HomeMy WebLinkAboutMINUTES - 12092003 - C35-C36 Recording Requested By: 111111
III I III II II II 111111 I III I IIII I IIII I II IIII II re 3%T
Contra Costa County Public works Dept. CONTRA COSTA Co Recorder Office
Maintenance Division STEPHEN L. WEIR Clerk-Recorder
255 Glacier Drive pp(;_ 200,3_0597$05-00
Martinez, CA 94553
Wednesday, DEC 10, 2003 11:50:13
Return to: FRE $0.00
Ttl Pd $0,00 Nbr=@061898278
WHEN RECORDED, RETURN TO THE 1 rc/R9/1-1
PUBLIC WORKS DEPARTMENT
BOARD OF SUPERVISORS, CONTRA COSTA COUNTY, CALIFORNIA, AS GOVERNING BOARD
OF THE FLOOD CONTROL AND WATER CONSERVATION DISTRICT
In the Matter of Accepting and Giving ) RESOLUTION OF ACCEPTANCE
Notice of Completion of Contract for ) and NOTICE OF COMPLETION
Wildcat Creek Basin 2003 Sedimentation ) (C.C. § 3086, 3093)
Removal Project )
Project No. 7527-6D9704-03 ) RESOLUTION NO. 2003/ 768
The Board of Supervisors of Contra Costa County RESOLVES that:
The County of Contra Costa on, contracted with Gilbert Excavating, Inc., for Wildcat Creek Basin 2003
Sedimentation Removal project in the North Richmond area,for work to be performed on the grounds of
the County; and
The Chief Engineer reports that said work has been inspected and complies with the approved plans,
special provisions and standard specifications and recommends its acceptance as complete as of
October 14, 2003.
Therefore, said work is ACCEPTED as completed on said date, and the Clerk shall file with the County
Recorder a copy of this Resolution and Notice as a Notice of Completion for said contract.
PASSED BY THE BOARD on December 9, 2003, by the following vote:
AYES: SUPERVISORS GIOIA, UILKEMA, GREENBERG, GLOVER AND DESAULNIER
NOES: NONE
ABSENT: NONE
CERTIFICATION AND VERIFICATION
hereby certify that this is a true and correct copy of an
action taken and entered on the minutes of the Board of
Contact: Mark de la O, 313-7012 Supervisors on the date shown.
Orig. Dept.:Public Works(Maintenance)
Recording to be completed by COB
cc: Auditor ATTESTED: DECKER 09, 2003
Public Works- Accounting JOHN SWEETEN, Clerk of the Board of Supervisors and
- Flood Control County Administrator
- Env., C.Sellgren
Gilbert Excavating, Inc.
MD:kd:lad By , Deputy
G:Mai nt\Kim\BO\BO 12-9
RESOLUTION NO. 2003/ 768
TO: BOARD OF SUPERVISORS,AS GOVERNING BOARD OF CONTRA COSTA COUNTY AND
CONTRA COSTA COUNTY FLOOD CONTROL AND WATER CONSERVATION DISTRICT
FROM: MAURICE M. SHIU, CHIEF ENGINEER
DATE: DECEMBER 9, 2003
SUBJECT: ADOPT the DA 33A Flood Facilities Improvement Project Mitigated Negative Declaration and
Mitigation Monitoring Program in compliance with the California Environmental Quality Act;
APPROVE the project and AUTHORIZE the Chief Engineer to advertise the project,Concord area.
[CDD-CP#03-41] (District IV) Project No. 7535-6F8472
Specific Request(s) or Recommend ation(s) & Background & Justification
I. RECOMMENDED ACTION:
FIND, on the basis of the DA 33A Flood Facilities Improvement Project Mitigated Negative Declaration
initial study and all comments received, that there is no substantial evidence that the project will have a
significant effect on the environment, and
ADOPT the Mitigated Negative Declaration and Mitigation Monitoring Program in compliance with the
California Environmental Quality Act,(the custodian ofwhich is the Community Development Director who
is located at 651 Pine Street, Martinez), and
DIRECT the Director of Community Development to file a Notice of Determination with the County Clerk,
and
Continued on Attachment: X SIGNATURE:
COMMENDATION OF COUNTY ADMINISTRATOR
RECOMMENDATION OF BOARD COMMITTEE
_,::�-APPROVE OTHER
000i� - A-V
SIGNATURE(S): Q,
ACTION OF BO r N DECEMBER 09, 2003 APPROVED AS RECOMMENDED Xx OTHER
VOTE OF SUPERVISORS
XX UNANIMOUS(ABSENT NONE
AYES: NOES: I hereby certify that this is a true and correct copy of an
ABSENT: ABSTAIN: action taken and entered on the minutes of the Board of
Supervisors on the date shown.
LC:sr
G:\GrpData\EngSvc\Enviro\BO\2003\(I 2-9-03)CEQA-DA33A.doc ATTESTED: DECEMBER 09, 2003
Orig.Div: Public Works(Eng Sery Division)
Contact: Leigh Chavez,Phone(925)313-2366 JOHN SWEETEN Clerk of the Board of Supervisors and
cc: Administrator-Attn: E.Kuevor County Administrator
Auditor-Controller
Community Development—K.Piona
Public Works: Accounting By Deputy
Construction-R.Bruno
Design-C.Standafer
Flood Control-K.Emigh
Engineering Services -L.Chavez,Enviro
SUBJECT: ADOPT the DA 33A Flood Facilities Improvement Project Mitigated Negative Declaration and
Mitigation Monitoring Program in compliance with the California Environmental Quality Act;
APPROVE the project and AUTHORIZE the Chief Engineer to advertise the project,Concord area.
[CDD-CP#03-41] (District IV) Project No. 7535-6F8472
DATE: December 9, 2003
PAGE: 2
I. RECOMMENDED ACTION (continued):
AUTHORIZE the Chief Engineer to arrange for payment of a $25 fee to Community Development for
processing, and a$25 fee to the County Clerk for filing the Notice of Determination.
DIRECT the Chief Engineer to arrange for the $1,250 Fish and Game filing fee to be transferred to the
County Clerk, and
APPROVE the DA 33A Flood Facilities Improvement Project, and
AUTHORIZE the Chief Engineer to advertise the project.
11" FISCAL IMPACT:
The estimated project cost is $600,000 funded by Drainage Area 33A funds.
111. REASONS FOR RECOMMENDATION/BACKGROUND:
The project includes construction of a detention basin,installation of road cross culverts,sediment removal
and construction of a floodwall or earthen berm along an unnamed creek identified as Line A of Drainage
Area 33A.
The project is necessary to provide 25-year storm protection to the surrounding area.
The project has been determined to be in compliance with the General Plan. A Mitigated Negative
Declaration of environmental significance pertaining to this proj ect was published on October 15,2003. The
Board has considered the Mitigated Negative Declaration together with all comments received during the
public review period.
IV. CONSEQUENCES OF NEGATIVE ACTION:
Delay in approving the project will result in a delay of design and construction and may jeopardize funding.
CONTRA PUBLIC WORKS DEPARTMENT
COSTA INITIAL STUDY
COUNTY OF ENVIRONMENTAL SIGNIFICANCE
PROJECT # 7535-6F8472
CP# 03-41
PROJECT NAME: DA 33A Flood Facilities Improvement Project
PREPARED BY: Leigh Chavez e/5 DATE: September 9, 2003
APPROVED BY: .00 DATE: 0
RECOMMENDATIONS:
( } Categorical Exemption (Class ) Negative Declaration
Environment Impact Report Required ( V) Mitigated Negative Declaration
The project will not have a significant effect on the environment. The recommendation is
based on the following: There is no substantial evidence that the project or any of its
aspects may cause a significant effect on the environment(Sec. 15063(b)(2)).
'd a&a
What changes to the project would mitigate the identified impacts. N/A
USGS Quad Sheet Clayton Quadrangle Base Map Sheet#J 179 K17 Parcel # N/A
GENERAL CONSIDERATIONS:
1. Location: The project is located on an unnamed creek that is a tributary to Mt.
Diablo Creek, near the Cities of Concord and Clayton. The project area is
bounded by Kirker Pass Road, Kirkwood Drive, Old Kirker Pass Road, and
Concord Boulevard (Fig. 1,2)
2. Project Description:
The project consists of construction of a detention basin, installation of road cross culverts,
sediment removal, and construction of a floodwall or earthen berm along an unnamed creek
identified as Line A of Drainage Area 33A. Line A is a tributary to Mt. Diablo Creek. Based on
the size of the watershed associated with this Drainage Area (less than 4 square miles), the
Flood Control District mandates 25-year flood protection at this location. The existing facilities
do not currently provide 25-year flood protection; therefore, the purpose of the project is to
provide the mandated level of flood protection through a variety of facility improvements. All of
the improvements will be constructed such that impacts to the existing creek channel and
vegetation are minimized. This project description addresses the various project components
starting with the furthest upstream improvement and progressing through the downstream
improvements (see Figure 3):
GAGrpData\EngSvc\ENV1R0\2003 Projects\DA 33A\Initial Study.doc2003Prpjects1DA33A\1 n itial Study
Page 1 of 3
1) Detention Basin: in order to construct the basin, approximately 17,000 cubic yards of
material will be excavated from a benched area located adjacent to the existing creek. All of the
excavation necessary to construct the basin will occur on the northwest bank of the drainage
-channel. A roughly 5-foot wide berm will be maintained between the creek and the excavation
area. At the far downstream end of the detention basin, a short break in the berm will allow the
water in the floodplain to reenter the creek such that ponding does not occur. The bank above
the channel will be graded at a 3:1 slope, creating a much wider and more gradually sloped
creek bank than currently 'exists. The weir structure at the downstream end of the basin will be
reconstructed and an embankment or small concrete bridge will be constructed outside of the
creek zone to provide access to the structure.
2) Culvert Maintenance under Kirker Pass Road and Desilting within Channel: at this location,
debris and silt that is currently clogging the existing culvert under Kirker Pass Road will be
removed to daylight the culvert, and an approximately 250-foot length of the channel
downstream of the culvert will be desilted. Once the excess silt is removed from the drainage, a
low-flow channel will be created in this section of the creek.
3) Culvert Replacement under Old Kirker Pass Road: the 48" culvert under Old Kirker Pass
Road will be replaced with a new 7211 culvert (or two side-by-side 48" culverts). During
replacement, the upstream invert of the pipe will be lowered by approximately two feet to ensure
effective hydraulics. A headwall will be constructed at the pipe inlet and rock slope protection
will be installed for energy dissipation at the pipe outlet. In order to replace the existing culvert,
the roadway will be excavated, the old culvert removed, and the new culvert placed in the same
location as the old culvert. Minor excavation up and downstream of the culvert will be required
to place the new pipe.
