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HomeMy WebLinkAbout07/16/2002, C11 - UPPER SAN LUIS OBISPO CREEK DAM REMOVAL: SPECIFICATION NO. 90296, AND APPROVAL OF MITIGATED NE councit '7-r' 6-02 j acEnaa RepoRt C11 CITY O F SAN LUIS 0 B I S P 0 FROM: Wendy George,Assistant City Administrative Officerl Prepared By: Neil Havlik,Natural Resources Manager SUBJECT: UPPER SAN LUIS OBISPO CREEK DAM REMOVAL: SPECIFICATION NO. 90296, AND APPROVAL OF MITIGATED NEGATIVE DECLARATION CAO RECOMMENDATION 1. Approve plans and specifications for the project known as "Upper San Luis Obispo Creek Dam Removal"; 2. Authorize staff to advertise for bids; 3. Authorize the City Administrative Officer to award the contract if the lowest responsible bid is within the project budget of$275,500; and 4. Approve a mitigated negative declaration for the project. DISCUSSION The upper San Luis Obispo Creek dam is a non-functional water diversion structure built in the late 1800's or early 1900's as part of the City's water supply. It is located along Stagecoach Road just above its intersection with Highway 101 (see attached map). This facility captured water from San Luis Obispo Creek and diverted it into apipeline, which conducted that water, plus water from the nearby Hansen and Gularte Creeks, to the reservoirs at Fox Hollow Road and the Miossi property. This system was abandoned in the 1950's or early 1960's and has not functioned since that time. The dam, which is approximately 14 feet high, is filled with sediment and today constitutes a complete barrier to the movement of steelhead and other native fishes in this area. The City applied for grant funds to effect removal of the dam and was successful in obtaining a grant from the California Department of Fish and Game of$310,000 for the project, and a contract in amount not to exceed $34,500 to Questa Engineering for permit preparation and engineering services was signed in October 2001. Engineering drawings for the project are completed, and we are now awaiting permits from Federal regulatory agencies, and anticipate having them by the end of July. Timing of the project has become critical due to some delays in the permit process, and therefore, it is recommended that the project be advertised now so that work may begin as soon as possible after receiving permits. The actual work will consist of partial removal of the dam, placement of rock into the streambed to create 16 "step pools" to facilitate fish passage over the site of the dam, and restoration work on vegetation impacted by the construction activity. If all goes according to schedule, work should begin in August and take six to eight weeks to complete. The goal is to complete the work before the fall rains begin- C11-1 Council Agenda Report—Upper San Luis Obispo Creek Dam Removal Page 2 The cost of the project (including removal of all or portions of the dam, sediment removal and disposal, and revegetation) is estimated by Questa Engineering to be $199,300, plus a 20% contingency ($39,860) bringing the total estimated cost to $239,160. This is approximately $35,000 less than the amount remaining from the grant. These funds will be held in the event bids are higher than the engineer's estimate, and for incidental expanses that may occur. A mitigated negative declaration for the project was prepared on May 29,2002, and duly noticed in the Tribune. Primary mitigation measures were those involved with protection of other sensitive species known or believed to occur in the area, protection of air and water quality by bypassing creek flows around the work site,proper use of equipment, and refueling methods, and revegetation of the site upon completion of the work. No comments were received during the 30 day comment period. Therefore it is recommended that the Council approve the mitigated negative declaration. FISCAL IMPACT This contract will have a beneficial fiscal effect by providing outside funding support for an identified City enhancement project. Costs of staff support can be absorbed within the existing Natural Resource Protection Program budget. The overall project budget (completely funded by the grant) is as follows: Engineering and Permit Services $34,500 Construction $275,500 TOTAL $310,000 CONCURRENCES The Utilities Department,which administers the property on which the dam is located, supports this effort, as removal of the dam is a clear benefit to fishery within San Luis Obispo Creek. The Public Works Department has provided assistance with this project since its inception and anticipates being able to continue to do so during the construction period itself. Natural Resources staff, however, is assumed to have the primary responsibility of carrying out of the project; this effort has been a major priority in the work program of the City Biologist for the current year. ALTERNATIVE The Council could decide not to proceed with the project. This is not recommended,however, as it would constitute a reversal of previously stated intentions of the Council in this matter. Attachments 1. Location Map 2. Initial Study (Note: Plans and specifications are available in the Council reading filer see site plan in the Initial Study) g/HavUlcouncilagendddam removal bid C11-2 U \ ' ` `)�' ti ATION i' %/1 ' ♦ ) , R'n 165 II �• \ $ \ r -ill ./95 1� o + I '27]] �S !� I O ♦ 4 •`+ ,/111 ..F +♦ .. O I. (ter' + i �i- ./iZO� ♦ ir�V�!.1� Fq 024 t' 07 BM. ` II � ♦ �I � o I \ ,•��'_vim Project Site - �11 1161 ' ''1 s n � . / \•\,` — � 1 i (f 1� 4 BOO 18 1 .951 I e00 spnng ^ %.�. � \ 11 ',��VL ..•. i � / �.- '\ �\\ � \-01 . Gb 2533< 411 Project Location Map City of San Luis Obispo UPPER SAN LUIS OBISPO CREEK DAM REMOVAL PROJECT San Luis Obispo, CA. U. S. G. S. Quadrangle: Lopez Mountain 1"= Z,000, C11-3 ATTACHMENT 2 INITIAL STUDY ENVIRONMENTAL CHECKLIST FORM For RR # 03 —(?Z 1. Project Title: Upper San Luis Obispo Dam Removal Project 2. Lead Agency Name and Address: City of San Luis Obispo q q o 0&Palm Street JSan Luis Obispo, CA 93401 J 3. Contact Person and Phone Number: Neil Havlik, Natural Resources Manager 805-781-7211 4. Project Location: Upper San Luis Obispo Creek in San Luis Obispo County. The project site is located in the upper reaches of the creek, approximately 4,500 in (3.0 miles) northeast of the City of San Luis Obispo. The dam is located 760 m (0.5 miles) upstream of the Highway 101 bridge near the Old Stagecoach Road entrance. I5. Project Sponsor's Name and Address: Same as above. 