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HomeMy WebLinkAboutMINUTES - 03072000 - C.12C.13C.14 C.14 to: BOARD OF SUPERVISORS FROM: J. MICHAEL WALFORD, CHIEF ENGINEER DATE: MARCH 7, 2000 SUBJECT: Approve the San Ramon Creek Drop Structure 3A Repair, Alamo Area. Project No. 7520-61391_59. CDD-CP# 00-09. Specific Request(s) or Recommendation(s) & Background & Justification 1. RECOMMENDED ACTION: APPROVE the San Ramon Creek Drop Structure 3A Repair Project, and DETERMINE that the project is a California Environmental Quality Act (CEQA) Class 1d Categorical Exemption, and DIRECT the Director of Community Development to file a Notice of Exemption with the County Clerk, and 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 Exemption. Continued on Attachment:�X _ _ SIGNA'TUR . �J -/APA. ./ RECOMMENDATION OF COUNTY ADMINISTRATOR _RECOMMENDATION OF BOARD COMMITTEE —APPROVE —OTHER SIGNATURE (S): ACTION OF BOARD ON MARCH 7, 700 APPROVED AS RECOMMENDED_X_OTHER VOTE OF SUPERVISORS I hereby b certify that this is a true and correct UNANIMOUS(ABSENT _ ) Y cerfY AYES: _ __ ----NOES: copy of an action taken and entered on the Lc:df ABSENT: ABSTAIN: minutes of the Board of Supervisors on the G:1GrpDatalEngSvcIENVIRO\2000projects\CEQAoniy\BoardOrdersl date shown. BODrop3A.doc Orig.Div: Public works(Engineering Services Division) Contact: B. Fernandez, Design cc: County Administrator ATTESTED: MARCH 7, 2000 Attn: E. Kuevor _ Auditor-Controller PHIL BATCHELOR, Clerk of the Board of Community Development–D. Foley Supervisors and Count PW Accounting p Y Administrator Construction L.Chavez, Eng.Services By , Deputy G SUBJECT: Approve the San Ramon Greek Drop Structure 3A Repair, Alamo Area. Project No. 7520-61391-59, CDD CP# 00-09. DATE: MARCH 7, 2000 PAGE: 2 11. FINANCIAL IMPACT: The estimated cost of the project is $50,000. Funding will be 70% Zone 3b or Clean Water and 30% FEMA. Ill. REASONS FOR RECOMMENDATIONIBACKGROUND: The project consists of repairing or replacing the failed concrete apron, reinstalling the sub- drain system and repairing the failing west wing wall of Drop Structure 3A. The project is needed to repair the damage caused by the '93 and'95 storms. The project has been determined to be in compliance with the General Plan and is exempt from CEQA because it consists of restoring or rehabilitating an existing deteriorating or damaged public facility. The repair will not involve an expansion of use beyond that previously existing. 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#7528.61391-59 CP#00-09 PROJECT NAME:ff San Ramon Creek Drop Structure 3A Repair PREPARED BY: Leigh Chave ez ) DATE: 1124100 APPROVED BY: 06AA__.-, DATE: 4(X160 RECOMMENDATIONS: (X) Categorical Exemption (Class 1d) ( ) Negative Declaration ( ) Environmental Impact Report Required ( ) Conditional Negative Declaration The project will not have a significant effect on the environment. The recommendation is based on the following: The project consists of restoring or rehabilitating an existing deteriorating or damaged public facility. The repair will not involve an expansion of use beyond that previously existing nor result in the removal of any scenic resource. What changes to the project would mitigate the identified Impacts NIA USGS Quad Sheet Las Trampas Ridge Base Map Sheet# R15 Parcel # NIA GENERAL CONSIDERATIONS: 1. Location: The project is located on San Ramon Creek at Drop Structure 3A near Lyman Lane and MacDonald Court (Figures 1-4) in the central county area near the community of Alamo. 2. Project Description: As a result of recent heavy storms (`93 and '95), Drop Structure#3A has sustained damage. Temporary repair measures, including pumping grout into the voids on the concrete apron have proven unsuccessful in stopping the deterioration of the drop structure. Therefore, the failing sections of the drop structure require rehabilitation. The project consists of repairing or replacing the failed concrete apron, reinstalling the sub-drain system and repairing the failing west wing wall. Currently only two weep holes within the sub-drain system are functioning. The repair will be conducted by removing the failed sections of the drop structure, reinstalling the sub-drain system, building the necessary forms to pour the concrete wing wall and apron, and pouring concrete to repair the failing sections of the drop structure. Pre-mixed concrete will be brought to the site to repair the failing sections. The entire work area will be dewatered and flows will be diverted around the construction zone to ensure continuous flows downstream of the project area. A sediment filter dam will be installed downstream of the project area to minimize sedimentation. Following completion of the project, all disturbed areas on the banks of the channel will be hydroseeded with a mix including native grasses. The work will impact the minimum amount of vegetation possible. No trees will require removal to repair the drop structure. Standard Best Management Practices(BMPs)such as locating stockpiles outside of the streamzone, fueling and maintaining equipment at designated staging areas, and maintaining a clean work site will be employed. /� lb 3. Dees It appear that any feature of the project will generate significant public concern? [] yes [X] no [] maybe (Nature of concern): 4. Will the project require approval or permits by other than a County agency? [X] yes [] no Agency Name(s) CDFQ, RWQCSf USACOE 5. Is the project within the Sphere of influence of any city? No G.iengservlenvirol2000projects\CEQAOnly\Catex\Drop3A '.,'2- CALIFORNIA ENVIRONMENTAL QUALITY ACT Notice of Exemption Contra Costa County Community Development Department 651 Pine Street, 4th Floor-North Wing,McBrien Administration Building Martinez, C.A.94553-0095 Telephone: (510)313-2298 Contact Person:Cece Sellgren-Public Works Dept. Project Description,Common Name(if any)and Location:San Ramon Creole Drop Structure#3A Repair,County File#:CP 00-09 Project Description: As a result of recent heavy storms('93 and'95), Drop Structure#3A has sustained damage. Temporary repair measures,including pumping grout into the voids on the concrete apron have proven unsuccessful in stopping the deterioration of the drop structure. Therefore,the failing sections of the drop structure require rehabilitation. The project consists of repairing or replacing the failed concrete apron, reinstalling the sub-drain system and repairing the failing west wing wall. Currently only two weep hales within the sub-drain system are functioning. The repair will be conducted by removing the failed sections of the drop structure, reinstalling the sub-drain system, building the necessary forms to pour the concrete wing wall and apron,and pouring concrete to repair the failing sections of the drop structure. Pre-mixed concrete will be brought to the site to repair the failing sections. The entire work area will be dewatered and flows will be diverted around the construction zone to ensure continuous flows downstream of the project area. A sediment filter dam will be installed downstream of the project area to minimize sedimentation. Following completion of the project,all disturbed areas on the banks of the channel will be hydroseeded with a mix including native grasses. The work will impact the minimum amount of vegetation possible. No trees will require removal to repair the drop structure. Standard Best Management Practices (BMPs)such as locating stockpiles outside of the streamzone, fueling and maintaining equipment at designated staging areas, and maintaining a clean work site will be employed. Project location: The project is located on San Ramon Creek at Drop Structure#3A(near Lyman Lane and MacDonald Court) in the central county area near the community of Alamo. This project Is exempt from CEQA as a: ,,,,_ Ministerial Project(Sec. 15288) tither Statutory Exemption, Section Declared Emergency(Sec. 15289(a)) i General Mule of Applicability (Section 15061(b)(3) _ Emergency Project(Seco 15269(b)or(c)) Categorical Exemption, Class 1_d_ for the following reason(s): The project consists of restoring or rehabilitating an existing deteriorating or damaged public facility. The repair will not involve an expansion of use beyond that previously existing nor result in the removal of any scenic resource.. 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: County Public Works Department 255 Glacier Drive Martinez,CA 94553 Atte_neigh Qua County Clerk Fee$50 Due G:\design\envlm\2000ProjectslCEQAOnly1NOE\Drop3A igure 1 WLJ oL-Li ` ) 0 � 0 0 < cn W r_' o �t (� Q (D ° �..✓ nn - �1 < <L o -- o •W 6 J < < LJ W <-r� �< _z ~ —J +� U < o0 Of (D - CI W C� W --t W CC C�o W o 0 CL < Mo CIS < o t� Figure �� � 'Project LOcaflola fOp CCWTrvu sem` B x CASNIS EEK is °i+ � � �..—•.��'""_ �••�"" �"yta 1�1 lam f � � ,,,, a • 1 3b �rq � t t� .,.--- ��� �� �"° t� '�g+����•.,.,,.,� ..moi, k � t `pyr"••`.,.,r`y4dY t � ,Sr �.�.r r.�.r���� {�` '`_; y iy 1� va it'y.� r a 4' 4 15 �,, aF+� � ..L aM }�i i„i d"ikvw .r .r�f�('�' r•"'.` ��r y4,. , Y1.�;,q+''sktt,:”,°.•.=�i:: ..h�&aw V _ --_.« }yY `.l 'r. rsi,Y F' 1"'";+d79 x ` '•r} tJ }y�,�ty t !+. 4 '00 OILa„•` fi F "SC' 34 •'+,,a�h e, $'j ,tR t a '"± fi 3Nx 1 t,a � uy,rti�}F�ysq� � at'�¢xtkl�i tµ"t1ty'F�' ,F a Y .�..,y.,,y;Y.e�., v f. w-;.' fi��u •�,. .'F:s P,� .L�t'k'.. 'a k � / t ��..:.x:t; (...,�:r f.;'"-+;••ai"e{. :��A. .. •q!a;a..'7.'1 °.,,�'.;:. t rFL,}`;;t`':�.�T+ iGf67w�'�+�: h�•:i r d Y tt,.,�..—,sa•�^',»v++'Trs+.,.. � �/�}�y(�.jur�i5.WItLJ�ER�I�SB , - 't ':3A,`. y 'ed,'.' ?iN}•rtyQ'"�( r°3.' .k l "::fi` .,,,..r..-. e •a. {`i 1.'357. 1,Sa5. Figure 3 PACC or. NkRRA.TM, SKETCH, AND CALCULATION SIM EA T APPUCANT: or�k-.,.