4) Culvert Replacement under Concord Boulevard: the existing 6099 culvert under Concord
Boulevard will be replaced with a new 72" culvert (or two side-by-side 48" culverts) that is
approximately 30 feet longer than the existing culvert. A wing wall will be constructed at the inlet
of the pipe and rock slope protection will be provided for energy dissipation at the pipe outlet.
The additional 30-foot length of culvert is necessary since the existing pipe does not extend the
full width of the road right of way, causing the road to narrow at this location. Increasing the
length of the culvert by 30 feet will allow the pipe to daylight outside the road right of way;
thereby allowing the constricted roadway at this location to be increased to a width that is
consistent with the rest of the roadway. Fill will be placed over the culvert in order to
accommodate the widened roadway. Minor excavation up and downstream of the culvert will be
required to place the new pipe.
5) Construction of Floodwall: downstream of Concord Boulevard a roughly 315' long, 3' high
flood wall or earthen berm will be constructed in the upland area around the creek to direct high
flows into the existing 8411 reinforced concrete pipe.
The Flood Control District will also conduct routine and ongoing maintenance in the basin and
channel area. Maintenance activities likely to be necessary in the project area consist of debris
and cattail removal and weed abatement activities with hand-held equipment, and limited silt
removal from the basin area. Based on the high level of build-out in the watershed, any silt
removal ultimately necessary for the basin is expected to be minimal and sporadic. Potential silt
removal in the basin will not necessitate the removal of any trees including any of the mitigation
plantings since the planting plan will provide for an appropriate access point.
G:\GrpData\EngSvc\ENVIR012003 Projects\DA 33A\Initial Study.doc2003PrpJ ects\DA33A\l n itial Study
Page 2 of 3
The project lies within the boundaries of the City of Concord. Real Property transactions may
be necessary between the District and the City as well as the District and private property
owners adjacent to the project. Construction of the floodwall will require Real Property
transactions with the property owner of APN 117-014-050.
3. Does it appear that any feature of the project will generate significant
public concern? [] yes [✓ ] no [] maybe (Nature of concern):
4. Will the project require approval or permits by other than a County agency?
[v' ] yes [ ] no Agency Name(s): U.S. Army Corps of Engineers (including
consultation with U.S. Fish and Wildlife Service), California Department of Fish
and Game, Regional Water Quality Control Board, City of Concord
5. Is the project within the Sphere of Influence of any city? Yes, the City of
Concord
GAGrpData\EngSvc\ENV1RO\2003 ProjectsTA 33A\Initial Study.doc2003 Proj ects\DA33A\l n itia I Study
Page 3 of 3
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Environmental Checklist Form
1. Project Title: DA 33A Flood Facilities Improvements Project
2. Lead Agency Name and Address: Contra Costa County
Community Development Department
651 Pine Street
Martinez, CA 94553
3. Contact Person and Phone Number: Leigh Chavez, Planner III
(925) 313-2366
Contra Costa County Public Works Department
255 Glacier Drive
Martinez, CA 94553
4. Project Location: The project is located on an unnamed creek
tributary to Mount Diablo Creek near the Cities
of Concord and Clayton. The project area is
bounded by Kirker Pass Road,, Kirkwood Drive,
Old Kirker Pass Road, and Concord Boulevard.
5. Project Sponsor's Name and Address: Contra Costa County Public Works Dept.
255 Glacier Drive
Martinez, CA 94553
6. General Plan Designation: Multiple: (Open Space, Multiple Family
Residential - Medium Density, Single Family
Residential - High Density)
7. Zoning: Public/Semi-public
8. Project Description:
The project consists of construction of a detention basin, installation of road cross culverts, sediment
removal, and construction of a floodwall or earthen berm along an unnamed creek identified as Line A of
Drainage Area 33A. Line A is a tributary to Mt. Diablo Creek. Based on the size of the watershed
associated with this Drainage Area (less than 4 square miles), the Flood Control District mandates 25-
year flood protection at this location. The existing facilities do not currently provide 25-year flood
protection; therefore, the purpose of the project is to provide the mandated level of flood protection
through a variety of facility improvements. All of the improvements will be constructed such that impacts
to the existing creek channel and vegetation are minimized. This project description addresses the
various project components starting with the furthest upstream improvement and progressing through
the downstream improvements (see Figure 3):
1) Detention Basin: in order to construct the basin, approximately 17,000 cubic yards of material will be
excavated from a benched area located adjacent to the existing creek. All of the excavation necessary
to construct the basin will occur on the northwest bank of the drainage channel. A roughly 5-foot wide
berm will be maintained between the creek and the excavation area. At the far downstream end of the
detention basin, a short break in the berm will allow the water in the floodplain to reenter the creek such
that ponding does not occur. The.bank above the channel will be graded at a 3:1 slope, creating a much
wider and more gradually sloped creek bank than currently exists. The weir structure at the downstream
end of the basin will be reconstructed and an embankment or small concrete bridge will be constructed
outside of the creek zone to provide access to the structure.
Page 1 of 25
2) Culvert Maintenance under Kirker Pass Road and Desi!ting within Channel: at this location, debris and
silt that is currently clogging the existing culvert under Kirker Pass Road will be removed to daylight the
culvert, and an approximately 250-foot length of the channel downstream of the culvert will be desilted.
Once the excess silt is removed from the drainage, a low-flow channel will be created in this section of
the creek.
3) Culvert Replacement under Old Kirker Pass Road: the 48" culvert under Old Kirker Pass Road will be
replaced with a new 7211 culvert (or two side-by-side 48" culverts). During replacement, the upstream
invert of the pipe will be lowered by approximately two feet to ensure effective hydraulics. A headwall
will be constructed at the pipe inlet and rock slope protection will be installed for energy dissipation at the
pipe outlet. In order to replace the existing culvert, the roadway will be excavated, the old culvert
removed, and the new culvert placed in the same location as the old culvert. Minor excavation up and
downstream of the culvert will be required to place the new pipe.
4) Culvert Replacement under Concord Boulevard: the existing 6011 culvert under Concord Boulevard will
be replaced with a new 7291 culvert (or two side-by-side 48" culverts) that is approximately 30 feet longer
than the existing culvert. A wing wall will be constructed at the inlet of the pipe and rock slope protection
will be provided for energy dissipation at the pipe outlet. The additional 30-foot length of culvert is
necessary since the existing pipe does not extend the full width of the road right of way, causing the
road to narrow at this location. Increasing the length of the culvert by 30 feet will allow the pipe to
daylight outside the road right of way; thereby allowing the constricted roadway at this location to be
increased to a width that is consistent with the rest of the roadway. Fill will be placed over the culvert
extension to accommodate the widened roadway. Minor excavation up and downstream of the culvert
will be required to place the new pipe.
5) Construction of Floodwall: downstream of Concord Boulevard a roughly 315' long, 3' high flood wall or
earthen berm may be constructed in the upland area around the creek to direct high flows into the
existing 84" reinforced concrete pipe.
The project lies within the boundaries of the City of Concord. Real Property transactions may be
necessary between the District and the City as well as the District and private property owners adjacent
to the project. Construction of the floodwall will require Real Property transactions with the property
owner of APIA 117-014-050.
The Flood Control District will also conduct routine and ongoing maintenance in the basin and channel
area. Maintenance activities likely to be necessary in the project area consist of debris and cattail
removal and weed abatement activities with hand-held equipment, and limited silt removal from the
basin area. Based on the high level of build-out in the watershed, any silt removal ultimately necessary
for the basin is expected to be minimal and sporadic. Potential silt removal in the basin will not
necessitate the removal of any trees including any of the mitigation plantings since the planting plan will
provide for an appropriate access point.
9. Surrounding Land Uses and Setting:
The project is located in the City of Concord, in the central County area. The project extends
approximately 1800 feet upstream of Kirkwood Drive in the east, to 1000 feet downstream from Concord
Boulevard in the west. The unnamed creek is a perennial tributary of Mount Diablo Creek. Urban run-
off enters the creek via numerous outfalls within the study area and the perennial nature of the stream is
believed to be due to irrigation. Within the study area, the unnamed creek flows through residential and
commercial sections of Concord. Adjacent land uses include residential, commercial and community
facilities.
Page 2 of 25
10. Other public agencies whose approval is U. S. Army Corps of Engineers (including
required (e.g., permits, financing consultation with U. S. Fish and Wildlife
approval, or participation agreement): Service), S. F. District of the Regional
Water Quality Control Board, and the
California Department of Fish and Game,
City of Concord
ENVIRONMENTAL FACTORS POTENTIALLY AFFECTED:
The environmental factors checked below would be potentially affected by this project, involving at least
one impact that is a "Potentially Significant Impact" as indicated by the checklist on the following pages.
Land Use& Planning Transportation/Circulation Public Services
Utilities &Service
Population & Housing Biological Resources Systems
Geological Problems Energy& Mineral Resources Aesthetics
Hydrology Hazards Cultural Resources
Air Quality Noise Recreation
Mandatory Findings of No Significant
Significance Impacts Identified
Page 3 of 25
DETERMINATION
On the basis of this initial evaluation:
I find that the proposed project COULD NOT have a significant effect on the environment, and a NEGATIVE
DECLARATION will be prepared.
I find that although the proposed project could have a significant effect on the environment, there will not be a
significant effect in this case because the mitigation measures described on an attached sheet have been
added to the project. A MITIGATED NEGATIVE DECLARATION will be prepared.
I find that the proposed project MAY have a significant effect on the environment, and an ENVIRONMENTAL
IMPACT REPORT is required.
I find that the proposed project MAY have a significant effect(s) on the environment, but at least one effect (1)
has been adequately analyzed in an earlier document pursuant to applicable legal standards, and (2) has been
addressed by mitigation measures based on the earlier analysis as described on attached sheets, if the effect is
a "potentially significant impact" or "potentially significant unless mitigated." An ENVIRONMENTAL IMPACT
REPORT is required, but it must analyze only the effects that remain to be addressed.
I find that although the proposed project could have a significant effect on the environment, there WILL NOT be
a significant effect in this case because all potentially significant effects (a) have been analyzed adequately in
an earlier E,IR pursuant to applicable standards and (b) have been avoided or mitigated pursuant to that earlier
EIR, including revisions or mitigation measures that are imposed upon the proposed project.
0,5
/�ez
Signature,0` Date
Contra Costa County
/ao 'A V1 cro Community Development Department
Print Name
Page 4 of 25
SOURCES
In the process of preparing the Checklist and conducting the evaluation, the following references (which
are available for review at the Contra Costa County Community Development Department, 651 Pine
Street 5th Floor-North Wing, Martinez)were consulted:
1. Contra Costa Resource Mapping System - Quad Sheet Panels - Clayton, CA
2. The (Reconsolidated) County General Plan (July 1996) and EIR on the General Plan
(January 1991)
3. Contra Costa County Important Farmland Map 1999, California Department of Conservation
Division of Land Resources Protection
4. Field reviews by Public Works staff and EIP Associates and/or Project Description
(including coordination with Design Engineer)
5. Special-Status Wildlife Habitat Assessment, DA 33A Detention Basin Project, Contra Costa
County, California. Prepared by BioSearch Wildlife Surveys for Contra Costa County Public
Works Dept. December 2000.