6. General Plan Designation: I 7. Zoning: I8. Description of the Project: I1 San Luis Obispo Creek contains a viable population of southern steelhead (Oncorhynchus mykiss ` irideus) and enhancement of this population is a high priority locally. While San Luis Obispo Creek is 1 relatively unobstructed to fish passage for much of its length, its upper reaches are blocked by an abandoned water supply dam located approximately 550 in (0.3 miles) upstream of the Old Stagecoach Road bridge. The reservoir behind the 4m (13 ft) high dam is filled with sediment. The dam constitutes a �. significant barrier to the movement of steelhead and other native fishes in this area. The purpose of the proposed project is to: 1 1) restore steelhead access to the upper reaches of San Luis Obispo Creek 2) create stable channel bed and banks 1 3) improve in-stream habitat _ The project proposes a partial removal of the existing dam and the creation of a new stable channel bed 1 and banks. Gradient control in the new channel entails the installation of low rock weir drop structures. Biotechnical bank stabilization on the newly graded slopes includes the use of erosion control blankets and willow pole staking. The proposed project is described in detail in the attached Project Description. C11-4 ATTACHMENT 2 9. Surrounding Land Uses and Settings: San Luis Obispo Creek runs from its headwaters near Cuesta Pass in the Santa Lucia Mountains southwest through the City of San Luis Obispo (the City) to the Pacific Ocean at Avila Beach. The project area is located in unincorporated San Luis Obispo County. The setting is rural and the population distribution is sparse. Land use designations in the San Luis Obispo Planning Area in the project vicinity include agriculture, rural lands, rural residential, and open space. No public facilities occur in or adjacent to the project area. The closest such use is the California State Polytechnic Institute, located more than one mile west of the existing Highway 101 corridor. 10. Project Entitlements Requested: . 11. Other public agencies whose approval is required: The proposed dam removal project will require a California Department of Fish & Game (CDFG) Streambed Alteration Agreement (Section 1601), a U.S. Army Corps of Engineers (Corps) Section 401- permit, 04permit, and a Water Quality Certification from the Central Coast Regional Water Quality Control Board. Discussions will be held with.the U.S. Fish and Wildlife Service and the National Marine Fisheries 7 Service to design steelhead access above the existing dam site and to minimize impacts to special status species. 7 l i_ I CITY OF SAN LUIS OBISPO 2 INITIAL STUDY ENVIRONMENTAL CHECKLIST 2002 C11-5 ATTACHMENT 2 .! 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. ,d Aesthetics X Geology/Soils Public Services JAgricultural Resources Hazards&Hazardous Recreation Materials Air Quality --X-- Hydrology/Water Quality Transportation&Traffic J --X-- Biological Resources Land Use and Planning Utilities and Service Systems J Cultural Resources Noise Mandatory Findings of Significance J Energy and Mineral Population and Housing Resources v xs: rr� � yq a, s al FISH AND GAME FEES There is no evidence before the Department that the project will have any potential adverse effects on fish and wildlife resources or the habitat upon which the wildlife depends. As such, the project qualifies for a de minimis waiver with regards to the filing of Fish and Game Fees. The project has potential to impact fish and wildlife resources and shall be subject to the payment of Fish --X— and Game fees pursuant to Section 711.4 of the California Fish and Game Code. This initial study has been circulated to the California Department of Fish and Game for review and comment. STATE CLEARINGHOUSE This environmental document must be submitted to the State Clearinghouse for review by one or more State agencies (e.g. Cal Trans, California Department of Fish and Game, Department of Housing and Community Development). The public review period shall not be less than 30 days (CEQA Guidelines 15073(a)). �A Crry OF SAN LUIS OBISPO 3 INIAL STUDY ENVIRONMeu"14ST 20112 -� ATTACHMENT 2 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 revisions in the project have been made, or the mitigation measures described on an attached sheet(s) have been added and X agreed to by the project proponent. 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 "potentially significant" impact(s) or "potentially significant unless mitigated" impact(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. 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, because all potentially significant effects (1) have been analyzed adequately in an earlier EIR or NEGATIVE DECLARATION pursuant to applicable standards, and (2) have been avoided or mitigated pursuant to that earlier EIR of NEGATIVE DECLARATION, including revisions or mitigation measures that are imposed upon the proposed project, nothing further is required. -April f212 2 cnZ Signature Date [7�,Zy-) M dpy-� e jay-) For:John Mandeville, Printed Name Community Development Dir. ® �a� CITY OF SAN LUIS 08ISPo 4 INITIAL STUDY ENVIAONIST 2002 ATTACHMENT 2 EVALUATION OF ENVIRONMENTAL IMPACTS: 1. A brief explanation is required for all answers except "No Impact" answers that are adequately supported by the information sources a lead agency cites in the analysis in each section. A "No Impact" answer is adequately supported if the referenced information sources show that the impact simply does not apply to projects like the one involved (e.g. the project falls outside a fault rupture zone). A "No Impact" answer should be explained where it is based on project-specific factors as well as general standards (e.g. the project will not expose sensitive receptors to pollutants,based on a project-specific screening analysis). 2. All answers must take.account of the whole action involved, including off-site as well as on-site, cumulative as well as project-level, indirect as well as direct, and construction as well as operational impacts. The explanation of each issue should identify the significance criteria or threshold, if any,used to evaluate each question. 