature environments below the surface of the earth when metamorphic
conditions are right for the formation of asbestos. The BAAQMD requires that projects implement the best
available dust control measures where NOA is likely to be found in order to reduce dust emissions as well
as notification to the BAAQMD (BAAQMD 2015c, CARB 2015). The project area is not located within
an area identified as having rocks associated with NOA (California Department of Conservation 2000).
a) Would the project conflict with or obstruct implementation of the applicable air quality plan?
There will be no operational air quality impacts as the project will not increase capacity of the roadways
and thus will not contribute to an increase of air pollutant emissions. However, construction of the project
will result in temporary increases of air pollutant emissions. Construction-related activities generate
criteria air pollutants including carbon monoxide, sulfur dioxide, particulate matter as well as precursor
emissions such as reactive organic gases and oxides of nitrogen and GHGs from equipment and vehicle
exhaust, fugitive dust from soil movement, and off-gas emissions from asphalt paving. Therefore,
anticipated construction emissions such as areas of disturbance, vehicle and truck trips, construction
equipment to be used, duration of use, and other features were quantified by an air quality specialist using
the Sacramento Metropolitan Air Quality Management District Road Construction Emissions Model
(RoadMod) (version 7.1.5.1) to determine if project-related construction emissions exceed the BAAQMD
2010 significance thresholds (LSA Associates 2015). The anticipated types of construction equipment that
will be used include excavators, graders, scrapers, loaders, sweepers/scrubbers, plate compactors, rollers,
backhoes, and pavers (although would not be used during all construction phases).
The total project site is approximately 3 acres of which approximately 1.5 acres consist of paved roads.
Approximately 1,300 cubic yards of roadway material and soil will be excavated and off-hauled from the
project site and approximately 2,000 cubic yards of soil will be imported to the site.. The results of the
model (as shown in the table below) indicate that estimated project construction emissions would not
exceed thresholds. Further, project contract specifications require that the construction contractor comply
with applicable air pollution control regulations and practices such as limiting equipment idling time,
implementing dust control measures, and ensuring all construction machinery and vehicles are properly
tuned. In addition, signs with contact name and phone number will be publicly posted for construction
emission complaints. The project will not conflict with or obstruct implementation of the Clean Air Plan
as project-related emissions were estimated in accordance with the BAAQMD Air Quality Guidelines and
determined to be below thresholds. Therefore, project impacts will be less than significant.
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Phases ROG
(lbs/day)
CO
(lbs/day)
NOx
(lbs/day)
PM10
Exhaust
(lbs/day)
PM2.5
Exhaust
(lbs/day)
CO2
(lbs/day)
Fugitive Dust
PM10 PM2.5
(lbs/day) (lbs/day)
Grubbing/Land
Clearing 3.1 15.8 28.1 1.6 1.4 3,008 5.0 1.0
Grading/Excavation 2.4 11.5 20.4 1.3 1.2 2,612 5.0 1.0
Drainage/Utilities/Su
b-Grade 4.1 20.9 38.1 2.1 1.9 4,234 5.0 1.0
Paving 2.6 15.0 21.9 1.4 1.3 2,680 - -
Maximum
(pounds/day) 4.1 20.9 38.1 2.1 1.9 4,234 5.0 1.0
BAAQMD 2011
CEQA Criteria 54 54 82 54
Less than Threshold? Yes Yes Yes Yes
ROG: reactive organic gases; CO: carbon monoxide; NOx: nitrogen oxides; PM10: particulate matter (10 microns or less);
PM2.5: particulate matter (2.5 microns or less); CO2: carbon dioxide.
b) Would the project violate any air quality standard or contribute to an existing or projected air quality
violation?
The project will not violate any air quality standard or contribute to an existing or projected air quality
violation as estimated project-related emissions were determined not to exceed the daily construction-
related thresholds as discussed above in item (a). In addition, the project will comply with contract
requirements for air pollution control practices. Therefore, project impacts will be less than significant.
c) Would the project result in a cumulatively considerable net increase of any criteria pollutant for which the
project region is a non-attainment under an applicable federal or state ambient air quality standard
(including releasing emissions which exceed quantitative thresholds for ozone precursors)?
The project is located within the San Francisco Bay Area Air Basin which is currently designated as
nonattainment for national and state ozone and particulate matter standards. The project will not result in a
cumulatively considerable net increase of any criteria pollutant as estimated project-related emissions were
determined not to exceed the daily construction-related thresholds as discussed above in item (a). In
addition, the project will comply with contract requirements for air pollution control practices. Therefore,
impacts will be less than significant.
d) Would the project expose sensitive receptors to substantial pollutant concentrations?
Sensitive receptors are locations of human populations such as residences, hospitals, schools, day care
centers, retirement homes, and convalescence facilities where there is reasonable expectation of
continuous human exposure to poor air quality standards (California Air Resources Board [CARB] 2005).
Construction-related emissions can expose sensitive receptors to toxic air contaminants (TAC), including
diesel particulate matter emissions which are considered to be the most significant potential TAC for
construction projects (BAAQMD 2010b). Individuals particularly vulnerable to diesel particulate matter
are children and the elderly.
The BAAQMD CEQA significance threshold for potential effects of diesel particulate matter applies to
the hypothetical exposure of a person continuously for 70 years. However, the BAAQMD considers fine
particulate matter (PM2.5) to be the most significant TAC in terms of its potential to cause a wide range of
health effects and recommends the analysis of TACs from construction activities to consider the types of
off-site receptors and their proximity to construction activity, construction duration, quantity and types of
diesel-powered equipment, number of hours of equipment operation, location(s) of equipment use,
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distance to nearest off-site sensitive receptors, and orientation with respect to the dominant wind direction,
location of equipment staging area, and amount of on-site diesel-generated PM2.5 exhaust (LSA Associates
2015).
The project site is immediately adjoined by residences along the east side of Byron Highway and north
and south sides of Camino Diablo Road; a gas station, convenience store, and small restaurant are located
at the southeast corner of the intersection, and a truck staging facility is located just southwest of the
intersection. As noted above, the anticipated types of construction equipment that will be used include
excavators, graders, scrapers, loaders, sweepers/scrubbers, plate compactors, rollers, backhoes, and pavers.
Construction would occur over a 4-month period and the greatest use of diesel-powered equipment would
occur for approximately 30 working days, no more than 5 hours per day for 5 days per week. Based on
wind statistics collected near Discovery Bay, winds in the project vicinity are from the west/northwest
throughout the year. The highest wind speeds occur from March through June (5-6 mph) with wind speeds
of 2-3 mph during the rest of the year (LSA Associates 2015).
Winds from the west/northwest could potentially carry construction emissions and particulates toward the
residences and gas station along the east side of Byron Highway and thus residences and customers could
be temporarily affected. However, based on the construction emission analysis discussed above in item
(a), the maximum amount of PM2.5 for any of the construction phases is estimated to be 1.9 lbs/day which
is far less than the BAAQMD CEQA threshold of 54 lbs/day (LSA Associates 2015). Further,
implementation of the project contract requirements for air pollution control practices (i.e., dust control) as
discussed above in item (a) would greatly reduce fine particulate matter. Therefore, the project would not
expose sensitive receptors to substantial pollutant concentrations and thus project impacts would be less
than significant.
e) Would the project create objectionable odors affecting a substantial number of people?
The operational aspects of the project will not generate any objectionable odors. However, construction
equipment exhaust and asphalt paving operations may create objectionable odors. Implementation of the
project air pollution control requirements described above will minimize construction-related odors.
Therefore, project impacts will be less than significant.
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IV. BIOLOGICAL RESOURCES
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact No Impact
Would the project:
a) Have a substantial adverse effect, either directly
or through habitat modifications, on any species
identified as a candidate, sensitive, or special
status species in local or regional plans, policies,
or regulations, or by the California Department
of Fish and Wildlife or U.S. Fish and Wildlife
Service?
b) Have a substantial adverse effect on any riparian
habitat or other sensitive natural community
identified in local or regional plans, policies,
regulations or by the California Department of
Fish and Wildlife or U.S. Fish and Wildlife
Service?
c) Have a substantial adverse effect on federally
protected wetlands as defined by Section 404 of
the Clean Water Act (including but not limited
to, marsh, vernal pool, coastal, etc.) through
direct removal, filling, hydrological
interruption, or other means?
d) Interfere substantially with the movement of
any native resident or migratory fish or wildlife
species or with established native resident or
migratory wildlife corridors, or impede the use
of native wildlife nursery sites?
e) Conflict with any local policies or ordinances
protecting biological resources, such as tree
preservation policy or ordinance?
f) Conflict with the provisions of an adopted
Habitat Conservation Plan, Natural Community
Conservation Plan, or other approved local,
regional or state habitat conservation plan?
Regulatory Background
In 1973, the federal Endangered Species Act (ESA) was passed by Congress to protect ecosystems supporting
special-status species to be administered by the U. S. Fish and Wildlife Service (USFWS). The California
Endangered Species Act was passed as a parallel act to be administered by the California Department of Fish
and Wildlife (CDFW). Special-status plant and wildlife species are defined as those species listed as
Endangered, Threatened, or Proposed for listing or are designated as Fully Protected species under one or more
of the following regulatory status:
Federal Endangered Species Act, as amended (Code of Federal Regulations, Title 50, Section 17);
California Endangered Species Act (California Code of Regulations Title 14, Section 670.5);
California Fish and Game Code (Section 1901, 2062, 2067, 3511, 4700, 5050, and 5515);
Species considered to be rare or endangered under the conditions of Section 15380 of the CEQA
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Guidelines such as those identified in the Inventory of Rare and Endangered Vascular Plants of
California by the California Native Plant Society (CNPS) (Native Plant Protection Act of 1977); and
Other species that are considered sensitive or of special concern due to limited distribution or lack of
adequate information to permit listing, or rejection for state or federal status such as Species of Special
Concern (SSC) designated by the CDFW as well as locally rare species defined by CEQA Guidelines
15125(c) and 15380, which may include species that are designated as sensitive, declining, rare, locally
endemic or as having limited or restricted distribution by various federal, state, and local agencies,
organizations, and watchlists such as those identified in the CDFW California Natural Diversity
Database; as well as birds and raptors protected under the Federal Migratory Bird Treaty Act (16 U.S.C.
703-711) (Executive Order 13186).
East Contra Costa County Habitat Conservation Plan/Natural Community Conservation Plan
The project is located within the HCP/NCCP inventory area and is a covered activity. The HCP/NCCP is
intended to provide an effective framework to protect natural resources and special-status species recovery in
eastern Contra Costa County while improving and streamlining the environmental permitting process for
impacts on these species and associated habitats. The HCP/NCCP complies with Section 10(a)(1)(B) of the
federal ESA and California Natural Community Conservation Planning Act of 2003 and as such covered
activities are authorized incidental take of HCP/NCCP-covered special-status species subject to mitigation fees
for both permanent and temporary impacts to species habitats and implementation of specific conditions and
conservation measures to avoid or minimize potential effects to species and/or its habitats. The HCP/NCCP
requires reporting and fee payment to the HCP/NCCP Implementing Entity, the East Contra Costa County
Habitat Conservancy (Habitat Conservancy), a joint exercise of powers authority formed by the Cities of
Brentwood, Clayton, Oakley and Pittsburg and Contra Costa County (Jones & Stokes 2006).
Environmental Setting
Qualified biologists conducted a habitat assessment to identify habitats within and around the project area to
determine if sensitive habitats, natural communities, and jurisdictional wetlands and waters of the U.S. occur as
well as potential presence of special-status species. Considering that this project will receive federal aid from
Caltrans, the federal lead agency on behalf of the Federal Highway Administration, a habitat assessment report
(Natural Environment Study-Minimal Impact [NES-MI]) was prepared in accordance with Caltrans guidance
for compliance with the National Environmental Policy Act. Special-status species not specifically covered by
the HCP/NCCP were addressed in this report. Site visits were conducted in May 2014. To prepare for the field
surveys, biologists reviewed the following existing resource information to evaluate whether special-status
species or other sensitive biological resources (e.g., wetlands) could occur in the study area and vicinity (ICF
International 2014a,b):
Sensitive species from the California Natural Diversity Database (CNDDB) (2014) that have been
documented within the U.S. Geological Survey (USGS) 7.5-minute Byron Hot Springs Quadrangle and
a two-mile radius of the project site.
CNPS Inventory of Rare and Endangered Plants of California (2014) for the USGS 7.5-minute Byron
Hot Springs Quadrangle.
Threatened and endangered species provided by the USFWS for the USGS 7.5 -minute Bryon
Quadrangle (2014).
Kruckeberg, A. R. 1954. The Ecology of Serpentine Soils: A Symposium. III. Plant species in relation to
serpentine soils. Ecology 35:267–274.
________. 1984. California Serpentines: Flora, Vegetation, Geology, Soils, and Management Problems.
Berkeley, CA: University of California Press.
Google Earth historic aerial imagery (2014)
National Wetland Inventory maps
G:\engsvc\ENVIRO\TransEng\Byron Highway-Camino Diablo (4094)\CEQA\IS-MND\Final-Public Review_4-3-15.docx
Habitats within the project area consists of roadways, gravel roadside parking areas, and ruderal portions
between the railroad and roads, and ornamental landscaping associated with the adjacent residences. Small
roadside ditches drain via pipe culverts to a seasonal depressional wetland located immediately west of the
concrete box culvert under Byron Highway at the intersection (Figure 3).
a) Would the project have a substantial adverse effect, either directly or through habitat modifications, on
any species identified as a candidate, sensitive, or special status species in local or regional plans,
policies, or regulations, or by the California Department of Fish and Wildlife or U.S. Fish and Wildlife
Service?
Based on the results of the resource information search, the following special-status species were
determined to potentially occur in the project vicinity:
Species Listing Status
Federal/State
Potential to Occur in Project
Area
Wildlife
California red-legged frog (Rana draytonii) T/SSC None
California tiger salamander (Ambystona californiense) T/T None
San Joaquin kit fox (Vulpes macrotis mutica) E/T None
Swainson’s hawk (Buteo swainsoni) MBTA/T None
Burrowing owl (Athene cunicularia hypugaea) MBTA/SSC None
Golden eagle (Aquila chrysaetos) MBTA/FP None
Loggerhead shrike (Lanius ludovicianus) MBTA/SSC Possible
Northern harrier (Circus cyaneus) MBTA/SSC Possible – observed nearby
during survey
White-tailed kite (Elanus leucurus) MBTA/FP Possible – observed nearby
during survey
California horned lark (Eremophila alpestris actia) MBTA/- Possible
Ferruginous hawk (Buteo regalis) MBTA/- Possible
Prairie falcon (Falco mexicanus) MBTA/- Possible
Curved foot hygrotus beetle (Hygrotus curvipes) -/- Possible
Plants
Alkali milk-vetch (Astragalus tener var. tener) -/-/CNPS 1B None
Brittlescale (Atriplex depressa) -/-/CNPS 1B None
San Joaquin spearscale (Atriplex joaquiniana) -/-/CNPS 1B None
Big tarplant (Blepharizonia plumosa) -/-/CNPS 1B.1 None
Recurved larkspur (Delphinium recurvatum) -/-/CNPS 1B None
Diamond-petaled poppy (Eschscholzia rhombipetala) -/-/CNPS 1B.1 None
Stinkbells (Fritillaria agrestis) -/-/CNPS 4 None
Chaparral ragwort (Senecio aphanactis) -/-/CNPS 2.2 None
Caper-fruited tropidocarpum (Tropidocarpum
capparideum) -/-/CNPS 1B.1 None
(E) Endangered; (T) Threatened; (SSC) Special Species of Concern; (MBTA) Migratory Bird Treaty Act; (FP) Fully Protected; (CNPS 1B) presumed
extinct in California; (CNPS 1B.1) seriously endangered in California; (CNPS 2) rare, threatened, or endangered in California but more common
elsewhere; (CNPS 2.2) fairly endangered in California [20-80% of occurrences threatened; (CNPS 4) limited distribution or infrequent throughout a
broader area in California.
After the field survey within and adjacent to the project area and further evaluation of species
requirements and habitats, it was determined that with the exception of MBTA-protected species, the
remaining special-status species are not likely to occur within the project area due to lack of suitable
habitat. MBTA-protected birds and raptors have the potential to occur due to the presence of trees and
shrubs that occur within or near the project area. No rare plant species were observed and they are not
likely to occur within the project area due to lack of suitable habitat (ICF International 2014). Further, the
project is located within the HCP/NCCP and permanent and temporary impacts to undeveloped habitats
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Figure 2Land CoverPath: K:\Projects_3\County_of_Contra_Costa\00218_14_ByronHwy_CaminoDiabl\mapdoc\Fig_2_LandCover_20140604.mxd; User: 29391; Date: 6/19/20140 400200
Feet´
Source: Basemap, ESRI 2013
Legend
Project SiteBiological Study Area
!CulvertHabitatDepresional Seasonal Wetland
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will be mitigated by payment of fees to the Habitat Conservancy regardless if sensitive habitats and/or
species are present.
POTENTIAL IMPACT BIO-1: NESTING BIRDS AND RAPTORS
Construction of the project will require removal of trees and shrubs located within the frontages of
residential properties along the east side of Byron Highway and north side of Camino Diablo Road, which
is expected to occur between April and October of the construction year. The general avian nesting season
is February 1 – August 31 (Swainson’s hawk: March 15 – September 15). Therefore, the project may
directly or indirectly impact listed and/or MBTA-protected nesting birds and/or raptors if present. The
project is not anticipated to impact these species with implementation of the following avoidance
measures. Therefore, project impacts will be less than significant.
AVOIDANCE MEASURE BIO-1A: NESTING BIRDS AND RAPTORS
If feasible, the trees and shrubs will be removed during the non-nesting season (September 16 –
January 31).
If not feasible, a qualified biologist will conduct nesting bird surveys prior to start of project-related
activities. In accordance with the HCP/NCCP, surveys for golden eagle will be conducted within a ½-
mile radius and 1,000 feet for Swainson’s hawk.
If no active nests are found within the survey area, no further avoidance measures will be necessary.
If active nest(s) are found, work will stop and the qualified biologist will evaluate the situation and
determine the appropriate non-disturbance buffer zone in consultation with the California Department
of Fish and Wildlife (CDFW) and the U.S. Fish and Wildlife Service (USFWS) Migratory Bird Permit
Office. If buffers are established but it is determined that project activities are resulting in nest
disturbance, work will cease immediately and the CDFW and USFWS will be contacted for further
guidance.