6. Wetland Delineation Report for DA 33 A — Kirker Basins. Prepared by EIP Associates, Inc.
for Contra Costa County Public Works Dept. February 2001.
7. Confirmation of Wetland Delineation, US Army Corps of Engineers, Calvin C. Fong, Corps
File No. 260895, July 2, 2001
8. Memorandum — Special-Status Invertebrates Habitat Assessment for Kirker Basin. Prepared
by EIP Associates, Inc. for Contra Costa County Public Works Dept., January 2001.
9. Results of Bat Habitat Assessment, DA 33A Flood Facilities Improvement Project, Wildlife
Research Associates, G. Tatarian, August 13, 2003.
10. September 13, 2000 Letter from the Northwest Information Center to Trina Torres Re: DA
33A Detention Basin (7535-6D8472).
11. Contra Costa County Flood Insurance Rate Zone Information Map, 2001
12. Contra Costa County Soils Report, Soil Conservation Service, 1977.
Page 5 of 25
EVALUATION OF ENVIRONMENTAL IMPACTS:
Potentially
Significant
Potentially Unless Less than
Significant Mitigation Significant
Impact Incorporation Impact No Impact
1. AESTHETICS. Would the proposal:
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, which would adversely affect day or
nighttime views in the area? V/
SUMMARY: Significant Unless Mitigation Incorporation. The project has been designed to cause as little
physical disturbance as possible while still providing for the appropriate 25-year storm protection
mandated by the size of the watershed (i.e., less than 4 square miles). In order to minimize impacts to
the riparian corridor at the proposed detention basin location, no excavation will occur along the entire
southeast bank of the channel and all riparian vegetation along this bank will be retained. In addition,
the majority of the riparian wetland habitat and riparian woodland habitat along the northwest bank will
be retained through establishment of a buffer zone defined by a five-foot wide berm at the edge of the
riparian band that will run the length of the proposed basin until it ties into the Kirker Pass Road culvert
at the far downstream end of the basin. This buffer zone will be delineated through the use of
Environmentally Sensitive Area fencing (highly visible orange construction fencing). ESA fencing will
also be installed in other sensitive areas to ensure impact is minimized.
Although every effort will be made to retain the maximum number of trees in place as feasible,
construction of the flood control improvements will result in the removal of approximately 18 native trees
and 10 non-native trees. The vegetation within the area of the proposed detention basin that will require
removal consists of approximately eight non-native orchard trees (almonds), approximately eight valley
oak trees (Quercus lobata) ranging in size from a minimum of 2" dbh to a maximum of 16" dbh (diameter
at breast height), and approximately seven willow trees ranging in size from 6" dbh to 16" dbh. The
vegetation within the area of the channel desilt consists or sparse riparian vegetation at the upstream
end of the channel becoming dense toward the middle and downstream end of the channel. In order to
minimize impacts to the riparian corridor, excavation of the silted area will be conducted where feasible
with the use of a long-reach excavator, allowing the equipment to operate from the top of bank rather
than within the bed or on the banks of the channel or through the use of a small Bobcat tractor that will
be lowered into the creek. These methods of excavation as well as the location of the excavation will
ensure that only minor tree removal will be required. Excavation in the channel is expected to require
the removal of two small willows (2" dbh and 3" dbh). In order to further ensure tree impact is minimized,
excavation activities will work around the base of large trees located in the bed of the channel leaving
their root structure intact to the extent feasible. Two non-native locust trees may require removal at the
Old Kirker Pass Road culvert location and one willow (8" dbh) may require removal at the Concord
Boulevard culvert extension location.
Page 6 of 25
In order to mitigate for trees removed as a result of the detention basin construction, the channel
desilting, and the culvert work, trees will be replaced at a ratio negotiated between the District and the
resource agencies that have jurisdiction over the riparian habitat (e.g., California Department of Fish and
Game). A total of 18 native trees and 10 non-native trees are expected to be removed as a result of the
project. Since the majority of trees on the project site will be retained and supplemental trees will be
planted to replace the trees removed, significant aesthetic impacts as a result of the project are not
expected. A representative from the PWD will be on-site during tree removal to document the number
and species of trees removed. Tree replacement will occur during the late fall or early winter of the year
construction is completed.
When construction activities are in close proximity to trees that are specified to remain, protective
measures will be implemented. These measures will include protecting the trunks from damage by
equipment, clean trimming of roots and limbs, and prohibiting the stockpiling of dirt or storage of
equipment under the drip line. The protective measures will be included within the construction
specifications.
Construction activities will be visible by users of Kirker Pass Road and from the immediately surrounding
area; however, construction is temporary and is not expected to cause significant aesthetic impacts. All
disturbed areas will be seeded with native grass and wildflower species. Construction activities are not
expected to occur at night, therefore, supplemental lights will not be necessary. The flood control basin
and channel will not require a lighting source once construction is completed. Routine maintenance
activities (i.e., debris and cattail removal, weed abatement, and minor silt removal) will be conducted on
an as-needed basis. Based on the amount of build-out in the area, silt removal is only expected to be
necessary every few years. These routine maintenance activities are not expected to cause a significant
aesthetic impact. No trees will be removed as a result of routine maintenance activities.
Potentially
Significant
Potentially Unless Less than
Significant Mitigation Significant
Impact Incorporation Impact No Impact
11. AGRICULTURAL RESOURCES. In determining
whether impacts to agricultural resources are
significant environmental effects, lead agencies
may refer to the California Agricultural Land
Evaluation and Site Assessment Model (1997)
prepared by the California Dept. of Conservation
as an optional model to use in assessing impacts
on agricultural and farmland. 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. Involve other changes in the existing
environment, which, due to their location or
nature, could result in conversion of Farmland,
to non-agricultural use? ✓
Page 7 of 25
SUMMARY: No Impact. The project will not affect any locally or statewide important farmland. The land
immediately adjacent to the project consists of roadways, residential areas, commercial properties, and
community facilities. The Contra Costa County Important Farmland Map (1988) identifies the project as
being entirely within an area designated as "Urban and Built-up Land". In addition, the County Resource
Mapping System did not identify any agricultural preserves in the immediate area. The proposed project
area is not currently used for agricultural purposes.
Potentially
Significant
Potentially Unless Less than
Significant Mitigation Significant
Impact Incorporation Impact No Impact
Ill. AIR QUALITY. Where available, the significance
criteria established by the applicable air quality
management or air pollution control district may be
relied upon to make the following determinations.
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 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?
SUMMARY: Less Than Significant Impact. Short-term emissions and objectionable odors may be
generated during construction; however, they will be minor and temporary. To minimize impacts due to
construction activities, contract specifications will stipulate the use of properly tuned and muffled
equipment and the elimination of unnecessary idling of equipment when not in use. Implementation of
dust control practices including general watering of exposed areas and/or use of chemical stabilizers will
also be utilized to minimize air quality impacts. The minor temporary deterioration of ambient air quality
during construction will end once construction is completed; therefore, there will be no potentially
adverse long-term impacts to air quality. Periodic maintenance visits will not contribute significantly to
the deterioration of air quality since maintenance would involve only widely distributed vehicle trips on an
as needed basis.
Page 8 of 25
Potentially
Significant
Potentially Unless Less than
Significant Mitigation Significant
Impact Incorporation Impact No Impact
IV. BIOLOGICAL RESOURCES. 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,
polices, or regulations, or by the California
Department of Fish and Game 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 Game or US 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? ✓
SUMMARY: Potentially Significant Unless Mitigation Incorporated. A Habitat Assessment of the DA
33A project site was conducted by BioSearch Wildlife Surveys to characterize the habitats present on-
site and the likelihood of special status species occurring on the project site. According to the special-
status wildlife habitat assessment report, the California red-legged frog (Rana aurora draytonfi) is the
only listed species with a likelihood of utilizing the project site since, although breeding habitat for red-
legged frog is not present at the project site, potential foraging and sheltering habitat is present. Based
on this determination by the biologist, environmental staff from the County met with a staff biologist from
the US Fish and Wildlife Service (D. Hankins, USFWS, 12/00) to review the project site. Since a known
breeding site is located within 1/4 mile of the proposed project, and dispersal from that and other locations
is possible, the biologist determined that formal consultation would be necessary to ensure the species
is protected. Therefore, the County has initiated formal consultation through the U.S. Army Corps of
Engineers Nationwide Permit Program.
Page 9 of 25
As a result of the consultation, the County will implement a number of avoidance and minimization
measures during construction activities. These measures are likely to include: 1) installation of silt
fencing or other sediment barriers to prevent soil from entering the creek during construction, 2) proper
maintenance of heavy equipment working near the water to ensure oils and other deleterious fluids do
not leak and enter the creek, 3) conducting the work during the dry summer months, and 4) retention of
a qualified biologist (approved by U.S. Fish and Wildlife Service) to survey the project site and adjacent
areas prior to the start of construction. As part of the formal consultation, an incidental take permit will
be issued by USFWS for the project site. The take permit will require the County to notify USFWS if
California red-legged frogs are identified at the project site, and will allow for relocation of the identified
frogs to a safe location outside of the work zone.
Construction of the basin will actually create higher quality and more plentiful red-legged frog habitat
than currently exists on the project site since the existing steep creek banks will be graded back at a
gradual 3:1 slope and the banks planted with native riparian species. This gradual slope will create a
floodplain area that is expected to develop into riparian wetland similar to the habitat currently localized
immediately around the existing narrow creek. The basin will be designed to drain rapidly to ensure
impounded water does not create a bullfrog breeding ground. As a result of the creation of this riparian
wetland bench, temporary impacts to red-legged frog habitat due to the project will be mitigated.
Based on the implementation of appropriate avoidance and minimization measures, the issuance of and
compliance with the incidental take permit with conditions to protect red-legged frog, and the creation of
a riparian wetland bench that will mitigate the temporary habitat impacts as a result of project
construction, impacts to red-legged frogs as a result of the project will be less than significant.
Since the project will actually improve the habitat for red-legged frog, future maintenance activities must
take into account the potential for impacts to the species. Therefore, prior to conducting maintenance
activities, a preconstruction survey will be conducted by a qualified biologist to ensure red-legged frogs
are not in the project area. If red-legged frogs are identified during the preconstruction survey, contact
with USFWS will be initiated and the individuals identified will not be moved without FWS authorization.