-k Cas- n k16 `t+..b1%c- W a r Ks DISAs-rER No: 1 py 4 PA NO: 013--cjz\00 DSR NO. 283 85 CATEGORY: i Q G-rgded ri'pr side balm Drop S+rvclure Cresf � COnc rhe. Pane 1 on �t rhe sl ku X15 Z �EkODC-D MAX bbatnaged Chianne l �an�. r� r`ucturntre f3as tm (3194) Figure 46,"0 PAGE of�YJ ENARRATIVE, SKETCH, ANIS CALCULATION SHEET "tra Costa C'r,un-� Public Works44-DR-CA PA NO: 9 is 0 -DSR NOCATEGORY: D SGOure rpra pej 5ecicok� s �. ! paw `'a 0� [Fct . of zoure4 Lko- Pro Sed ed of ex.Ulq�l to xt- k k Sectk cK A-a` `y? , ► cuio (0(e „ Al 46 Place new cQ r , po'ka e xlid e upstOpe -t� tp cf rcoure-d Tec h I`n f ieu. op pto S rC TO: BOARD OF SUPERVISORS FROM: J. MICHAEL WALFORD, CHIEF ENGINEER DATE: MARCH 7, 2000 SUBJECT: Approve the Rossmoor Basin-Tice Creek Streambank Repair Project, Walnut Creek Area. Project No. 7575-6D9P20. CDD-CP# 00-17. Specific Request(s) or Recommendation(s) & Background & Justification 1. RECOMMENDED ACTION: APPROVE the Rossmoor Basin —Tice Creek Streambank Repair Project, and DETERMINE that the project is a California Environmental Quality Act (CEQA) Class 1d Categorical Exemption, and DIRECT the Director of Community Development to file a Notice of Exemption with the County Clerk, and 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 Exemption. Continued on Aftachment:—,X SIGNATOR . RECOMMENDATION OF COUNTY ADMINISTRATOR RECOMMENDATION OF BOARD COMMITTEE APPROVE OTHER SIGNATURE (S): ACTION OF BOARD ON MARCH 7, 2000 APPROVED AS RECOMMENDED OTHER i VOTE,OF SUPERVISORS Norse X UNANIMOUS {ABSENT _ _. } I hereby certify that this is a true and correct AYES: NOES: copy of an action taken and entered on the LC:df ABSENT: ABSTAIN: minutes of the Board of Supervisors on the G:\GrpData\EngSvc\ENVIRO\2000projects\CEQAonly\BoardOrders\ date shown. BORossmoorBasin.doc Odg.Div: Public works(Engineering Services Division) Contact: J. Fahy, Maintenance 7, 2000 cc: County Administrator ATTESTED: Attn: E. Kuevor Auditor-Controller PHIL BATCHELOR, Clerk of the Board of Community Development–D. Foley PW Accounting Supervisors and County Administrator Construction L.Chavez,Eng.Services By , Deputy SUBJECT: Approve the Rossmoor Basin —Tice Creek Streambank Repair Project, Walnut Creek Area. Project No. 7575-6D9P20. CDD-CP# 00-17. DATE: MARCH 7, 2000 PAGE: 2 II. FINANCIAL IMPACT: The estimated cost of the project is $16,500. Funding will be 75% FEMA, 18.75% State and 6.25% Drainage Area 67A. III. REASONS FOR RECOMMENDATIONIBACKGROUND: The project consists of the repair of an approximately 45' by 20' bank slipout by removing eroded earthen material and replacing it with rock slope protection. The project is needed to repair the damaged Streambank. The project has been determined to be in compliance with the General Plan and is exempt from CEQA because it consists of the repair of an existing damage public facility and will not involve an expansion of use beyond that previously existing. 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#7575-6139P20 CP#00-17 PROJECT NAME: Rossmoor Basin —Tice Creek Streambank Repair PREPARED BY: Leigh Chave (,- J DATE: 1/24/00 APPROVED BY' DATE: �!'��' RECOMMENDATIONS: (X) Categorical Exemption (Class 1d) ( ) Negative Declaration ( ) Environmental Impact Report Required ( ) Conditional Negative Declaration The project will not have a significant effect on the environment. The recommendation Is based on the following: The project consists of the repair of an existing damaged public facility. The repair will not involve an expansion of use beyond that previously existing nor result in the removal of any scenic resource. What changes to the project would mitigate the Identified Impacts N/A USGS Quad Sheet Las Trampas Ridge Base Map Sheet# R13 Parcel # NIA GENERAL CONSIDERATIONS: 1. Location: The project is located along Tice Creek at the Rossmoor Basin approximately 1200' upstream of Tice Valley Boulevard in the central county area near the City of Walnut Creek (Figure 1,2). 2. Project Description: The project consists of repairing an approximately 45' by 20' bank slipout by removing eroded earthen material and replacing it with rock slope protection. The riprap will be placed such that it ties into existing riprap on the channel bank. The construction will occur during the dry season, however, Tice Creek is perennial and flows will need to be diverted around the project site. A sediment filter dam will be installed downstream of the project site to minimize sedimentation within the creek as a result of the project. The repair activity will be kept to the minimum necessary to accomplish the repair, and the work site will be kept clear of construction debris. Operation of equipment within the channel will be kept to the minimum amount possible. All exposed slopes will be hydroseeded and the loose rock slope protection will be backfilled with soil above the ordinary high water mark and hydroseeded. Standard Best Management Practices (BMPs) such as locating stockpiles outside of the streamzone, fueling and maintaining equipment at designated staging areas, and maintaining a clean worksite will be employed. USFWS representatives have visited the project site and determined the site to be either a No Effect or Not Likely to Adversely Affect project for red-legged frogs based on the high level of urbanization surrounding the project site. Based on this determination from USFWS, the County will incorporate the conditions typically required by USFWS to minimize potential impacts to red- legged frogs for Not Likely to Adversely Affect projects. These conditions include working during the dry season (April through September), dewatering the project site, and conducting preconstruction surveys within two weeks of Initiating the project. `3. Does it appear that any feature of the project will generate significant public concern? [] yes [X] no [] maybe (Nature of concern): 4. Will the project require approval or permits by other than a County agency? [X] yes Q no Agency Name(s) CDFG, RWQCB, USACOE 5. is the project within the Sphere of influence of any city? Yes, the City of Walnut Creek G:\engserv\enviro\2000projects\CEQAOnly\Catex\Rossmoor 3-me* y CALIFORNIA ENVIRONMENTAL QUALITY ACT Notice of Exemption Contra Costa County Community Development Department 651 Pine Street, 4th Floor-North Wing,McBrien Administration Building Martinez, C.A.94553-0495 Telephone: (510)313-2296 Contact Person:Cece Seligren-Public Works Deo#. Project Description,Common Name(if any)and Location: Rossmoor Basin-Tice Creek Streambank Repair,County File#:CP 00-17 Project Description: The project consists of repairing an approximately 45'by 20'bank slipout by removing eroded earthen material and replacing it with rock slope protection. The riprap will be placed such that it ties into existing riprap on the channel bank. The construction will occur during the dry season, however,Tice Creek is perennial and flows will need to be diverted around the project site. A sediment filter dam will be installed downstream of the project site to minimize sedimentation within the creek as a result of the project. The repair activity will be kept to the minimum necessary to accomplish the repair, and the work site will be kept clear of construction debris. Operation of equipment within the channel will be kept to the minimum amount possible.All exposed slopes will be hydroseeded and the loose rock slope protection will be backfilled with soil above the ordinary high water mark and hydroseeded. Standard Best Management Practices (BMPs) such as locating stockpiles outside of the streamzone, fueling and maintaining equipment at designated staging areas,and maintaining a clean worksite will be employed. USFWS representatives have visited the project site and determined the site to be either a No Effect or Not Likely to Adversely Affect project for red-legged frogs based on the high level of urbanization surrounding the project site. Based on this determination from USFWS, the County will incorporate the conditions typically required by USFWS to minimize potential impacts to red-legged frogs for Not Likely to Adversely Affect projects. These conditions include working during the dry season (April through September), dewatering the project site, and conducting preconstruction surveys within two weeks of initiating the project. Project location: The project Is located on Tice Creek at the Rossmoor Basin approximately 1200'upstream of Tice Valley Boulevard in the central county area near the City of Walnut Creek. This project is exempt from CEQA as a: _ Ministerial Project(Sec. 15268) Other Statutory Exemption, Section Declared Emergency(Sec. 15269(a)) General Rule of Applicability (Section 15061(b)(3) _ Emergency Project(Sec. 15269(b)or(c)) Categorical Exemption, Class 1 d for the following reason(s): The project consists of the repair of an existing damaged public facility. The repair will not involve an expansion of use beyond that previously existing nor result in the removal of any scenic resource. 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: County Public Works Department 255 Glacier Drive Martinez,CA 94553 gtfr�: L21gh Chavez County Clerk Fee$50 Due C.idesign\enviro12000Projects\CEQAOnly\NOElRossmoor 1 e, �, %3 igwe V 1` 0 Lli w Y � s^, j 0 �+ +� ry Df (' 0 z z zLJJ O `�.�✓' `e'�"� tea" �" /^`'�y W W C� Cl-LLJ O CC C� C ? m t.� r� 1. C w� - - 0 iJ l . _ W. . 0 -J ==== a 0 cn Figure sEE 631 "P +`tai y.�� ,�p�� i" iJ>Z ' >S:__ ,a... �r� •+Y' /% J,.-, li .••^,'' `s$ YI Yfs•.t i" +� �,"+ r.vvr"'� �..� y��d r "."`4 6 J (� ��'\ J!r/ tJ +1re..�,r +i�• f` 'Y +�R' Yl E X102 ■^q•Ci LN 771. '.jr ef Y 1 �.A l ' + , r� i + R._..y..a- .•11d Nri! x y2 i� irt f ��yffjtl t > •� �i � Cl'1 1 10 '•_ 4M 47 ti tf •t,�. 4 +ry 77Yi4 SAY ALAM OL .''l t....•, � tL t5� it ��: ' yt�ylLY to 40 r t b •, '�—+-�`�'d'..�- s ,"�;',��,.' "fir TO: BOARD OF SUPERVISORS jl3� FROM: J. MICHAEL WALFORD, Chief Engineer DATE: March 07, 2000 SUBJECT: APPROVE AND DETERMINE THAT THE PROJECT IS A CEQA MITIGATED NEGATIVE DECLARATION. PROJECT NO. 7520-6B8508. CDD-CP#994103, GRAYSON CREEK PHASE 1B IS IN THE CENTRAL COUNTY AREA NEAR THE CITY OF PLEASANT DILL. FUNDING IS DRAINAGE AREA 45 FEES (47%), ZONE 3H (43%), CITY OF PLEASANT (10%) Specific Request(s) or Recommendation(s) & Background & Justification I. RECOMMENDED ACTION: APPROVE Grayson Creek Phase lb, and DETERMINE that the project is a California Environmental Quality Act (CEQA) Mitigated. Negative Declaration, and DIRECT the Chief Engineer to prepare contract plans and specifications for construction, and DIRECT the Director of Community Development to file a Notice of Exemption with the County Clerk. { Continued on Attachment: x SIGNATURE.,,,-, -y y RECOMMENDATION OF COUNTY ADMINISTRATOR _RECOMMENDATION OF BOARD COMMITTEE APPROVE OTHER SIGNATURE(S): ACTION OF BOARD ON MARCH 7 9 2000 APPROVED AS RECOMMENDED X OTHER I hereby certify that this is a true and correct copy of an action taken and entered on the minutes of VOTE OF SUPERVISORS the Board of Supervisors on the date shown. UNANIMOUS (ABSENT NONE ) AYES: NOES: MARCH 7, 2000 ABSENT: ABSTAIN: ATTESTED: PHIL BATCHELOR, Clerk of the Board of EC:df Supervisors and County Administrator G:\GrpData\EngSvc\ENVIRO\2000projects\Board Orders\Board Order Grayson Creek Phase lb.doc Orig.