IMPACT BIO-1B: HCP/NCCP HABITATS
The project is located within the HCP/NCCP inventory area and will have permanent and temporary
impacts to undeveloped habitats (approximately 1.3 acres). The following mitigation measure will be
implemented to offset impacts to undeveloped habitats. Therefore, project impacts will be less than
significant with mitigation incorporated.
MITIGATION MEASURE 1B: HCP/NCCP HABITATS
The project will mitigate permanent and temporary impacts to undeveloped habitats by fee payment to the
Habitat Conservancy regardless if sensitive habitats and/or species are present. The fee is based on the
impact acreage to undeveloped habitats, which is approximately 1.3 acres. The development fee per acre
for permanent and temporary impacts is $12,117.05 and therefore, approximately $2,313 will be paid. In
addition, applicable avoidance and minimization measures noted above for nesting birds and raptors and
below in item (c) will be implemented which are required by the HCP/NCCP.
A Mitigation and Monitoring Reporting Plan (MMRP) will identify when these measures will be
implemented, the parties that are responsible for ensuring implementation of these measures, and
verification that the measures were implemented.
b) Would the project have a substantial adverse effect on any riparian habitat or other sensitive natural
community identified in local or regional plans, policies, and regulations or by the California
Department of Fish and Wildlife or U.S. Fish and Wildlife Service?
Trees and shrubs associated with residential landscaping along Byron Highway and Camino Diablo
Road will need to be removed to accommodate the road widening. While these trees are not
G:\engsvc\ENVIRO\TransEng\Byron Highway-Camino Diablo (4094)\CEQA\IS-MND\Final-Public Review_4-3-15.docx
considered sensitive natural communities they may provide nesting habitat for birds and/or raptors.
Therefore, as described above, the trees and shrubs will be removed outside of the nesting season, and
if not feasible, nest surveys will be conducted by a qualified wildlife biologist prior to tree removal
and construction to ensure no active nests will be disturbed. If active nests are found, the CDFW
and/or USFWS will be contacted for further guidance. Therefore, project impacts will be less than
significant.
c) Would the project have a substantial adverse effect on federally protected wetlands as defined by
Section 404 of the Clean Water Act (including but not limited to, marsh, vernal pool, coastal, etc.)
through direct removal, filling, hydrological interruption, or other means?
A seasonal depressional wetland is located immediately west of the concrete box culvert under Byron
Highway southwest of the intersection which collects stormwater runoff from small roadside runoff
and piped culverts along Camino Diablo. Vegetation in this wetland consisted of scattered patches of
Italian rye grass, a non-wetland species that occur in wetlands. This wetland feature is expected to be
subject to U. S. Army Corps of Engineers (USACE) and Regional Water Quality Control Board
(RWQCB) jurisdictions; a wetland delineation verification will be requested from the USACE prior to
construction. The project will not permanently impact this wetland but temporary impacts may occur
to construct the project and therefore, a permit application will be submitted to the USACE and
RWQCB to receive authorization for the temporary impacts.
The drainage ditch is ephemeral and likely only carries water during storm events where they receive
both direct precipitation and urban runoff. During the field survey, the ditch was dry and either
characterized by either barren clay soil or dominated by Bermuda grass, another non-wetland species
that occur in wetlands. Although the ditch was constructed in uplands, aerial imagery indicates that
flow from the drainage ditch and through the culvert under Byron Highway into a drainage ditch east
of Byron Highway that eventually ties into the Byron-Bethany Irrigation Canal which is considered
waters of the U. S. as it connects to Old River in the Delta. Therefore, the drainage ditch could be
considered other waters of the U.S. (and State) that are expected to be subject to regulation by the
USACE and RWQCB. This feature will also be addressed in the wetland verification request. The
project will not permanently impact the drainage ditch, but temporary impacts may occur to construct
the project and therefore, permit applications will be submitted as discussed above.
POTENTIAL IMPACT BIO-2A: SEASONAL WETLAND
The project may temporarily impact this wetland to construct the project. If the impact to the wetland
can be avoided, the following avoidance measures as required by the HCP/NCCP will be implemented
to avoid impacts. Therefore, project impacts will be less than significant.
AVOIDANCE MEASURE BIO-2A: SEASONAL WETLAND
The wetland will be temporarily staked by a qualified biologist.
Temporary filter and Environmental Sensitive Area (ESA) fencing will be erected between the
outer edge of the buffer zone and the project area.
Construction personnel conducting ground-disturbing activities adjacent to the wetland will be
trained by a qualified biologist of these measures and permit obligations of the County.
Trash generated during construction will be promptly and properly removed from the site.
Appropriate erosion control measures will be used such as filter fences and hydroseeding which
will not contain invasive nonnative species and will be composed of native or sterile nonnative
species.
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IMPACT BIO-2B: SEASONAL WETLAND
The project may temporarily impact this wetland to construct the project. If temporary impacts to the
wetland cannot be avoided, the impact will be minimal (<0.001 acre) and the following mitigation
measure will be implemented. Therefore, project impacts will be less than significant with
mitigation incorporated.
MITIGATION MEASURE BIO-2B: SEASONAL WETLAND
Impacts to the wetland will be mitigated through payment of applicable temporary impact fees to
the Habitat Conservancy. In addition, the disturbed areas will be re-vegetated with the appropriate
wetland seed mix to return the wetland to pre-project conditions in accordance with the
HCP/NCCP and anticipated permit conditions.
Permits will be obtained from the USACE and RWQCB and applicable best management practices
as conditioned in the permits will be implemented to minimize impacts to downstream waters and
seasonal wetlands.
Avoidance Measure BIO-2A will also be implemented.
d) Would the project interfere substantially with the movement of any native resident or migratory fish or
wildlife species or with established native resident or migratory wildlife corridors, or impede the use
of native wildlife nursery sites?
The project will not result in permanent disruption to movement of wildlife species. However,
activities associated with construction of the project may temporarily inhibit dispersal, migration, and
daily movement of common wildlife. This disruption is temporary and short term in nature. Therefore,
project impacts will be less than significant.
e) Would the project conflict with any local policies or ordinances protecting biological resources, such
as tree preservation policy or ordinance?
The project will not conflict with any local policies or ordinances protecting biological resources as
potential impacts and anticipated impacts will be avoided where feasible and where not feasible will
be mitigated through the HCP/NCCP which is consistent with the policies included in the
Conservation Element section of the County General Plan. The project is not subject to the County
Tree Ordinance (Contra Costa County Cod e [CCCC] Title 8, Chapter 816-6.10(6) as the County
Public Works Department for tree trimming and clearing within public ROWs. Therefore, the project
will have no impact.
f) Would the project conflict with the provisions of an adopted Habitat Conservation Plan, Natural
Community Conservation Plan, or other approved local, regional or state habitat conservation plan?
The project is consistent with the HCP/NCCP mitigation fees will be paid to offset impacts and the
required surveys and implementation of avoidance and minimization measures as described above.
Therefore, the project will have no impact.
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V. CULTURAL RESOURCES
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Cause a substantial adverse change in the
significance of a historical resource as
defined in §15064.5?
b) Cause a substantial adverse change in the
significance of an archaeological resource
pursuant to §15064.5?
c) Directly or indirectly destroy a unique
paleontological resource or site or unique
geological feature?
d) Disturb any human remains, including
those interred outside of formal
cemeteries?
Regulatory Background
CEQA requires lead agencies to determine if a project will have an adverse impact on a significant
cultural resource (includes historical and archaeological) (Public Resources Code Sections 21084,
21084.1, 21083.2). A resource is considered significant if it 1) is listed in or has been determined
eligible for listing in the California Register of Historic Resources (CRHR); 2) is included in a local
register of historical resources, as defined in Public Resources Code 5020.1(k); 3) has been identified as
significant in an historical resources survey, as defined in Public Resources Code 5024.1(g); or 4) is
determined to be historically significant by the CEQA lead agency [CCR Title 14, Section 15064.5(a)].
The following CRHR eligibility criteria need to be considered when making a significance
determination.
1. is associated with events that have made a significant contribution to the broad patterns of
California’s history and cultural heritage;
2. is associated with the lives of persons important in our past;
3. embodies the distinctive characteristics of a type, period, region, or method of construction or
represents the work of an important creative individual, or possesses high artistic values; or
4. has yielded, or may be likely to yield, information important in prehistory or history.
If a significant resource will be impacted, the lead agency must determine whether there is "substantial
evidence" in the administrative record to support a finding of significant effect (Section 21080(e)).
CEQA requires examination of mitigation measures or feasible project alternatives that would avoid or
minimize any impacts or potential impacts.
Cultural and Historical Resource Assessment
In order to determine if the project area contains potential significant cultural and/or historical
resources, a qualified cultural resource specialist conducted research of recorded sites and surveys and
historic maps and literature at the Northwest Information Center (NWIC) at California State University,
Sonoma as well as at various libraries and local historical societies for historic context and backgrounds,
contacted the Native American Heritage Commission and Contra Costa County record offices, and
conducted a field survey of the project area. Considering that this project will receive federal aid from
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Caltrans, the federal lead agency on behalf of the Federal Highway Administration, historical and
archaeological assessment reports were prepared (Historic Property Survey Report, Historic Resource
Evaluation Report, Archaeological Survey Report) in accordance with Caltrans guidance for compliance
with NEPA (CardnoEntrix 2014a,b,c).
Historical Overview and Results
Byron is a small unincorporated community that consists of residential and light commercial and retail
development in its downtown area primarily developed in the early twentieth century surrounded by
rural residential and farm lands. The project area is adjoined by residences along the east side of Byron
Highway and railroad tracks along the west side. A gas station occupies the southeast corner of the
intersection and a trucking company southwest of the intersection. Residences primarily adjoin the north
and south sides of Camino Diablo within the project area and small commercial and retail buildings
fronting Main Street are located just north of Camino Diablo (Figure 2).
Residential frontage properties along Byron Highway and Camino Diablo primarily range from 0.5 to 2
acres. The majority of the lots are rectangular, with narrow footages and deep rear yards with the
majority featuring a single-family residence and a small number of ancillary structures including
secondary dwellings, sheds, garages, and small barns. A railroad along the west side of Byron Highway
was constructed in 1878 and operated as a freight and passenger line. Construction of the railroad
fostered development of the town both by creating Byron as a bustling commercial and residential stop
along the line, and by providing ready markets for numerous farms and other extractionary industries
operating in the town’s periphery. Thus, Byron developed as an intermediary between the railroad and
the surrounding working landscape, with the economic, social, and physical development of the town in
large predicated upon the ongoing development of transportation infrastructure and the evolving
regional economic activities it afforded (CardnoEntrix 2014b).
a) Would the project cause a substantial adverse change in the significance of a historical resource as
defined in §15064.5?
Most of the properties that will be impacted by the project (sliver rights-of-way takes) contain structures
older than 50 years and thus were evaluated by an architectural historian to determine their significance
which included record searches and visual inspection of the project area on foot, along with an
archaeologist. No evidence of historical materials was encountered during the field survey and the
residential buildings located on the properties were not listed or eligible for listing on the National
Register of Historic Places or the California Register of Historic Places (CardnoEntrix 2014a,b). The
evaluations determined that none of the structures were eligible for listing which was confirmed by the
California Office of Historic Preservation (2014). Therefore, the project will not create a substantial
adverse change in the significance of a historical resource. Regardless of these results, project contract
specifications will include contingency plans to address any unearthed historical resources. These will
include the stoppage of work in the immediate area of any discovery and having a qualified archeologist
evaluate the finding. Therefore, project impacts will be less than significant.
b) Would the project cause a substantial adverse change in the significance of an archaeological resource
pursuant to §15064.5?
As discussed above, a records search and field survey were conducted which did not reveal any recorded
or unrecorded archaeological resources (CardnoEntrix 2014c). Therefore, the project will not create a
substantial adverse change to archaeological resources of significance. Regardless of these results,
project contract specifications will include contingency plans to address any unearthed historical
resources. These will include the stoppage of work in the immediate area of any discovery and having a
qualified archeologist evaluate the finding. Therefore, project impacts will be less than significant.
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c) Would the project directly or indirectly destroy a unique paleontological resource or site or unique
geological feature?
The project will not destroy any unique paleontological resources or sites because the project is
underlain primarily by alluvium soil deposits which are not considered formations that include unique
paleontological features (Contra Costa County 2005d). However, if paleontological resources are
encountered, work will stop in the vicinity of the finding and a qualified paleontologist will evaluate the
findings. Therefore, project impacts will be less than significant.
d) Would the project disturb any human remains, including those interred outside of formal cemeteries?
The project will not impact any formal or informal cemeteries because none are present within or
adjacent to the project location. In order to determine if there are any unrecorded burial grounds and/or
sacred land sites in the vicinity of the project area, a list of Native American tribal representatives for the
region was obtained from the Native American Historic Commission (NAHC). The listed Native
American representatives were notified of the project via certified mail and follow up emails or phone
calls. None of the representatives who provided responses expressed any concerns relating to this project
(CardnoEntrix 2014c). Construction work will stop if human remains are encountered and the
appropriate contacts will be made including immediately contacting the County Coroner, NAHC, and a
qualified archeologist to determine how to appropriately deal with the remains in accordance with the
California Health and Safety Code (Health and Safety Code Section 7050.5[b]). Therefore, project
impacts will be less than significant.
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VI. GEOLOGY AND SOILS
Potentially
Significant
Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Expose people or structures to potential substantial
adverse effects, including the risk of loss, injury, or
death involving:
1 Rupture of a known earthquake fault, as delineated
on the most recent Alquist-Priolo Earthquake Fault
Zoning Map issued by the State Geologist for the
area or based on other substantial evidence of a
known fault? Refer to Division
2 Strong seismic ground shaking?
3 Seismic-related ground failure, including
liquefaction?
4 Landslides?
b) Result in substantial soil erosion or the loss of topsoil?
c) Be located on a geologic unit or soil that is unstable, or
that would become unstable as a result of the project,
and potentially result in on-or off-site landslide, lateral
spreading, subsidence, liquefaction or collapse?
d) Be located on expansive soil, as defined in Table 18-1-
B of the Uniform Building Code (1994), creating
substantial risks to life or property?
e) Have soils incapable of adequately supporting the use
of septic tanks or alternative waste disposal systems
where sewers are not available for the disposal of
wastewater?
Environmental Setting
Geology
The Quaternary Alluvium geological formation occurs beneath the project area which consists of consolidated
and unconsolidated sediments and can cause localized problems for building due to expansive clays, hillside
earth flows and unstable cut slopes (Contra Costa County 2005d).
Soil
Soil types in the project area consists of Brentwood Clay loam and Capay clay. Brentwood soils are on nearly
level to gently sloping fans and formed in valley fill from sedimentary rocks and are well to moderately well -
drained with very slow to medium runoff and moderately slow permeability. Capay soils are on all uvial fans,
alluvial flats, in interfan basins, basin rims and basins at elevations below 1,200 feet. They formed in
moderately-fine and fine-textured alluvium derived from sandstone and shale or other mixed rock sources.
Slopes are 0 to 9 percent. The soils are moderately well-drained with negligible to high runoff and slow to
very slow permeability (ICF International 2014; U. S. Department of Agriculture 2015). The boring logs
results reported in a monitoring workplan for the adjacent gasoline service station (Valero) indicated the soil
to be mostly silty clay to the explored depth of 20 feet below ground surface (AGS 2014).
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Seismic Hazards
Contra Costa County is located within a region of high seismicity; the San Francisco Bay Region has been
impacted by severe earthquakes during historic time (Contra Costa County 2005d). In order to provide safety
of structures for human occupancy, the Alquist-Priolo Earthquake Fault Zoning Act was passed in 1972 to
mitigate the hazards. The law requires the State Geologist to establish regulatory zones (known as Earthquake
Fault Zones) around the surface traces of active faults and to issue appropriate maps. The project area is not
located within or near a fault zone (California Department of Conservation 2015).
a) Would the project expose people or structures to potential substantial adverse effects, including the risk of
loss, injury, or death involving?
1 Rupture of a known earthquake fault, as delineated on the most recent Alquist -Priolo Earthquake
Fault Zoning Map issued by the State Geologist for the area or based on other substantial evidence of
a known fault? Refer to Division
The project is not expected to expose people or structures to potential substantial adverse effects from a
rupture of a known earthquake fault as the project area is not within an Alquist-Priolo Fault Zone and there
are no known faults within the project area. Although, a thrust fault is shown to occur approximately 3
miles east of the project area and seismic activity of about 2.0 magnitude has occurred between 1934 and
1971 in the Byron area (Contra Costa County 2005d). While thrust faults are not considered to pose a risk
of surface rupture it is considered a potential seismic source. The project does not include features that
would increase risk to people or structures as it is primarily limited to shoulder widening of an existing
roadway and installation of traffic signal light structures. Nevertheless, the project design and construction
will incorporate measures that are in accordance with local design practice and guidelines to ensure the
project will withstand seismic activity as defined in the Caltrans Highway Design M anual. Therefore,
project impacts will be less than significant.
2 Strong seismic ground shaking?
As discussed above, while the project area is not located in a fault zone, a thrust fault is located to the east
and while not considered to pose a risk of surface rupture it is considered a potential seismic source. The
project area is located within in an area known to have moderate damage susceptibility; dry alluvium areas
will perform satisfactory whereas as water-saturated areas are potentially hazardous (Contra Costa County
2005d). As discussed above, the project is not expected to expose people or structures to potential
substantial adverse effects as the project does not include features that would increase risk to people or
structures as it is primarily limited to shoulder widening of an existing roadway and installation of traffic
signal light structures. Nevertheless, the project design and construction will incorporate measures that are
in accordance with local design practice and guidelines to ensure that the project will withstand seismic
activity as defined in the Caltrans Highway Design Manual. Therefore, project impacts will be less than
significant.
3 Seismic-related ground failure, including liquefaction?
The project area is primarily located within a generally moderate to low liquefaction potential whereas the
area along the east side of Byron Highway is located within a generally high liquefaction potential (Contra
Costa County 2005d). The project design and construction will incorporate recommended measures in
accordance with local design practice and guidelines as defined in the Caltrans Highway Design Manual to
ensure that the project will withstand seismic activity and liquefaction. Therefore, project impacts will be
less than significant.
4 Landslides?
The project area is not located within a potential landslide area (Contra Costa County 2005d). Therefore,
the project will have no impact.
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b) Would the project result in substantial soil erosion or the loss of topsoil?