In addition, in order to further ensure impacts are minimized, maintenance activities within the basin and
channel will be minimized to the extent feasible. Any cattail, debris, or weed removal necessary will be
conducted through the use of hand held equipment rather than mechanical mowing and silt removal will
be conducted only on an as-needed basis with no tree removal authorized.
Suitable nesting habitat is present at the project site for Cooper's hawk (Accipiter cooperi), loggerhead
shrike (Lanius ludovicianus) and yellow warbler (Dendroica petechia), all California Species of Special
Concern. In order to ensure these species are not impacted by the project, the County will either: 1) trim
and/or remove all trees that will be impacted by the project in the late fall or winter of the year prior to
construction, or 2) conduct preconstruction surveys for these species prior to construction. If the second
option is chosen and nesting birds are identified during the surveys, construction will be delayed until the
young have fledged. In addition, if feasible, excavation activities will be initiated after mid-July to
minimize the potential for impacts to nesting birds.
The Habitat Assessment indicated that roosting and foraging habitat is potentially present on-site for
several bat species. Based on the potential habitat presence, the County hired a bat specialist to
conduct a bat habitat survey of the project site. According to the bat specialist (G. Tatarian, Wildlife
Research Associates, 8/03), there is some potential, albeit marginal, foliage roosting habitat in the
impact area for a variety of bat species possibly including pallid bat (Antrozous pallidus), Yuma myotic
(Myotis yumanensis), fringed myotic (Myotis thysanodes), California myotis (Myotis califomicus), big
brown bat (Eptesicus fuscus), Mexican free-tailed bat (Tadarida brasiliensis), western red bat (Lasiurus
blossevillfi), and hoary bat (Lasiurus cinereus). However, foliage-roosting bats do not colonize and they
do not roost in cavities where they might become trapped as a result of limb trimming or tree removal,
therefore, impacts to bats as a result of the project are not expected to be significant. If it becomes
necessary to trim or remove trees that are greater than 18" diameter breast height (dbh), limb removal
Page 10 of 25
will be conducted in two stages over two days: limbs without cavities will be removed on the first day,
and limbs with cavities will be removed on the second day. Conducting tree removal in two stages will
allow bats to escape, minimizing impacts associated with the project to a less than significant level.
The project has been specifically designed to avoid impact to the riparian habitat at the project site to the
extent possible while still meeting the flood control goals of the project. In order to minimize impacts to
the riparian corridor at the proposed detention basin location, no excavation will occur along the entire
southeast bank of the channel and all riparian vegetation on the southeast bank will be retained. In
addition, the majority of the riparian wetland and riparian woodland habitat along the northwest bank will
be retained through establishment of a buffer zone defined by a five-foot wide berm at the edge of the
riparian band. This buffer zone will be delineated through the use of Environmentally Sensitive Area
fencing (highly visible orange construction fencing). The vegetation within the area of the proposed
detention basin that will require removal consists of approximately eight non-native orchard trees
(almonds), approximately eight valley oak trees (Quercus lobata) ranging in size from a minimum of 2"
dbh to a maximum of 16" dbh (diameter at breast height), and approximately seven willow trees ranging
in size from 6" dbh to 16" dbh. The habitat in the creek channel downstream of Kirker Pass Road
consists of sparse riparian vegetation at the upstream end of the channel becoming moderately dense
toward the middle and dense at the downstream end of this portion of the channel. Vegetation in the
area includes species such as willow, oaks, and some non-native orchard trees. The majority of these
trees are located on the southern side of the channel outside the area slated for desilting. In order to
minimize impacts to this riparian corridor, excavation of the silted area will be conducted primarily
through the use of either a long reach excavator, allowing the heavy equipment to operate from the top
of bank rather than within the bed or banks of the channel or a small Bobcat tractor that will be lowered
into the bed of the channel. These methods of excavation as well as the location of the excavation will
ensure that only minor tree removal will be required. In addition, in order to further ensure tree removal
is minimized, excavation activities (with the long reach excavator and/or Bobcat tractor)will work around
large trees located in the bed of the channel leaving their root structures intact to the extent feasible. It
is expected that the necessary desilting can be accomplished with the removal of approximately two
small willow trees ranging in size from 2" dbh to 3" dbh. One to two non-native locust trees may require
removal in order to replace the existing culvert under Old Kirker Pass Road and one native willow may
require removal in order to install the Concord Boulevard culvert extension. Riparian vegetation at the
proposed floodwall location is sparse and the majority of the vegetation consists of non-native trees
including Monterey pine, eucalyptus and English walnut. No tree removal is expected to be necessary in
order to install the floodwall.
In order to mitigate for riparian trees removed, replacement trees will be planted at the basin location at
a ratio negotiated between the District and the resource agencies that have jurisdiction over the riparian
habitat (e.g., California Department of Fish and Game). A total of 18 native and 10 non-native trees are
expected to be removed from the riparian zone as a result of the project. Staff from the District's
Environmental Section will be present at the project site during tree removal to ensure the number of
trees removed is documented for mitigation purposes. All replacement trees will be planted in the newly
excavated detention basin. The newly planted trees will be maintained for a period of three years and
monitored annually for a period of five years. At the conclusion of the five-year monitoring period, the
replacement trees will be required to meet the success criteria negotiated during the permitting process.
If the survival rate has not been achieved, additional plantings will occur, and monitoring will be extended
for an additional year.
Orange construction fencing will be installed to delineate the limits of construction. The fencing will
serve to isolate environmentally sensitive areas (ESAs) from construction activities. The ESA fencing will
be installed at the expected limits of construction impact as delineated on the construction plans. In
order to minimize damage to additional trees that may be affected by construction, contract
specifications will include protective measures such as clean trimming of roots and limbs. Construction
activities will also affect non-native annual grasses. Areas exposed as a result of the grading activities,
will be seeded with a mix including native grasses and wildflowers.
Page 11 of 25
A Section 404 Clean Water Act Jurisdictional Delineation was conducted by EIP Associates, and
confirmed by the United States Army Corps of Engineers on July 2, 2001. Activities associated with
construction of the project will occur within California Department of Fish and Game, RWQCB, and
Corp's jurisdiction, and the project will require fill within Corps jurisdiction in order to install the
replacement culverts. County staff will coordinate with staff from the resource agencies regarding the
project, and the appropriate agreements and permits will be obtained prior to implementation of the
project. The County will comply with all conditions negotiated during the permit acquisition process.
Potentially
Significant
Potentially Unless Less than
Significant Mitigation Significant
Impact Incorporation Impact No Impact
V. CULTURAL RESOURCES. 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
geologic feature? ✓
Disturb any human remains, including those
interred outside of formal cemeteries? ✓
SUMMARY: Less Than Significant Impact. A records search conducted by the Northwest Information
Center (NW IC) at Sonoma State University indicated a low possibility of identifying Native American
resources in the project area. The NW IC researcher recommended that no further archival and field
study by an archaeologist be conducted. Nevertheless, construction contract specifications for the
project will include measures related to discovery of cultural resources, including informing personnel
connected with the project of the possibility of finding archaeological and/or historical resources,
requiring notification of the Resident Engineer in the event of a discovery, and retention of a cultural
resources consultant to provide assistance in the event of a discovery. In addition, the Resident
Engineer for the project will receive instruction regarding identification of archaeological and historical
resources in the field. In particular, the specifications will require work to be halted in the event of an
archaeological discovery within 85 feet of the discovery. An archaeological consultant shall be
contacted and he/she shall inspect the site before advising the resident engineer to authorize further
work.
Page 12 of 25
Potentially
Significant
Potentially Unless Less than
Significant Mitigation Significant
Impact Incorporation Impact No Impact
VI. GEOLOGY AND SOILS. 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 of Mines and
Geology Special Publication 42. ✓
2. Strong seismic ground shaking? ✓
3. Seismic-related ground failure, including
liquefaction? V/
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? ✓
SUMMARY: Less Than Significant Impact. Grading and excavation associated with the detention
basins and channel improvements will result in a minor change in topography and temporarily increase
the exposure of soils to wind erosion. However, this is a less than significant and temporary impact.
Adherence to standard dust control and erosion control practices, including, but not limited to, general
watering of exposed areas and/or use of chemical stabilizers will minimize impacts. Contract
specifications will require the installation of silt fencing or other effective sediment barrier below the limits
of excavation to prevent soil from entering the creek due to construction activities. These measures will
be incorporated into the construction contract.
Exposure of people or property to geologic hazards is not expected to increase as a result of the project.
The site soils and nearby faults lines have been accounted for in the design process and the flood
facilities improvements will be designed to handle the Maximum Credible Earthquake (MCE) event
(California Seismic Hazard Map, 1996). The MCE event is the largest earthquake reasonably expected
to impact the structure based on recorded data.
Page 13 of 25
Superficial grading of the project area is not expected to result in unstable earth conditions or change
geologic substructures. Exposure of people or property to geologic hazards is not expected to occur as
a result of the project. In order to stabilize exposed soils, all areas left exposed due to construction of
the flood facilities will be seeded with a mix that includes native grasses and wildflowers upon completion
of the project.
Potentially
Significant
Potentially Unless Less than
Significant Mitigation Significant
Impact Incorporation Impact No Impact
VII. HAZARDS AND HAZARDOUS MATERIALS.
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 65862.5 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 interferes
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 wildland fires,
including where wildlands are adjacent to
urbanized areas or where residences are
intermixed with wildlands? ✓
Page 14 of 25
SUMMARY: Less Than Significant Impact. The project has the potential to release hazardous
substances, such as accidental petroleum spills from equipment, during construction. Per the contract
specifications, standard construction safety practices will be followed during construction to ensure no
accidental release of hazardous substances occurs and no increase in the potential for exposure to
these substances occurs.
Two sets of high-tension power lines cross over the project site. These power lines are being accounted
for in project design and the contractor will be notified of the need to avoid these utilities. Plans and
specifications for the project will identify these and any other similar facilities identified during project
design as "high risk facilities".
No interference with an emergency evacuation or response is expected to result from the project. The
majority of the work will occur within the detention basin area, within the channel, and at the culvert
replacement locations. Traffic control measures around the work area will minimize the potential for
accidents and specifications for the project will require installation of sufficient warning signs regarding
the construction and associated work hours. In the location of the culvert extension under Concord
Boulevard, traffic control measures will be enforced to ensure the work is conducted in a safe and
efficient manner while maintaining two 10-foot lanes at all times to minimize traffic delays.
Approximately 20 truck trips per hour will be required during basin excavation activities in order to allow
for off-haul of the soil excavated from the detention basin location. In order to ensure trucks are able to
enter and exit the project site safely, flaggers will be required on Kirker Pass Road to alert oncoming
vehicles of truck entry to and egress from the site. Traffic may be briefly stopped with the assistance of
a flagger on an as-needed basis to allow trucks to enter traffic. Alternatively, in a very localized area
around the entry/exit location, one lane of Kirker Pass Road may be closed to accommodate trucks
entering and exiting the site. Any closures will only be for a short length of Kirker Pass Road and they
will occur only during off-peak traffic hours. The flaggers will serve to ensure traffic flow continues as
efficiently as possible. With the assistance of traffic control flaggers and avoidance of peak commute
hours, significant traffic impacts as a result of the project are not expected.