1 "Potentially Significant Impact'is appropriate if there is substantial evidence that an effect is significant. If there are one or more"Potentially Significant Impact" entries when the determination is made, an EIR is required. 4: "Potentially Significant Unless Mitigation Incorporated" applies where the incorporation of mitigation measures has reduced an effect from "Potentially Significant Impact" to a "Less than Significant Impact." The lead agency must describe the mitigation measures, and briefly explain how they reduce the effect to a less than significant level (mitigation measures from Section 17, "Earlier Analysis," may be cross-referenced). 5. Earlier analysis may be used where,pursuant to the tiering,program EIR,or other CEQA process,an effect has been adequately analyzed in an earlier EIR or negative declaration. Section 15063 (c) (3) (D) of the California Administrators Code. Earlier analyses are discussed in Section 17 at the end of the checklist. 6: Lead agencies are encouraged to incorporate into the checklist references to information sources for potential impacts (e.g. general plans, zoning ordinances). Reference to a previously prepared or outside document should, where appropriate, include a reference to the page or pages where the statement is substantiated. 7. 'Supporting Information Sources: A source list should be attached,and other sources used or individuals contacted should be cited in the discussion. In this case,a brief discussion should identify the following: J �.ti CrrY OF SAN LUIS OBISPO 5 INITIAL STUDY ENVIROVIVf ICKLIST 2002 ATTACHMENT 2 a) Earlier Analysis Used. Identify and state where they are available for review. b) Impacts Adequately Addressed. Identify which effects from the above checklist were within the scope of an, adequately analyzed in an earlier document pursuant to applicable legal standards, and state whether such effects were addressed by mitigation measures based on earlier analysis. c) Mitigation Measures. For effects that are "Less than Significant with Mitigation Measures Incorporated," describe the mitigation measures which were incorporated or refined from the earlier document and the extent J to which they address site-specific conditions for the project. 7 7 7 1 1 l 1 1 C11-9 JIssues, Discussion and SupF g Information Sources Sources ntially Potentially Less 7}inn No stglificant Significant Significant Impact ER # Issues Unless Impact 1 Mitigation Inc orated J1.AESTHETICS. Would the roject: a) Have.a substantial advers e•effect on a scenic vista? --X-- b) Substantially damage scenic resources,including, but not limited to,trees, rock outcroppings;open space,and historic buildings X within a local or state scenic highway? e) Substantially degrade the existing-visual character or quality of ' the site and its surroundings? X-- d) Create a new source of substantial light or glare which would -- adversely ersel effect-da -cifTii htdme views in the area? X posed project would result in the partial removal of the existing dam. Implementation of the proposed project would effect on a scenic vista. Implementation of the proposed project would not substantially damage scenic resources scenichighway. Implementation of the project would result in an overall long-term beneficial effect on the visual and quality of the creek corridor. Implementation of the project would not result in a new source of substantial light or glare. 2.AGRICULTURE RESOURCES Would the ro"ect: ha) ConveifP.rimelarmland,UniqueFarmland,oi:Farmland.of tatewide:lmpoiYance�Faimland);'as's'hown%op ihe'maps pursuani.to the Farmland Ntappmg and,);1tnrttlg Program of X- K theLafifotntaResourcesA ency,to-notagraculturalaie� �� K Qnflicf:withex>stmgzoninglonagi�rculturxl;use Williamson Ali eontradT X— x),,:Involveother changes.in,the existing_environment,which;due to -#heirlocation or nature;could xesult'in conversion of Farmland, l to non-a ictiltural use? J The proposed project occurs on public property owned by the City of San Luis Obispo.No conversion of land uses, including agricultural lands,would occur as a result of these projects.No impact would occur. 3. AIR QUALITY. Would the ro'ect: a) idl£te ian�air quahtytandard nrctan ontnbute apbstia'llyno an � xxisf�tii�;oc�noleoted.artju'ality�a�ad�ato$?�' : --X-- 1 )$� orifl}ot�wtth`'or obstiuct implemeniaiidn of ie applicable air �� xpose'sensiiivereceptors to+substantial p0llut2nt ' 1 concentratiiirls? - X-- d) 'Crdate o'bjedtionable odors affecting a substantial number of people? X- .e) Result in a cumulatively considerable net increase of any criteria polIdtarit for which the projeci region is non=attaitiment under an applida'ble federal or state ambient air quality standard (including"Teleasiag emissions which exceed qualitative thresholds-for ozoneprecursors)? r The project site is located in the San Luis Obispo County Air Pollution Control District (APCD), which monitors air quality at nine locations throughout the County. The APCD shares responsibility with the California Air Resources r Board (ARB) for ensuring that all State and Federal ambient air quality standards are attained within the District. The closest station to the project site was located in the City of San Luis Obispo at Marsh Street. Table I shows air quality data for criteria pollutants measured at this station for 1998-2000. r �r CiTY OF SAN LUIS Oeispo 7 INITIAL STUDY ENVIROtQyleJ0LIST 2002 TACH ENT 2 Issues, Discussion and SupF ig Information Sources Sources \tially Potentially Ltss Than No ... "ificarn Significant Significant Impact Issues Unless Impact 1 ER # Mitigation Inco orated 1 Both the U.S. Environmental Protection Agency(EPA) and the California Air Resources Board (ARB) have established ambient air quality standards for common pollutants. The EPA has jurisdiction under the Federal Clean Air Act to develop Federal air quality standards and require individual states to prepare State Implementation Plans to attain these standards. The ARB has jurisdiction under the California Health and Safety Code and the California Clean Air Act to develop California air quality standards, to require regional plans to attain these standards, and to coordinate the preparation by local air districts of plans required by both the Federal and State Clean Air Acts. The Federal and state ambient standards were developed independently with differing purposes and methods, although both processes attempted to avoid heath-related effects. As a result, the Federal and states