The project will not result in substantial soil erosion or the loss of topsoil because minor grading and
excavation associated with the road improvements will result in a negligible change in topography.
Construction of the project will temporarily increase the exposure of soils to wind erosion from grading
and excavation activities. However, standard dust control and erosion control practices will be
implemented during construction, including, but not limited to, general watering of exposed areas to
minimize impacts. Therefore, project impacts will be less than significant.
c) Would the project be located on a geologic unit or soil that is unstable, or that would become unstable as
a result of the project, and potentially result in on-or off-site landslide, lateral spreading, subsidence,
liquefaction or collapse?
As discussed above, the project area is not located within an area subject to landslides but within a
moderate to low potential for liquefaction. The project design and construction will incorporate
recommended measures in accordance with local design practice and guidelines as defined in the Caltrans
Highway Design Manual to ensure that the project will withstand seismic activity and liquefaction.
Further, the project is limited to lane and shoulder widening of an existing road and will not introduce new
land uses that could be impacted by unstable soils. Therefore, project impacts will be less than
significant.
d) Would the project be located on expansive soil, as defined in Table 18-1-B of the Uniform Building Code
(1994), creating substantial risks to life or property?
The project area is located on clay type soils, which tend to be expansive soils. The project will be
engineered according to standard industry practice, which includes design considerations for soil type.
Further, the project is limited to lane and shoulder widening of an existing road, which will not create
substantial risk to life or property from expansive soils. Therefore, project impacts will be less than
significant.
e) Would the project have soils incapable of adequately supporting the use of septic tanks or alternative
waste disposal systems where sewers are not available for the disposal of wastewater?
The constructed project and project construction will not require septic or other waste systems. Therefore,
the project will have no impact.
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VII. GREENHOUSE GAS EMISSIONS
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Generate greenhouse gas emissions, either directly or
indirectly, that may have a significant impact on the
environment?
b) Conflict with an applicable plan, policy or regulation
adopted for the purpose of reducing the emissions of
greenhouse gases?
Regulatory Background
Climate change refers to any significant change in measures of climate, such as average temperature,
precipitation, or wind patterns over a period of time. There is a general scientific consensus that global
climate change is occurring, caused in whole or in part by increased emissions of greenhouse gases
(GHGs) that keep the earth’s surface warm by trapping heat in the atmosphere. Climate change may
result from natural factors, natural processes, and human activities that change the composition of the
atmosphere and alter the surface and features of the land (California Office of Planning and Research
[OPR] 2008b).
Assembly Bill 32 (AB 32), the California Global Warming Solutions Act of 2006, recognized that
California is the source of substantial amounts of GHG emissions which poses a serious threat to the
economic well-being, public health, natural resources, and the environment of California (OPR 2008b).
Potential adverse impacts of global warming include severe air quality problems, a reduction in the
quality and supply of water from the Sierra snowpack, a rise in sea levels causing the displacement of
coastal businesses and residences, damage to marine ecosystems and the natural environment, and an
increase in the incidences of infectious diseases, asthma, and other human health-related problems (OPR
2008b). This bill directed the California Air Resources Board (CARB) to begin developing discrete
early actions to reduce GHGs to reach the GHG reduction goals by 2020.
As discussed in the air quality section, in order to address global climate change associated with air
quality impacts, CEQA statutes were amended to require evaluation of greenhouse gas (GHG)
emissions (global pollutants) which includes criteria air pollutants (regional pollutants) and toxic air
contaminants (local pollutants). As a result, the BAAQMD adopted CEQA thresholds of significance
for criteria air pollutants and GHGs, and issued updated CEQA guidelines to assist lead agencies in
evaluating air quality impacts to determine if a project’s individual emissions would be cumulatively
considerable. Various modeling tools are used to estimate emissions based on the type of project (i.e.,
land use developments, linear transportation and utility projects) (BAAQMD 2010a). While the
BAAQMD does not have an adopted threshold of significance for construction-related GHG emissions,
sources of construction-related GHGs include exhaust (carbon dioxide, nitrous oxide) for which the
same detailed guidance as described for criteria air pollutants and precursors should be followed
(BAAQMD 2010b).
a) Would the project generate greenhouse gas emissions, either directly or indirectly, that may have a
significant impact on the environment?
The constructed project would not result in an increase of GHG emissions as no additional travel lanes
will be constructed; however, construction activities will generate GHGs through exhaust from
construction equipment and vehicles. While the BAAQMD does not have an adopted threshold of
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significance for construction related-GHG emissions Lead Agencies should quantify and disclose GHG
emissions that would occur during construction, and make a determination on the significance of these
construction-generated impacts. As discussed in the Air Quality section, estimated project construction
emissions were determined to be below the thresholds of significance. Further, project contract
specifications will require air pollution control practices. Therefore, project impacts will be less than
significant.
b) Would the project conflict with an applicable plan, policy or regulation adopted for the purpose of
reducing the emissions of greenhouse gases?
The project will not conflict with an applicable plan, policy or regulation as project emissions were
estimated and determined to be below the thresholds of significance. Further, project contract
specifications will require implementation of air pollution control practices. Therefore, project impacts
will be less than significant.
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VIII. HAZARDS AND HAZARDOUS MATERIALS
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Create a significant hazard to the public or the
environment through the routine transport, use or
disposal of hazardous materials?
b) Create a significant hazard to the public or the
environment through reasonably foreseeable upset and
accident conditions involving the release of hazardous
materials into the environment?
c) Emit hazardous emissions or handle hazardous or
acutely hazardous materials, substances or waste within
one-quarter mile of an existing or proposed school?
d) Be located on a site which is included on a list of
hazardous materials sites compiled pursuant to
Government Code Section 65962.5 and, as a result,
would it create a significant hazard to the public or the
environment?
e) For a project located within an airport land use plan or,
where such a plan has not been adopted, within two
miles of a public airport or public use airport, would the
project result in a safety hazard for people residing or
working in the project area.
f) For a project within the vicinity of a private airstrip,
would the project result in a safety hazard for people
residing or working in the project area?
g) Impair implementation of or physically interfere with
an adopted emergency response plan or emergency
evacuation plan?
h) Expose people or structures to a significant risk of loss,
injury or death involving wild land fires, including
where wildlands are adjacent to urbanized areas or
where residences are intermixed with wildlands?
Regulatory Background
A material is considered hazardous if it appears on a list of hazardous materials prepared by a federal, state,
or local agency, or if it has characteristics defined as hazardous by such an agency. The release of hazardous
materials into the environment could potentially contaminate soils, surface water, and groundwater supplies.
The California Environmental Protection Agency which consists of the Air Resources Board, Department of
Pesticides Regulation, Department of Resources and Recycling and Recovery, Department of Toxic
Substance Control (DTSC), Office of Environmental Health Hazard Assessment, and State Water Resources
Control Board regulates hazardous materials and waste. Under Government Code Section 65962.5, the
DTSC maintains a list of hazardous substance sites (CORTESE List) which includes leaking underground
storage tank sites, hazardous material sites, and landfills with evidence of groundwater contamination. The
Contra Costa County Health Services, Hazardous Materials Program serves area residents by responding to
emergencies and monitoring hazardous materials (CalEPA 2015).
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a) Would the project create a significant hazard to the public or the environment through the routine
transport, use or disposal of hazardous materials?
The project will not create a significant hazard to the public or the environment because once
constructed, the project would not result in routine transport, use or disposal of hazardous materials other
than what already occurs by the traveling public. There is the potential for a release of hazardous
substances from equipment operations (e.g., accidental petroleum spills) during construction. Project
contract specifications will require that the contractor prepare a Water Pollution Control Plan (WPCP) to
identify safety and best management practices (e.g., placement of drip pans under stationary equipment,
routine equipment inspections, and on-site spill cleanup materials) to prevent accidental releases of
hazardous substances and potential worker exposure. In addition, project contract specifications will
require the contractor to contact Underground Service Alert (USA) prior to conducting any work that
could potentially impact utilities. Therefore, project impacts will be less than significant.
b) Would the project create a significant hazard to the public or the environment through reasonably
foreseeable upset and accident conditions involving the release of hazardous materials into the
environment?
Construction activities will occur within the adjacent railroad track crossing. Some contaminants
associated with the railroad may be encountered in the soil (AGS 2014). Therefore, a shallow subsurface
investigation will be conducted in areas of planned excavation prior to construction. If contaminants are
present, the excavated soil will be disposed of at an appropriate disposal facility and if levels are higher
than agency-set limits, the appropriate agencies will be notified. In addition, as discussed above, there is
the potential for a release of hazardous substances from construction equipment operations (e.g.,
accidental petroleum spills) during construction. The required preventative measures discussed above
will minimize potential impacts to the environment and worker exposure. Therefore, project impacts will
be less than significant with mitigation incorporated.
IMPACT HAZ-1: CONTAMINATED SOIL
The soil around the railroad track crossing may be contaminated with contaminants associated with the
railroad operation.
AVOIDANCE MEASURE HAZ-1: CONTAMINATED SOIL
A subsurface investigation will be conducted prior to start of construction. If the soil is contaminated, the
excavated soil will be disposed of at an appropriate disposal facility and the contractor will be required
to prepare a health and safety worker plan.
c) Would the project emit hazardous emissions or handle hazardous or acutely hazardous materials,
substances or waste within one-quarter mile of an existing or proposed school?
The closest school is located approximately 1 mile from the project site. The constructed project will
not emit hazardous emissions or handle hazardous or acutely hazardous materials or substances. While
construction equipment exhaust will generate an increase in air pollutant concentrations, it would be
temporary and effects would be negligible as estimated emissions were determined to be less than the
BAAQMD thresholds of significance as discussed in the Air Quality section. Further, project contract
specification requirements for air control pollution practices will be implemented. Therefore, the project
will have no impact.
d) Would the project be located on a site which is included on a list of hazardous materials sites compiled
pursuant to Government Code Section 65962.5 and, as a result, would it create a significant hazard to
the public or the environment?
The project is not located on a site or near a site that is included on a list of hazardous material sites
compiled pursuant to Government Code 65962.5 (Cortese List). The adjacent gas station (Valero) had
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leaking underground storage tanks and monitoring wells were installed in 2004; the case was closed by
the RWQCB in 2008 (DTSC 2015, AGS 2014). Therefore; the project will have no impact.
e) For a project located within an airport land use plan or, where such a plan has not been adopted, within
two miles of a public airport or public use airport, would the project result in a safety hazard for people
residing or working in the project area.
The project is not located within 2 miles of a public airport; the closest public airport is the Byron
airport, located approximately 2.5 miles south of the project area. Therefore, the project will have no
impact.
f) For a project within the vicinity of a private airstrip, would the project result in a safety hazard for
people residing or working in the project area?
The project is not located in the vicinity of a private airstrip. Therefore, the project will have no impact.
g) Would the project impair implementation of or physically interfere with an adopted emergency response
plan or emergency evacuation plan?
The constructed project nor project construction will not impair implementation of or physically interfere
with an adopted emergency response plan or emergency evacuation plan because access for emergency
vehicles will be provided at all times during construction. Therefore, project impacts will be less than
significant.
h) Would the project expose people or structures to a significant risk of loss, injury or death involving
wildland fires, including where wildlands are adjacent to urbanized areas or where residences are
intermixed with wildlands?
The project will not expose people or structures to a significant risk of loss, injury or death involving
wildland fires as the project area is not located adjacent to wildlands (CalFire 2007, 2009). Therefore,
the project impact will have no impact.
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IX. HYDROLOGY AND WATER QUALITY
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Violate any water quality standards or waste discharge
requirements?
b) Substantially deplete groundwater supplies or interfere
substantially with groundwater recharge such that there
would be a net deficit in aquifer volume or a lowering
of the local groundwater table (e.g., the production rate
of pre-existing nearby wells would drop to a level
which would not support existing land uses or planned
uses for which permits have been granted)?
c) Substantially alter the existing drainage pattern of the
site or area, including through the alteration of the
course of a stream or river, in a manner which would
result in substantial erosion or siltation on- or off-site?
d) Substantially alter the existing drainage pattern of the
site or area, including through the alteration of the
course of a stream or river, or substantially increase the
rate or amount of surface run-off in a manner which
would result in flooding on-or off-site?
e) Create or contribute runoff water which would exceed
the capacity of existing or planned stormwater drainage
systems or provide substantial additional sources of
polluted runoff?
f) Otherwise substantially degrade water quality?
g) Place housing within a 100-year flood hazard area as
mapped on a Federal Flood Hazard Boundary or Flood
Insurance Rate Map or other flood hazard delineation
map?
h) Place within a 100-year flood hazard area structures
that would impede or redirect flood flows?
i) Expose people or structures to a significant risk of loss,
injury or death involving flooding, including flooding
as a result of the failure of a levee or dam?
j) Inundation by seiche, tsunami, or mudflow?
Environmental Setting
Hydrological Resources
The project is located in the lower part of the Brushy Creek watershed which receives an average annual
rainfall of 10 inches or less. Brushy Creek has been diverted and altered by farmers in the north and eastern
portions of the watershed where Brushy Creek enters the alluvial Plain (Contra Costa Watershed Atlas
2003). The project is not located within or adjacent to any water resources; the closest surface water features
are Brushy Creek, located approximately 3 miles to the south, Clifton Court Forebay, located approximately
3 miles to the southeast, and Kellogg Creek, located approximately 4 miles to the west . However, there is an
ephemeral drainage area located just southwest of the intersection which primarily receives stormwater
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runoff from storm drain inlets and culverts along the unimproved shoulders (roadside ditches) of Camino
Diablo Road. The drainage area drains flows into a concrete box culvert beneath Byron Highway. Based on
field observations, stormwater flows is conveyed beneath the road into a corrugated metal pipe under that
opens into an earthen drainage ditch along the south side of Camino Diablo Road, east of the intersection
that appears to go behind the gas station. According to aerial imagery, it appears that the drainage ditch
flows to the east behind the gas station and residences and then to the south where it eventually ties into the
Byron-Bethany Irrigation Canal which connects to Old River.
The project site is located at an elevation of approximately 33 feet above mean sea level. Based on a review
of a workplan for groundwater monitoring wells installed for the present adjoining gasoline service station,
15031 Byron Highway, Byron, California (Valero), the groundwater flow direction ranged from the
northeast to the southeast which is consistent with the topographic setting inferred from the USGS
topographic map. Depth to groundwater measured from the same monitoring wells, ranged from 7 to 12 feet
below ground surface (bgs). The Modesto, Riverbank, and Turlock Lake Formations and overlying recent
alluvium are the principal sources of domestic ground water in the 13,500-square mile San Joaquin Valley
Ground Water Basin (Basin 5-22) (AGS 2014).
Flood Hazard Areas
Special flood hazard areas are subject to 1% chance of flooding in any given year (100-year flood), also
known as the base flood. The Federal Emergency Management Agency (FEMA) conducts flood elevation
studies to determine flood-prone areas which are mapped for local communities to administer floodplain
management regulations and mitigate flood damage as well as to determine flood insurance rates. FEMA
produces flood insurance rate maps (FIRM) that show areas that have been evaluated which are updated
periodically. The project area is located within a 100-year floodplain zone but no base flood elevation has
been determined (FEMA 2009).
a) Would the project violate any water quality standards or waste discharge requirements?
The drainage area is potentially considered other waters of the U.S. (and the State) that could be
expected to be subject to regulation by the U.S. Army Corps of Engineers (USACE) and Regional Water
Quality Control Board (RWQCB) that would require authorization for impacts to this feature by the
USACE Regional General Permit for small activities in the HCP/NCCP area and Water Quality
Certification from the RWQCB for any discharges.
The National Pollutant Discharge Elimination System (NPDES) Waste Discharge Requirements for
Storm Water Discharges from Municipal Separate Storm Sewer Systems for jurisdictions in East Contra
Costa County (Order No. R5-2010-0102) has requirements for new development and redevelopment
projects that create more than 10,000 square feet of impervious surface area (Provision C.3) (Central
Valley Regional Water Quality Control Board 2010). The constructed project will create approximately
56,944 square feet (1.3 acres) of additional impervious surface area for the road and shoulder pavements
and sidewalk at the intersection. The project will not violate this waste discharge permit as this public
works capital improvement project is exempt from creating stormwater treatment facilities as no
additional travel lanes will be created that would contribute to additional pollutant runoff (Contra Costa
County Public Works Department 2012).
The project will be subject to the NPDES General Permit for Storm Water Discharges Associated with
Construction and Land Disturbances (Order No. 2012-0006-DWQ). According to the permit, if soil
disturbance will be less than 5 acres and the project qualifies for an erosivity waiver a Stormwater
Pollution Prevention Plan (SWPPP) is not required to be prepared and submitted to the State Water
Resources Control Board. The area of soil disturbance is approximately 1.3 acres, therefore, a waiver
will be requested. However, project contract specifications will still require the construction contractor to
prepare a Water Pollution Control Plan, which is consistent with the SWPPP to identify applicable best
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management practices for water quality control that will be implemented during and after construction.
Therefore, project impacts will be less than significant.
b) Would the project substantially deplete groundwater supplies or interfere substantially with
groundwater recharge such that there would be a net deficit in aquifer volume or a lowering of the local
groundwater table (e.g., the production rate of pre-existing nearby wells would drop to a level which
would not support existing land uses or planned uses for which permits have been granted)?
The project will not require groundwater supply. Therefore, the project will have no impact.
c) Would the project substantially alter the existing drainage pattern of the site or area, including through
the alteration of the course of a stream or river, in a manner which would result in substantial erosion
or siltation on- or off-site?
The project will not alter the course of a stream or river as there is no permanent water source within or
near the project area. The constructed project will not alter the drainage pattern in the area as the
existing storm drainage system will be re-established within the new road alignment and thus will not
result in substantial on- or off-site erosion or siltation as the existing storm drain inlets are primarily
located within unpaved areas and will be re-established within the new pavement which will reduce
erosion and siltation runoff. However project construction could result in erosion or siltation from soil
disturbance. Implementation of applicable BMPs for water quality and erosion control will avoid
potential impacts to the drainage area. Therefore, project impacts will be less than significant.
d) Would the project substantially alter the existing drainage pattern of the site or area, including through
the alteration of the course of a stream or river, or substantially increase the rate or amount of surface
run-off in a manner which would result in flooding on-or off-site?
As noted above, the project will not alter the course of a stream or river as there is no permanent water
source within or near the project area. The constructed project will not significantly alter the existing
drainage pattern of the area that would result in flooding on or off-site because the existing drainage will
be re-established and additional surface run-off from the increased impervious area will be negligible.