Page 15 of 25
Potentially
Significant
Potentially Unless Less than
Significant Mitigation Significant
Impact Incorporation Impact No Impact
VIII. HYDROLOGY AND WATER QUALITY.
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 level (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 runoff 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 storm
water 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, which 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? ✓
SUMMARY: Less Than Significant Impact. Neither the basin nor channel improvements will increase
exposure of people or property to flooding. In fact, the goal of the project is to lessen the potential
exposure of people and property to flooding. The project will not impair the flow of water; nor will it alter
the course or flow of floodwaters. The amount of surface water in the unnamed creek will not change
significantly as a result of the project.
Page 15 of 25
Construction of the basin and channel improvements will not adversely affect the quantity or quality of
surface water, ground water or public water supply. Measures will be undertaken in the design and
construction of the basin and channel improvements to avoid adverse impacts to water quality. Contract
specifications will require the installation of silt fencing or other effective sediment barrier below the
excavation limits to prevent soil from entering the creek due to construction activities. Contract
specifications will require the storage, servicing and fueling of construction equipment outside of the
basins and channel. Standard construction safety practices will be incorporated into the project to
reduce the possibility of a spill of gasoline, oil, or other pollutant that could have a significant impact on
water quality. In addition, stockpiled materials will be located far enough from the banks of the channel
to prevent construction materials from entering the creek.
In order to ensure the work can be conducted with limited impact to water quality, normal creek flows will
be bypassed around the channel desilting activities and the culvert replacements and the immediate
work areas will be dewatered. Dewatering will likely entail installation of cofferdams to isolate the work
areas and a silt settling area to allow sediment-laden work area water to settle prior to release into the
creek. Normal creek flows will be maintained around the work site at all times through either a gravity
flow or pumping system. Design of the dewatering system will be at the discretion of the contractor;
however, it must function effectively to isolate the work areas from the flowing creek and ensure water
quality is not impacted by the construction activities.
Total disturbance due to construction of the basin and channel improvements will be greater than an
acre; therefore, in order to comply with the State Water Resources Control Board National Pollutant
Discharge Elimination System (NPDES) General Construction Permit requirements, a Storm Water
Pollution Prevention Plan (SWPPP) will be required by the contract plans and specifications. The
SWPPP will specify the Best Management Practices that will be used during project construction to
ensure water quality impacts are minimized. The SWPPP will address erosion control, sediment control,
non-stormwater management, post-construction storm water management, and maintenance,
inspection, and repair of the BMPs used on-site. At the completion of the project, all disturbed areas
including the exposed soils on the earthen berm will be stabilized through the use of hydroseeding with a
mix including native grasses and wildflowers and/or erosion control blanketing, as appropriate.
Water Quality Certification will be obtained from the San Francisco Bay Regional Water Quality Control
Board (SFBRWCB) prior to construction of the project. Special conditions required by the certification
will be complied with during construction in order to minimize the possibility of water quality impacts.
Routine maintenance activities (i.e., debris and cattail removal, weed abatement, and minor silt removal)
will be conducted on an as-needed basis and are not expected to cause a significant impact to water
quality. Based on the high level of build-out in the area, desilting activities are expected to be minimal
and sporadic. In order to avoid water quality impacts as a result of maintenance activities, the drainage
will be dewatered prior to any desilting activities and vegetation removal will be accomplished through
the use of hand-held equipment (e.g., weed eaters).
Page 17 of 25
Potentially
Significant
Potentially Unless Less than
Significant Mitigation Significant
Impact Incorporation Impact No Impact
IX LAND USE AND PLANNING. Would the project:
a. Physically divide an established community? ✓
b. Conflict with any applicable land use plan,
policy, or 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? ✓
SUMMARY: No Impact. The project will not result in a substantial alteration of the present or planned
land use of the area. The area adjacent to the creek that will be graded to function as a detention basin
is currently undeveloped, and the additional project work that will be conducted (e.g., culvert
replacement, sediment removal, etc.) will not modify the current land use in those areas. Construction
of the basin and channel improvements will provide the existing surrounding neighborhoods with
protection from the 25-year storm event. The work will not result in an increase in population,
displacement of people, or create a demand for additional housing.
X. MINERAL RESOURCES. 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 of availability of a locally
important mineral resource recovery site
delineated on a local general plan, specific plan
or other land use plan? ✓
SUMMARY: Less Than Significant Impact. Construction and operation of the project would not involve
quarrying, mining, or extraction of any known regionally or locally important mineral, oil, or gas resources
on site, nor would it deplete any non-renewable natural resource. During construction, the project will
use paving materials (i.e., asphalt), wood products, concrete and other materials derived from natural
resources; however, the project will not significantly impact these resources.
Page 18 of 25
Potentially
Significant
Potentially Unless Less than
Significant Mitigation Significant
Impact Incorporation Impact No Impact
XI. NOISE. Would the project result in:
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? ✓
SUMMARY: Less Than Significant Impact. The dominant source of ambient noise in the project area is
vehicles already using Kirker Pass Road. Construction of the flood control basin and channel
improvements will not increase the capacity of Kirker Pass Road; therefore no additional vehicle trips will
be generated as a result of the implemented project. There will be a limited number of additional vehicle
trips during construction resulting from worker vehicles accessing the site; however, this will be a minor
and temporary impact that would not significantly increase the ambient noise level at the project site and
is, therefore, deemed less than significant.
Construction of the project will increase the ambient noise level near the project site temporarily.
Typically, construction activities produce average noise levels of about 86 dBA at 50 feet from any given
construction site. This construction project is expected to be consistent with this generalized average
due to the standard construction activities that will occur. Increased noise as a result of construction
activities will be temporary and will; therefore, remain at a level that is less than significant. Based on
the proximity of the nearby residences, no nighttime work will be conducted and working hours will be
limited to 7 am to 5 pm on weekdays and 9 am to 5 pm on weekends and holidays. Any modification to
these working hours must be approved by the Resident Engineer and surrounding neighbors will be
notified in advance of any changes. These working hours will be incorporated as part of the
construction contract. Contract specifications will also require the use of properly tuned and muffled
equipment to minimize noise due to construction activities.
Routine maintenance activities (i.e., debris and cattail removal, weed abatement, and minor silt removal)
will be conducted on an as-needed basis and are not expected to cause a significant noise impact.
Page 19 of 25
Potentially
Significant
Potentially Unless Less than
Significant Mitigation Significant
Impact Incorporation Impact No Impact
XII. POPULATION AND HOUSING. 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? ✓
SUMMARY: Less Than Significant Impact. The goal of the project is to provide the mandated level of
flood control protection to the area. This goal will be achieved without creating additional infrastructure
that could encourage population growth. Since the watershed area is less than 4 square miles, the
Flood Control District plans to provide 25-year storm protection to the area. Downstream of the
proposed flood control improvements (the location the project will benefit), the area is essentially built-
out, therefore the project will not induce further population growth. The project will not result in the
displacement of any homes or residents, nor will it result in a change in the location, distribution, density
or growth rate of human population in the area. The project will not affect existing housing, or create a
demand for additional houses nor will it require the removal of any homes or the displacement of any
people.
X111. PUBLIC SERVICES
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? ✓
SUMMARY: Less Than Significant Impact. The flood control basin and culvert replacements will be
constructed adjacent to the existing roadways and will not increase the capacity of Kirker Pass Road,
Old Kirker Pass Road, or Concord Boulevard, nor the number of vehicles using these roadways.
Page 20 of 25
During construction, residents and emergency service vehicles will be able to access the construction
site and all adjacent neighborhoods at all times. Replacement of the culvert under Old Kirker Pass Road
may require closure of the road at the immediate location of the culvert; however, Old Kirker Pass Road
has two outlet points onto Kirker Pass Road; therefore, access to and egress from the neighborhood will
be maintained at all times.
Approximately 20 truck trips per hour will be required during basin excavation activities in order to allow
for off-haul of the soil excavated from the detention basin location. In order to ensure trucks are able to
enter and exit the project site safely, flaggers will be required on Kirker Pass Road to alert oncoming
vehicles of truck entry to and egress from the site. Traffic may be briefly stopped with the assistance of
a flagger on an as-needed basis to allow trucks to enter traffic. Alternatively, in a very localized area
around the entry/exit location, one lane of Kirker Pass Road may be closed to accommodate trucks
entering and exiting the site. Any closures will only be for a short length of Kirker Pass Road and they
will occur only during off-peak traffic hours. The flaggers will serve to ensure traffic flow continues as
efficiently as possible. With the assistance of traffic control flaggers and avoidance of peak commute
hours, significant traffic impacts as a result of the project are not expected.
Once constructed, the flood control improvements will not increase the need for fire or police protection,
schools, parks or other governmental services. Periodic maintenance of the flood control improvements
will be performed by the County to ensure the facilities are operating in a safe and effective manner.
Potentially
Significant
Potentially Unless Less than
Significant Mitigation Significant
Impact Incorporation Impact No Impact
XIIII. RECREATION
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, which might have an
adverse physical effect on the environment? ✓
SUMMARY: No Impact. The County Resource Mapping System and the field reviews did not identify
any recreational opportunities in the immediate project area. The facilities improvements are expected
to have no effect on existing neighborhood parks and other recreational facilities in the area.
Page 21 of 25
Potentially
Significant
Potentially Unless Less than
Significant Mitigation Significant
Impact Incorporation Impact No Impact
XV. TRANSPORTATION/TRAFFIC. Would the project:
a. Cause an increase in traffic, which is substantial
in relation to the existing traffic load and
capacity of the street system (i.e., result in a
substantial increase in either the number of
vehicle trips, the volume to capacity ratio on
roads, or congestion at intersections)? V/
b. Exceed, either individually or cumulatively, a
level of service standard 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 inter-
sections) or incompatible uses (e.g., farm
equipment)? ✓
e. Result in inadequate emergency access?
f. Result in inadequate parking capacity? ✓
g. Conflict with adopted policies, plans, or
programs supporting alternative transportation
(e.g., bus turnouts, bicycle racks)? ✓
SUMMARY: Less Than Significant Impact. Approximately 20 truck trips per hour will be required during
basin excavation activities in order to allow for off-haul of the soil excavated from the detention basin
location. In order to ensure trucks can enter and exit the project site safely, flaggers will be required on
Kirker Pass Road to alert oncoming vehicles of truck entry to and egress from the site. Traffic may be
briefly stopped with the assistance of a flagger on an as-needed basis to allow trucks to enter traffic.