standards differ in some cases. In general, the California state standards are more stringent.This is particularly true for ozone and fine particulate matter(PM-10). Both ozone and PM-10 are considered regional pollutants in that concentrations are not determined by proximity to J individual sources, but show a relative uniformity over a region. Thus, the data shown in Table I for ozone and PM-10 provide a good characterization of levels of these pollutants on the project site. Carbon monoxide is a local pollutant, i.e., high concentrations are normally only found very near sources. The major source of carbon monoxide, a colorless, odorless, poisonous gas, is automobile traffic. Elevated concentrations, therefore,are usually only found in or near areas 7 of high traffic volumes. The project site is actually.located 3 miles outside the City of San Luis Obispo in a more rural setting. As a result, the data shown in Table 1 for carbon monoxide are most likely higher than concentrations that would be found near the proposed project site. 1 Table 1.Summary of Air Quality Monitoring Data from the City of San Luis Obispo at Marsh Street Monitoring Station s+,r:. .�3'': 4 ` j�' '} , a"liforntay _�Monttor►n Resultsl ,E' N.rL ua d�ra1Y^� wk+ 7.ny a.an r «n „ollutant c�aramete �rY tanda�r $ar 2OWT4i.-N-1 ON, !IFO-Ox Ozone 1-hour maximum 0.12 pprn 0.09 ppim 0.07 0.09 0.08 J Days above state standard 0 0 0 J Carbon Monoxide 8-hour maximum 9 pprn 9 ppm 2.34 3.13 2.25 Da s above state standard 0 0 0 PM-10 24-hours 150pg/in 3 50 m' 32.2 42.0 44.0 Das above state standard 0 0 0 The Federal Clean Air Act and the California Clean Air Act of 1988 require that the ARB, based on air quality monitoring data, designate portions of the state where the Federal or state ambient air quality standards are not met as .1nonattainment areas" This designation is different under the Federal and state legislations due to differences between national and state standards. San Luis Obispo County is in attainment of the Federal air quality standards and is not subject to the planning requirements of the Federal Clean Air Act. Under the state air quality program, San Luis Obispo County has been identified as a non-attainment area for both ozone(1-hr standard)and PMIO by the ARB. a-b)Implementation of the proposed project would not conflict with an existing or projected air quality violation. Implementation of the project would not conflict with or obstruct implementation of air quality attainment plans for the County of San Luis Obispo,specifically the 1995 County Clean Air Plan(CAP). c) The APCD defines sensitive receptors as facilities where sensitive receptor population groups (children, the elderly, the acutely ill and the chronically ill) are likely to be located. With the primary surrounding land uses being agriculture and rural residential, sensitive receptors are not located in high densities near the project site. With the implementation of the mitigation measures described below, impacts to sensitive receptors will be reduced to less- than-significant. d) Implementation of the project would not create objectionable odors. No impact would occur. e) Implementation of the proposed project would not result in long-term changes in air quality in the city. However, project construction activities will likely result in short-term changes to air quality. These temporary construction emissions include tailpipe emissions of ozone precursors, carbon monoxide, and PM-l0 and fugitive dust emissions from earth-moving activities and vehicle travel on unpaved maintenance roads. Fugitive dust can be emitted by the 1 action of equipment and vehicles and as a result of wind erosion over exposed earth surfaces. Clearing, grading and 7 2011=0 C.rry OF SAN Luis OBISPO 8 INMAL STUDY ENVIRel ,1614cKLIST 2002 - ATTACHMENT 2 No Issues, Discussion and Suppor, nformation Sources Sources P: lly Potentially Less'Man Sig),rtfcant Significant Significant Impact Issues Unless Impact ] ER # Mitigation Inco orated earthmoving activities comprise the major source of construction dust emissions, but traffic and general disturbance of the soil also generate significant dust emissions. In addition, demolition of existing pavement and revetment,and removal of demolition debris from the site, will also generate dust. However, the impacts are temporary, and with the mitigation measures described below, impacts to air quality will be less-than-significant. The APCD specifies Best Available Control Technology for construction projects contained within the CEQA Air Quality Handbook (San Luis Obispo County APCD, 1997). Equipment Emission Control Measures: AIR-1: The District shall require that all fossil-fueled equipment shall be properly maintained and tuned according to:manufacturer specifications AIR-2: The District shall require that all off-road and portable diesel-powered equipment, including but not limited to bulldozers, graders, cranes, loaders, scrapers, backhoes, generator sets, compressors, auxiliary power units,shall be fueled exclusively with ARB motor vehicle diesel fuel AIR-3: The District shall require installation of oxidation catalysts on the two pieces of diesel-fueled equipment project to.generate the greatest emissions. It is expected that bulldozers would be the highest emitters. Dust Control Measures: These measures augment dust control requirements of Section 7-8.1 of the Standard Specifications for Public Works Construction. AIR-4: During clearing, grading, earth moving, excavation, or transportation of cut or fill materials, water trucks or sprinkler systems are to be used to prevent dust from leaving the site and to create a crust after each day's activities cease. AIR-5: During construction, water trucks or sprinkler systems shall be used to keep all areas of vehicle movement damp enough to prevent dust from leaving the site. At a minimum, this would include wetting down such areas in the morning and after work is completed for the day and whenever wind exceeds 15 mph. AIR-6:Stockpiled earth material shall be sprayed as needed to minimize dust generation AIR-7: During construction, the amount of disturbed area shall be minimized, and on-site vehicle speeds should be reduced to 15 mph or less. JAIR-8: Exposed ground areas that are planned to be reworked at dates more than one month after initial grading should be sown with a fast-germinating