€)iv: Public Works (Flood Control) By Contact: M. Boucher; (923) 313-2311 Deputy cc: Administrator-Attn: E. Kuevor Auditor-Controller Community Development-D. Foley Public Works:Accounting M. Boucher, Flood Control E. Crosby, Engineering Services SUBJECT: APPROVE AND DETERMINE THAT THE PROJECT IS A CEQA MITIGATED NEGATIVE DECLARATION. PROJECT NO. 7520-688508. CDD-CP#99-103, GRAYSON CREEK. PHASE 1B IS IN THE CENTRAL COUNTY AREA NEAR THE CITY OF PLEASANT HILL. FUNDING IS DRAINAGE AREA 46 FEES (47010), ZONE 3B (43%), CITY OF PLEASANT (10%) DATE: March 07, 2000 PAGE: 2 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 Exemption. II. FINANCIAL IMPACT: The estimated project cost is $ 350,000.00 funded by Drainage Area 46 Fees (47%), Zone 3B (43°10), City of Pleasant (10%) Funds III. REASONS FOR RECOMMENDATION]BACKGROUND: The Contra Costa County Flood Control District proposes to install 145 linear meters (475 linear feet) of twin 102 inch spiral ribbed metal pipe from the existing terminus of a prior year pipe installation, upstream to a point approximately 180 feet north of Boyd Road. The purpose of Drainage Area 46 Grayson Creek Bypass Phase lb is to extend the storm water bypass pipe to a point off of school property. The bypass pipe will eventually become an integral component to the Drainage Area 46 Plan. The trench will be excavated to a dimension of 7 meters (23 feet) wide and 4.6 meters (15 feet) in depth. The pipes will be bulkheaded at the upstream terminus to allow for future extension. The pipe will be placed in the trench, and the trench back-filled. The installation of the pipe will result in the removal of 469 square meters (5,046 square feet) of riparian habitat. This includes approximately nineteen mature trees that have a diameter at breast height (dbh) greater than 6", seventy-two saplings which have a dbh of 1" -y 6", and one hundred seventy-two seedlings with a dbh of 1" or less. The riparian vegetation is predominately characterized by the presence of valley oaks (Quercus lobata), although some coast live oak (Quercus agrifolia) and non-native ornamental trees are also found. Four small storm drain lines, originating from the adjacent school site, will be connected to the western most pipe. A chain link fence will be temporarily removed and replaced at the conclusion of the project. Due to the depth of the excavation the contractor will be required to shore the excavation, and California State Architect approved permanent shoring will be placed along a school building. At the completion of the pipe installation, the project area will be revegetated with native grass/herbaceous species. The total acreage of riparian area to be restored will be three times the acreage of riparian area removed. Appropriate understory species will also be planted to achieve a diversity of species that is not present at this time. This will be accomplished within guidelines set forth by the City of Pleasant Hills' Public Works Department, Directions and Guidelines for Creek Maintenance (September 1998). In addition the disturbed area will be re-seeded with a mixture of native grasses. The onsite planting will extend the number and diversity of riparian SUBJECT: APPROVE AND DETERMINE THAT THE PROJECT IS A CEQA MITIGATED NEGATIVE DECLARATION. PROJECT NO. 7520-688508. CDD-CP#99-103, GRAYSON CREED PHASE 113 IS IN THE CENTRAL COUNTY AREA NEAR THE CITY OF PLEASANT HILL. FUNDING IS DRAINAGE AREA 46 FEES (47%), ZONE 3B (43%), CITY OF PLEASANT (10%) DATE: March 07, 2000 PAGE: 3 plant species both upstream and downstream of the project area. This plan will also add age diversity to this portion of Grayson Creek. The restoration plantings will be irrigated for three years and monitored for five years. Success criteria of 65% survivorship after five years shall be achieved. Failure to achieve the success criteria shall result in additional plantings to achieve the 65% success rating. IV. CONSEQUENCES OF NEGATIVE ACTION: Delay in approving the project will result in a delay of design and construction and may jeopardize funding. nni Community Contra Own De i Dire4or Development�► of Department County County Administration Building JAN3 +651 Pine Street t 4th Floor,North Vying WEI Martinez,California 94553-0095 _ 4".,x BY Phone: Jan a 11, 2000 NOTICE OF PUBLIC REVIEW AND INTENT TO ADOPT A PROPOSED MITIGATED NEGATIVE DECLARATION County File # CP #99-103 Pursuant to the State of California Public Resources Code and the "Guidelines for Implementation of the California Environmental Quality Act of 1970" as amended to date, this is to advise you that the Community Development Department of Contra Costa County has prepared an initial study on the following project: Drainage Area 46 Grayson Creek Bypass-Phase 1d # CP#99-103: The Contra Costa County Flood Control District proposes to install 145 linear meters (475 linear feet) of twin 102 inch spiral ribbed metal pipe from the existing terminus of a prior year pipe installation, upstream to a point approximately 180 feet north of Boyd Road. The purpose of Drainage Area 46 Grayson Creek Bypass Phase 1 b is to extend the storm water bypass pipe to a point off Sequoia Middle School property. The bypass pipe will eventually become an integral component to the Drainage Area 46 Plan. The trench will be excavated to a dimension of 7 meters (23 feet) wide and 4.6 meters (15 feet) in depth. The pipes will be bulkheaded at the upstream terminus to allow for future extension. The pipe will be placed in the trench, and the trench back-filled. The spoils not used to backfill the trench will disposed of by the contractor at an offsite location. Due to the depth of the excavation the contractor will be required to shore the excavation, and California State Architect approved permanent shoring will be placed along a school building. Four small storm drain lines, originating from the adjacent school site, will be connected to the western most pipe. A chain link fence will be temporarily removed and replaced at the conclusion of the project. The installation of the pipe will result in the removal of 469 square meters (5,046 square feet) of riparian habitat. This includes approximately nineteen mature trees that have a diameter at breast height (dbh) greater than 6", seventy-two saplings which have a dbh of 1" _ 6", and one hundred seventy-two seedlings with a dbh of 1" or less. The riparian vegetation is predominately characterized by the presence of valley oaks (Quercus lobata), although some coast live oak (Quercus agrifolia) and non-native ornamental trees are also found. At the completion of the pipe installation, the project area will be revegetated with native herbaceoustgrass species. The total acreage of riparian area to be planted will be three times the acreage of riparian area removed. Trees and understory species will also be planted to achieve a diversity of species that is not present at this time. Page 1 of 2 Office Hours Monday-Frday:8:00 a.m.-5:00 p.m. Office is closed the 1 st, 3rd&5th Fridays of each month NOTICE OF PUBLIC REVIEW AND INTENT TO ADOPT A PROPOSED NEGATIVE DECLARATION Drainage Area 46 Grayson Creek Bypass-Phase 1 b County file#CP#99403 This will be accomplished within guidelines set forth by the City of Pleasant Hills' Public Works Department, Directions and Guidelines for Creek Maintenance, (September 1998). The onsite planting will extend the number and diversity of riparian plant species both upstream and downstream of the project area (Figure 4). This plan will also add age diversity to this portion of Grayson Creek by interspersing younger trees beneath the canopy of mature trees. The restoration plantings will be irrigated for three years and monitored for five years. Success criteria of 65% survivorship after five years shall be achieved. Failure to achieve the success criteria shall result in additional plantings to achieve the 650 success rating. Project Location. The project site is located in the City of Pleasant Hill. The project is located 180 feet (55 meters) upstream of Boyd Road and extending 475 feet (145 meters) further upstream along the top of bank of Grayson Creek(Figure 1-4) The proposed development will not result in any significant impacts. A copy of the mitigated negative declaration and all documents referenced in the negative declaration may be reviewed in the offices of the Community Development Department, and Application and Permit Center at the McBrien Administration Building, North Wing, Second Floor, 651 Pine Street, Martinez, during normal business hours. Public Comment Period —The period for accepting comments on the adequacy of the environmental documents extends to 5:00 P.M., Monday, February 14, 2000. Any comments should be in writing and submitted to the following address: Debbie Chamberlain, Principal Planner Community Development Department Contra Costa County 651 Pine Street, North Wing, 4"' Floor Martinez, CA 94553 Any questions regarding the project itself, should be directed to: Earl Crosby (925)313-2293 255 Glacier Drive Martinez, CA 94553 Debbie Chamberlain Principal Planner At 9AEn9SvdENVIR0k2000 projects\ Grayson Creek Phase IMNotice of Public Review.doc Cc County Clerk's office (2 copies) Public Works—E.Crosby, Engineering Services Page 2 of 2 _rte CONTRA PUBLIC WORKS DEPARTMENT COSTA INITIAL STUDY COUNTY OF ENVIRONMENTAL SIGNIFICANCE PROJECT# 7520-6138508 CP#951-103 PROJECT NAME: Grayson Creek Phase 1b PREPARED BY: DATE: 12121/99 APPROVED BY: DATE:. p r//C /� wm*44,f _ 1 1 RECOMMENDATIONS: Categorical Exemption (Class ) (,() Mitigated Negative Declaration { ) Environment Impact Report Required () Conditional Negative Declaration The project will not have a significant effect on the environment The recommendation is based on the following: 1. 6esthetics/Sce_nic Resources: The project location is not within view of a scenic vista or a state scenic highway. The project area will be cleared; requiring the removal of up to 469 square meters (5046 square feet) of riparian habitat. This includes approximately nineteen mature trees that have a diameter at breast height (dbh) greater than 6", seventy-two saplings which have a dbh of 1"— 6", and one hundred seventy-two seedlings with a dbh of 1" or less. The riparian vegetation is predominately characterized by the presence of valley oaks (Quercus lobata), although some coast live oak(Quercus agrifolia) and non-native ornamental trees are also found. At the completion of the pipe installation the project area will be revegetated with herbaceous native plant species. Native trees and shrubs will be planted between the project area and the edge of top of bank. Additional trees and shrubs will be planted further upstream and downstream along the top of bank. The total riparian acreage to be restored will be three times the riparian area disturbed, will be approximately 1,407 square meters (15,145 square feet)(Figure 4). The restoration plantings will be irrigated for three years and monitored for five years. Success criteria of 65% survivorship after five years shall be achieved. Failure to achieve the success criteria shall result in additional plantings to achieve the 65% success rating. See the Mitigation Summary for more details. There are no designs to install any lighting, either temporary or permanent 2. iolggical Resources: The project limits are outside U.S. Army Corps of jurisdiction as defined by Section 404 Clean Water Act, and wetlands will not be affected by the construction of this project. The riparian vegetation is predominately characterized by the presence of valley oaks (Quercus lobata), although some coast live oak(Quercus agrifolia) and non-native ornamental trees are also found. Clue to maintenance activities,the understory is a mixture of herbaceous species without the typical shrub species usually associated with this type of habitat. At the completion of the pipe installation,the project area will be re-seeded with native grass/herbaceous species. The lost riparian area will be planted at three times the acreage of riparian area removed (Figure 4). Appropriate understory species will also be planted to achieve a diversity of species that is not present at this time. This will be accomplished within guidelines set forth by the City of Pleasant Hills' Public Works Department, Directions and Guidelines for Creek Maintenance, (September, 1998). The onsite planting will extend the number and diversity of riparian plant species both upstream and downstream of the project area. This restoration will also add age diversity to this portion of Grayson Creek by interspersing younger trees amongst mature individuals. Furthermore this plan is consistent with Contra Costa General Plan Conservation Element Policies 8-88 (New development which modifies or destroys riparian habitat because of needed flood control, shall be responsible for restoring and enhancing an equivalent amount of habitat within or near the project area), 8-91, (Grading,filling and construction activity near watercourses shall be conducted in such a manner as to minimize impacts from increased runoff, erosion, I 7410 Grayson Creek Phase 1 b— Initial Study Project No. 7520-688508; CP 99-108 Page 2 of 4 2.cwt. sedimentation, biochemical degradation, or thermal pollution.), 8-92 (revegetation of watercourse shall employ native vegetation, providing the type of vegetation is compatible with the watercourse's maintenance program and does not adversely alter channel capacity). The restoration plantings will be irrigated for three years and monitored for five years. Success criteria of 65% survivorship after five years shall be achieved. Failure to achieve the success criteria shall result in additional plantings to achieve the 66% success rating. 