Alternatively, in a very localized area around the entry/exit location, one lane of Kirker Pass Road may
be closed to accommodate trucks entering and exiting the site. Any closures will only be for a short
length of Kirker Pass Road and they will occur only during off-peak traffic hours. Language regarding
restriction of lane closures to off-peak hours will be included within the project contract plans and
specifications. The flaggers will serve to ensure traffic flow continues as efficiently as possible. With the
assistance of traffic control flaggers, and avoidance of peak commute hours, significant traffic impacts as
a result of the project are not expected.
During construction, residents and emergency service vehicles will be able to access the construction
site and all adjacent neighborhoods at all times. Replacement of the culvert under Old Kirker Pass Road
may require closure of the road at the location of the culvert; however, Old Kirker Pass Road has two
outlet points onto Kirker Pass Road; therefore, access to and egress from the neighborhood will always
be maintained. In addition, at least two 10' wide lanes will be maintained at all times on Concord
Boulevard during extension of the culvert under the roadway to minimize the potential for traffic impacts.
No interference with an emergency evacuation or response is expected to result from the project. The
majority of the work will occur within the detention basin area, within the channel, and at the culvert
replacement locations. Traffic control measures around the work area will minimize the potential for
Page 22 of 25
accidents and standard specifications for the project will require installation of sufficient warning signs
regarding the construction and associated work hours. Although there will be additional traffic generated
due to the construction of the basin and the downstream channel improvements, the traffic will be
temporary and less-than-significant. Once constructed, the flood control improvements will not increase
the need for fire or police protection, schools, parks or other governmental services.'
Potentially
Significant
Potentially Unless Less than
Significant Mitigation Significant
Impact Incorporation Impact No Impact
XVI. UTILITIES AND SERVICE SYSTEMS.
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
or which could cause significant environmental
effects? ✓
c. Require or result in the construction of new
storm water drainage facilities or expansion of
existing facilities, the construction of which could
cause significant environmental effects?
d. Have sufficient water supplies available to serve
the project from existing entitlement and
resources, or are new or expanded entitlement
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 solid
waste disposal needs? ✓
g. Comply with federal, state and local statutes and
regulations related to solid waste? ✓
SUMMARY: Less Than Significant Impact. Two sets of high-tension power lines cross over the project
site. These power lines are being accounted for in project design and the contractor will be notified of
the need to avoid these utilities. Plans and specifications for the project will identify these and any other
similar facilities identified during design as "high risk facilities". Any necessary utility relocations will be
conducted in coordination with the appropriate utility companies, and the contractor will be required to
contact Underground Service Alert (or other utility locating company) to determine whether any utilities
are present in the area that must be avoided.
Page 23 of 25
Potentially
Significant
Potentially Unless Less than
Significant Mitigation Significant
Impact Incorporation Impact No Impact
XVII. MANDATORY FINDINGS OF SIGNIFICANCE
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,
which will cause substantial adverse effects on
human beings, either directly or indirectly? ✓
SUMMARY: Potentially Significant Unless Mitigation Incorporated. Potential foraging and sheltering
habitat for red-legged frog is present on the project site. Based on the implementation of appropriate
avoidance and minimization measures, the issuance of and compliance with the incidental take permit
and its associated conditions to protect red-legged frog, and the creation of a riparian wetland bench
that will mitigate the temporary habitat impacts as a result of project construction, impacts to red-legged
frogs as a result of the project will be less than significant. Construction of the basin will actually create
higher quality and more plentiful red-legged frog habitat than currently exists on the project site since the
existing steep creek banks will be graded back at a gradual 3:1 slope and the banks planted with native
riparian species. This gradual slope will create a floodplain area that is expected to develop into riparian
wetland similar to the habitat currently localized immediately around the existing narrow creek. The
basin will be designed to drain rapidly to ensure impounded water does not create a bullfrog breeding
ground. As a result of the creation of this riparian wetland bench, temporary impacts to red-legged frog
habitat due to the project will be mitigated.
Since the project will actually improve the habitat for red-legged frog, future maintenance activities must
take into account the potential for impacts to the species. Therefore, prior to conducting maintenance
activities, a preconstruction survey will be conducted by a qualified biologist to ensure red-legged frogs
are not in the project area. If red-legged frogs are identified during the preconstruction survey, contact
with USFWS will be initiated and the individuals identified will not be moved without FWS authorization.
In addition, in order to further ensure impacts are minimized, maintenance activities within the basin and
channel will be minimized to the extent feasible. Any cattail, debris, or weed removal necessary will be
conducted through the use of hand held equipment rather than mechanical mowing and silt removal will
be conducted only on an as-needed only basis with no tree removal authorized.
Page 24 of 25
A total of 18 native and 10 non-native trees are expected to be removed from the riparian zone as a
result of the project. In order to mitigate for riparian trees removed, replacement trees will be planted at
the new basin location at a ratio negotiated between the District and the resource agencies that have
jurisdiction over the riparian habitat (e.g., California Department of Fish and Game). Staff from the
District's Environmental Section will be present at the project site during tree removal to ensure the
number of trees removed is documented for mitigation purposes. The newly planted trees will be
maintained for a period of three years and monitored annually for a period of five years. At the
conclusion of the five-year monitoring period, the replacement trees will be required to meet the success
criteria negotiated during the permitting process. If the survival rate has not been achieved, additional
plantings will occur, and monitoring will be extended for an additional year.
The project does not have the potential to cause cumulative or indirect impacts.
G:1GrpData\EngSvc\Enviro12003Projects1DA33A\CEQACurrent
Page 25 of 25
CALIFORNIA ENVIRONMENTAL QUALITY ACT
NOTICE OF DETERMINATION
CONTRA COSTA COUNTY COMMUNITY DEVELOPMENT DEPARTMENT
651 PINE STREET 4TH FLOOR NORTH WING MARTINEZ,CALIFORNIA 94553-0095
Telephone.* (925)313-2296 Contact Person: Cece Sellgren, Environmental Planner
Project Description,Common Name(if any)and Location: DA 33A Flood Facilities Improvements Project.County File#CP 03-41
Project Description: The purpose of the project is to provide 25-year flood protection through a variety of facility improvements including
construction of a detention basin,silt and debris removal from an existing culvert,desilting of a portion of the channel,culvert replacements,
and construction of a floodwall. In order to construct the basin, approximately 17,000 cubic yards of material will be excavated from a
benched area located adjacent to the existing creek. All of the excavation necessary to construct the basin will occur on the northwest bank
of the drainage. A roughly 5-foot wide berm will be maintained between the creek and the excavation area. At the far downstream end of
the detention basin,a short break in the berm will allow the water in the floodplain to reenter the creek such that ponding does not occur.
The bank above the channel will be graded at a 3:1 slope,creating a much wider and more gradually sloped creek bank than currently
exists. The weir structure at the downstream end of the basin will be resized and an embankment or small concrete bridge will be
constructed outside of the creek zone to provide access to the structure. At the culvert location under Old Kirker Pass Road.debris and silt
that is currently clogging the existing culvert will be removed to daylight the culvert,and an approximately*250-foot length of the channel
downstream of the culvert will be desilted. The 48"culvert under Old Kirker Pass Road will be replaced with a new 72"culvert or two 48"
culverts. During replacement,the upstream invert of the pipe will be lowered by approximately two feet to ensure effective hydraulics. A
headwall will be constructed at the pipe inlet and rock slope protection will be installed for energy dissipation at the pipe outlet. In order to
replace the existing culvert,the roadway will be excavated,the old culvert removed,and the new culvert placed in the same location as the
old culvert. The existing 60$9 culvert under Concord Boulevard will be replaced with a new 72" culvert (or two 48" culverts) that is
approximately 30 feet longer than the existing culvert.A wing wall will be constructed at the inlet of the pipe and rock slope protection 411 be
provided for energy dissipation at the pipe outlet. Increasing the length of the culvert by 30 feet will allow the pipe to daylight outside the
road right of way;thereby allowing the constricted roadway at this location to be increased to a width that is consistent with the rest of the
roadway. Downstream of Concord Boulevard a roughly 315'long,Xhigh flood wall or earthen berm will be constructed in the upland area
around the creek to direct high flows into the existing 84"reinforced concrete pipe. The Flood Control District will also conduct routine and
ongoing maintenance in the basin and channel area. Maintenance activities likely to be necessary in the project area consist of debris and
cattail removal and weed abatement activities with hand-held equipment,and limited silt removal from the basin area every several years.
The project lies within the boundaries of the City of Concord Real Property transactions may be necessary between the District and the City
as well as the District and private property owners adjacent to the project. Construction of the floodwall will require Real Property
transactions with the property owner of APN 117-014-050. Project Location: the project area is bounded by Kirker Pass Road,Kirkwood
Drive,Old Kirker Pass Road and Concord Boulevard in central County between the Cities of Concord and Clayton.
The project was approved on
Pursuant to the provisions of the California Environmental Quality Act:
An Environmental Impact Report was prepared and certified(SCH#
The Project was encompassed by an Environmental Impact Report previously prepared
far (SCH# ).
(✓) A Mitigated Negative Declaration was prepared following identification of a potentially significant impact
Copies of the record of project approval and the Negative Declaration or the final EIR may be examined at the office of the Contra
Costa County Public Works Department.
(✓) The Project will not have a significant environmental effect with incorporated mitigation measures
The Project will have a significant environmental effect.
Mitigation measures were made a condition of approval of the project.
A statement of overriding considerations was adopted.
Findings were adopted pursuant to Section 15091 of the State CEQA Guidelines.
Date: By:
Community Development Department Representative
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:
Public Works Department EIR-$850 Total Due: $
255 Glacier Drive,Martinez,CA 94553 _X_ Neg.Dec.-$1,250 Total Paid $
Attn:Leigh Chavez DeMinimis Findings-$0
F)3EAST SAY
MUNICIPAL UTILITY DISTRICT
NOV 1 7 2003
WX
-7--NTA
November 14, 2003
Leigh Chavez, Planner III
Contra Costa County Public Works Department
255 Glacier Drive
Marinez, CA 94553
Dear Mr. Chavez:
Re: Notice of Intent to Adopt Proposed Mitigated Negative Declaration—
DA 33A Flood Facilities Improvement Project - Concord
The East Bay Municipal Utility District (EBMUD) appreciates the opportunity to review
the DA 33A Flood Facilities Improvement Project in Concord. The proposed project has
no impact on EBMUD's transmission facilities. Therefore, EBMUD has no comments
on this project.
If you have any questions or comments concerning this response, please contact Marie
Valmores, Senior Civil Engineer at (510) 287-1084.