native grass seed and watered until vegetation is established AIR-9: After clearing, grading, earth moving, or excavation is completed, the entire area of disturbed soil shall be treated immediately by watering or revegetating or spreading soil binders to minimize dust lgeneration until the area is paved or otherwise developed to prevent dust generation AIR-10: Grading and scraping operations shall be suspended when wind speeds exceed 20 mph (one hour average) JAIR-11: All roadways, driveways, and sidewalks associated with construction activities should be paved as soon as possible, In addition, building and other pads shall be laid as soon as possible after grading unless seeding or soil binders are used. AIR-12: All trucks hauling dirt, sand, soil, or other loose material shall be covered or shall maintain at least two feet of freeboard (minimum vertical distance between the top of the load and the top of the trailer). JCRY OF SAN Luis OBISPO 9 INITIAL STUDY ENVIROCA 4AJQ42LIST 2002 - AT HMENT "c Issues, Discussion and Supp g Information Sourcesttial Potentially Less Than No s.roificam Significant Significant Impact Issues Unless Impact ER ri sources Mitigation Inco orated 4. BIOLOGICAL RESOURCES. Would theproject: a) Have a substantial4tiversezffect,either directly or indirectly or -X-- through habitat'modifications,on any species identified as a candidate,.'sensitive,or special status species in local or regional plans,policies,or regulations,or.bythe California Department of Fish and Game or'U.S.Fish and Wildlife Service? b) Have a substantial adverse effect,on any riparian habitat or other sensitive natural community identified in local or regional plans,policies,or regulations,or by the California Department X ofEi&h and,Game-orVU S.Fish and Wildlife Service"? c) Couflict.withany local policies or ordinances protecting biological resources,such as a tree preservation policy or X._ ordinance(e.g.!Heritage Trees)? d)' Interfere sali'stanhally with the movement of any native resident or mrgmtoryfish or wildlife specie's or with'establrshed rIAttve- resident or migratory wildlife corridors,or impede the use of wtldl'ifeiiurserysites. " e) Conflict.with the provisions of.an adopted habitat Conservation Pla>4t;Natural'Com'munity Conservation Plan,or other apprgved local 4i gional,or•state habitat conservation plan.) ' 7 fl Have a substantial adverse effect on Federally protected wetlands as defined to Sectton"4Q4.of the Clean Water Act (ihdluaing;'but not lttnife3 to;marshes,veinal pools,etc), }{__ _ through direct removal,f lling,'hydrological interruption,6,f' otherineans? 7 .J 1 J `� CnY OF SAN LUIS OBISPO 110 INITIAL STUDY ENVIR I 12�KLIST 2002 Issues, Discussion and Sup' ;ng Information Sources sources entially Potentially Less Than No �mifcant Significant Significant impact Issues Unless Impact ER # Mitigation Inco orated aImplementation of the proposed project would result in long-term benefits to biological resources in San Luis Obispo Creek. A biological reconnaissance and review of the California Natural Diversity Database were conducted for the proposed project. The California Natural Diversity Database (CNDDB) maintained by the California Department of Fish and Game (CDFG) I was reviewed for special status species documented within the USGS San Luis Obispo (SLO) and Lopez Mountain quadrangle maps (CDFG, 2002). These 7.5-mile quadrangles encompass the Upper San Luis Obispo Creek watershed. The I CNDDB inventories for the SLO and Lopez Mtn. quadrangles list 36 special status species: 13 animal and 24 plant species. Of those special status species, 9 animal (Table 1) and 15 plant species (Table 2) occur within the Upper San Luis Obispo JCreek watershed. Special status species that are state or federally listed are described in more detail below. I California Red-Legged Frog The California Red-Legged Frog(Rana aurora dratonii) was listed in May 1996 as federally threatened and is a California species of special concern. California Red-Legged Frogs (CRLF) occur primarily in ponds or pools of intermittent stream courses where pools remain long enough for breeding and development of young. Adult require dense, emergent or shoreline I riparian vegetation closely associated with deep(greater than or equal to 2.25 feet), still, or slow-moving water(Jennings and 1 Hayes, 1994). Good water quality is a key habitat indicator, as is the absence of introduced bullfrogs and predatory fishes, which predate larvae at higher levels than co-evolved predators. California Red-Legged Frogs can aestivate in small mammal ` burrows and moist leaf litter(Jennings and Hayes, 1994). Boulders, rocks and downed woody debris also provide cover and moisture during the dry season. CRLF prefer lowland and foothill habitat in or near permanent sources of deep water with dense, shrubby or emergent riparian vegetation. California red-legged frog eggs are usually found in ponds or in backwater pools in creeks attached to emergent vegetation such as cattails (Typha sp.) and California tule(Scilpus californicus). Red- legged frogs are often found in creeks and ponds with dense growths of woody riparian vegetation,especially willows (Salix sp.). There are four recorded occurrences within the Upper San Luis Obispo watershed.The closest occurrence to the dam removal site is approximately 2 miles downstream in the vicinity of San Luis Obispo Creek. The other occurrences were documented in tributaries to San Luis Obispo Creek, also downstream of the dam removal site. The frogs were found in sites with dense willow cover,basking sites, undercut banks,and associated with vegetation such as sedges,rushes,and duckweed. The CRLF is predicted to have a high potential to occur within the dam removal site due to recorded occurrences within the project watershed. CRLF may move up to one mile up or down a drainage (USFWS, 1997), and their populations are presumed extant through the Upper San Luis Obispo watershed. Southwestern Pond Turtle The Southwestern pond turtle(Clemmys marmorata pallida)is a California Species of Concern.It is a mostly aquatic turtle of ponds, marshes, and rivers with aquatic vegetation. They require basking sites and suitable upland habitat for egg-laying. They over-winter in underground burrows in upland habitats. In the warmer months the pond turtle will bask on rocks and logs near slow-moving streams. They are predicted to have low to moderate potential to occur within the project site. The closest recorded occurrence is approximately 1.5 miles upstream of the project site at the north portal of Cuesta Tunnel— north of Highway 101 at the railroad crossing. 