3. Land Use and Planning. The proposed project will not result in a substantial alteration of the present or planned land use of the area, nor conflict with any applicable habitat conservation plan or natural community conservation plan. 4. Cultural Resources: The Northwest Information Center at Sonoma State University reviewed records and literature on file, and determined that there is no indication of historical archaeological sites or historic structures in the project area, and the possibility of identifying cultural resources in the project area is low. The contract specifications shall include measures related to discovery of cultural and/or archeological resources. The construction site resident engineer will receive training regarding identification of cultural resources and procedures to follow in the event of discovery. The majority of the impacts will occur during or directly proceeding the construction phase of the project. In order to minimize the impacts associated with construction of the bypass, the following will be adhered to; 5. Geology and Soils: During the construction phases the contractor will abide by Best Management Practices, for exampled the use of Environmental Sensitive Area fencing will minimize the area exposed to disturbance. The installation of erosion control blankets, silt fencing and the hydroseeding of native plant species will stabilize the project area before the winter rains. Adherence to standard dust control including, but not limited to, general watering of exposed areas and/or use of chemical stabilizers will minimize air quality impacts. These measures shall be incorporated into the construction contract. 6. Hazards and HazardousMaterials: Per contract specifications, standard construction safety practices shall be followed during construction to ensure no accidental release of hazardous substances or increase the potential for exposure to these substances. The project has no potential for interfering with an emergency response, but emergency response agencies in the area shall be notified prior to the onset of construction. The timing of project construction coincides with summer break to reduce the exposure of school children to potential emissions. In addition, contract specifications shall stipulate the use of properly tuned and muffled equipment and the elimination of unnecessary idling of equipment when not in use. These measures shall reduce construction period emissions. 7. lydrology and Water Quality,All nuisance groundwater encountered during the course of the project will be adequately treated before being discharged. Groundwater infiltration during the excavation of the trench will be pumped into a baffled tank. The baffled tank is designed to allow sediment to drop out of the water column, and be discharged without further treatment. This method will be employed before any groundwater is discharged into Grayson Creek. I Grayson Creek Phase 1 b-- Initial Study Project No. 7520-688508; CP 99-103 Page 3 of 4 8. Noise: The dominant source of noise in the project area is from traffic on Boyd Road. Since there is a sensitive noise receptor(Sequoia Middle School)within 150 feet of the project, construction activity may result in exposure of people to elevated noise levels. The installation of the bypass pipe will temporarily increase the noise level of the project area during construction. in general, construction activities produce noise levels of approximately 86 dBA at 50 feet (15 meters), which is well below the threshold of pain of 120-140 dBA. School will not be in session during construction, and will not be affected by the increase in noise. The noise level from the construction activities, between the hours of 7:00 p.m. and 7:30 a.m. on weekdays and between 7:00 p.m. and 9:00 a.m. on weekends and holidays will not exceed 86 dBa at a distance of 50 fleet (15 meters). In addition the working hours will be restricted between 7:30a.m. to 7:00 p.m. Monday through Friday, an on Saturday and Sunday. 9:00 a.m. to 6:00 p.m. What changes to the project would mitigate the Identified Impacts. At the completion of the pipe installation, the project area will be revegetated with native herbaceous/grass species. The total acreage of riparian area to be planted will be three times the acreage of riparian area removed. Trees and understory species will also be planted to achieve a diversity of species that is not present at this time. This will be accomplished within guidelines set forth by the City of Pleasant Hills' Public Works Department, Directions and Guidelines for Creek Maintenance, (September, 1998). The onsite planting will extend the number and diversity of riparian plant species both upstream and downstream of the project area (Figure 4). This plan will also add age diversity to this portion of Grayson Creek by interspersing younger trees beneath the canopy of mature trees. The restoration plantings will be irrigated for three years and monitored for five years. Success criteria of 65% survivorship after five years shall be achieved. Failure to achieve the success criteria shall result in additional plantings to achieve the 65% success rating. USGS Quad Sheet Walnut Creek Base Map Sheet# K-14 Parcel # 150-20-15 GENERAL CONSIDERATIONS: 1. Location: The project site is located in the City of Pleasant Hill. The project is located 180 feet (55 meters) upstream of Boyd Road and extending 475 feet(145 meters)further upstream along the top of bank of Grayson Creek (Figure 1-3) 2. Project Description: The Contra Costa County Flood Control District proposes to install 145 linear meters(475 linear feet)of twin 102 inch spiral ribbed metal pipe from the existing terminus of a prior year pipe installation, upstream to a point approximately 180 feet north of Boyd Road. The purpose of Drainage Area 46 Grayson Creek Bypass Phase 1 b is to extend the storm water bypass pipe to a point off Sequoia Middle School property. The bypass pipe will eventually become an integral component to the Drainage Area 46 Plan. The trench will be excavated to a dimension of 7 meters (23 feet) wide and 4.6 meters (15 feet) in depth. The pipes will be bulkheaded at the upstream terminus to allow for future extension. The pipe will be placed in the trench, and the trench back-filled. The spoils not used to backfill the trench will disposed of by the contractor at an offsite location. Due to the depth of the excavation the contractor will be required to shore the excavation, and California State Architect approved permanent shoring will be placed along a school building. Four small storm drain lines, originating from the adjacent school site, will be connected to the western most pipe. A chain link fence will be temporarily removed and replaced at the conclusion of the project. Grayson Creek Phase 1 b— Initial Study Project No. 7520-6138509; CP 99-103 Page 4 of 4 2.c©nt. The installation of the pipe will result in the removal of 469 square meters (5,046 square feet) of riparian habitat. This includes approximately nineteen mature trees that have a diameter at breast height (dbh) greater than 6", seventy-two saplings which have a dbh of 1" — 6", and one hundred seventy-two seedlings with a dbh of I"or less. The riparian vegetation is predominately characterized by the presence of valley oaks (Quercus lobata), although some coast live oak(Quercus agrifolia) and non-native ornamental trees are also found. At the completion of the pipe installation, the project area will be revegetated with native herbaceous/grass species. The total acreage of riparian area to be planted will be three times the acreage of riparian area removed. Trees and understory species will also be planted to achieve a diversity of species that is not present at this time. This will be accomplished within guidelines set forth by the City of Pleasant Hills' Public Works Department, Directions and Guidelines for Creek Maintenance, (September, 1998). The onsite planting will extend the number and diversity of riparian plant species both upstream and downstream of the project area (Figure 4). This plan will also add age diversity to this portion of Grayson Creek by interspersing younger trees beneath the canopy of mature trees. The restoration plantings will be irrigated for three years and monitored for five years. Success criteria of 65% survivorship after five years shall be achieved. Failure to achieve the success criteria shall result in additional plantings to achieve the 65% success rating. 3. Does it appear that any feature of the project will generate significant public concern? [] yes [J"] no [] maybe (Nature of concern): 4. Will the project require approval or permits by other than a County agency? [J]yes [] no Agency Name(s) California Department of Fish and Game (Streambed Alteration Agreement Extension and Amendment) 5. Is the project within the Sphere of Influence of any city? 'Yes, City of Pleasant Hill G:\GrpData\EngSvc\ENVIRO\2000projects\DEQAonly\Grayson Cr 1 b Initiai Study.doc (Rev 2/97) ,:�o// ,mss fr'IrG2� OVA 0 4 4- c� � LLA ' r-� 4. 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PHASE 1B AREAS FOR MITIGATION PLANTING 4 BoY�._. ___.....__ .. ._..__..1._._..a..___ Environmental Checklist Form 1. Project Title: Drainage Area 46 Grayson Creek Bypass Phase lb 2. Lead Agency Name and Address: Contra Costa County Community Development Department 651 Pine Street,North Wing-4th Floor Martinez,CA 94553 3. Contact Person and Phone Number: Earl Crosby (925)313-2293 4. Project Location:The project site is located in the City of Pleasant Hill. The project is located 180 feet(55meters)upstream of Boyd Road and extending 475 feet(145 meters)further upstream along the top of bank of Grayson Creek.