Therefore, project impacts will be less than significant.
e) Would the project create or contribute runoff water which would exceed the capacity of existing or
planned stormwater drainage systems or provide substantial additional sources of polluted runoff?
As noted above, the constructed project will create approximately 56,944 square feet (1.3 acres) of
additional impervious surface area for the road and shoulder pavements and sidewalk at the intersection.
The project will not contribute to stormwater run-off which would exceed the capacity of existing or
planned stormwater drainage systems because while the project will create an additional surface run-off
it will be negligible as no additional through travel lanes will be created. Further, BMPs will be
implemented during and after construction to avoid impacts to the drainage area. Therefore, project
impacts will be less than significant.
f) Would the project otherwise substantially degrade water quality?
The constructed project will not otherwise substantially degrade water quality as no additional through
travel lanes, with the exception of the 5-foot wide shoulders, will be constructed that could contribute to
polluted runoff. Project construction will implement BMPs during construction to avoid adverse impacts
to the drainage area. Therefore, project impacts will be less than significant.
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g) Would the project place housing within a 100-year flood hazard area as mapped on a Federal Flood
Hazard Boundary or Flood Insurance Rate Map or other flood hazard delineation map?
The project is located within a 100-year flood plain hazard area but will not place any housing within a
flood hazard area. Therefore, the project will have no impact.
h) Would the project place within a 100-year flood hazard area structures that would impede or redirect
flood flows?
While the project is located within a 100-year flood plain zone it will not create any structures other than
the traffic signal light which will not impede or redirect flood flows. In addition, while there will be an
increase in impervious area for the shoulders closer to residential properties, the project design and
construction will incorporate recommended measures in accordance with local design practice and
guidelines as defined in the Caltrans Highway Design Manual to ensure that the project will not subject
existing housing to flooding. Therefore, the project will have less than significant.
i) Would the project expose people or structures to a significant risk of loss, injury or death involving
flooding, including flooding as a result of the failure of a levee or dam?
The project will not expose people or structures to a significant risk of loss, injury or death involving
flooding as the project will not create levees or dams. Therefore, the project will have no impact.
j) Would the project the expose people or structures to risk of inundation by seiche, tsunami, or mudflow?
The project is located in East Contra Costa County and not in an area subject to seiche, tsunami, or
mudflow. Therefore, the project will have no impact.
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X. LAND USE AND PLANNING
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Physically divide an established community?
b) Conflict with any applicable land use plan, policy, or the
regulation of an agency with jurisdiction over the
project (including, but not limited to the general plan,
specific plan, local coastal program, or zoning
ordinance) adopted for the purpose of avoiding or
mitigating an environmental effect?
c) Conflict with any applicable habitat conservation plan
or natural community conservation plan?
a) Would the project physically divide an established community?
The project will not physically divide an established community because the project involves
improvement of existing roadways. Therefore, the project will have no impact.
b) Would the project conflict with any applicable land use plan, policy, or the regulation of an agency with
jurisdiction over the project (including, but not limited to the general plan, specific plan, local coastal
program, or zoning ordinance) adopted for the purpose of avoiding or mitigating an environmental
effect?
The project will not result in an alteration of the present or planned land use of the area. The project is
consistent with the County General Plan Transportation Circulation Element’s Roadway and Transit
Goals #5-A (To provide a safe, efficient and balanced transportation system), Policy #5-9 (Existing
circulation facilities shall be improved and maintained by eliminating structural and geometric design
deficiencies), and Policy #5-17 (The design and scheduling of improvements to arterials and collectors
shall give priority to safety over other factors including capacity). Therefore, the project will have no
impact.
c) Would the project conflict with any applicable habitat conservation plan or natural community
conservation plan?
The project is located within the East Contra Costa County HCP/NCCP inventory area and is a covered
activity. As such, required mitigation fees will be paid prior to construction and applicable avoidance
and minimization measures will be implemented as required by the HCP/NCCP and as discussed in the
Biological Resources section. Therefore, the project will have no impact.
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XI. MINERAL RESOURCES
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Result in the loss of availability of a known mineral
resource that would be of value to the region and the
residents of the state?
b) Result in the loss or availability of a locally important
mineral resource recovery site delineated on a local
general plan, specific plan, or other land use plan?
Mineral resources such as crushed rock, sand, among other resources, are important minerals in the region as
they provide the necessary components for construction materials including asphalt and concrete for current
and future development in our region. The most important mineral resources that are currently mined in the
County include diabase near Mt. Zion on the north side of Mt. Diablo, which provides crushed rock
primarily for roadbase and streambank stabilizations; domegine sandstone, located in the eastern portion of
the County just south of Camino Diablo and east of Vasco Road in the Byron area, which is the sole deposit
in the state; and shale in the Port Costa area, which has been designated for protection by the County General
Plan (Contra Costa County 2005g).
a) Would the project result in the loss of availability of a known mineral resource that would be of value to
the region and the residents of the state?
There are no mapped mineral resource areas in the project area. Therefore, the project will have no
impact.
b) Would the project result in the loss or availability of a locally important mineral resource recovery site
delineated on a local general plan, specific plan, or other land use plan?
There are no mapped mineral resource areas in the project area. Therefore, the project will have no
impact.
There are no mapped mineral resource areas in the project area. As such, the project will not adversely
affect the availability of a locally important mineral resource recovery site delineated on a local general
plan, specific plan, or land use plan. Therefore, the project will have no impact.
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XII. NOISE
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Exposure of persons to or generation of noise levels in
excess of standards established in the local general plan
or noise ordinance, or applicable standards of other
agencies?
b) Exposure of persons to or generation of, excessive
ground borne vibration or ground borne noise levels?
c) A substantial permanent increase in ambient noise
levels in the project vicinity above levels existing
without the project?
d) A substantial temporary or periodic increase in ambient
noise levels in the project vicinity above levels existing
without the project?
e) For a project located within an airport land use plan or,
where such a plan has not been adopted, within two
miles of a public airport or public use airport, would the
project expose people residing or working in the project
area to excessive noise levels?
f) For a project within the vicinity of a private airstrip,
would the project expose people residing or working in
the project area to excessive noise levels?
Background
The effects of noise on people include subjective effects of annoyance, nuisance, and dissatisfaction.
Persistent and escalating noise sources can affect one’s overall health including stress -related illnesses,
high blood pressure, hearing loss, speech interference, sleep disruption, and lost productivity (USEPA
2010). The main contributors to a community noise problem are transportation sources such as
highways, railroads, and airport as they are the most pervasive and continual. Other temporary noise
sources can add to the noise problem such as a jackhammer at a construction site. The dynamic of the
noise problem are based on the relationship between the noise source, the person or place exposed to the
noise (receiver or sensitive receptor) and the path the noise will travel from the noise source to the
receiver/sensitive receptor. Since the ear is not as sensitive at some frequencies and sound pressure level
as at others, several methods of expressing average noise levels over a period of time have been
developed (HUD 2010).
Sound intensity is typically measured in decibels (dB) from a range of 0 (threshold of hearing) to 140
(threshold of pain); the higher the decibels, the greater the intensity. For example, a decibel level of 10 is
the sound of leaves rustling, a decibel level of 30 is a whisper, a decibel level of 60 is freeway traffic, a
decibel of 90 is a noisy urban street, and a decibel level of 140 is a nearby jet engine. Prolonged
exposure from at least 75 dB increases tension affecting blood pressure, heart function, and nervous
system; prolonged exposure from at least 85 dB causes physical damage to human hearing; above 90 dB
results in permanent cell damage, at 140 dB feeling of pain, and 190 dB will rupture the eardrum and
permanently damage the inner ear (HUD 2010).
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Human sound perception, in general, is such that a change in sound level of 3 dB is just noticeable; a
change of 5 dB is clearly noticeable; and a change of 10 dB is perceived as doubling or halving the
sound level. A doubling of actual sound energy is required to result in a 3 dB (i.e., barely noticeable)
increase in noise from existing conditions; in practice, for example, this means that the volume of traffic
on a roadway typically needs to double to result in a noticeable increase in noise (ICF International
2014).
When distance is the only factor considered, sound levels from isolated point sources of noise typically
decrease by about 6 dB for every doubling of distance from the noise source. When the noise source is a
continuous line, such as vehicle traffic on a highway, sound levels decrease by about 3 dB for every
doubling of distance. Noise levels can also be affected by several factors other than the distance from the
noise source. Topographic features and structural barriers that absorb, reflect, or scatter sound waves can
affect the reduction of noise levels over distance. Atmospheric conditions (wind speed and direction,
humidity levels, and temperatures) and the presence of dense vegetation can also affect the degree of
sound attenuation (ICF International 2014).
Sound from multiple sources operating in the same area such a multiple pieces of construction
equipment will result in a combined sound level that is greater than any individual source. The individual
sound levels for different noise sources cannot be added directly to give the sound level for the combined
noise sources. Rather, the combined noise level produced by multiple noise sources is calculated using
logarithmic summation. For example, if one bulldozer produces a noise level of 80 dBA, then two
bulldozers operating side by side would generate a combined noise level of 83 dBA (only 3 dBA louder
than the single bulldozer) (ICF International 2014).
Section 65302(f) of the California Government Code requires that a noise element be prepared as a part
of all city and county general plans. This state law requires that a jurisdiction’s noise element identify
and work toward mitigation of noise problems in the community and include implementation measures
and possible solutions that address any existing and perceivable noise problems. The Contra Costa
County General Plan (2005) Noise Element follows the guidelines established by the California
Department of Health Services entitled Guidelines for the Preparation and Content of the Noise Element
of the General Plan, which defines noise metrics, discusses the process of noise element development,
and present land use compatibility guidelines based on various noise levels and provides goals, policies,
and implementation measures for consideration.
Contra Costa County Code does not have a noise ordinance and therefore, does not specify construction
or operational noise level limits. However, the Contra Costa County General Plan Noise Element (2005)
does specify that construction activities shall be concentrated during the hours of the day that are not
noise-sensitive for adjacent land uses and should be commissioned to occur during normal work hours.
Construction activities are generally limited to the hours between 7 a.m. to 5 p.m.
In addition, based on the Caltrans Standard Specifications Section 14-8.02, Noise Control, which
regulates construction noise for activities on state highways, the following rules are applicable to the
project’s construction activities.
Do not exceed 86 dBA at 50 feet from the job site activities from 9:00 p.m. to 6:00 a.m.
Equip an internal combustion engine with the manufacturer-recommended muffler. Do not
operate an internal combustion engine on the job site without the appropriate muffler.
For operational noise impacts, the General Plan establishes the outdoor noise standard of 60 dBA Ldn for
residential areas. However, based on the traffic noise contours prepared for the Noise Element, outdoor
noise levels at existing residences along Byron Highway and Camino Diablo Road were estimated to be
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greater than 60 dBA Ldn. The General Plan does not establish the allowable noise increase by a project
for existing residences with ambient noise levels greater than 60 dBA Ldn. Therefore, for this CEQA
noise analysis, the project is considered to have a significant operational noise impact if it would create a
traffic noise increase of greater than 3 dB over the noise levels without the project at these residences.
The threshold of perceptible change is generally considered to be 3 dB (ICF International 2014).
For construction noise impacts, the General Plan requires construction activities to occur during the
hours of the day that are not noise-sensitive for adjacent land uses, but neither the General Plan nor the
County Code establishes a numerical noise standard for the allowable noise levels generated by
temporary construction activities. Therefore, for this CEQA noise analysis, the project is considered to
have a significant construction noise impact if it would create a temporary noise increase of greater than
10 dB over the ambient noise levels at residences adjacent to the construction activities. A change of 10
dB is generally perceived as doubling or halving the sound level. Maximum sound levels (Lmax) at 50
feet are considered along with the typical acoustical use factors which is the percentage of time each
piece of construction equipment is assumed to be operating at full power (i.e., its noisiest condition)
during construction operation and is used to estimate Leq values from Lmax values. For example, the Leq
value for a piece of equipment that operates at full power 50% of the time (acoustical use factor of 50) is
3 dB less than the Lmax value. A reasonable worst-case construction noise level assumes that the three
loudest pieces of equipment would operate concurrently (backhoe, compactor, and excavator). The
combined level for these three pieces of equipment is 80.6 dBA Leq at 50 feet (ICF International 2014).
Environmental Setting
Land uses surrounding the project intersection consist of residential and commercial uses located
immediately adjacent to the Byron Highway and Camino Diablo intersection. The adjacent railroad
tracks is located to the west of Byron Highway. Noise sensitive land uses consist of residences located
along the south leg of the intersection approximately 65–110 feet from Byron Highway, residences
located along the north leg of the intersection approximately 55–150 feet from Byron Highway,
residences located along the east leg of the intersection approximately 60 feet from Camino Diablo, and
residences located along the west leg of the intersection approximately 45 feet from Camino Diablo
(distances are measured from the primary outdoor areas in back or side yards to the outside edge of the
closest travel lane). Commercial uses are also situated southeast, southwest, and northwest of the
intersection (ICF International 2014) (Figure 2).
The existing noise environment in the project area is governed primarily by vehicular traffic traveling on
Byron Highway and Camino Diablo. Based on the traffic noise contours prepared for the Noise Element,
traffic noise levels range between 65 and 70 dBA Ldn at 100 feet from the centerline of Byron Highway,
and traffic noise levels are about 60 dBA Ldn at 100 feet from the centerline of Camino Diablo (Contra
Costa County 2005). The typical hourly noise levels for suburban arterial roadways range between 60
and 65 dBA Leq at 50 feet from the centerline of an arterial road (ICF International 2014).
a) Would the project cause exposure of persons to or generation of noise levels in excess of standards
established in the local general plan or noise ordinance, or applicable standards of other agencies?
The constructed project will result in widening of the road along the east side of Byron Highway and
north side of Camino Diablo Road which primarily adjoin residential-occupied properties. The widening
would result in through travel lanes moving closer to residences between 7 and 29 feet and would result
in residences being situated between 45–65 feet from outside edge of the closest travel lane which could
increase traffic noise levels received at these residences.
Traffic noise impacts associated with project operation were evaluated in terms of how project-related
traffic noise increases could affect existing residences on existing roadways. Traffic noise levels at the
existing residences along the project alignment were modeled using the FHWA traffic noise model
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(TNM) Version 2.5 for both No Build and Build scenarios under the existing and 2030 cumulative
conditions. Traffic data used in this analysis were provided by the project engineering consultant
(Kimley-Horn and Associates, Inc. 2014) based on the vehicle traffic counts conducted in 2012 and
future traffic projected by the Contra Costa Transportation Authority (CCTA) travel demand forecasting
model (ICF International 2014).
To determine the predicted traffic noise increases that would result from the constructed project, largest
alignment alterations of the first row residences located along Byron Highway and Camino Diablo Road
within the project area were identified and included in the model. P.M. peak hour traffic volumes were
used for the analysis, because these volumes are the highest hourly traffic volumes during a 24 -hour day.
The project’s engineering consultant provided the 2012 traffic counts (both peak hour and daily traffic
volumes) and the 2030 daily traffic projection. The 2030 peak-hour traffic volumes were developed by
applying the growth rates between 2012 and 2030 daily traffic volumes. The modeling results indicate
that the increases in traffic noise levels at the modeled receivers are expected to be less than 3 dB, which
is the threshold of perceptible change for operation impacts (ICF International 2014). However, noise
from construction activities could impact nearby residences. While construction work would occur
during the daytime hours between 7:00 a.m. and 7:00 p.m. on weekdays and between 9:00 a.m. and 7
p.m. on weekends, if necessary, which is in accordance with the County General Plan Policy 11-8 and
the Caltrans Standard Specifications Section 14-8.02, the nearest residences could experience noise
levels as high as 81 dBA Leq at 45 feet and 78 dBA Leq at 65 feet. Due to the intermittent nature of
construction, construction noise would likely be considerably lower than this at these land uses most of
the time. Nevertheless, the construction noise would be substantially higher than the ambient noise level
(60–65 dBA Leq) when construction activities occur near the residences. Therefore, the impact would be
potentially significant as it would result in more than 10 dB; however implementation of Mitigation
Measure NOISE-1 below would reduce this impact to a less-than-significant level (ICF International
2014). Therefore, project impacts will be less than significant with mitigation incorporated.
IMPACT NOISE-1: TEMPORARY NOISE INCREASE DURING CONSTRUCTION
Construction activities would result in temporary ambient noise increases to nearby residences which
would be considered a significant impact.
MITIGATION MEASURE NOISE-1: EMPLOY NOISE-REDUCING PRACTICES DURING
CONSTRUCTION
Locate stationary equipment as far as practical from noise-sensitive uses.
Turn off construction equipment when not in use, when feasible.
Comply with manufacturers’ muffler requirements on all construction equipment engines.
Construction activities are generally limited to the hours between 7 a.m. to 5 p.m. Construction
noise-generating activities will be limited to 8 a.m. to 5 p.m.
Provide advance written notification of construction activities to noise-sensitive uses around the
construction sites. Notification will include a brief overview of the proposed Project and its purpose,
as well as the proposed construction activities and schedule. It also will include the name and contact
information of the project manager or representative responsible for resolving any noise concerns.
b) Would the project cause exposure of persons to or generation of, excessive ground borne vibration or
ground borne noise levels?
Traffic traveling on roadways is rarely the source of perceptible groundborne vibration. Exceptions to
this occur when there is a significant discontinuity in the roadway surface. Vehicles traveling over a
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discontinuity can impart energy into the ground that can be perceived as groundborne vibration. The
project will result in a smoother road pavement surfaces. Accordingly, the constructed project is not
expected to result in perceptible groundborne vibration (ICF International 2014). Therefore, project
impacts will be less than significant.
The operation of heavy construction equipment may generate localized ground-borne vibration at
buildings adjacent to the construction site, especially during the operation of high-impact equipment,
such as pile drivers. Vibration from typical non-impact construction equipment is typically below the
threshold of perception when the activity is more than about 50 feet from the noise -sensitive land uses
(ICF International 2014). Vibration could be perceptible for the first row residences when construction
activities move within 50 feet of these residences. However, the duration that equipment would be within
50 feet of the residences would be short (about 3 - 4 days out of 4 month construction period) and such
construction would not involve high-impact equipment for this project (i.e., pile drivers). Therefore,
project impacts will be less than significant.
c) Would the project cause a substantial permanent increase in ambient noise levels in the project vicinity
above levels existing without the project?