1 California Coast Range Newt The California Coast Range Newt (Taricha torosa torosa) is a California Species of Concern. The Coast Range Newt is a diurnal salamander, and migrations to and from breeding sits may occasionally exceed 1000m(3300 ft), but few individuals move that far. Coastal Newts frequent terrestrial habitats, but breed in pools, reservoirs, and slow-moving streams: This 1 species has been depleted by large-scale historical commercial exploitation coupled with the loss and degradation of stream habitats(CDFG, 1997).The Coast Range Newt is also a Local Species of Concern for the City of San Luis Obispo. California Tiger Salamander The California Tiger Salamander (Ambystorna californiense) is a California Species of Concern.The one recorded occurrence within the Upper San Luis Obispo watershed was documented in 1939 in the vicinity of Stenner Creek,a tributary of San Luis Obispo Creek, approximately one mile north of San Luis Obispo. However, its presence is considered extirpated. They are ~ g A Crry OF SAN Luis OBIsPO R■1 INfT1AL STUDY ENV"EIT6d14CKLIST 202 ATTACHMENT 2 --I Issues, Discussion and Sup, ng Information Sources Sources al'3 lyNo No Potentially Less Than ,..gmificam Significant ' Impact ER # Issues Unless Impact Mitigation Inco orated q [either redicted to have little to no potential to occur in the project site. JI irds of the two special status bird species that have recorded occurrences within the project watershed is predicted to occur the project site. The Western Yellow-billed Cuckoo (Coccyzus americanus occidentalis) prefers nesting sites along the oad, lower floodplains of larger river systems. The one-recorded occurrence in the CNDDB dates from 1921 and is presumed extirpated. Prairie Falcons (Falco mexicant s) prefer rolling foothills of mountainous areas and use cliff-walled Jcanyons as nesting habitat. The closest recorded occurrence is within the Santa Lucia Range at Tinker Toy Ranch. Central Coast Steelhead J Central California Coast Steelhead Salmon (Onchorhyncus mykiss irideus) were listed as federally threatened in 1997. Habitat loss, including loss of water flows, and the failure to protect the runs due to inadequate regulatory measures have been the major, or at least the most conspicuous, causes of the decline of southern California steelhead. San Luis Obispo Creek contains a viable population of southern steelhead and enhancement of this population is a high priority of the City of San Luis Obispo. The primary objective of dam removal is the restoration of steelhead access to spawning and rearing habitat currently blocked by the 4 in (13-ft) high dam. Steelhead have been documented in the San Luis Obispo Creek watershed, with the closest recorded occurrence within Cuesta County Park on San Luis Obispo Creek approximately 2.5 miles y downstream of the project site. Plants The two special status plant species with recorded occurrences in the Upper San Luis Obispo watershed have little to no potential to occur within the project site due to their restriction to serpentine soil habitat. The Chorro Creek bog thistle (Cirsiran fontirrale var obispoense) is of extremely limited distribution, found only in perennial serpentine seeps and springs in western San Luis Obispo County. The closest recorded occurrence was documented approximately 10 miles southwest of the project site on the slopes above Miossi Creek, 0.5 miles north of Cuesta Canyon County Park. There.it was found in very wet seeps on serpentine clay soils. Cuesta Pass Checkerbloom (Sidalcea hickmdnii sp. anontala) populations are restricted to a small area of San Luis Obispo County on West Cuesta Ridge, northwest of Cuesta Pass. The closest recorded occurrence J was documented on West Cuesta Ridge, the northern watershed boundary for Upper San Luis Obispo Creek, approximately 3 miles northwest of the project site. The California Natural Diversity Database lists 24 special status species within the Upper San Luis Obispo Creek watershed.Of these,four are state-or federally-listed or species of concern and are predicted as likely to occur within the project site: the California Red-Legged Frog, the Southwestern Pond Turtle, the California Coastal Newt and the Central Coast Steelhead.Due to the nature of the project,the removal or partial removal of an existing dam,impacts to these sensitive species will be beneficial in the long-term Dam removal (full or partial) will improve and increase access to headwater habitat. J The potential occurrence of these species in the project site requires the inclusion of mitigation measures to protect their aquatic and riparian habitats during construction. Their habitat requirements must also be addressed under the changed hydraulic conditions following construction. Typical mitigation procedures include daily pre-construction surveys to insure the absence of special status species within work zones, clearing and re-locating any encountered protected species, monitoring of construction activities, and inspection of design considerations (e.g. creation of new in-stream habitat via step pools). Though the potential presence of these three special status species requires careful mitigation of the project site and project design, it also is a good indicator that the project has the potential to benefit many riparian and aquatic species. Extended habitat and improved access to the upper reaches of San Luis Obispo Creek due to partial or full dam removal will have positive impacts for the Upper San Luis Obispo Creek watershed ecosystem. a) On the basis of reconnaissance surveys conducted on-site, information on the local distribution of the plants, and the lack of appropriate micro-habitats (e.g. serpentine based soils), it was concluded that there is little to no potential for special-status plant species to occur on-site. Project development thus is predicted as unlikely to have impacts on special-status Plant species. Crry OF SAN Luis OBISPO 12INITIAL STUDY ENVIRON L Y ST 2002 TAC Issues, Discussion and Suppol 'Information Sources Sources r ally Potcntially Less Than No Ste scant Significant Significant Impar