- 5. Project Sponsor's Name and Address: Contra Costa County Flood Control and Water Conservation District 255 Glacier Drive Martinez,CA 94553 6. City of Pleasant Hill General Plan Designation: School(Sequoia Middle School),Single family high density 7. Zoning: R7 8. Description of Project: The Contra Costa County Flood Control District proposes to install 145 linear meters(475 linear feet)of twin 102 inch spiral ribbed metal pipe from the existing terminus of a prior year pipe installation,upstream to a point approximately 180 feet north of Boyd Road.The purpose of Drainage Area 46 Grayson Creek Bypass Phase 1b is to extend the storm water bypass pipe to a point off of school property. The bypass pipe will eventually become an integral component to the Drainage Area 46 Plan. The trench will be excavated to a dimension of 7 meters(23 feet)wide and 4.6 meters(15 feet) in depth. The pipes will be bulkheaded at the upstream terminus to allow for future extension.The pipe will be placed in the trench,and the trench back-filled. The installation of the pipe will result in the removal of 469 square meters(5,046 square feet)of riparian habitat. This includes approximately nineteen mature trees that have a diameter at breast height(dbh)greater than 6",seventy-two saplings which have a dbh of 1"—6",and one hundred seventy-two seedlings with a dbh of l"or less. The riparian vegetation is predominately characterized by the presence of valley oaks(Quercus lobata),although some coast live oak(Quercus agrifolia)and non-native ornamental trees are also found. Four small storm drain lines,originating from the adjacent school site, will be connected to the western most pipe. A chain link fence will be temporarily removed and replaced at the conclusion of the project. Due to the depth of the excavation the contractor will be required to shore the excavation,and California State Architect approved permanent shoring will be placed along a school building. At the completion of the pipe installation,the project area will be revegetated with native grass/herbaceous species. The total acreage of riparian area to be restored will be three times the acreage of riparian area removed.Appropriate understory species will also be planted to achieve a diversity of species that is not present at this time.This will be accomplished within guidelines set forth by the City of Pleasant Hills'Public Works Department,Directions and(guidelines far Creek Maintenance(September 1998). In addition the disturbed area will be re-seeded with a mixture of native grasses. The onsite planting will extend the number and diversity of riparian plant species both upstream and downstream of the project area. This plan will also add age diversity to this portion of Grayson Creek.The restoration plantings will be irrigated for three years and monitored for five years. Success criteria of 65%survivorship after five years shall be achieved. Failure to achieve the success criteria shall result in additional plantings to achieve the 65%success rating.. 9. Surrounding Land Uses and Setting: Urban Single Family Housing and Public School Facility 10. Other public agencies whose approval California Department of Fish&Game, San Francisco Regional Water Quality Control Board 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 and Planning _ Transportation/ — Public Services Population&Housing Circulation _ Utilities&Service Systems Geological Problems Biological Resources Aesthetics Water Energy & Mineral Cultural Resources Air Quality Resources _ Recreation Mandatory Findings of Significance _ Hazards _ No Significant Noise Impacts Identified Potentially '/''D Significant . Potentially Unless Less than Significant Mitigation Significant No lit Incomoration Imp4c Iffmact 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 EIR pursuant to applicable standards and ve been avoided or mitigated pursuant to that earlier EIR,including revisions or mitigation measures that are ' osed the ropo project. ignature Date CCC Community Development Department Printed Name For 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 Walnut Creek,CA 2. The(Reconsolidated)County General Plan(July 1996)and EIR on the General Plan(January 199 1) 3. General Plan and Zoning Maps 4. General Plan City of Pleasant Hill 1990 5. Field reviews and/or Project Description(including consultation with Flood Control and Design Engineers) 6. Northwest Information Center,Sonoma State University,Rohnert Park,CA December 07, 1999 7. Soil Survey of Contra Costa County,Soil Conservation Service,9/77 8. Contra Costa County Important Farmland Map 1998, California Department of Conservation Division of Land Resources Protection, 1999 9. State of California Hazardous Waste and Substances Sites List,April 1998 10. Caltrans Storm Water Quality Handbook,April 1997 11. Draft Environmental Impact Report for The Grayson-Murderers' Creeks Watershed Area and Drainage Improvement Plan Drainage Area 46 April, 1984 12. Consultations with City of Pleasant Hill Planning Department 13. Informal Consultation with the United States Fish and Wildlife Service,February 5, 1999 14. Federal Emergency Management Agency's Flood Insurance Rate Map,with County Ease Map Overlay 3 Potentially Significant Potentially Unless Less than Significant Mitigation Significant No Impact Incorporation Irnoact Impact EVALUATION OF ENVIRONMENTAL IMPACTS: 1. AESTHETICS. Would the proposal: a. Have a substantial adverse effect on a scenic vista?(Source#2) b. Substantially damage scenic resources, — including,but not limited to,trees,rock outcroppings,and historic buildings within a state scenic highway?(Source#2} C. Substantially degrade the existing — visual character or quality of the site and its surroundings?(Source#5) d. Create a new source of substantial light — Z– or glare which would adversely affect day or nighttime views in the area? (Source#5) SUMMARY:The project location is not within view of a scenic vista or a state scenic highway.The project area will be cleared,requiring the removal 469 square meters (5046 square feet) of riparian habitat. This includes approximately nineteen mature trees that have a diameter at breast height(dbh)greater than 6",seventy-two saplings which have a dbh of 1"–6",and one hundred seventy-two seedlings with a dbh of 1"or less.The riparian vegetation is predominately characterized by the presence of valley oaks(Quercus labata),although some coast live oak(Quercus agrffolia)and non-native ornamental trees are also found. This impact is necessary to install the storm water conveyance pipe,which will affect the visual quality of Grayson Creek within the project boundaries.At the completion of the pipe installation the project area will be revegetated with herbaceous native plant species.Native trees and shrubs will be planted between the project area and the edge of top of bank.Additional trees and shrubs will be planted further upstream and downstream along the top of bank.In addition,the disturbed area will be re-seeded with a mixture of native grasses.The total acreage to be restored will be three times the area disturbed.The total restoration area will be approximately 1,407 square meters(15,145 square feet).The restoration plantings will be irrigated for three years and monitored for five years. Success criteria of 65%survivorship after five years shall be achieved. Failure to achieve the success criteria shall result in additional plantings to achieve the 65%success rating.There are no designs to install any lighting,either temporary or permanent. 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?(Source#8) b. Conflict with existing zoning for agricultural use,or a Williamson Act contract?(Source#3) 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? (Source#5,8} SUMMARY:The project area is within the city limits of Pleasant Hill and will not affect any agricultural resources within Contra Costa County. Potentially Significant Potentially Unless Less than Significant Mitigation Significant No lnMact Incoroaragon Impact Impact III. 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 implementationof the applicable air quality pian? (Source#4) b. Violate any air quality standard or — contribute to an existing or projected air quality violation? (Source#4) C. Result in a cumulatively considerablenet 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)? (Source#4) d. Expose sensitive receptors to substantial pollutant concentrations? (Source#4,5) e. Create objectionable odors affecting a substantial number of people? (Source#5} SUMM.P►RY: Short-term emissions and objectionable odors may be generated during construction; however,they will be minor and temporary.All construction will be completed when Sequoia Middle School is not in session. Contract specifications shall stipulate the use of properly tuned and muffled equipment and the elimination of unnecessary idling of equipment when not in use. These measures reduce construction period emissions. Adherence to standard dust control practices including,but not limited to, general watering of exposed areas and/or use of chemical stabilizers will minimize air quality impacts. Please see the Mitigation Summary for Best Management Practices that will be implemented as part of the contract. 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? (Source#5,13) 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?(Source#5) C. Have a substantial adverse effect on — V 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?