Sincerely,
Marie A. Valmores
Senior Civil Engineer of Water Service Planning
MAV:DFC:sb
sb03-316.doc
80
Y E A R S
375 ELEVENTH STREET OAKLAND CA 94607-4240 (510) 836-3000 1923-2003
Leigh Chavez
From: Leigh Chavez
Sent: Thursday, October 30,2003 1:39 PIVI
To: 'Janet Lindsay
Subject: RE: DA 33A Flood Facilities Improvement Project
Yes, as long as CEQA clearance is completed and we have the necessary authorizations from
the resource agencies, we will remove the trees this winter outside the nesting season to
minimize potential impacts to nesting birds including raptors (such as Cooper's hawk) .
-----Original Message-----
From: Janet Lindsay [mailto:JLindsay@pdbi.com]
Sent: Thursday, October 30, 2003 1:28 PM
To: Leigh Chavez
Subject: RE: DA 33A Flood Facilities Improvement Project
Leigh, is the tree removal and trimming going to be done this winter? On page 10 of the
report it states that is the best time remove the trees because it is a nesting habitat of
the Cooper's hawk and other birds.
Janet
-----Original Message-----
From: Leigh Chavez [mailto.-lchavez@pw.co-contra-costa.ca.us]
Sent: Thursday, October 30, 2003 1:17 PM
To: Janet Lindsay
Subject: RE: DA 33A Flood Facilities Improvement Project
Janet,
The contractor will ultimately have discretion over exactly how they want to
stage the project. They may opt to have crews working on the basin at the
same time they do the culvert work, or they may construct the different
portions of the project consecutively. Construction is expected to start in
mid to late summer and run through early October.
Thanks Janet '.
Leigh
-----Original Message-----
From: Janet Lindsay [mailto:JLindsay@pdbi.com]
Sent: Thursday, October 30, 2003 11:54 AM
To: Leigh Chavez
Subject: RE: DA 33A Flood Facilities Improvement Project
Leigh, I did receive the report and it was very helpful in understanding the
work that will be done in the creek area. After reading the report it looks
like the project will be done in stages. When is the work going to start
and how long will it take to complete.
Thank you for answering all my questions.
Janet
-----Original Message-----
From: Leigh Chavez [mailto:lchavez@pw.co.contra-costa.ca.us]
Sent: Thursday, October 30, 2003 11:41 AM
To: Janet Lindsay
Cc: Craig Standafer
Subject: RE: DA 33A Flood Facilities Improvement Project
Hi Janet,
Hopefully you have received your copy of the Mitigated Negative Declaration
(I believe it was sent on Monday) . If not, please let me know.
In answer to your questions:
1) The detention basin will cover approximately two acres
2) During a 25-year storm event the basin will hold approximately 8,300
cubic meters (2 million gallons) of water
3) The basin is being designed with a very slight slope to allow storm water
to be metered out slowly during storm events (to minimize flooding
downstream of the basin) without storing water for extended periods of time.
For example, following a 25 year storm event, it will take approximately 5
hours to drain from peak flow conditions to standard low flow conditions.
Based on this design, the basin is not expected to pond water for long
periods of time, and therefore is not expected to create a mosquito breeding
ground.
4) As you know, the Pacific treefrogs that you hear from your home
typically focus their activity in the evening/night hours. Although the
project will have noise and vibration conditions similar to any construction
project, construction activities will only occur during the day and they
will be temporary. In addition, most of the material that will be removed
to create the basin is the drier upland soil above the existing creek.
Pacific treefrogs are generally found close to water, and the basin has been
designed to avoid impact to the creek to the extent feasible. Any pumps
used to dewater sections of the creek will be covered with a fine gauge
screen to ensure treefrogs and treefrog tadpoles do not enter the pump.
Based on these avoidance and minimization measures, impacts to Pacific
treefrog are expected to be less than significant.
I hope this answers your questions. Please let me know if you have any
further questions.
Thanks Janet
Leigh Chavez
(92 5) 313-2366
Message-----
From: Janet Lindsay [mailto:JLindsay@pdbl' .com]
Sent.- Thursday, October 23, 2003 1:56 PM
To: lchavez@pw.co-contra-costa.ca.us
Subject: FW: DA 33A Flood Facilities Improvement Project
> Leigh, I would like a copy of the Mitigated Negative Declaration document.
You can it to at: Janet Lindsay, 5455 Kirkwood Dr #B6, Concord, CA 94521.
> Also, I do have a few question: How big is the Detention Basin going to
be? How much water will it hold? Will there be standing water in the
spring and summer for mosquitos to bred in? And how will this effective the
frogs that current live in the creek? I live by the creek and through out
the spring and part of the summer the frogs are "singing" all night long and
I hope this project won't negatively impacted them.
> Thank you,
> Janet Lindsay
2
Lelah Chavez
From: Leigh Chavez
Sent: Thursday, November o6,2003 3:27 PIVI
To: 'mike martin'
Subject: RE: Reference DA33A Flood Facilities Improvement Project
Hi Mr. Martin,
In order to minimize construction impacts to neighbors, contract plans and specifications
will stipulate the use of properly tuned equipment and the elimination of unnecessary
idling when equipment is not in use. The specs will also stipulate the use of dust
control practices including general watering of exposed areas and/or the use of chemical
stabilizers.
In order to ensure that noise impacts are minimized, no nighttime work will be conducted
and working hours will be limited to 7 am to 5 pm on weekdays, and 9 am to 5 pm on
weekends and holidays. Based on the timing of construction (during the summer months) , it
is unlikely that any work will occur on holidays. In addition, the contract
specifications will require the use of properly muffled equipment.
All water from any necessary dewatering operations will be treated (i.e. , silt will be
settled out) , and the clean water will be released back into the creek in a non-erosive
fashion.
The time and location of the neighborhood meeting is still to be determined (it will
likely occur in early December at a local school) . You will be notified regarding the
date and location of the meeting when it is finalized. You can also contact Kevin Emigh
at kemigh@pw.co.contra-costa.ca.us for further questions about the meeting.
Please let me know if you have any further questions. Thank you for your interest in the
project.
Leigh Chavez
(925) 313-2366
-----original Message-----
From: mike martin (mailto:reid5371@hotmail.coml
Sent: Thursday, November 06, 2003 1:18 PM
To: lchavez@pw.co-contra-costa.ca.us
Subject: Reference DA33A Flood Facilities Improvement Project
Good Afternoon Ms Chavez,
I reside at 5371 Saddlewood Court,Concord,Ca 94521. 1 would appreciate
recieving further details of this project. Of especial 'interest is the the
construction mitigation measures that will be implemented to control dust,
construction equipment emmisions, noise and disposal of ground water from
dewatering operations.
I understand that a neighborhood meeting is planned when and where will this
meeting be held.
Regards.
M. R. Martin
MSN Shopping upgraded for the holidays! Snappier product search. . .
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Leigh Chavez
From: Leigh Chavez
Sent: Tuesday, November 18,2003 9:00 AM
To: 'mike martin'
Subject: RE: DA33A Flood Facilities Improvement Project
Hi Mr. Martin,
You're welcome. I appreciate your interest in the project, and I fully anticipate a safe
and successful project.
Leigh Chavez
(925) 313-2366
-----original Message-----
From: mike martin [mailto:reid5371@hotmail.com]
Sent: Friday, November 14, 2003 8:13 AM
To: lchavez@pw.co.contra-costa.ca.us
Subject.- RE: DA33A Flood Facilities Improvement Project
Hi Ms Chavez,
Thank you for your very detailed reply, I appreciate the time, effort and
research that you put into providing this information.
Obviously I defer to City Staff in the interpretation of the City Codes. I
am somewhat suprised that the City has no ordinance that that addresses
noise generating activities within the City.
I understood that this was covered in Chapter 62 Neighborhood Preservation
Article 2 section 62-32.
Perhaps you would be good enough to forward this e mail to City Staff for
comment?
Again many thanks for you replies and my hope is for a safe and successfull
project.
Regards.
Mike Martin.
5371 Saddlewood
Court, Concord.
>From: Leigh Chavez <lchavez@pw.co.contra-costa.ca.us>
>To: 'mike martin' <reid5371@hotmail.com>
>CC: Craig Standafer <cstandaf@pw.co.contra-costa.ca.us>
>Subject: RE: DA33A Flood Facilities Improvement Project
>Date: Thu, 13 Nov 2003 13:28:04 -0800
>Hi Mr. Martin,
>Below are answers to your follow-up questions:
>The project is expected to take roughly three months to complete (give or
>take a couple of weeks) . Please keep in mind that it is unlikely the
>contractor would be at any one location for the entire duration of the
>project.
>Weekend and holiday work is not anticipated (and is actually highly 6_0
>unlikely) ; however, depending on the contractor's schedule and work window
>limitations potentially imposed by various resource agencies, there is a
>possibility that work could occur on weekend days (including Sundays) . I
>have reviewed the City of Concord's website for the City's General Plan
>Noise Element. I also contacted staff at the City of Concord Planning
1
>Department. The General Plan does not appear to address noise generated by
>construction projects, and I learned from Planning staff that the City does
>not actually have a Noise ordinance. Nevertheless, the District recognizes
>the importance of minimizing noise impacts on local residents. As I
>mentioned in my previous response, no nighttime work will be allowed, and
>project specifications will require the use of properly tuned and muffled
>equipment. Based on the muffling requirements, the limited working hours,
>and the temporary nature of the construction, significant noise impacts as
>a
>result of the project are not expected. A Resident Engineer will be
>available on-site to address any specific questions or concerns that you
>may
>have during construction.
>The contractor will need to export material from the project site primarily
>during excavation of the detention basin. In order to ensure trucks. can
>enter and exit the project site safely, flaggers will be required on Kirker
>Pass Road to alert oncoming vehicles of truck entry to and egress from the
>site. Traffic may be briefly stopped with the assistance of a flagger on
>an as-needed basis to allow trucks to enter traffic. Alternatively, in a
>very localized area around the entry/exit location, one lane of Kirker Pass
>Road may be closed to accommodate trucks entering and exiting the site.
>Any
>closures will only be for a short length of Kirker Pass Road and they will
>occur only during off-peak traffic hours. Language regarding restriction
>of
>lane closures to off-peak hours will be included within the project
>contract
>plans and specifications, and signs will be posted notifying motorists of
>the project. The flaggers will serve to ensure traffic flow continues as
>efficiently as possible. Replacement of the culvert under Old Kirker Pass
>Road may require closure.of the road at the culvert location; however,
>since
>there are two outlet points on the roadway, access to the neighborhood will
>always be maintained. In addition, at least two 101 wide lanes will be
>maintained on Concord Boulevard during extension of the culvert under the
>roadway. With the assistance of traffic control flaggers, avoidance of
>peak
>commute hours, and installation of notification signs, significant traffic
>impacts as a result of the project are not expected.
>I hope this addresses your remaining concerns. Thanks again for your
>interest in the project.