Issues Unless Impact ER # Mitigation IncorporatedInco orated J Some special-status bird species, such as the Prairie Falcon, may have the potential to be occasional visitors, migrants, or transients. The project would have n6 effect on the breeding success of any of these.species,although it will result in a small reduction of foraging and/or roosting habitat available to them regionally. The proposed project Jis expected to have a less than significant impact on these species that do not breed at the site. Habitat for four of the special-status wildlife species, however, could potentially be affected by construction activities at San Luis Obispo Creek. • California Red-Legged Frog(Rana aurora draytonii), a federally threatened species • Southwestern Pond Turtle(Clemmys marmorata pallida), a California Species of Concern J • California Coastal Newt(Taricho torosa torosa),a California Species of Concern • Central California Coast Steelhead Salmon (Onchorhyncus nzykiss irideus),a federally threatened species 1 The California Red-Legged Frog and the Southwestern Pond Turtle are predicted to have low to moderate potential of occurrence in San Luis Obispo Creek. Additional surveys are required to determine if the species are present at the project site California Coastal Newts, adults and eggs, have been observed at the project site. Though the 1 proposed project will have long-term benefits to riparian and aquatic habitat, short-term impacts on potential habitat could occur during construction activities. Implementation of the mitigation measures proposed below would minimize impacts on biological resources: J BIO-1: Consultation with the California Department of Fish and Game (CDFG) and the U.S. Fish and Wildlife Service(USFWS)and conduct surveys for special-status species prior to final construction design . The City of San Luis Obispo would confer with the CDFG and the USFWS prior to final construction design for restoration of the San Luis Obispo Creek channel to determine if the project site is potentially suitable habitat for the California Red-Legged Frog. If CDFG and USFWS determine those areas are potentially suitable, the City would conduct surveys to determine whether or not the species are present in the project site. USFWS protocols would be used to determine presence of special status amphibians were present,the following BWs would be implemented: BI0-2: Minimize areas of disturbance in riparian habitat and replant disturbed areas after construction Construction practices should be used that minimize impacts on existing trees and riparian habitat along San Luis Obispo Creek Construction equipment would use the existing maintenance and access road on the east side (left bank) of the Creek. Implementation of the proposed project includes riparian re-vegetation of graded slopes. Replacement plants would be monitored for establishment success for a minimum of three years by a qualified biologist. BI0-3: Limit in-channel construction activities to the summer low-precipitation period To reduce the potential for impacts on aquatic species and water quality, in-channel construction activities should be limited to the summer low-precipitation period (April 1 —October 15). Limiting construction activities to this period would also reduce the risk of streambank erosion. After construction is completed, streambanks and adjacent areas disturbed by construction activities would be stabilized to avoid increased erosion during subsequent storms and runoff. BI04: Ensure that turbidity does not substantially increase during construction If the stream turbidity increases substantially during construction, mitigation measures must be implemented immediately to reduce and maintain turbidity near natural levels. Potential mitigation measures include: o minimizing disturbance of soils and streambed gravels, if present, o constructing silt barrier immediately downstream of the construction site, and reducing the rate of J _ �1 �`� CfTY OF SAN LUIS 08tSPo 13 INrr1AL STUDY ENvIRO4Cq4 r-46uST 2002 ,J Issues, Discussion and SupporInformation Sources Sources Pr illy Potentially Less Than No Si, am Significant Significant Impact Issues Unless Impact ER # Mitigation Inco orated construction activities BIO-5: Implement a construction worker education program that includes an explanation of California Red. Legged Frog natural history and identification,avoidance measures,and federal laws that protect the frog 1 11I0-6: Conduct work and maintenance during clear,dry daylight hours.Work shall not be conducted during periods of rain when frogs tend to be more active BI0-7: Construct a water conveyance/diversion system to de-water the creek during construction activity BIO-8: Designate a fueling and vehicle maintenance area outside of the creek away from sensitive biological Iresources The measures stated above will reduce the impact to the special status amphibian species to less-than-significant. Specific requirements for reducing impacts on stream habitats should be coordinated with CDFG during the streambed alteration agreement process required under Sections 1601-1603 of the California Fish and Game Code. b)To mitigate the short-term effects on existing habitat during construction, the following measures (as described in detail above) would be implemented: BIO-2: Minimize areas of disturbance in riparian habitat and replant disturbed areas after construction ' BI0-3 Limit in-channel construction activities to the summer low-precipitation period IBIO-4: Ensure that turbidity does not substantially increase during construction c)The proposed project would not conflict with any local policies or ordinances protecting biological resources. The General Plan for the City of San Luis Obipso states: • The City should manage its lake, creeks, wetlands, floodplain, and associated wetlands to achieve the objective of maintaining and restoring natural conditions and fish and wildlife habitat (San Luis Obispo General Plan,Land Use Element Policy 6.4.1:Creek and Wetlands Management Objectives) • Restore degraded creeks to provide high quality habitat and to augment aesthetic resources,and to reverse the historical trend of creek channelization and modification. (San Luis Obispo General Plan, Open Space Element Policy 3.1.3:Creek Restoration) The proposed project is in accordance with City policy. d)Implementation of the proposed