(Source#5) Potentially Significant Potentially Unless Less than Significant Mitigation Significant No mat Ineorooration Impac ct 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? (Source#5) e. Conflict with any local policies or ordinances protecting biological resources, such as tree preservation policy or ordinance? (Source#4,5) 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? (Source#2,4) StimdMARY:The project limits are outside U.S.Army Corps of jurisdiction as defined by Section 404 Clean Water Act,and wetlands will not be affected by the construction of this project. The project area will be cleared,requiring the removal 469 square meters (5046 square feet)of riparian habitat. This includes approximately nineteen mature trees that have a diameter at breast height(dbh) greater than 6",seventy-two saplings which have a dbh of 1"—6",and one hundred seventy-two seedlings with a dbh of 1"or less. The riparian vegetation is predominately characterized by the presence of valley oaks(Quercus lobata),although some coast live oak (Quercus agrifolia)and non-native ornamental tree are also found. Due to maintenance activities,the understory is a mixture of grass species,without the typical shrub species usually associated with this type of habitat. The removal of riparian vegetation(720sq. meters)will likely interfere with the resident and migratory wildlife utilizing this section of Grayson Creek. The removal of the trees may interfere with nesting and rearing of migratory and non-migratory bird species that utilize the project area. Removal of the trees will occur prior to nesting season to avoid impacting any nesting birds. boss of shade provided by the canopy will occur with the removal of the trees. The removal of the understory will displace any small mammals or amphibians residing in the project area. The United States Fish and Wildlife Service has issued a no effect determination in regards to red-legged frogs(Rana aurora draytonii). The trenching will expose soul during the duration of the project. At the completion of the pipe installation,the project area will be re- seeded with herbaceous native plant species. The lost riparian area will be planted at three times the acreage of riparian area removed. Appropriate understory species will also be planted to achieve a diversity of species that is not present at this time. This will be accomplished within guidelines set forth by the City of Pleasant Hills'Public Works Department,Directions and Guidelines for Creek Maintenance, (September 1998). The onsite planting will extend the number and diversity of riparian plant species both upstream and downstream of the project area. This revegetation plan will also add age diversity to this portion of Grayson Creek by interspersing younger trees amongst mature individuals. Furthermore this plan is consistent with Contra Costa General Plan Conservation Element Policies 8-88(New development which modes or destroys riparian habitat because of needed flood control,shall be responsible for restoring and enhancing an equivalent amount of habitat within or near the project area),8-91,(Grading,filling and construction activity near watercourses shall be conducted in such a manner as to minimize impacts from increased runoff, erosion,sedimentation, biochemical degradation,or thermal pollution.),8-92(revegetation of a watercourse shall employ native vegetation,providing the type of vegetation is compatible with the watercourse's maintenance program and does not adversely alter channel capacity).The restoration plantings will be irrigated for three years and monitored for five years. Success criteria of 65%survivorship after five years shall be achieved. Failure to achieve the success criteria shall result in additional plantings to achieve the 65%success rating. V. CULTURAL RESOURCES. Would the project: a. Cause a substantial adverse change in the significance of a historical resource as defined in§15064.5?(Source#6) b. Cause a substantial adverse change in the significance of an archaeological resource pursuant to§15064.5?(Source#6) C. Directly or indirectly destroy a unique paleontological resource or site or unique geologic feature?(Source#6) Potentially !/G/ Significant Potentially Unless Less than Significant Mitigation Significant No Imbact Inwrrloration IrroactImpact d. Disturb any human remains,including those interred outside of formal cemeteries? (Source#6) SUMMARY: The Northwest Information Center at Sonoma,State University reviewed records and literature on file,and determined that there is no indication of historical archaeological sites or historic structures in the project area,and the possibility of identifying cultural resources in the project area is low. The contract specifications shall include measures related to discovery of cultural and/or archeological resources. The construction site resident engineer will receive training regarding identification of cultural resources and procedures to follow in the event of discovery.Please see the Mitigation Summary for Best Management Practices that will be implemented as part of the contract. V1. 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. (Source#4) 2.Strong seismic ground shaking? 3.Seismic-related ground failure,including liquefaction?(Source#4) 4.Landslides?(Source#4 b. Result in substantial soil erosion or the loss of topsoil?(Source#5) 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? (Source#4) 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?(Source#4) 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?(Source#7) SUMMARY:According to the Soil Survey of Contra Costa County,Soil Conservation Service,9/77,the project area is identified as a Clear Lake Clay soil with a 0 to 2 percent slope. The potential for runoff is very slow,and there is no hazard of erosion where the soil is tilled and exposed. Excavation of the site will result in temporarily increasing the exposure of soils to erosive forces. However,this impact is temporary given that the disturbed area will be immediately stabilized using best management practices. In particular,the use of Environmental Sensitive Area fencing will minimize the area exposed to disturbance. The installation of erosion control blankets,silt fencing and the hydroseeding of native plant species will stabilize the project area before the winter rains. Adherence to standard dust control including,but not limited to,general watering of exposed areas and/or use of chemical stabilizers will minimize air quality impacts. These measures shall be incorporated into the construction contract The excavation of the project area is not expected to result in unstable C�'✓yf 7 Potentially �yJee �y � Significant Potentially Unless Less than Significant Mitigation Significant No Impact Incorporation Irmac Impact earth conditions or change geographical substructures. Exposure of people or property to geologic hazards will not increase as a result of the project.Please see the Mitigation Summary for Best Management Practices that will be implemented as part of the contract. 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?(Source#5) 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?(Source#5) C. Emit hazardous emissions or handle _ V hazardous or acutely hazardous materials, substances,or waste within one-quarter mile of an existing or proposed school?(Source#5} 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?(Source#9) 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. (Source#3,4) 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? (Source#5) g. Impair implementation of or physically V interfere with an adopted emergency response plan or emergency evacuation plan?(Source#5) 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? (Source#5) SID04ARY:The project has the potential to release hazardous substances,such as accidental petroleum spills,during construction. Per contract specifications,standard construction safety practices shall be followed during construction to ensure no accidental release of hazardous substances or increase the potential for exposure to these substances. The project has no potential for interfering with an emergency response,but emergency response agencies in the area shall be notified prior to the onset of construction. The timing of project construction coincides with summer break to reduce the exposure of school children to potential emissions. In addition, 8 Potentially Q/ Significant Potentially Unless Less than Significant Mitigation Significant No Invac Incomora ion Impact Impact contract specifications shall stipulate the use of properly tuned and muffled equipment and the elimination of unnecessary idling of equipment when not in use. These measures reduce construction period emissions. Implementation of dust control practices including,but not limited to,general watering of exposed areas and/or use of chemical stabilizers will minimize air quality impacts associated with excavation and grading.Please see the Mitigation Summary for Best Management Practices that will be implemented as part of the contract. VIII. HYDROLOGY AND WATER QUALITY- Would the project: a. Violate any water quality standards or waste discharge requirements?(Source# 10) b. Substantially deplete groundwater supplies — — V _ 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? (Source#5} 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? (Source#5,10) 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? (Source#5,10) f. Otherwise substantially degrade water ,[ quality?(Source#5,10) — — 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?(Source# 14} h. Place within a 100-year flood hazard area structures which would impede or redirect flood flows?(Source#N/A) I. Expose people or structures to a significant ,C risk of loss,injury or death involving flooding, — — — including flooding as a result of the failure of a levee or darn?(Source#N/A) 44"/� - 7 Potentially Significant Potentially Unless Less than Significant Mitigation Significant No Impact 1ncoM2 tion I IMpact j. Inundation by seiche,tsunami,or mudflow? (Source#NIA) SUMMARY:According to the Federal Emergency Management Agency's Flood Insurance hate Map,with County Base Map Overlay,the project area is in a flood hazard area. Excavation and installation of the storm drain will not increase the exposure of people or property to flooding. The project is designed to alleviate the potential of flooding within the drainage area. The project,as designed will not increase the amount of impermeable surface. The conveyance of floodwaters via the pipe will decrease the amount of water available for infiltration,and subsequent groundwater recharge. This would not result in an increase in storm water runoff that would be directed to local drainages. The project will not affect the quantity or quality of ground water,irrigation water or public water supply. All groundwater encountered in the trench during the course of the project will be adequately treated using a baffled tank or similar device before being discharged into the storm drain network or Grayson Creek.The baffled tank is designed to allow sediment to drop out of the water column,and be discharged without further treatment. This method will be employed before any groundwater is discharged into a storm drain or Grayson Creek.Please see the Mitigation Summary for Best Management Practices that will be implemented as part of the contract. IX. LAND USE AND PLANNING-Would the project: a. Physically divide an established community? (Source#5) 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?(Source#4,5,12) C. Conflict with any applicable habitat conservation plan or natural community conservation plan? (Source#5,14, 11,12) SUMMARY:The land uses within the project area consist of urban residential and public school facility. The land is currently zoned by the city as,R7-Single Family High Density. The proposed project will not result in a substantial alteration of the present or planned land use of the area,nor conflict with any applicable habitat conservation plan or natural community conservation plan. Through discussions with the City of Pleasant Hill Planning Department,the Community Development Director has been notified of project and the impacts. The Community Development Director has determined that with the involvement of CA Dept.of Fish and Game and Contra Costa County Flood Control Districts' commitment to replace the trees removed,there will be no need for a tree removal permit. There are no right of way issues associated with access to the project site. X. MINERAL RESOURCES-Would the project: a. Result in the loss of availability of a known _ 1 mineral resource that would be of value to the region and the residents of the state?