As discussed above in item (a), the road along the east side of Byron Highway and north side of Camino
Diablo Road will be shifted closer to the residences. Modeling results indicate that the increases in traffic
noise levels at the modeled receivers (adjacent residences) are expected to be less than 3 dB, which is the
threshold of perceptible change for operation impacts. Therefore, project impacts will be less than
significant.
d) Would the project cause a substantial temporary or periodic increase in ambient noise levels in the
project vicinity above levels existing without the project?
As discussed above in item (a), the nearest residences could experience noise levels as high as 81 dBA
Leq at 45 feet and 78 dBA Leq at 65 feet. While the intermittent nature of construction would likely be
considerably lower than this at these land uses most of the time, the construction noise would be
substantially higher than the ambient noise level (60–65 dBA Leq) when construction activities occur
near the residences. Therefore, the impact would be potentially significant as it would result in more than
10 dB; however implementation of Mitigation Measure NOISE-1 above would reduce this impact to a
less-than-significant level (ICF International 2014).Therefore, project impacts will be less than
significant with mitigation incorporated.
e) For a project located within an airport land use plan or, where such a plan has not been adopted, within
two miles of a public airport or public use airport, would the project expose people residing or working
in the project area to excessive noise levels?
There is no public airport located within 2 miles of the project area. The nearest airport is the Byron
Airport, located approximately 2.5 miles south of the project. Therefore, the project will have no impact.
f) For a project within the vicinity of a private airstrip, would the project expose people residing or
working in the project area to excessive noise levels?
The project is not located in the vicinity of a private airstrip. Therefore, the project will have no impact.
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XIII. POPULATION AND HOUSING
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Induce substantial population growth in an area, either
directly (for example, by proposing new homes and
businesses) or indirectly (for example, through
extension of roads or other infrastructure)?
b) Displace substantial numbers of existing housing,
necessitating the construction of replacement housing
elsewhere?
c) Displace substantial numbers of people, necessitating
the construction of replacement housing elsewhere?
Section 15126.2(d) of the CEQA Guidelines states that the lead agency shall discuss ways in which the
proposed project could foster economic or population growth, or the construction of additional housing,
either directly or indirectly in the surrounding environment including the removal of obstacles that would
encourage population growth. Increases in the population may stress existing community service facilities,
requiring construction of new facilities that could cause significant environmental effects.
a) Would the project induce substantial population growth in an area, either directly (for example, by
proposing new homes and businesses) or indirectly (for example, through extension of roads or other
infrastructure)?
The project is a road safety improvement and does not include new development or creation of new
travel lanes or other infrastructure that could induce substantial population growth. Therefore, the project
will have no impact.
b) Would the project displace substantial numbers of existing housing, necessitating the construction of
replacement housing elsewhere?
While the project will require sliver right-of-way acquisitions along the frontage of privately-owned
parcels to accommodate the road shoulder improvements, the project will not result in the displacement
of existing homes because no homes will be demolished or removed by the project. Therefore, the
project will have no impact.
c) Would the project displace substantial numbers of people, necessitating the construction of replacement
housing elsewhere?
The project will not displace residents because as stated above no residences will be removed or
demolished. Therefore, the project would have no impact.
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XIV. PUBLIC SERVICES
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Would the project result in substantial adverse physical
impacts associated with the provision of new or
physically altered governmental facilities, need for new
or physically altered governmental facilities, the
construction of which could cause significant
environmental impacts, in order to maintain acceptable
service ratios, response times or other performance
objectives for any of the public services?
1 Fire Protection?
2 Police Protection?
3 Schools?
4 Parks?
5 Other public facilities?
a) Would the project result in substantial adverse physical impacts associated with the provision of new or
physically altered governmental facilities, need for new or physically altered governmental facilities, the
construction of which could cause significant environmental impacts, in order to maintain acceptable
service ratios, response times or other performance objectives for any of the public services?
1 Fire Protection?
The East Contra Costa Fire Protection District provides fire protection services and emergency services
for the Byron area (East Contra Costa Fire Protection District 2015). The project will not increase
demand for fire protection services and thus no new government facilities or expansion of existing
facilities will be required. However, to alleviate any disruption to fire protection services during
construction, the contractor will contact local fire protection response services prior to project
construction and provide at least one passable lane at all times during construction for fire protection
vehicles. Therefore, project impacts will be less than significant.
2 Police Protection?
The Contra Costa County Sheriff’s Department provides general public safety and law enforcement
services in unincorporated areas of Contra Costa County (Contra Costa County 2015). The project will
not increase demand for police services and thus no new government facilities or expansion of existing
facilities will be required. However, to alleviate any disruption to police protection services during
construction, the contractor will contact local police protection response services prior to project
construction and provide at least one passable lane at all times during construction for police vehicles.
Therefore, project impacts will be less than significant.
3 Schools?
The project area is located in the Byron Union School District (Byron Union School District 2015). The
project will not increase demand for school services and thus no new government facilities or expansion
of existing facilities will be required. The closest school is Excelsior Middle School located on Byron
Highway approximately 1.25 miles north of the project area. Access to the school is from Byron
Highway and Byer Road. Construction could result in disruption during morning and afternoon school
commute times. However, the school and community will be notified in advance of the construction start
date by notices and construction area signs. Therefore, the project will have less than significant.
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4 Parks?
The project area is not located within or near a park (Contra Costa County 2005). The constructed project
will not increase demand for parks and thus no new facilities or expansion of existing facilities will be
required. Therefore, the project will have no impact.
5 Other public facilities?
There are no other public facilities that would require new or expanded service facilities. Therefore, the
project will have no impact.
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XV. RECREATION
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Would the project increase the use of existing
neighborhood and regional parks or other recreational
facilities such that substantial physical deterioration of
the facility would occur or be accelerated?
b) Does the project include recreational facilities or require
the construction or expansion of recreational facilities
that might have an adverse physical effect on the
environment?
a) Would the project increase the use of existing neighborhood and regional parks or other recreational
facilities such that substantial physical deterioration of the facility would occur or be accelerated?
The project is a road safety improvement and does not include new development that could increase the
use of existing parks or recreational facilities that could result in deterioration of facilities. Therefore, the
project will have no impact.
b) Does the project include recreational facilities or require the construction or expansion of recreational
facilities that might have an adverse physical effect on the environment?
As noted above, the project is a road safety improvement and does not include new development that
could require construction or expansion of existing recreational facilities. Therefore, the project will have
no impact.
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XVI. TRANSPORTATION/TRAFFIC
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Conflict with an applicable plan, ordinance or policy
establishing measures of effectiveness for the
performance of the circulation system, taking into
account all modes of transportation including mass
transit and non-motorized travel and relevant
components of the circulation system, including but not
limited to intersections, streets, highways and freeways,
pedestrian and bicycle paths, and mass transit?
b) Conflict with an applicable congestion management
program, including, but not limited to level of service
standards and travel demand measures, or other
standards established by the county congestion
management agency for designated roads or highways?
c) Result in a change in air traffic patterns, including
either an increase in traffic levels or a change in
location that results in substantial safety risks?
d) Substantially increase hazards due to a design feature
(e.g. sharp curves or dangerous intersections) or
incompatible uses (e.g. farm equipment)?
e) Result in inadequate emergency access?
f) Conflict with adopted policies, plans or programs
regarding public transit, bicycle, or pedestrian facilities,
or otherwise decrease the performance or safety of such
facilities?
Regulatory Background
The Contra Costa Transportation Authority (CCTA) is a public agency formed to manage the County's
transportation sales tax program and to conduct countywide transportation planning. CCTA is responsible for
maintaining and improving the County’s transportation system by planning, funding, and delivering critical
transportation infrastructure projects and programs that connect the communities safely and efficiently
including bicycle and pedestrian projects as described in the 2009 Countywide Bike and Pedestrian Plan. In
addition, the Transportation and Circulation Element of the General Plan includes goals and policies regarding
Contra Costa County bikeways.
Existing Traffic Conditions
Byron Highway and Camino Diablo Road are heavily used truck and commuter arterial routes that provide a
vital transportation link between Contra Costa and Alameda Counties well as San Joaquin County. Both Byron
Highway and Camino Diablo Road are two-lane roads with no turning lanes and no shoulders at this
intersection. Neither road is signalized, with free-through movements on Byron Highway and stop controls on
both legs of Camino Diablo Road. In the project area, Byron Highway has a speed limit of 35 miles per hour;
the eastern leg of Camino Diablo Road has a speed limit of 25 miles per hour while the western leg west of the
railroad at-grade has a speed limit of 35 miles per hour.
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CCCPWD conducted traffic count surveys in December 2012 which included weekday AM and PM peak
period turning movement counts and 24-hour directional counts. Traffic volumes are fairly constant during the
mid-day and are at a minimum around 12:00 PM. The AM peak period begins around 6:00 AM and terminates
around 8:00 AM. The heaviest vehicle movement during the AM peak period is on Byron Highway
southbound which provides access to Tracy and I-205 to the Central Valley. Other increased vehicle
movements during the AM peak period include eastbound right on Camino Diablo Road and the northbound
through and lefts on Byron Highway. As the PM peak period begins, traffic begins to pick up around 4:00 PM
at the intersection. The peak traffic on Byron Highway is the northbound direction; both the northbound left -
turn and through movements are heavy resulting in measurable delay. The eastbound right-turn and the
southbound through movements on Byron Highway also have elevated traffic levels double what is
experienced during the AM peak period. The PM peak period ends around 6:00 PM as volumes calm to lower
levels.
The existing two-way stop-controlled intersection configuration creates minimal delay for vehicles traveling on
Byron Highway. However, the relatively heavy northbound left-turn onto Camino Diablo Road in both the AM
and PM peaks created friction for northbound traffic, especially during the PM peak period. The stop-
controlled approaches of Camino Diablo Road cause moderate to heavy delay and queuing for vehicles
approaching the intersection from the west. The eastbound right-turn on Camino Diablo Road to Byron
Highway is moderate during the AM peak period and quite heavy during the PM peak period. Because all the
approaches to the intersection are single-lane, these turning vehicles cause delay for other drivers.
The Union Pacific Railroad at-grade crossing just west of the intersection is currently protected by actuated
gates and flashing beacons. There are also railroad crossing pavement markings on the eastbound Camino
Diablo Road approach. Since the intersection is only stop-controlled there are no other active traffic control
devices other than the railroad gates and flashing beacons.
Proposed Improvements
The proposed improvements are a combination of roadway geometry changes, adding turn lanes to the three
heaviest approaches (north and southbound left turn lanes on Byron Highway and right-turn lane on eastbound
Camino Diablo Road), and installation of a traffic signal to decrease delay and improve flow for vehicles and
pedestrian crossings. The traffic signal will also be equipped with railroad pre-emption working in conjunction
with the at-grade railroad crossing (Figure 2):
Proposed Traffic Control Plan
Project construction is anticipated to take up to 80 working days (4 months). Construction would occur from
Monday to Friday between 7 a.m. and 5 p.m. Construction of the project will temporarily require one-way
traffic control for approximately 8 weeks. If feasible, one-way traffic control will begin outside of the peak
commute hours to minimize delays to commuters and will not exceed 10 minute stopped delays. In addition,
road closure will be required on Camino Diablo Road just west of the Byron Highway and Camino Diablo
Road intersection for work around the railroad for approximately 6 weeks. The detour plan will require
motorists traveling to the west to take Byron Highway north to Holway Drive south to Camino Diablo Road
west; motorists traveling east would travel east on Camino Diablo Road to Holway Drive north to Byron
Highway south. Detour signs will be set up in various locations within and outside of the construction area as
well as portable message signs ahead of the detour signs to announce the construction traffic control and detour
route. The roads will be open for use by public traffic on Saturdays, Sundays, and designated legal holidays;
after 3:00 p.m. on Fridays and the day before designated legal holidays, and when construction operations are
not actively in progress.
Local residents will be notified of the construction start date in advance and will be able to use Byron Highway
and Camino Diablo Road under one-way traffic control during construction; the roads will be made available
for through traffic during non-construction activities with the exception of when work at the railroad tracks on
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Camino Diablo Road west of the intersection occurs, which is when detour routes on local roads will be
available. Driveway access to properties outside the project area will not be affected. Driveways for properties
within the project area will remain accessible throughout the project.
a) Would the project conflict with an applicable plan, ordinance or policy establishing measures of
effectiveness for the performance of the circulation system, taking into account all modes of transportation
including mass transit and non-motorized travel and relevant components of the circulation system,
including but not limited to intersections, streets, highways and freeways, pedestrian and bicycle paths,
and mass transit?
The project will not conflict with applicable plans, ordinances or policies establishing measures of
effectiveness for the performance of the circulation system as the project will improve the traffic flow and
provide pedestrian crossings at the intersection which is consistent with local and regional plans to provide
safe and convenient circulation and pedestrian facilities (Contra Costa County 2005, Contra Costa
Transportation Authority 2009a).
There are no existing designated bicycle facilities within the Byron area at this time (Contra Costa
Transportation Authority 2009b). While the Plan shows Byron Highway and Camino Diablo Road as
proposed routes they do not represent specific suggested alignments, rather they represent corridors and
general connections to link existing segments. Although, while the widened paved shoulders will not be
designated as a bicycle facility, the improved shoulders will provide shared use of the road for bicyclists
and motorists within the project area.
Tri-Delta Transit provides public transit for east Contra Costa County however there are no public bus
routes to the Byron area; the closest is in Discovery Bay. There are no designated school bus routes in the
Byron area; although, the East Contra Costa Schools Transportation Department provides alternate
transportation for the Byron Union School District, and other school districts in the area, but there are no
designated routes.
While the constructed project will improve traffic circulation and will not interfere with other modes of
motorized and non-motorized transportation, construction of the project will disrupt traffic circulation as it
will result in traffic congestion and delays from one-way road closures and detour around Camino Diablo
Road at the railroad tracks. However, it will be temporary and measures will be in place to minimize
disruption as described above. Therefore, project impacts will be less than significant.
b) Would the project conflict with an applicable congestion management program, including, but not limited
to level of service standards and travel demand measures, or other standards established by the county
congestion management agency for designated roads or highways?
As discussed above, the project will improve the traffic circulation at the intersection which was verified by
a traffic operations analysis. The Camino Diablo Road approaches experience more delay than Byron
Highway due to the stop signs. Existing conditions with and without the project and future conditions with
and without the project were analyzed using 2030 traffic volumes derived projected by the CCTA travel
demand forecasting model and assumed annual background growth rates. The proposed intersection
geometry will improve the average delay and corresponding levels of service for both peak periods with
future conditions and during the PM peak at existing conditions; the existing conditions during the morning
will remain unchanged (Kimley-Horn and Associates, Inc. 2014., ICF International 2014).
While the constructed project will improve traffic circulation, construction of the project will temporarily
disrupt traffic circulation as it will result in traffic congestion and delays from one-way road closures if
required and detour around Camino Diablo Road at the railroad tracks. As discussed above, it will be
temporary. Therefore, project impacts will be less than significant.
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c) Would the project result in a change in air traffic patterns, including either an increase in traffic levels or
a change in location that results in substantial safety risks?
Byron Airport, a county-owned and public use airport, is located approximately 2.5 miles south of the
project site. The project will not result in a change in air traffic patterns as the project will not create
structures or different land uses that could result in substantial safety risks. Therefore, the project will have
no impact.
d) Would the project substantially increase hazards due to a design feature (e.g. sharp curves or dangerous
intersections) or incompatible uses (e.g. farm equipment)?
The project will decrease existing hazards of the roadways at the intersection and railroad tracks.
Therefore, the project will have no impact.
e) Would the project result in inadequate emergency access?
The project would not result in inadequate emergency access. Local emergency response services will be
contacted by the construction contractor to coordinate alternate routes before construction begins. In
addition, traffic control measures during construction will provide access for emergency vehicles and the
full width of the unfinished roadway will be made passable and open for use by local and emergency traffic
at the end of each working day. Therefore, project impacts will be less than significant.
f) Would the project conflict with adopted policies, plans or programs regarding public transit, bicycle, or
pedestrian facilities, or otherwise decrease the performance or safety of such facilities?
As discussed above, the constructed project will provide pedestrian facilities at the intersection. There are
no existing designated bicycle facilities or public transit routes within the Byron area at this time. As noted
above, there are no existing designated bicycle facilities within the Byron area at this time. While the Plan
shows Byron Highway and Camino Diablo Road as proposed routes they do not represent specific
suggested alignments, rather they represent corridors and general connections to link existing segments.
Although, while the widened paved shoulders will not be designated as a bicycle facility, the improved
shoulders will not conflict with future bicycle class designation.While the widened paved shoulders will
not be designated as a bicycle facility at this time, the improved shoulders will provide shared use of the
road for bicyclists and motorists within the project area. Therefore, the project will have no impact.
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XVII. UTILITIES AND SERVICE SYSTEMS
Potentially
Significant Impact
Less Than
Significant with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Exceed wastewater treatment requirements of
the applicable Regional Water Quality Control
Board?
b) Require or result in the construction of new
water or wastewater treatment facilities or
expansion of existing facilities, the construction
of which could cause significant environmental
effects?
c) Require or result in the construction of new
storm water drainage facilities, the construction
of which could cause significant environmental
effects?
d) Have sufficient water supplies available to
serve the project from existing entitlements and
resources, or are new or expanded entitlements
needed?
e) Result in a determination by the wastewater
treatment provider which serves or may serve
the project that it has adequate capacity to serve
the project’s projected demand in addition to
the provider’s existing commitments?
f) Be served by a landfill with sufficient permitted
capacity to accommodate the project’s waste
disposal needs?
g) Comply with federal, state and local statutes
and regulations related to solid waste?
The Byron Sanitary District provides wastewater services to the Byron community (Contra Costa County
2013). The Byron community relies on well water for their water supply (Nichuls 2015). Brentwood Disposal
Service provides solid waste disposal services for the Byron community (Brentwood Disposal Service 2015).
a) Would the project exceed wastewater treatment requirements of the applicable Regional Water Quality
Control Board?
The project will not exceed wastewater requirements because the completed project would not result in the
need for wastewater treatment. Therefore, the project will have no impact.
b) Would the project require or result in the construction of new water or wastewater treatment facilities or
expansion of existing facilities, the construction of which could cause significant environmental effects?
The project will not require or result in the construction of new water or wastewater treatment facilities or
expansion of existing facilities because the completed project would not require or result in the need for
water or wastewater services. Therefore, the project will have no impact.
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c) Would the project require or result in the construction of new storm water drainage facilities, the
construction of which could cause significant environmental effects?