>Leigh Chavez
>Contra Costa County Public Works Department
>P: (925) 313-2366
>-----Original Message-----
>From: mike martin [mailto:reid5371@hotmail.com)
>Sent: Wednesday, November 12, 2003 9:08 AM
>To: lchavez@pw.co.contra-costa.ca.us
>Subject: RE: DA33A Flood Facilities Improvement Project
>Hi Ms Chavez,
>Thank you for the reply, I apologize for the abrupt end to my original e
>mail, I hit the send command inadvertently before reviewing and signing.
> Regards.
> Mike
2
• >From: Leigh Chavez <lchavez@pw.co-contra-costa.ca.us>
• >To- 'mike martin' <reid5371@hotmail.com>
0
• >Subject: RE: DA33A Flood Facilities Improvement Project
• >Date: Wed. 12 Nov 2003 07:22:24 -0800
> >Hi Mr. Martin,
• >I was out of the office at the beginning of the week and have an all day
• >meeting today, but I wanted to let you know I will respond to your
• >follow-up
• >questions as soon as possible. Sorry for the delay!
> >Leigh
• >-----original Message-----
• >From: mike martin [mailto:reid5371@hotmail-com]
• >Sent: Friday, November 07, 2003 7:23 AM
• >To: lchavez@pw.co.contra-costa.ca.us
• >Subject: DA33A Flood Facilities Improvement Project
• >Good Morning Ms Chavez,
• >Thank you for the rapid and comprehensive response to my e mail of
• >yesterday,a few follow up questions.
• >What is is scheduled duration of the project?
• >Is weekend and holiday work anticipated. Is your definition of weekend
>work
• >including Sundays,are you seeking a variance to the city of Concord noise
• >ordinance?
• >Is it anticipated that there will be a balance of cut and fill or will
>the
• >contractor need to import or export material from the site? Is the
• >contractor required to produce and have approved a construction activity
• >traffic plan.?
• >Are any street or lane closures anticipated?
• >I would suggest that the nieghborhood meeting is held sooner rather than
• >later to enhance communication and gauge local interest.
• >Is your computer infected with a virus? Find out with a FREE computer
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• >http-.//clinic-mcafee.com/clinic/ibuy/campaign.asp.9cid=3963
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3
Leigh Chavez
From: Leigh Chavez
Sent: Monday, November 24, 2003 11:43 AM
To: 'ronald parini'
Cc: Kevin Emigh
Subject: RE: drainage area 33A initial study
Hi Ron
I spoke with Kevin Emigh - he is fine incorporating your language below. I will append
your e-mail and this response to the final CEQA document. The County Board of Supervisors
will approve the final document including all comments and District responses.
Thank you for your input on the initial study.
Leigh
Message-----
From: ronald parini [mailto:rparini@yahoo-com]
Sent: Thursday, November 20, 2003 2 :17 PM
To: Leigh chavez
Cc : alex Pascual; fill mercurio; kevin emigh
Subject : drainage area 33A initial study
Initial Study of Environmental Significance
Drainage Area 33A Flood Facilities Improvement Project
The Study appears to be done very well. I think it would be valuable to add this kind of
information in the "Hydrology & Water Quality" section:
As part of the preliminary design and alternatives analysis, the Flood Control District
examined the affect that the proposed project would have farther downstream, on Mt.
Diablo Creek. Their analysis showed that the project would produce a negligible change
for a 10 year storm, and it would reduce the flow in Mt. Diablo Creek for a 25 year and
100 year storm.
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COSTA
Contra Costa County Maurice M. Shiu
ex officio Chief Engineer
��� �' FLOOD CONTROL 255 Glacier Drive, Martinez, CA 94553-4825
& Water Conservation District Telephone: (925) 313-2000
tv FAX (925) 313-2333
November 25, 2003
Ms. Joan Ryan
Associate Planner
City of Concord
1950 Parkside Drive
Concord, CA 94519-2578
Our File: DA 33A Flood Facilities Improvement Project
Project Number: 7535-6F8472
Dear Ms. Ryan:
The Flood Control District has received your letter dated November 20, 2003 regarding
the DA 33A Flood Facilities Improvement Project initial study. Thank you for reviewing
the CEQA document. Following are responses to your comments (the numbering below
corresponds to the numbering indicated in the margins of your attached comment
letter):
1. As you are aware from your review of the initial study, the District has specifically
designed the project to avoid impact to the existing riparian habitat to the extent
feasible. The basin excavation will occur on the northern bank exclusively, and a
buffer zone between the excavation area and the creek zone will be maintained.
Therefore, no impact to trees on the southern bank will occur and a substantial
number of trees on the northern bank will be retained within the buffer zone. In
addition, the desilting activities occurring downstream of Kirker Pass Road will be
conducted around existing trees located in the channel area in order to minimize
impact to riparian habitat.
The total number of trees anticipated to be removed (18 native and 10 non-
native) is actually a conservative estimate and is likely to be revised downward
based on our ability to "field-fit" the edge of the excavation activities and minimize
tree removal during construction of the project. Many of the trees to be removed
are small non-native orchard trees that are not the focal point from Kirker Pass
Road based on the abundance of larger surrounding riparian trees in the area.
Preliminary discussions with the resource agencies have tentatively defined a
replacement ratio of 3:1 for native trees and 1:1 for non-native trees. Although
the size of the replacement plantings has not yet been negotiated, the District
typically plants replacement trees in 1 gallon or 5 gallon sizes. Planting this size
of trees is expected to help ensure that the specimens are better able to adapt to
Ms. Joan Ryan
City of Concord
November 25, 2003
Page 2
site conditions rather than planting trees that have adapted to conditions
associated with a lengthy nursery propagation.
Preliminary discussions with the resource agencies have tentatively defined a
replacement ratio of 3:1 for native trees and 1:1 for non-native trees. Although
the size of the replacement plantings has not yet been negotiated, the District
typically plants replacement trees in 1 gallon or 5 gallon sizes. Planting this size
of trees is expected to help ensure that the specimens are better able to adapt to
-site conditions rather than planting trees that have adapted to conditions
associated with a lengthy nursery propagation.
The District believes the ratios of 3:1 for native trees and 1:1 for non-native trees
in 1 or 5 gallon sizes will adequately mitigate the aesthetic impact associated
with the loss of trees as a result of the project.
2. Kevin Emigh, Flood Control District Senior Engineer, is in the process of
coordinating with Mr. Ron Parini, City of Concord consultant, to schedule a
neighborhood meeting to inform the residents about the project. The meeting is
tentatively scheduled for the week of December 8, 2003.
Mr. Emigh has been coordinating with Mr. Parini regarding the project to ensure the City
is on-board with the District's approach. Following completion of the project, the City
will accept maintenance responsibilities for the project.
I hope this adequately addresses your concerns with the project. If you have any
further concerns or feel that the project may be out of compliance with the City's Tree
Ordinance, please feel free to contact me at (925) 313-2366 or Ichavez6d�Pw.co.contra-
costa.ca.us for additional discussion. Thank you.
Sincerely,
Leigh Chavez
Planner III
Engineering Services
LC:sr
G:1GrpData\EngSvc\Enviro12003 Projects\DA 33A\ResponseConcordComment.doc
cc: E.Whan,Engineering Services
K.Emigh,Flood Control
C.Sellgren,Engineering Services
X1/20103 17: 16 FAX 0256713381 ConcordPermitCenter L]001
CITY of CONCORD � CITY COUNCIL
PERm.rr Ce4TER Mark.A.Peterson,.Mayor
1950 Parkside Drive ' ' ; Helen M.Allen,vice Mayor
Concord,California 94519-2578
Susan Bonilla
Laura A Hoffine is to r
-
Telephone; (925) 671345 :�;,�;+.:'`,
:: dill McMann al
Fax: (925) 671-3381
Conegi Mary Rae Lehman,City Clerk
Thomas wending,City Treasurer
November 20, 2003
Edward R.James,City Manager
Fax: 313-2333
Contra Costa County Public works Department
255 Glacier Drive
Martinez, CA 94553
Attn: Leigh Chavez, Planner III
RE: Drainage Area 33A Flood Facilities Improvement Project, CP#:,03-41
Kirker Pass Road, near Kirkwood Drive
Dear Ms. Chavez.-
Thank
havez:Thank you for the opportunity to review the initial study for the above referenced project. The
project includes property within the City of Concord, as wall as facilities planned on property
owned by the City of Concord.
The project includes a number of components including the construction of a detention basin,
performance of culvert maintenance under Kirker Pass Road and desilting within the channel,
culvert replacement under Old Kirker Pass Road, culvert replacement under Concord Boulevard,
and construction of a floodwall downstream of Concord Boulevard, The detention basin would
be constructed on property owned by the City. Ron Parini of the City's Public Forks Division
has been coordinating with the County on this project.
Staff understands that 18 native and 14 non-native trees of 2" to 16" diameter would be removed
to facilitate the project. Such trees would not meet the City's definition of heritage trees,
however, the City does have a standard replacement ratio of 3:1 for non-heritage trees. Due to
the visibility of the area from Kirker Pass Road, the City is requesting a 50/50 mix of 15 gallon
(42 trees) and 24-inch box size (42) trees for re-planting at the basin and adjacent areas.
We strongly recommend and encourage you to hold a neighborhood meeting to inform the
residents of this proposal and obtain their feedback. Should you have any questions, please feel
free to contact ane at (925) 671-3154.
Sincerely,
Jon yan
Ass ciate Plan
Deborah Raines,Planning Manager
Cathy Munneke,Principal Planner
County File
Chron.
03ltr.293County.doc
e-rnaik cityinfo@ci.concord.ca.us 7vebtsite: www.cityofconcord.org
OF
a,.
�AVtrf'
a J STATE OF CALIFORNIAGovernor's Office of Planning and Research
1
�4 1!F O a C1�LifQS
State Clearinghouse
Gray Davis Tal Finney
Governor Interim Director
November 18,2003 '
NOV 2 6 2003
Leigh Chavez
Contra Costa County Community Development =ivl NT AL
651 Pine Street
Martinez, CA 94553
Subject: DA 33A Flood Facilities Improvement Project
SCH#: 2003102078
Dear Leigh Chavez:
The State Clearinghouse submitted the above named Negative Declaration to selected state agencies for
review. The review period closed on November 17, 2003,and no state agencies submitted comments by
that date. This letter acknowledges that you have complied with the State Clearinghouse review
requirements for draft environmental documents,pursuant to the California Environmental Quality Act.
Please call the State Clearinghouse at(916)445-0613 if you have any questions regarding the
environmental review process. If you have a question about the above-named project,please refer to the
ten-digit State Clearinghouse number when contacting this office.
Sincerely,
Terry Roberts
Director, State Clearinghouse
1400 TENTH STREET P.O.BOX 3044 SACRAMENTO,CALIFORNIA 95812-3044
(916)445-0613 FAX(916)323-3018 www.opr.ca.gov
o ct_ 26