(Source# 1 ) 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? (Source#4) SUMMARY:Implementation of the project will not result in the loss of availability of a known resource. The use of oil and gasoline to operate the machinery for construction purposes is negligible and of a temporary nature. The temporary expenditure of resources will end with the completion of the project. Best management practices(e.g.,using properly tuned equipment and eliminating unnecessary idling of equipment) will minimize the consumption of natural resources. Please see the Mitigation Summary for Best Management 10 Potentially , Significant Potentially Unless Less than Significant Mitigation Significant No lalp—R—Ct Inc-mmtion Impact Impact Practices that will be implemented as part of the contract. Xl. 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? (Source#4) b. Exposure of persons to or generation of _ 3L a excessive ground borne vibration or ground borne noise levels?(Source#4) C. A substantial permanent increase in _ ambient noise levels in the project vicinity above levels existing without the project?(Source#4,5) d. A substantial temporary or periodic increase — _ in ambient noise levels in the project vicinity above levels existing without the project? (Source#5 ) 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?(Source#N/A) 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?(Source#N/A) Sl IMIARY:The dominant source of noise in the project area is from traffic on Boyd Road. Since there is a sensitive noise receptor (Sequoia Middle School)within 150 feet of the project,construction activity may result in exposure of people to elevated noise levels. The installation of the bypass pipe will temporarily increase the noise level of the project area during construction. In general, construction activities produce noise levels of approximately 86 dBA at 50 feet(15 meters),which is well below the threshold of pain of 120-140 dBA. School will not be in session during construction,and will not be affected by the increase in noise. The noise level from the construction activities,between the hours of 7:00 p.m.and 7:30 a.m.on weekdays and between 7:00 p.m.and 9:00 a.m.on weekends and holidays will not exceed 86dBa at a distance of 50 feet(15 meters). In addition the working hours will be restricted between 7:30a.m.to 7:00 p.m.Monday through Friday,an on Saturday and Sunday.9:00 a.m.to 6:00 p.m.. The use of properly muffled construction equipment will reduce construction noise levels and shall be incorporated as part of the construction specifications.Please see the Mitigation Summary for Best Management Practices that will be implemented as part of the contract. X11. POPULATION AND MOUSING- Would the project: a. Induce substantial population growth in an If area,either directly(for example,by proposing new homes and businesses)or indirectly(for example,through extension of roads or other infrastructure)?(Source# 12) b. Displace substantial numbers of existing housing,necessitating the construction of ,/Y 1 W Potentiallyo Significant Potentially Unless Less than Significant Mitigation Significant No IM21c-t Inc2MQm-tion Iniout I ac_t replacement housing elsewhere? (Source#5) C. Displace substantial numbers of people, necessitating the construction of replacement housing elsewhere?(Source#5) gadMARY:The location and design of this project may result in impacts to housing and population in Contra Costa County,in particular the City of Pleasant Hill. The proposed project will reduce the potential for flooding,thus have a positive impact on overall development potential. The extent of this impact is considered less than significant. The construction will be completed along a existing public right- of-way and will not displace any existing housing or persons. XIII. 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(Source#4): 1. Fire Protection? 2. Police Protection? _ 3. Schools? _ 4. Parrs? 5. tither Public facilities? _ 4 $JadMARY:A fire lane will be temporarily blocked during construction activities. Contra Costa Consolidated Fire Department has indicated that the temporary usage of this fire lane will not affect their ability to respond in the event of an emergency. They have alternative access to this portion of the school. The construction will occur outside of the school year.Please see the Mitigation Summary for Best Management Practices that will be implemented as part of the contract. XIV. 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? (Source#5,11 ) 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? (Source#5) SUMMARY:The project will not result in an impact upon the quality or quantity of any recreational opportunities in the area. 12 Potentially � �� Significant s" Potentially Unless Less than Significant Mitigation Significant No InmKt Incorporation InmautmI nact XV. TItANSPORTATI©NITRAFFIC-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)?(Source#5) b. Exceed,either individually or cumulatively, _ a level of service standard established by the county congestion management agency for designated roads or highways? (Source#5) 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?(Source#5) d. Substantially increase hazards due to a design — _ feature(e.g.,sharp curves or dangerous inter- sections)or incompatible uses(e.g.,farm equipment)?(Source#5) e. Result in inadequate emergency access? w —. (Source#5) f. Result in inadequate parking capacity? (Source#5) g. Conflict with adopted policies,plans,or — e programs supporting alternative transportation (e.g.,bus turnouts,bicycle racks)? (Source#5,4) SUI D AR.Y:The project as designed will not substantially affect transportation and/or traffic.A portion of fill generated by construction activities will be utilized onsite. It is anticipated that the project will generate ten truck trips per day to off haul the spoils over the life of the project. The contractor will implement traffic control. The fire lane on school property will be temporarily blocked during certain phases of the project. Contra Costa Consolidated Fire Department has indicated that the temporary usage of this fire lane will not affect their ability to respond in the event of an emergency.Please see the Mitigation Summary for Best Management Practices that will be implemented as part of the contract. XVI. UTILITIES AND SERVICE SYSTEMS- Wouid the project: a. Exceed wastewater treatment requirements _ of the applicable Regional Water Quality Control Board? (Source#5) 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?(Source#5,10) C. Require or result in the construction of new ` 13 Potentially Significant Potentially Unless less than Significant Mitigation Significant No Impact lncoMgrj on Impact storm water drainage facilities or expansion of existing facilities,the construction of which could cause significant environmental effects?(Source#5,10) d. Have sufficient water supplies available to serve the project from existing entitlement and resources,or are new or expanded entitlement needed?(Source#5) 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?(Source#5) f. Be served by a landfill with sufficient IL _ permitted capacity to accommodate the project's solid waste disposal needs?(Source#5) g. Comply with federal,state and local statutes and regulations related to solid waste?(Source#5 ) SSLTMMARY:The project as designed will have a less than significant impact utilities and/or service systems. A portion of fill generated by the project will be utilized on site. The fill generated by the project may be taken to a landfill,but in the past has been utilized at an offsite location. Ultimately, the remainder of the spoils is removed and disposed of at the contractors` discretion and responsibility. XVII. MANDATORY FINDINGS OF SIGNIFICANCE- a. Does the project have the potential to degrade >L the quality of the environment,substantially reduce the habitat of a fish and wildlife species, cause a flush 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 indiv- idually 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 _ - ILI which will cause substantial adverse effects on human beings,either directly or indirectly? y 14 Potentially Significant Potentially Unless Less than Significant Mitigation Significant No impact Incom2ratiort Imnaci Impact Sl1MMARY.The project does have a potential to temporarily degrade the environment during the construction phase. This potential will lessen considerably by the implementation of Best Management Practices during the coarse of construction. A representative of Contra Costa County will be onsite to insure compliance of all environmental conditions imposed by either the regulatory agencies and/or in accordance to our own policies. Habitat for native plant and wildlife species within the project area will be impacted by this project. At the completion of the pipe installation,the project area will be revegetated with native grass/herbaceous species. The total number of riparian acres to be planted will be three times the number of riparian acres removed. Trees and understory species will also be planted to achieve a diversity of species that is not present at this time. The onsite planting will extend the number and diversity of riparian plant species both upstream and downstream of the project area.The restoration plantings will be irrigated for three years and monitored for five years. Success criteria of 65%survivorship after five years shall be achieved. Failure to achieve the success criteria shall result in additional plantings to achieve the 65%success rating. The project construction will have impacts that are limited and temporary,and are not cumulatively considerable.The Best Management Practices implemented during construction,and the subsequent mitigation plan will lessen the project impacts to less than significant. Environmental effects incurred,as a result of this project will not cause substantial adverse effects on human beings either directly or indirectly. G.