The constructed project will re-establish the existing stormwater drainage facilities which include grading
roadside ditches and tying into existing storm drains as well as extending existing culverts at three
locations and modifying existing storm drain inlets and manholes to accommodate the improvements.
Water quality control practices will be implemented during construction to minimize impact to the
adjacent seasonal wetland and drainage features. Therefore, the project will have a less than significant
impact.
d) Would the project have sufficient water supplies available to serve the project from existing entitlements
and resources, or are new or expanded entitlements needed?
The completed project will not require water service, and any water needed during construction activities
would be provided by water trucks from off-site water sources. Therefore, the project will have no impact.
e) Would the project result in a determination by the wastewater treatment provider which serves or may
serve the project that it has adequate capacity to serve the project’s projected demand in addition to the
provider’s existing commitments?
The completed project will not require wastewater treatment services. Therefore, the project will have no
impact.
f) Would the project be served by a landfill with sufficient permitted capacity to accommodate the project’s
waste disposal needs?
The project will not generate the need for a new solid waste facility. Solid waste generated by the project
would be limited to construction debris, including asphalt and concrete, generated by the excavation of
exiting roadway and construction of associated improvements. Therefore, the project will have a less than
significant impact.
g) Would the project comply with federal, state and local statutes and regulations related to solid waste?
The project specifications will require that the contractor dispose of solid waste generated from construction
in accordance with federal, state and local regulations. Therefore, the project will have no impact.
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XVIII. MANDATORY FINDINGS OF SIGNIFICANCE
Potentially
Significant
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Would the project:
a) Does the project have the potential to degrade the
quality of the environment, substantially reduce the
habitat of a fish and wildlife species, cause a fish or
wildlife population to drop below self-sustaining levels,
threaten to eliminate a plant or animal community,
reduce the number or restrict the range of a rare or
endangered plant or animal or eliminate important
examples of the major periods of California history or
prehistory?
b) Does the project have impacts that are individually
limited, but cumulatively considerable? (“Cumulatively
considerable” means that the incremental effects of a
project are considerable when viewed in connection
with the effects of past projects, the effects of other
current projects, and the effects of probable future
projects)?
c) Does the project have environmental effects that will
cause substantial adverse effects on human beings,
either directly or indirectly?
a) Does the project have the potential to degrade the quality of the environment, substantially reduce the
habitat of a fish and wildlife species, cause a fish or wildlife population to drop below self-sustaining
levels, threaten to eliminate a plant or animal community, reduce the number or restrict the range of a
rare or endangered plant or animal or eliminate important examples of the major periods of California
history or prehistory?
The project will not degrade the quality of the environment. There are no natural or historic resources of
importance that will be impacted due to absence in the project area or implementation of avoidance
measures as described in the Air Quality, Biological Resources, Cultural Resources, and Greenhouse Gas
Emissions sections. Therefore, project impacts will be less than significant.
b) Does the project have impacts that are individually limited, but cumulatively considerable?
(“Cumulatively considerable” means that the incremental effects of a project are considerable when
viewed in connection with the effects of past projects, the effects of other current projects, and the
effects of probable future projects)?
There are several County capital improvement projects that have been identified for the Byron area;
Main Street Sidewalk Improvements, currently in design, will provide pedestrian improvements along
the west side of Main Street and Byron Highway-Byer Road Improvements, pending funding, involves
widening the roadway to install a left turn lane from southbound Byron Highway onto Byer Road (pers.
comm. Villar 2015). These projects would not result in significant cumulative impacts as they are
limited and would provide beneficial improvements to the community. There is one regional proposed
project that would create a new road, State Route 239, to link State Route 4 near Brentwood and
Interstate 205 west of Tracy in San Joaquin County (Contra Costa Transportation Authority 2014). This
proposed project is years in planning and will not be considered a cumulative effect in association with
this project as the route options being considered will bypass the Byron area and thus minimize through
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traffic in Byron. Therefore, project impacts will be less than significant.
c) Does the project have environmental effects that will cause substantial adverse effects on human beings,
either directly or indirectly?
The project will not cause substantial adverse direct or indirect effects on human beings as impacts will
be limited and avoidance measures will be implemented to minimize impacts as described in the Air
Quality, Geology and Soils, Greenhouse Gas Emissions, Hazards and Hazardous Materials, Hydrology
and Water Quality, Noise, and Transportation/Traffic sections. Therefore, project impacts will be less
than significant.
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California Department of Conservation (CDC). 2015. Farmland Mapping and Monitoring Program:
http://www.conservation.ca.gov/dlrp/fmmp/Pages/Index.aspx ; California Government Code §51290(a)(b),
51291 (Williamson Act Contract Program):. Accessed January 21, 2015.
http://www.conservation.ca.gov/dlrp/lca/basic_contract_provisions/Pages/wa_overview.aspx.
California Department of Conservation (CDC). 2012. Contra Costa County Important Farmland Map.
Division of Land Use Protection, Farmland Mapping and Monitoring Program.
ftp://ftp.consrv.ca.gov/pub/dlrp/FMMP/pdf/2012/con12.pdf. Accessed website January 21, 2015.
California Department of Conservation (CDC). 2000. A General Location Guide for Ultramafic Rocks in
California – Areas More Likely to Contain Naturally Occurring Asbestos. August. Accessed website January
21, 2015: http://www.conservation.ca.gov/cgs/minerals/hazardous_minerals/asbestos/Pages/index.aspx.
California Department of Toxic Substance Control (DTSC). 2015. EnviroStor Hazardous Waste and
Substances Site List. Website accessed: March 12, 2015:
http://www.calepa.ca.gov/SiteCleanup/CorteseList/.
California Department of Transporation (Caltrans). 2015. California Scenic Highway Mapping System.
Accessed website January 21, 2015: http://www.dot.ca.gov/hq/LandArch/scenic/schwy.htm.
California Environmental Protection Agency (CalEPA). 2015. General information. Website accessed March
12, 2015: http://www.calepa.ca.gov/About/History01/.
California Natural Resources Agency. 2015. CEQA Guidelines. Website accessed January 21, 2015:
http://resources.ca.gov/ceqa/guidelines/.
California Office of Historic Preservation (State Historic Preservation Office [SHPO]). November 2014.
Determinations of Eligibility for the Proposed Byron Highway/Camino Diablo Intersection Improvements
Projects in Byron, Contra Costa County, CA. Sacramento, CA.
California Office of Planning and Research (OPR). 2008a. Governor’s Office of Planning and Research,
State of California. July 2008 (revised). Technical Advisory: CEQA AND ASBESTOS: Addressing
Naturally Occurring Asbestos in CEQA Documents. http://opr.ca.gov/docs/asbestos_advisory.pdf.
Sacramento, CA.
California Office of Planning and Research (OPR). 2008a. Governor’s Office of Planning and Research,
State of California. July 2008 (revised). Technical Advisory: CEQA AND ASBESTOS: Addressing
Naturally Occurring Asbestos in CEQA Documents. Sacramento, CA.
California Office of Planning and Research (OPR). 2008b. Governor’s Office of Planning and Research,
State of California. June 19, 2008. Technical Advisory: CEQA and Climate Change: Addressing Climate
Change Through California Environmental Quality Act (CEQA) Review. Sacramento, CA.
CardnoEntrix. October 2014a. Historic Property Survey Report for the Byron Highway-Camino Diablo
Intersection Improvements Project. Sacramento, CA.
G:\engsvc\ENVIRO\TransEng\Byron Highway-Camino Diablo (4094)\CEQA\IS-MND\Final-Public Review_4-3-15.docx
CardnoEntrix. October 2014b. Historic Resource Evaluation Report for the Byron Highway-Camino Diablo
Intersection Improvements Project. Sacramento, CA.
CardnoEntrix. October 2014c. Archaeological Survey Report for the Byron Highway-Camino Diablo
Intersection Improvements Project. Sacramento, CA.
Contra Costa County. 2013. Directory of Local Agencies. May. Page 89. Accessed website February 10,
2015: http://www.contracostalafco.org/local_agency_directory.htm.
Contra Costa County. January 2005. Contra Costa County General Plan 2005-2020. Contra Costa County
Community Development Department. Martinez, CA.
2005a: Aesthetics: 9. Open Space Element, 9.6 Scenic Resources, page 9-4, Figure 9-1; 5. Transportation
and Circulation Element: 5.9 Scenic Routes; Figure 5-4.
2005b: Agricultural Resources: 5. Transportation and Circulation Element, 5.6 Roadways and Transit, 5-9,
5-17, 5-x, 5-ai.
2005c: Air Quality: 8. Conservation Element, 8.14 Air Resources, page 8-51.
2005d: Geology: 10. Safety Element, Figures 10-1 – 10-6.
2005e: Hydrology/Water Quality: 10. Safety Element, 10.8 Flood Hazards, 10-26 – 10-30
2005f: Land Use and Planning: 3: Land Use Element, page 3-1; 5: Transportation and Circulation Element;
5.6: Roadways and Transit, pages 5-13-5-15
2005g: Mineral Resources: 8. Conservation Element, 8.9-Mineral Resource Areas; page 8-33, Figure 8-4
2005h: Noise: 11: Noise Element, pages 11-1-11-40
2005i: Population and Housing: 6. Housing Element, pages 6-1 and 6-3)
2005j: Public Services: 7: Public Facilities/Services Element: 7.10 Fire Protection, page 7-25; 7.9: Public
Protection, page 7-23
2005k: Transportation: 5. Transportation and Circulation Element: 5.6 Roadways and Transit, page 5-12.
2005l: Utilities: 7: Public Facilities/Services Element, 7.6 Water Service, page 7-6, Figure 7-1; Figure 7-3,
page 7-13; 7.11 Solid Waste Management, page 7-31, Figure 7-7
Contra Costa County Department of Conservation and Development (CCCDCD). 2015. Williamson Act
Program, 2012 Agricultural Preserve Map. Advanced Planning Division. Martinez, CA. Website accessed
January 21, 2015: http://www.co.contra-costa.ca.us/depart/cd/current/advance/williamsonact/index.htm.
Contra Costa County Public Works Department. 2012. Tracking Form for Capital Improvement Projects for
Compliance with Provision C.3. December 19. Watershed Program. Martinez, CA.
Contra Costa Transportation Authority. 2009a. Countywide Comprehensive Transportation Plan. Accessed
website March 3, 2015.
Contra Costa Transportation Authority. 2009b. Contra Costa Countywide Bicycle and Pedestrian Plan.
Accessed website March 3, 2015
Contra Costa Transportation Authority. 2014. TriLink (SR 239) Feasibily Study Report. May 30, 2014.
Website accessed March 17, 2015: http://trilink239.org/FeasibilityStudy/Final/FinalStudy.html.
Contra Costa County. 2015. Sherriff’s Department. Accessed website February 10, 2015.
Contra Costa County Department of Conservation and Development. 2003. Watershed Altas. November.
Martinez, CA.
East Contra Costa Fire Protection District. 2015. Accessed website February 10, 2015:
http://www.eccfpd.org/FAQ/index.htm.
G:\engsvc\ENVIRO\TransEng\Byron Highway-Camino Diablo (4094)\CEQA\IS-MND\Final-Public Review_4-3-15.docx
Federal Emergency Management Agency (FEMA). 2009. Flood Insurance Rate Map, Contra Costa County,
Panel 525 of 602 (060025-0525). June 16.
ICF International. 2014a. Natural Environment Study-Minimal Impact, Byron Highway-Camino Diablo
Intersection Improvements Project, Byron, Contra Costa County. November. San Francisco, CA.
ICF International. 2014b. Delineation of Potential Waters of the United States, Byron Highway-Camino
Diablo Intersection Improvements Project, Byron, Contra Costa County. June. San Francisco, CA.
Jones & Stokes. 2006. East Contra Costa County Habitat Conservation Plan and Natural Community
Conservation Plan. October. (J&S 01478.01.) http://www.co.contra-costa.ca.us/depart/cd/water/HCP/. San
Jose, CA.
Kimley-Horn. August 2014. Traffic Analysis Memorandum - Byron Highway and Camino Diablo Road
Intersection Improvements.
LSA Associates. 2015. Byron Highway & Camino Diablo Intersection Improvements Project Air Quality
Analysis Technical Memorandum. February 15. Concord, CA.
Regional Water Quality Control Board – Central Valley. 2015. Water Quality Certification for Discharges of
Dredged or Fill Materials Under CWA Section 401. Website accessed: January 21, 2015:
http://www.swrcb.ca.gov/centralvalley/help/business_help/permit2.shtml.
Regional Water Quality Control Board. 2010. Waste Discharge Requirements for Storm Water Discharges
from Municipal Separate Storm Sewer Systems, East Contra Costa County (Order No. R5-2010-0102).
September 23.Central Valley Region, Rancho Cordova, CA.
State Water Resources Control Board [SWRCB]. 2015. National Pollution Discharge Elimination System
(NPDES) General Permit for Storm Water Discharges Associated with Construction and Land Disturbance
Activities (Order 2012-0006-DWQ). Accessed website March 3, 2015:
http://www.waterboards.ca.gov/water_issues/programs/stormwater/constpermits.shtml.
Tri-Delta Transit. 2015. Accessed website March 3, 2015: http://www.trideltatransit.com/.
United States Army Corps of Engineers (USACE). 2015. Regional Permit Program. Accessed website March
3, 2015: http://www.spk.usace.army.mil/Missions/Regulatory.aspx.
United States Environmental Protection Agency (USEPA). 2015. Six Common Air Pollutants. Website
accessed March 24, 2015: http://www.epa.gov/air/urbanair/.
United States Geological Survey (USGS). 1953. Byron Hot Springs 7.5-Minute Topographic Quadrangle.
United States Department of Agriculture. 2015. Natural Resources Conservation Service. Web Soil Survey
Map. Website accessed March 26, 2015: http://websoilsurvey.nrcs.usda.gov/app/.
Personal Communications:
Nuchols, Alicia. 2015. Contra Costa County Board of Supervisors – District III. Email correspondence
regarding drinking water supplier for the Byron area. February 10, 2015.
Villar, Angela. March 2015. Other planned projects in the Byron area. Contra Costa County Public Works
Department, Transportation Engineering, Martinez, CA.
APPENDIX A: MITIGATION AND MONITORNG REPORTING PLAN (MMRP)
Byron Highway-Camino Diablo Intersection Improvements Project Initial Study/Mitigated Negative Declaration
Contra Costa County Public Works Department April 2015
Project No.: 0662-6R4094 CEQA No.: 15-01
Page 1 of 4
IMPACT MITIGATION, AVOIDANCE, AND
MINIMIZATION MEASURES
IMPLEMENTATION
TIMING
IMPLEMENTATION
RESPONSIBILITY
VERIFICATION
RESPONSIBILITY
COMPLIANCE
VERIFICATION
DATE
IV. BIOLOGICAL RESOURCES
POTENTIAL IMPACT
BIO-1A
NESTING BIRDS AND
RAPTORS
AVOIDANCE MEASURE BIO-1A
If feasible, the trees and shrubs will be
removed during the non-nesting season
(September 16 – January 31).
If not feasible, a qualified biologist will
conduct nesting bird surveys prior to start of
project-related activities. In accordance with
the HCP/NCCP, surveys for golden eagle will
be conducted within a ½-mile radius and
1,000 feet for Swainson’s hawk.
If no active nests are found within the survey
area, no further avoidance measures will be
necessary.
If active nest(s) are found, work will stop and
the qualified biologist will evaluate the
situation and determine the appropriate non-
disturbance buffer zone in consultation with
the California Department of Fish and
Wildlife (CDFW) and the U.S. Fish and
Wildlife Service (USFWS) Migratory Bird
Permit Office. If buffers are established but it
is determined that project activities are
resulting in nest disturbance, work will cease
immediately and the CDFW and USFWS will
be contacted for further guidance.
Prior to and during
construction or project-
related activities,
whichever occurs first
CCCPWD
Environmental Services
Division
CCCPWD
Environmental
Services Division
APPENDIX A: MITIGATION AND MONITORNG REPORTING PLAN (MMRP)
Byron Highway-Camino Diablo Intersection Improvements Project Initial Study/Mitigated Negative Declaration
Contra Costa County Public Works Department April 2015
Project No.: 0662-6R4094 CEQA No.: 15-01
Page 2 of 4
IMPACT MITIGATION, AVOIDANCE, AND
MINIMIZATION MEASURES
IMPLEMENTATION
TIMING
IMPLEMENTATION
RESPONSIBILITY
VERIFICATION
RESPONSIBILITY
COMPLIANCE
VERIFICATION
DATE
IMPACT BIO-1B
HCP/NCCP HABITATS
MITIGATION MEASURE BIO-1B
The project will mitigate permanent and temporary
impacts to undeveloped habitats by fee payment to
the Habitat Conservancy regardless if sensitive
habitats and/or species are present. The fee is
based on the impact acreage to undeveloped
habitats, which is approximately 1.3 acres. The
development fee per acre for permanent and
temporary impacts is $12,117.05 and therefore,
approximately $2,313 will be paid. In addition,
applicable avoidance and minimization measures
noted above for nesting birds and raptors and
below in item (c) will be implemented which are
required by the HCP/NCCP.
Prior to construction or
ground disturbance,
whichever occurs first
CCCPWD
Environmental Services
Division
CCCPWD
Environmental
Services Division,
East Contra Costa
County Habitat
Conservancy
POTENTIAL IMPACT
BIO-2A
SEASONAL WETLAND
AVOIDANCE MEASURE BIO-2A
Stake the outer edge of the buffer zone of
seasonal wetland and seasonal wetland.
Prior to construction or
ground disturbance,
whichever occurs first
CCCPWD Biologist
CCCPWD Resident
Engineer,
Environmental
Services Division
Erect temporary filter and Environmental
Sensitive Area (ESA) along perimeter of
seasonal wetland as delineated by stakes.
Prior to construction or
ground disturbance,
whichever occurs first
CCCPWD Construction
Contractor
CCCPWD Resident
Engineer, Biologist
Conduct worker awareness training of
compliance requirements to construction
personnel conducting ground-disturbing
activities adjacent to the wetland by a
qualified biologist of these measures and
permit obligations of the County.
Prior to construction or
ground disturbance,
whichever occurs first
CCCPWD Biologist
CCCPWD Resident
Engineer,
Environmental
Services Division
Remove trash generated during construction
promptly and properly from the site.