\GRPDATA\ENGSVG\EtMRO\2000PROJECTS\CEQAONLY\NEGr-DMCEQACHECKLIST GRAYSON CREEK PHASEIB.DOC January 10,2000 Mitigation Summary-, Grayson Creek Bypass Phase lb Project Name: Drainage Area 46 Grayson Creek Bypass Phase 1 Project Proponent: Contra Costa County Flood Control and Water Conservation District 255 Glacier Drive Martinez, CA. 94553 Project Location: The project site is located in the City of Pleasant Hill, 180 linear ft (55m) downstream of Boyd Road and extending 475 linear feet (145m) along the top of bank of Grayson Creek (Figure 1-3) Project Description: The Contra Costa County Flood Control District proposes to install 145 linear meters (475 linear feet) of twin 102 inch spiral ribbed metal pipe from the existing terminus of a prior year pipe installation, upstream to a point approximately 180 feet north of Boyd Road. The purpose of Drainage Area 46 Grayson Creek Bypass Phase lb is to extend the storm water bypass pipe to a point off Sequoia Middle School property. The bypass pipe will eventually become an integral component to the Drainage Area 46 Plan. The trench will,be excavated to a dimension of 7 meters (23 feet) wide and 4.6 meters (15 feet) in depth. The pipes will be bulkheaded at the upstream terminus to allow for future extension. The pipe will be placed in the trench, and the trench back-filled. The spoils not used to backfill the trench will disposed of by the contractor at an offsite location. Due to the depth of the excavation the contractor will be required to shore the excavation, and California State Architect approved permanent shoring will be placed along a school building. Four small storm drain lines, originating from the adjacent school site, will be connected to the western most pipe. A chain link fence will be temporarily removed and replaced at the conclusion of the project. The installation of the pipe will result in the removal of 469 square meters (5,046 square feet) of riparian habitat. This includes approximately nineteen mature trees that have a diameter at breast height (dbh) greater than 6", seventy-two saplings which have a dbh of 1" - 6", and one hundred seventy-two seedlings with a dbh of 1" or less. The riparian vegetation is predominately characterized by the presence of valley oaks (Quercus lobata), although some coast live oak (Quercus agrifolia)and non-native ornamental trees are also found. At the completion of the pipe installation, the project area will be revegetated with native herbaceous/grass species. The total acreage of riparian area to be planted will be three times the acreage of riparian area removed. Trees and understory species will also be planted to achieve a diversity of species that is not present at this time. 1 This will be accomplished within guidelines set forth by the City of Pleasant Hills' Public Works Department, ,Directions and Guidelines for Creels Maintenance, (September, 1998). The onsite planting will extend the number and diversity of riparian plant species both upstream and downstream of the project area (Figure 4). This plan will also add age diversity to this portion of Grayson Creek by interspersing younger trees beneath the canopy of mature trees. The restoration plantings will be irrigated for three years and monitored for five years. Success criteria of 65% survivorship after five years shall be achieved. Failure to achieve the success criteria shall result in additional plantings to achieve the 65% success rating. Project Impacts: Prior to construction the area will be cleared. This will require the removal 469 square meters (5046 square feet) of riparian habitat. Within this riparian corridor are approximately nineteen (19) mature trees that have a diameter at breast height (dbh) greater than 6", and seventy-two (72) saplings which have a dbh of 1" - 6", and one hundred seventy-two seedlings with a dbh of 1" or less. The riparian vegetation is predominately characterized by the presence of valley oaks (Quercus tobata), although some coast live oak (Quercus agrifotia) and non-native ornamental trees are also found. Due to maintenance activities, the understory is a mixture of grass species, without the typical shrub species usually associated with this type of habitat. The removal of riparian vegetation (469 sq. meters) will likely interfere with the resident and migratory wildlife utilizing this section of Grayson Creek. The removal of the trees will interfere with any feeding, roosting and rearing of migratory and non- migratory bird species that utilize the project area. The removal of the understory will displace any small mammals or amphibians residing in the project area. The trenching will result in exposed soil during the duration of the project Mitigation Measures Included; In order to avoid significant environmental effects on biological/aesthetics resources found within the project area, Contra Costa County Flood Control and Water Conservation District will implement the mitigation measures. This will be accomplished by measures taken pre and post construction. Past Construction; * Removal of trees before bird nesting season. Post Construction. * Revegetation with native riparian species will be at a rate of three to one based on acreage. The total acreage anticipated to be disturbed on this section of Grayson Creek will be 1,407 square meters (.1407 hectare) or 5,046 square feet (.12 acres). 2 G'f1 so • Appropriate understory species will also be planted to achieve a diversity of species that is not present at this time. The amount of understory vegetation planted will be limited to areas outside of active channel. The onsite mitigation planting will extend the number and diversity of riparian plant species both upstream and downstream of the project area. This plan will also add age diversity to this portion of Grayson Creek by interspersing younger trees beneath the canopy of mature trees. The restoration plantings will be irrigated for three years and monitored for five years. Success criteria of 65% survivorship after five years shall be achieved. Failure to achieve the success criteria shall result in additional plantings to achieve the 65% success rating. Bent Management Practices: The pre/during/post construction Best Management Practices (BMPs) incorporated into the contract are designed to minimize the impact of this project. These methods have been proven in the past to accomplish this task. The construction BMPs to be implemented are ecologically sound, and necessary to offset the impacts envisioned resulting from this project. Pre Construction: The area of disturbance will be kept to a minimum; this is to be accomplished by incorporating the following measures. • The design and excavation of the trench will utilize shoring devices that minimize the width needed to accommodate the pipe. • Environmentally sensitive area (ESA) fencing will be installed gust outside the project area to ensure the project boundary is well defined during the construction phase. During Construction: • Silt Fence will be installed and maintained on the stream side of the ESA fencing • Adherence to standard dust control including, but not limited to, general watering of exposed areas and/or use of chemical stabilizers will minimize impacts. • A Baker Tank (baffle tank) will be utilized to treat nuisance groundwater before it is discharged. • All construction vehicles will be tuned, and have proper functioning muffler. • Construction specifications and resident engineer training which prevent disturbance to archeological and historical resources. 3 • Project timing to avoid school session, and work hours to coincide with the City of Pleasant Hill noise ordinance. • Any stationary equipment (ie generators...) will have a drip pan to catch any fluid leakage. • Any non-listed wildlife encountered during construction will be safely removed from the site, and released downstream of project limits. Post Construction: On the completion of the pipe installation, the following measures will become part of our post construction BMPs. • Installation of erosion control blankets, silt fencing and the hydroseeding of native plant species will stabilize the project area before the winter rains. EC: G:1CrpData\EngSvc\ENVIRO\2000projects\CEQAonlyl13ackup of Grayson Crk mit summary.doc Attachments Cc: M.Boucher,Flood Control K. Emigh,Design C.Sellgren,Eng.Svc. 4 Jjv , m c *-34 -r-' C(- =� t1- _ � On 0. .rte ir Yd I IP Ad A K44 , ;a 44 R TC •� � T . �f.��� �E,�- �-t� �� +�'1 ��+�l1:iL T�i�f•,st �".'u ��x''" , i 7�,:.i�►+��' .� w�`�� r OV// *x�►•. . 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Q r .�.\s [ ., .i r ..i,} i al�.'�`E r i'`•� �{-..,' k 1 ,yR ; .J►�^�" • + � lam^ ff S • Mw.+ � � •A-1 E....,,�M�'M1�y�rr:��^��M ���/I.trr.+rli+ .�F t• • =".�,•i.,ice � Fl` i t r� - I � ; i ►� ar i 0 i ; ! � 9•L3 a3 � •+t'.err �i r x �l i y e LEGEND GRAYSON CREEK PHASE 1B AREAS FOR MiTiGATION PLANTING 1 i e � • Ntrl'C ]l AY 03/02/00 17.49 FAX 510 676 1125, CITY OF PLEASANT HILL y� { i 002 rM / ILA. ► "90 c.wor ejeascarit March 2,' 2000 Mi, Fail Crosby : .. .. - Contra-Costa= auity' `Iood Co 0-01/ - : : Wateir Conservation'Disti dt .255 Glacier.Driv_e... - :..• . . .. .. '.f.'x.a.. Martin@z, CA.945 RE: Genual y3?`IenCcriipliance for.Iristallation.of a Storin..Ijrain.Pipe £or : Drainage Area 46 Dear Mr. Crosby: - - "fJn F lii•iiary 22, 2000' tho*PleAsant Hill PlCnrmnission reviewed.Contra Costa:'County project, CP 99-103, and found the profect to be in compliance with the City.of Pleasant Hill's General Plan.,.. Attached you will find a copy of'the staff-report for-.the February 22, 2000, Planning Commission meetiiag. If you have any questions .or need idditiaiial information; pleasephone me any -. week day at-(925)-671-5209. S` cerely; Richard T.-Bottarixu -Secreta to:the Architectural Review taommiission RTB/jf Fn zisure ' a:lcanwr:laystts.ur - .. , . - • . :- _-. - '100 Gregory.Lene .- Pleasant Hill - caiitori'ia'W' 23-33'23. = (925) 571-5270 - FAX(925).:956=8190 03/02/00 17:48 FAX 510 676 2125 CITY OF PLEASANT HILL 11003 e/-V planning commission staff report Date: February 22, 2000 Consent Item: 4 File: General Plan Compliance for Installation of a Storm Drain Pipe for Drainage Area 46 The Contra Costa County Community Development Department staff has requested the City of Pleasant Bill's confirmation of compliance with the General Plan prior to proceeding with the pipeline project. Attached is the supporting documentation for construction of twin 102 inch drainage pipes from below(north)Sequoia Middle School to Boyd Road. This portion of the pipe will eleviate flooding at the school and areas south. The major impact of the project is the removal of several significant trees. A mitigation program has been proposed. The General Plan policy supports the project in general and specifically in the Community, Health and Safety Element. The General Plan, in the Community, Health and Safety element states: "Program 4.2: Cooperation with the Flood District: Continue to work with the Contra Costa Flood Control District in the project review process to ensure that adequate measures are implemented to prevent flooding, to establish and maintain effective storm drainage systems and collect the required mitigation fees.'} The improvements to Drainage Area 46 has been a longstanding goal of the City, and the City has been very supportive of this project in the past. Finally, this segment of the drainage project is critical to the drainage of the downtown. Recommendation Staff recommends that the Commission have a letter prepared and signed by the Secretary of the Commission finding the project in compliance with the General Plan. The letter will be forwarded to the Contra Costa County Community.Development Department. Project Planner: Richard T. Bottarini R113ljf F tprr.Ymt�axairas.rpe