During and after
construction
CCCPWD Construction
Contractor
CCCPWD Resident
Engineer,
Environmental
APPENDIX A: MITIGATION AND MONITORNG REPORTING PLAN (MMRP)
Byron Highway-Camino Diablo Intersection Improvements Project Initial Study/Mitigated Negative Declaration
Contra Costa County Public Works Department April 2015
Project No.: 0662-6R4094 CEQA No.: 15-01
Page 3 of 4
IMPACT MITIGATION, AVOIDANCE, AND
MINIMIZATION MEASURES
IMPLEMENTATION
TIMING
IMPLEMENTATION
RESPONSIBILITY
VERIFICATION
RESPONSIBILITY
COMPLIANCE
VERIFICATION
DATE
Services Division
Apply appropriate erosion control measures
such as filter fences and hydroseeding that do
not contain invasive nonnative species and
composed of native or sterile nonnative
species
During and after
construction
CCCPWD Construction
Contractor
CCCPWD Resident
Engineer,
Environmental
Services Division
IMPACT
BIO-2B
SEASONAL WETLAND
MITIGATION MEASURE BIO-2B:
Mitigate permanent and temporary impacts to
unavoidable impacts to seasonal wetlands by
fee payment to the East Contra Costa Habitat
Conservancy.
Prior to construction or
ground disturbance,
whichever occurs first
CCCPWD
Environmental Services
Division
CCCPWD
Environmental
Services Division,
East Contra Costa
County Habitat
Conservancy
Permits will be obtained from the USACE and
RWQCB and applicable best management
practices as conditioned in the permits will be
implemented to minimize impacts to
downstream waters and seasonal wetlands.
Prior to construction or
ground disturbance,
whichever occurs first
CCCPWD
Environmental Services
Division
CCCPWD
Environmental
Services Division
Avoidance Measure BIO-2A will also be
implemented. See BIO-2A See BIO-2A See BIO-2A
VIII. HAZARDS AND HAZARDOUS MATERIALS
IMPACT HAZ-1:
CONTAMINATED
SOIL
AVOIDANCE MEASURE HAZ-1:
A subsurface investigation will be conducted prior
to start of construction. If the soil is contaminated,
the excavated soil will be disposed of at an
appropriate disposal facility and the contractor will
be required to prepare a health and safety worker
plan.
Prior to and during
construction or project-
related activities,
whichever occurs first
CCCPWD
Design/Construction
Division
CCCPWD
Environmental
Services Division
APPENDIX A: MITIGATION AND MONITORNG REPORTING PLAN (MMRP)
Byron Highway-Camino Diablo Intersection Improvements Project Initial Study/Mitigated Negative Declaration
Contra Costa County Public Works Department April 2015
Project No.: 0662-6R4094 CEQA No.: 15-01
Page 4 of 4
IMPACT MITIGATION, AVOIDANCE, AND
MINIMIZATION MEASURES
IMPLEMENTATION
TIMING
IMPLEMENTATION
RESPONSIBILITY
VERIFICATION
RESPONSIBILITY
COMPLIANCE
VERIFICATION
DATE
XII. NOISE
IMPACT NOI-1
TEMPORARY NOISE
INCREASE DURING
CONSTRUCTION
MINIMIZATION MEASURE NOI-1:
Provide advance written notification of
construction activities to noise-sensitive uses
around the construction sites. Notification
shall include a brief overview of the project
and its purpose as well as the proposed
construction activities and schedule. It also
shall include the name and contact
information of the CCCPWD Resident
Engineer to resolve reported noise concerns.
Prior to construction or
ground disturbance,
whichever occurs first
CCCPWD Resident
Engineer or Contractor
CCCPWD
Environmental
Services Division
Locate stationary equipment as far as practical
from noise-sensitive uses.
Turn off construction equipment when not in
use, when feasible.
Comply with manufacturers’ muffler
requirements on all construction equipment
engines.
Construction activities are generally limited to
the hours between 7 a.m. to 5 p.m.
Construction noise-generating activities will
be limited to 8 a.m. to 5 p.m.
During construction CCCPWD Contractor
CCCPWD Resident
Engineer,
Environmental
Services Division
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
ATTACHMENT B
Response to Comments
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
LIST OF COMMENT LETTERS
1. JONATHAN DORR (May 1, 2015)
2. RAY PERRY (May 1, 2015)
3. MIKE NISEN (April 24, 2015)
4. DEBBIE NISEN (April 24, 2015)
5. CENTRAL VALLEY REGIONAL WATER QUALITY CONTROL BOARD (April 28,
2015)
6. CHEVRON ENVIRONMENTAL MANAGEMENT COMPANY (April 30, 2015)
7. GOVERNOR’S OFFICE OF PLANNING AND RESEARCH (STATE CLEARINGHOUSE)
(May 6, 2015)
Flaws in the Initial study/Mitigated Negative Declaration
Air quality
Air quality during construction is estimated at 109lbs/day. Is someone going to measure this to
make sure that it is within guidelines for the proximity to the homes. Much dust is going to be created
and blown onto our homes. Is someone going to pay to have our windows and walls washed when
construction is done?
Storm drains / run off
With a side walk going in, are storm drains going to be put in as well? Is the sewer going to be
moved over to accommodate the expansion? Several of the homes on Byron Highway originally had
septic systems with leach lines. Have all lines and tanks been accounted for since the expansion may
uncover hidden lines that are not on any maps?
The run off from this sidewalk: is it going to go into the seasonal creek that is detailed on the
south west side of Byron and Camino Diablo? If so, that creek flows into the many backyards along
Byron Highway and Camino Diablo to the east. This area was left of the biological study area, but is
connected to the area that is on the study.
Along the lines of the creek, there are many wild animals not mentioned in the animal study;
Including fox, coyote, skunks, opossum, frogs, owls, and Hawks. There are also domesticated livestock
in this area.
Noise
With the widening of the road the homes will now be closer to the road by several feet. In the
report there is no mention of any samples being taken at peak driving times with the approximate set
back that the road will have when done, to see if it is a significant increase in noise levels.
Traffic volume report
The report sites data from a 2012 study. Current rates and flow of traffic are significantly more
than they were at that time.
Tree removal
If trees are to be removed it says that they are only going to be a minor impact but this is wrong.
In the spring and fall we get winds that reach 60 mph and the trees are a significant wind block for the
homes along the high way. They are also used for shade in the summer time to cut back on cooling bills.
Carbon dioxide levels
Once the construction is done, the signal will back traffic up in the north bound direction. This
will leave cars idling for long periods of time along the way. During peak traffic conditions this will
significantly increase the levels of carbon dioxide in the air, and with the homes being closer to the road,
and less trees, it will be even worse for occupants of the homes.
Power lines
The report says nothing about the moving of the power lines that are overhead. When they
widen the road they are going to have to move the lines closer to the homes. There are studies that
show major concerns for proximity of power lines to children and the elderly. The EMF or
electromagnetic field generated by the lines must be measured to see if there will be a considerable
negative impact.
Schools
The report states that there are no schools in the area so nothing needs to be researched about
that. But, there are three home schooling families in the direct vicinity of the construction zone. These
homes need to be treated as school sites. The children are home all day working on education just as
they would if they were at a traditional school site. The construction noise alone will be a considerable
negative impact.
Visual curb appeal
The road widening will be taking trees, fences, and established ground cover. This will very
significantly affect the home owners curb appeal and potential property value.
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
COMMENT LETTER #1. JONATHAN DORR (May 1, 2015)
Comment 1-1: Air quality
Air quality during construction is estimated at 109lbs/day. Is someone going to measure
this to make sure that it is within guidelines for the proximity to the homes. Much dust
is going to be created and blown onto our homes. Is someone going to pay to have
our windows and walls washed when construction is done?
Response:
There is no estimate of construction emissions of 109 lbs/day. However, the maximum
construction emissions for particulate matter (PM2.5) is estimated to be 1.9 lbs/day for
any of the construction phases. According to the Bay Area Air Quality Management
District (BAAQMD), it is not reasonably feasible to measure equipment emissions during
construction as the thresholds are based on averages. Rather, it will be the
responsibility of the CCCPWD on-site project Resident Engineer and Environmental
Services Division staff to ensure that the construction contractor is complying with
minimizing construction emissions (i.e., controlling dust with water application,
minimizing idling times). In addition, dust complaint signs with contact information to
CCCPWD and the BAAQMD will be posted within and near the construction area.
CCCPWD will not pay to have windows and walls of houses washed when construction
is done as implementation of measures to minimize construction emissions and dust are
not anticipated to result in particulate residue on the houses that would require
washing.
Comment 1-2: Storm Drains/Run Off
Comment 1-2A: With a side walk going in, are storm drains going to be put in as
well? Is the sewer going to be moved over to accommodate the expansion? Several
of the homes on Byron Highway originally had septic systems with leach lines. Have
all lines and tanks been accounted for since the expansion may uncover hidden lines
that are not on any maps?
Response: Yes, storm drains will be installed.
The project will not require relocation of the main sewer line servicing homes along
Byron Highway. The Byron Sanitary District was contacted to obtain location
information of the main sewer line alignment and associated manholes. Access to
the manholes will be made available. Sewer laterals (from the house to the main
line) are anticipated to be exposed during construction and will be repaired if
damaged. Septic systems and associated leach lines are typically placed behind
residential structures and therefore are not anticipated to be encountered during
construction.
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
Comment 1-2B: The run off from this sidewalk: is it going to go into the seasonal
creek that is detailed on the south west side of Byron and Camino Diablo? If so,
that creek flows into the many backyards along Byron Highway and Camino Diablo
to the east. This area was left of the biological study area, but is connected to the
area that is on the study.
Response: Yes, the runoff from the sidewalk will enter the storm drain inlets and
culvert system which will enter into the drainage area on the southwest side of the
intersection. The CEQA document acknowledges that the drainage area flows into a
culvert underneath Byron Highway and drains into an earthen ditch behind the gas
station and residential properties. The drainage area behind the residential
properties was not included in the biological study area as the project will not have
direct or indirect impacts to this drainage. The project will incorporate applicable
best management practices during construction (i.e., silt fence barriers, fiber rolls,
etc.) to avoid and minimize construction-related pollutants, debris, and sediment
from entering the drainage area. Further, the disturbed areas will be hydroseeded
upon project completion or prior to a rain event if still under construction. The
hydroseed mix will consist of native seasonal wetland vegetation.
The design considered the additional storm water flows being introduced in the
creek from the impervious area being added. A small storm water detention basin
will be constructed at the northeast corner of Byron Highway and Camino Diablo
Road. It is designed so that runoff discharge rates and durations match the pre-
project discharge rates and durations.
Comment 1-2C: Along the lines of the creek, there are many wild animals not
mentioned in the animal study; including fox, coyote, skunks, opossum, frogs, owls,
and Hawks. There are also domesticated livestock in this area.
Response: The Biological Resources section (IV) of the CEQA Guidelines directs the
evaluator to determine if the project will have a substantial adverse effect, either
directly or through habitat modifications, on any species identified as a candidate,
sensitive, or special status species in local or regional plans, policies, or regulations,
or by the California Department of Fish and Wildlife or U.S. Fish and Wildlife Service
and if the project will interfere substantially with the movement of any native
resident or migratory fish or wildlife species or with established native resident or
migratory wildlife corridors, or impede the use of native wildlife nursery sites. As
noted above, the project will not impact the drainage area behind the residences.
The drainage area southwest of the intersection was not identified to support
special-status species nor as a native resident migratory wildlife corridor. The CEQA
document identifies several raptors that may occur in the project area and notes
that surveys for nesting birds and raptors will be conducted prior to tree removals
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
and start of construction activities. If active nests are present avoidance measures
as outlined in the CEQA document will be implemented.
The constructed project will not permanently interfere with wildlife movements in
the area as the project is limited to road improvements and there are no features
that would potentially pose a barrier. However, construction activities may
temporarily inhibit dispersal, migration, and daily movement of common wildlife but
it is not anticipated considering its location within a heavily traveled road.
Livestock will not be impacted by the project as impacts will be limited to the
roadway and frontage of residential properties.
Comment 1-3: Noise
With the widening of the road the homes will now be closer to the road by several feet.
In the report there is no mention of any samples being taken at peak driving times with
the approximate set back that the road will have when done, to see if it is a significant
increase in noise levels.
Response:
As noted in the Noise section (XII) of the CEQA document, traffic noise impacts
associated with project operation (constructed project) were evaluated in terms of how
project-related traffic noise increases could affect existing residences on existing
roadways. Traffic noise levels at the existing residences along the project alignment
were modeled using the Federal Highway Administration Traffic Noise Model Version 2.5
for both No Build and Build scenarios under the existing and 2030 cumulative
conditions. The existing traffic conditions used in this analysis were from the most
recent traffic data collected for this project in December 2012 and January 2013 and
future traffic conditions projected by the Contra Costa Transportation Authority travel
demand forecasting model which is based on applying growth rates between 2012 and
2030 daily traffic volumes.
To determine the predicted traffic noise increases that would result from the
constructed project, the largest alignment alterations of the first row residences located
along Byron Highway and Camino Diablo Road within the project area were identified
and included in the model. PM peak hour traffic volumes were used for the analysis
because these volumes are the highest hourly traffic volumes during a 24-hour day.
The modeling results indicate that the increases in traffic noise levels at the modeled
receivers are expected to be less than 3 dB, which is the threshold of perceptible
change for operation impacts.
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
Comment 1-4: Traffic volume report
The report sites data from a 2012 study. Current rates and flow of traffic are
significantly more than they were at that time.
Response:
More recent traffic volume and turning movement count data is not available; the traffic
volume data was collected in December 2012 and January 2013 which was during the
preliminary design phase of the project when data collection typically occurs. If traffic
rates have increased beyond those documented in 2012 and 2013, this would further
support the need for the traffic signal to improve the overall flow of traffic at the
intersection.
Comment 1-5: Tree removal
If trees are to be removed it says that they are only going to be a minor impact but this
is wrong. In the spring and fall we get winds that reach 60 mph and the trees are a
significant wind block for the homes along the high way. They are also used for shade
in the summer time to cut back on cooling bills.
Response:
Your comments are not CEQA considerations and rather are related to physical and
financial impacts to the property which will be valued during the appraisal process.
Comment 1-6: Carbon dioxide levels
Once the construction is done, the signal will back traffic up in the north bound
direction. This will leave cars idling for long periods of time along the way. During peak
traffic conditions this will significantly increase the levels of carbon dioxide in the air,
and with the homes being closer to the road, and less trees, it will be even worse for
occupants of the homes.
Response:
The existing queue for vehicles traveling northbound on Byron Highway turning onto
Camino Diablo Road is approximately 50 feet and the backup with the addition of the
signal would be 150 feet. While there is an increase in the queue created by the signal,
the length is not expected to extend past the Valero gas station. The northbound
through traffic will be able to continue unimpeded by the light as the signal will be
timed in a manner that will give more green time to the heavier movements and will
change throughout the day to accommodate peak time periods. The signal will allow
the intersection to function more efficiently, decreasing the overall idling time for
vehicles in all directions. Therefore, carbon dioxide levels are not anticipated to
increase. Further, the project will not create additional travel through-lanes that would
generate a potential increase in traffic and thus an increase in air pollutants.
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
Comment 1-7: Power lines
The report says nothing about the moving of the power lines that are overhead. When
they widen the road they are going to have to move the lines closer to the homes.
There are studies that show major concerns for proximity of power lines to children and
the elderly. The EMF or electromagnetic field generated by the lines must be measured
to see if there will be a considerable negative impact.
Response:
In the project description of the CEQA document we state that utility relocations will be
required to accommodate the road widening and thus will require moving the existing
utility poles closer to the residences. Electric and magnetic fields (EMF) are present
where electricity is used. This includes not only utility transmission lines, distribution
lines, and substations, but also the building wiring in homes, offices, and schools, and
in the appliances and machinery used in these locations.
Recognizing that there is public interest and concern regarding potential health effects
from exposure to EMF, the California Public Utilities Commission (CPUC) has repeatedly
noted that EMF is not an environmental impact to be analyzed in the context of CEQA
because (1) there is no agreement among scientists that EMF does create a potential
health risk, and (2) there are no defined or adopted CEQA standards for defining health
risk from EMF.
Comment 1-8: Schools
The report states that there are no schools in the area so nothing needs to be
researched about that. But, there are three home schooling families in the direct vicinity
of the construction zone. These homes need to be treated as school sites. The children
are home all day working on education just as they would if they were at a traditional
school site. The construction noise alone will be a considerable negative impact.
Response:
The Public Services section (XIV) of the CEQA document notes that the closest public
school is Excelsior Middle School located approximately 1.25 miles north of the project
area. Schools and residences are considered sensitive receptors and therefore, as noted
in the Noise section (XII) of the CEQA document, noise-reduction measures will be
implemented as outlined in Mitigation Measure NOI-1 of the document which would be
the same for projects occurring near public schools.
Comment 1-9: Visual curb appeal
The road widening will be taking trees, fences, and established ground cover. This will
very significantly affect the home owners curb appeal and potential property value.
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
Response:
As noted above in Response 1-5, your comments are not CEQA considerations and
rather are related to physical and financial impacts to the property which will be valued
during the appraisal process.
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
COMMENT LETTER #2. RAY PERRY (May 1, 2015)
Comment 2-1: Section 1
1. Losing chain link fence on both parcels.
2. Losing portion of driveway on both parcels.
3. Trees on both parcels (which provide sound barriers and reduce cooling costs).
4. Aesthetics (will have to build barrier fence on both parcels to block sound resulting
in loss of mountain view).
5. Reduced market value on both parcels due to closeness of house to highway. This
also will increase difficulty in renting houses and may result in having to reduce rent.
Hopefully, I do not lose my current renters.
6. Reduce income and plans to renovate vacant house on parcel 002-140-005-6. I
delayed plans to renovate till informed how much property would be taken and now
am unable to renovate because road nearness to house would render it extremely
difficult to rent or perhaps eventually sell.
Response 2-1:
Most of your comments aren’t related to the CEQA considerations and rather are related
to physical and financial impacts to the property which will be valued during the
appraisal process. CCCPWD has notified the community of this project and associated
impacts through Supervisor Mary Piepho’s office and held presentations at the Byron
Municipal Advisory Committee (MAC) meetings for the community to express questions
and concerns related to project impacts.
Comments 2-2: Section 2
1. The sewer line is close to 60 years old and could present a potential problem
because it appears it will have to be relocated.
Response: The sewer line system will not be relocated.
2. There is the possibility of leaking underground storage tanks and contaminated soil
at the Trucking Company located at the corner of main street & Camino Diablo
because years ago this was an oil and gas Distributor for Signal Oil.
Response: A Phase I Environmental Site Assessment was conducted to identify
recorded contaminated sites and assess potential contaminated sites in the project
area. Considering the present and historical land uses of the area, subsurface
investigations will be conducted where there will be excavations at potentially-
contaminated areas prior to construction. If contamination is identified through
subsurface investigations, the appropriate agencies and qualified professionals will
be notified to determine any remedial actions and handling and disposal
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
requirements.
3. At one time there was a gas service station across the street from the Trucking
Company therefore the possibility of leaking underground storage tank sites and
contaminated soil could be encountered there as well.
Response: See above response.
4. Utilities lines will have to be relocated which is going to be detrimental to property
owners.
Response: The only utility that will be relocated is the PG&E pole and distribution
line which will vary between 5 and 15 feet toward the residential structures.
CCCPWD is not able to respond further as it is not clear what is meant by
detrimental.
5. Water Quality could be affected with wells in the project area.
Response: As noted in the Hydrology and Water Quality section (IX) of the CEQA
document, depth to groundwater measured from monitoring wells at the Valero gas
station located at the southeast corner of the intersection ranged from 7 to 12 feet
below ground surface. Maximum excavation is anticipated to be approximately 6.5
feet. Considering the present and historical land uses of the area, subsurface
investigations will be conducted where there will be excavations at potentially-
contaminated areas prior to construction. If contamination is identified through
subsurface investigations, the appropriate agencies and qualified professionals will
be notified to determine any remedial actions and handling and disposal
requirements.
6. There is a greater noise problem than acknowledged in your report because the
removal of the trees along the frontage will mean loss of a sound barrier for houses
on both parcels.
Response: Previous studies conducted by Caltrans and other Department of
Transportation agencies have shown that vegetation provides minimal noise
attenuation and is not considered an effective noise barrier. The project is
anticipated to be beneficial as it will result in a smoother road pavement which will
contribute to some noise reduction. The removal of trees will be valued during the
appraisal process.
Comment 2-3:
The report is wrong when it states that the project would be no impact or have a
substantial adverse effect on a scenic vista. The scenic and privacy impact on homes
with loss of trees will devalue property worth as well as potential sales of homes.
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
Response:
A scenic vista is defined as a viewpoint that provides expansive views of a highly valued
landscape for the benefit of the general public. As noted in the Aesthetics section (I) of
the CEQA document, the Contra Costa County General Plan identifies the scenic ridges
and hills as one of the main scenic resources in Contra Costa County as it forms the
backdrop for much of the developed portions of the area. The rolling hills and Mount
Diablo ridgelines to the west of Byron provide a scenic vista from Byron Highway. The
view of this scenic vista from your property will not be affected by the project. Loss of
the trees will be valued during appraisal process.
Comment 2-4:
Air quality will be adversely affected for the residents in houses that will now sit
extremely close to road with this project because the olive trees provide oxygen and
sequester CO2. Also, with the removal of all trees for this project will produce more
exhaust that will flow unobstructed from vehicles and directly to the house.
Response:
The project will not create additional travel through-lanes that would generate a
potential increase in traffic and thus there would be no increase in air pollutant
emissions.
Comment 2-5:
In the report the wind speeds are incorrect. My family and I have lived and owned
these parcels since the 1940s and the winds are much higher than your report. This is
known by all residents to be an extremely windy area, especially in the late afternoon
including during “rush hour traffic.”
Response:
Comment noted. Further review of wind speeds in the Byron area indicates that
average wind speeds range from 7 mph in the winter months to 10 mph in the summer
months.
Comment 2-6:
The Biological Resource Section is in error. There are hawks that nest in the effected
trees along with other species of birds. Also, there are frogs in the area. Fish & Game
needs to provide a indept report. Also, less than a mile away there have been siting of
foxes. There is the possibility of eagles with a ½ mile radius.
Response:
The Biological Resources section (IV) of the CEQA Guidelines directs the evaluator to
determine if the project will have a substantial adverse effect, either directly or through
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
habitat modifications, on any species identified as a candidate, sensitive, or special
status species in local or regional plans, policies, or regulations, or by the California
Department of Fish and Wildlife or U.S. Fish and Wildlife Service and if the project will
interfere substantially with the movement of any native resident or migratory fish or
wildlife species or with established native resident or migratory wildlife corridors, or
impede the use of native wildlife nursery sites. As noted in the Biological Services
section of the CEQA document, Department of Fish and Wildlife (DFW) (formerly
Department of Fish and Game) special-status species database was reviewed by a
qualified biologist to determine the likelihood of species presence in the area. The CEQA
document identifies several raptors that may occur in the project area and notes that
surveys for nesting birds and raptors will be conducted prior to tree removals and start
of construction activities. If active nests are present, avoidance measures as outlined in
the CEQA document will be implemented. The CEQA document was submitted to the
DFW and no responses were received.
The constructed project will not permanently interfere with wildlife movements in the
area as the project is limited to road improvements and there are no features that
would potentially pose a barrier. However, construction activities may temporarily
inhibit dispersal, migration, and daily movement of common wildlife but it is not
anticipated considering its location within a heavily traveled road.
Further, the project is located within the East Contra Costa County Habitat Conservation
Plan/Natural Community Conservation Plan (HCP/NCCP) inventory area and is a covered
activity. The HCP/NCCP complies with Section 10(a)(1)(B) of the federal Endangered
Species Act administered by the U.S. Fish and Wildlife Service and the California Natural
Community Conservation Planning Act of 2003 administered by the California
Department of Fish and Wildlife (formerly Fish and Game). The HCP/NCCP is intended
to provide an effective framework to protect natural resources and special-status
species recovery in eastern Contra Costa County while improving and streamlining the
environmental permitting process for potential impacts on these species and associated
habitats. While the project is not anticipated to impact special-status species or suitable
habitat, the HCP/NCCP requires compensatory mitigation to the East Contra Costa
County Habitat Conservancy for both permanent and temporary impacts to
undeveloped lands and reporting applicable species-specific avoidance and minimization
measures that will be implemented. The mitigation fees will contribute to recovery of
special-status species and associated habitats within East Contra Costa County through
purchase and management of preserve lands.
Comment 2-7:
When the drainage ditch was inspected in this report it stated the ditch was dry. Well,
there has been a 4 year drought. What about the years when we have an abundance of
rainfall. This was not considered in the report. Therefore, the assertion in the report is
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
not accurate.
Response:
The Biological Resources section (IV) of the CEQA document reported observations
made at the time of the field visits and acknowledged that the drainage ditch is
ephemeral and likely only carries water during storm events where they receive both
direct precipitation and urban runoff.
Comment 2-8:
The Utilities & Service System section is in error when it states that no impact to comply
with federal, state, & local statu[t]es and regulations related to solid waste. The almost
60 year sewer system which is going to be relocated could produce serious effects to
property owners and the sewer district.
Response:
The sewer line system will not be relocated.
Comment 2-9:
I feel a NMPDES General Permit must be attained and a waiver is not acceptable. Also,
setback requirements have not been address in the report. I am very concerned about
15103 Byron Highway in regards to setback requirements.
Response:
The NPDES General Permit allows for a waiver to be issued if the project meets the
specific criteria which include soil disturbance between 1 and 5 acres and not exceeding
the erosivity value for the proposed construction period. Even if the project qualifies for
a waiver, CCCPWD will still be responsible for ensuring that best management practices
for water pollution control are identified and implemented during construction activities.
The reduction of the property would be assessed as part of the appraisal process.
Property owners impacted by the project would be able to request a variance from the
Contra Costa County Department of Conservation and Development considering the loss
is a result of this project.
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
COMMENT LETTER #3. MIKE NISEN (April 24, 2015)
Comment 3-1:
The California Air Resources Board (CARB) has implemented a “five minute idling rule”
for heavy construction equipment. Under most circumstances, the machines cannot idle
for more than five consecutive minutes under normal operations. This is stipulated
under Title 13, Sec. 2449(3)(a). The construction equipment engines have been
categorized as Tier 0, Tier 1, Tier 2, Tier 3, and Tier 4 by CARB. Tier 0 engines are the
oldest and emit more particulate matter (PM) which are basically a mixture of solids and
some liquid material. The tier 0 engines also produce more nitrogen oxide (NOx), which
is a gas produced when fuel is burned at high temperatures. The higher the tier rating,
the less of the PM and NOx produced from the engines. The state has scheduled a
timetable which mandates a complete turnover of construction equipment to tier 4
standards on a sliding scale process, depending on the size of the fleet. Not all
construction companies have had the opportunity to completely change their fleets over
to the newest machines yet, mainly due to economic reasons. Although all categories of
the machines are still allowed in use on most projects, I would suggest that only
equipment with tier 3 or tier 4 engines be allowed in use [at] the jobsite and stipulated
in the contract.
Comment 3-2:
The construction firm awarded the project should ensure that these vehicles all have
the proper certificate of reported compliance for truck and bus regulation issued by the
California EPA/Air Resources Board, and also should be stipulated in the contract.
Response:
As noted in the Air Quality section (III) of the CEQA document, estimated construction
emissions were analyzed and determined to be below the Bay Area Air Quality
Management District (BAAQMD), CEQA Air Quality Guidelines thresholds using an
approved model. It is the responsibility of the respective fleet companies to comply with
the CARB regulation. The County cannot impose these requirements as it could limit a
significant volume of the bidding pool to bid on the job because they did not have new
equipment. Imposing this requirement would be particularly restrictive given that the
project was determined not to exceed thresholds. In addition to air pollution control
measures identified for this project, the project contract specifications require the
contractor to comply with air pollution control rules, regulations, ordinances, and
statutes. Further, it will be the responsibility of the County’s on-site Resident Engineer
to ensure that the construction contractor and their subcontractors are in compliance
with the air pollution control requirements stipulated in the contract specifications. The
project site will also have air pollution complaint signs with contact numbers for the
County and BAAQMD if there are air quality concerns during construction.
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
Comment 3-3:
In the portion of the document entitled “Existing Traffic Conditions”, it is stated that
Byron Highway and Camino Diablo Road are heavily used truck and arterial routes. It
should be noted that efforts are presently underway to remove truck traffic off of
Camino Diablo entirely, except for local ingress and egress. Truck traffic is being routed
to Marsh Creek Road (State Route 4) via the Byron Highway and vice versa, due to the
adverse impact to the residents of Camino Diablo, the narrow configuration of the
roadway itself, the lack of consistent shoulders, and the deterioration of the pavement.
Response:
Comment noted.
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
COMMENT LETTER #4. DEBBIE NISEN (April 24, 2015)
Comment 4-1: The commenter states that she reviewed the CEQA document which
appears to be very thorough in addressing the environmental aspects at the site and
agrees and supports the Mitigated Negative Declaration. The commenter further states
that the project is very important to the Byron community considering that traffic
volume along with unsafe conditions at the intersection have made it very dangerous
especially during commute hours.
Response: Letter in support of this project is acknowledged. No further response is
necessary.
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
COMMENT LETTER #5. CENTRAL VALLEY REGIONAL WATER QUALITY
CONTROL BOARD (April 28, 2015)
Comment 5-1: The Central Valley Regional Water Quality Control Board (RWQCB)
states that their agency is delegated with the responsibility of protecting the quality of
surface and groundwaters of the state and as such their comments will address
concerns surrounding those issues. The RWQCB identifies various permits that may be
required for the project.
Response: The Biological Resources (IV) of the CEQA document notes that permits will
be obtained for impacts to the drainage area which is considered state (Regional Water
Quality Control Board) and federal (Army Corps of Engineers) jurisdictions, and the
Hydrology and Water Quality section notes that a NPDES General Permit for Storm
Water Discharges Associated with Construction and Land Disturbances [Order No. 2012-
0006-DWQ] will be obtained. No further response is necessary.
Mike N. Oliphant
Project Manager
Mining and Specialty
Portfolios
Chevron Environmental
Management Company
P.O. Box 6012
San Ramon, CA 94583
Tel (925) 790 6431
Fax (925) 790 6772
mike.oliphant@chevron.com
April 30, 2015 Stakeholder Communication – Contra Costa County
Ms. Claudia Gemberling
Environmental Analyst II
Contra Costa County Public Works Department
255 Glacier Drive
Martinez, California 94553
Subject: Comments on the Proposed Mitigated Negative Declaration for the
Byron Highway-Camino Diablo Road Intersection Improvements Project
Chevron Environmental Management Company
Historical Pipeline Portfolio–Bakersfield to Richmond
Dear Ms. Gemberling:
On behalf of Chevron Environmental Management Company (CEMC), Leidos Engineering LLC (Leidos; CEMC
contract consultant) recently reviewed the Proposed Mitigated Negative Declaration for the Byron Highway-
Camino Diablo Road Intersection Improvements Project (County File No. CP 15-01). The information contained in
this letter may help you in planning this project and to understand something about Chevron's former pipeline
operations in the unincorporated community of Byron in Contra Costa County, as residual weathered crude oil,
abandoned pipeline, and asbestos-containing materials (ACM) could potentially be encountered during subsurface
construction activities in these former pipeline rights of way (ROWs).
Portions of the former Old Valley Pipeline (OVP) and Tidewater Associated Oil Company (TAOC) pipelines
existed in the vicinity of the proposed project area. These formerly active pipelines were constructed in the early
1900s and carried crude oil from the southern San Joaquin Valley to the San Francisco Bay Area. Pipeline
operations for the OVP ceased in the 1940s, and in the 1970s for the TAOC pipelines. When pipeline operations
ceased, the pipelines were taken out of commission. The degree and method of decommissioning varied: in some
instances the pipelines were removed, while in others, they remained in place. Because these pipelines have been
decommissioned, with the majority of pipelines having been removed, they are not readily identified as
underground utilities through the Underground Service Alert North System or utility surveys. Figure 1 illustrates
the location of the former OVP and TAOC ROWs with respect to the proposed site overview plan. The location of
the pipelines shown on Figure 1 is based on historical as-built drawings and the approximated positional accuracy
of the alignments is generally +/- 50 feet. The OVP and TAOC pipelines were installed at depths of up to 10 feet
below ground surface. The steel pipelines were typically encased in a protective coating composed of coal tar and
ACM.
Working under the direction of State regulatory agencies, CEMC conducted risk assessments at numerous locations
with known historical crude-oil release points along the former OVP and TAOC pipelines. Analytical results from
these risk assessments indicated that the crude-contaminated soil was non-hazardous. Accordingly, it is likely that
Ms. Claudia Gemberling – Contra Costa County Public Works Department
April 30, 2015
Page 2 of 2
if soil affected by the historical release of crude oil from these former pipelines is encountered during construction
activities it may be reused as backfill on site. Properly abandoned crude-oil pipeline may be left in the ground.
Parties conducting construction activities in the vicinity of these former pipeline ROWs may wish to use the
information provided in this letter to help prepare for the possibility of encountering abandoned pipelines and
pipeline-related ACM during the course of their work.
For more information regarding these historic pipelines, please visit http://www.hppinfo.com/. If you would like
additional information, or would like to request more detailed maps, please contact Leidos consultants Mike Hurd
(michael.t.hurd@leidos.com) at (510) 466-7161 or Tan Hoang (tan.t.hoang@leidos.com) at (916) 979-3742.
Sincerely,
Mike Oliphant
MO/klg
Enclosure:
Figure 1. Historical Pipeline Rights of Way – Byron Highway-Camino Diablo Road Intersection Improvements
cc: Mr. Mike Hurd – Leidos
1000 Broadway, Suite 675, Oakland, California 94607
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!!!!!!!!!!!!!!!!! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !
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BYRON HIGHWAY-CAMINODIABLO ROAD INTERSECTIONIMPROVEMENTS 1DATE: 4/17/2015 ANALYST: HOANGTA FIGURE:Map is compiled from data sources that vary in accuracy; features may not be displayed in exact relationship to one another. Do not rely on map for legal information or underground work.I0 50 100
Feet
FILE: Q:\HPPBTR\MANAGEMENTSTRATEGY\POTENTIAL PROJECTS\CONTRA COSTA\BYRONCAMINODIABLOINTERSECTION\PROJECTS\FIGURE 1\PSEP_FIG1_BYRONCAMINO_2015_04.MXDXXXHistorical Old Valley Pipeline (OVP)
! ! !
Historical Tidewater AssociatedOil Company (TAOC) PipelineHISTORICAL PIPELINE RIGHTS OF WAY
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
COMMENT LETTER #6. CHEVRON ENVIRONMENTAL MANAGEMENT COMPANY
(April 30, 2015)
Comment 6-1: Leidos Engineering LLC, on behalf of Chevron Environmental
Management Company (CEMC), describes the background of inactive, historic crude-oil
pipelines within the project vicinity and identifies the approximate location of the former
Old Valley Pipeline (OVP) and Tidewater Associated Oil Company (TAOC) alignments
with respect to the project’s layout. Leidos further states that CEMC conducted risk
assessments at numerous locations within known historical crude-oil release points
along the former OVP and TAOC pipelines and analytical results have indicated that the
crude-contaminated soil was non-hazardous. If soil affected by the historical release of
crude oil from these former pipelines is encountered during construction activities it
may be reused as backfill on site. Parties conducting construction activities in the
vicinity of these former pipeline right-of-ways may wish to use the information provided
in the letter to help prepare for the possibility of encountering pipelines and pipeline-
related ACM during the course of their work.
Response: Comments noted. No further response is necessary.
INITIAL STUDY/MITIGATED NEGATIVE DECLARATION
CONTRA COSTA COUNTY PUBLIC WORKS DEPARTMENT
BYRON HIGHWAY-CAMINO DIABLO IMPROVEMENTS PROJECT (#0662-6R4094)
COUNTY CEQA FILE #: CP 15-01
COMMENT LETTER #7. GOVERNOR’S OFFICE OF PLANNING AND RESEARCH
(STATE CLEARINGHOUSE) (May 6, 2015)
1-1: Letter from Governor’s Office of Planning and Research, State Clearinghouse and
Planning Unit stating that the Initial Study Mitigated Negative Declaration (SCH#
2015042014) was submitted to selected state agencies for review and that comments
from the responding agencies are provided. The letter further states that a responsible
or other public agency shall only make substantive comments regarding those activities
involved in a project which are within an area of expertise of the agency or which are to
be carried out or approved by the agency. The State Clearinghouse received and
forwarded one comment letter; Central Valley Regional Water Quality Control Board
(Comment Letter #5).
RESPONSE: Acknowledgement letter from the State Clearinghouse is noted. No further
response is necessary.