project would not interfere with the movement of wildlife and fish in the San Luis Obispo Creek watershed. Actually, the proposed project will partially remove an existing dam that is currently a significant obstruction to movement within the channel. The primary objective of the project is to increase federally threatened Central Coast Steelhead access to the upper reaches of San Luis Obispo Creek, increasing migratory corridor lengths and access to spawning areas. Construction impacts to Steelhead habitat will be temporary and beneficial in the long-term. e)Implementation of the proposed project would not conflict with the provisions of an adopted habitat Conservation Plan,Natural Community Conservation Plan,or other approved local,regional,or state habitat conservation plan. f)Implementation of the proposed project would not have a substantial adverse effect on Federally protected wetlands as defined in Section 404 of the Clean Water Act. 1 CRY OF SAN LUIS Osispo 14 INITIAL STUDY ENVIRONm6pruf H ffsT 2002 Ui1 � ATTACHMENT 2 �f Issues, Discussion and Supp, g Information Sources Sources J,niauy Poieniially Less Than No Significant Significant Significant Impact ER # Issues Unless Impact Mitigation loco orated Table 1. Special status wildlife species with potential to occur in the Upper San Luis Obispo Creek watershed.Status of all species is based on the CDFG Threatened and Endangered Animals List of California,January 2002. % tt',t,� .�.`"a M. ti ilka a r Y i .+ Mccorded axae' h nqU y k2c i4 3 w,>s rc art 2 t^y� F S F f ,, t x t S) 1i4 .W @�; $I '� :t i sY. t .,••L na d�v.� y `�� �4 Gj �a- X acDUrr(allC t , a nr + K( s �tSPs,fyl,t'� ,p¢Cl¢5 L11n:IIQA x P ''t °' , "S .ecjesfLatln'? t8'r ; i r�''r „� 's'A' S'y x + "' r 1• Atascadero June Beetle. Polyphylla nubila 3 None Species of Concern None California Red-Legged Frog iRana aurora dra tonii 4 None Threatened S ecies of Concern California Tiger Ambystonza Salamander tali orniense 1 None Endangered* Species of Concern California Coast Range observed in the Newt Toricha torosa torosa field None None Species of Concern Monarch Butterfly Danaus plexippus 1 None None None Prairie Falcon Falco ntexicanus 2- None None Species of Concern Southwestern Pond Clemnrys marmorata Turtle pallida 7 None None Species of Concern teelhead-Central Oncorhynchus nzykiss California Coast irideus 2 Threatened S ecies of Concern Western Yellow-Billed Coccyzus antericanus Cuckoo occidentalis 1 =None None None *Federal listing applies to Santa Barbara County,California only 7 d CITY OF SAN LUIS OBISPO 15 INrrIAL STUDY ENvIROkW_&14 sT 20D2 J Issues, Discussion and Suppo Information Sources sources P ally Potentially Less Than No S. ,cant Significant Significant Impact J ER # Issues Unless impact Mitigadon Incorporated Table 2.Special status plant species with potential to occur in the Upper San Luis Obispo Creek watershed. Status of species is based on the CDFG Rare, Threatened and Endangered Plants List (January,2002). California Native Plant Society (CNPS) list designations are based on the Inventory of Rare and Endangered Vascular Plants(2002). "'1 w>. •--+�-}.i r.yrwr tc, o-n a-a `{ ii' i'itk�u'Fn7El rry A. �'F Ffti LL ��41 } i}-"{'_,,q��t � iYl' sW A: FhZ �� StL �.1 � kkT '+.FA"a�t1' tt'i�`�1•r't .4�t�"��i7��r,°�+,.r� r,F° nq''.�dk°.�`�2 -:'�r`V'n s 4 sL ,,�` 4�i;rt3�tt,,.,°�,L*.''y'`,t�� �jF �,� i}y�• a��7"�'`.�•sv'���. �?,�`Ti-n..,r,� '�+� �,�f,�'�ZF�' .$�" t:r i �.� Te_•sr:� #}'<`'x�Y� /i,��tr,..,A: -u.}� N• d �vR' te'j�` ' '� J. '3�%TTM�.„t�".. �h1+f.d.d T"h' ��, '�� ,�k�iha� 3%''X.{.'i. }, y"'^ eete$� tttm snrf"t cY f''Stx` <. .rte 1 �dtr�,},�pp'. liQ�4, ,W y�FS p ti Sw.tF..tSe fir: +t F�'�y"6 Y"r'Stl r .twRS' N�e W �� S e`c�e Name" Cree"kWatefstied ' S to@ arsF �eraltl R -D code.*, CNPS**. Blochman's Dudleya blochmaniae Dudle a ssp. Blochmaniae. 1 None None 2-3-2 1B Brewer's S ineflower Chorizanthe breweri 13 None None 3-1-3 111 Cambria Morning Calystegia subacaulis Glory ssp. E Isco alis 2 None None 3-2-3 1B Chorro Creek Bog Cirsium fontinale var Thistle obis oense 3 Endangered Endangered 3-2-3 1B Cuesta Pass Sidalcea hickmanii Checkerbloom ssp. Anomala 1 Rare None 3-2-3 IB Delphinium parryi ssp. J Dune Larkspur Blochmaniae 1 None None 3-2-3 1B Chloragalum omeridianum var Dwarf Soa root minus 2 None None 2-2-3 113 Jones's La is La is jonesii 2 None None 3-2-3 113 Astragalus didymocarpus var Miles's Milk-vetch milesianus 3 None None 2-2-3 1B Most Beautiful Streptanthus albidus Jewel-Flower ssp. Peramoenus 4 None None .2-2-3 IB Rayless Ragwort Senecio a hanactis 2 None None 3-2-1 2 San Benito JFritillary ritillaria viridea 2 None None 2-2-3 IB San Luis Mariposa Calochortus Lily obis oensis 17 None None 2-2-3 1B San Luis Obispo Sedge Carex obis oensis 2 None None 2-2-3 1B Santa Lucia A rcrostaphylos Manzanita luciana G None None 2-2-3 1B *R-E-D Code.CNPS uses a scheme that combines three complementary elements that are scored independently.These components are: rarity,which addresses the extent of the plant,both in terms of numbers of individuals and the nature and extent of distribution; endangerment,which embodies the perception of the plant's vulnerability to extinction for any reason;and distribution,which focuses on the overall range of the plant. Each element in the code is divided into three classes or degrees of concern,represented by the number 1,2, or 3. In each case, higher numbers indicate greater concern. **CNPS Plant lists IB:Plants rare,threatened or endangered in California and elsewhere;2: Rare or endangered in California,more common elsewhere 7 tel— CrrY OF SAN LUIS OaisPO 16 INITIAL STUDY ENVIROCFft-C{IqICLIS r 2002 ATTA Issues, Discussion and Supporl nformation Sources Sources Pr Ily Potentially LcssTT,an No Sig. _.an[ Significant Stgnificam Impact ER # Issues Unless Impact Mitigation IInco ora[ed 5. CULTURAL RESOURCES. Would theproject: a) Cause:a substantial adverse change in the significance of a __ historic resource?(See CEQA Guidelines 15064.5) X b) Cause a substantial adverse change in the significance of an archeological resource?(See CEQA Guidelines 15064.5) X c) Directly or indirectly,destroyer unique paleontological resource __ or site or unique geoogic feature? X d) Disturb any human femaing including those interred outside df formal cemeteries? X The proposed project would not adversely affect any known historic, archeological, or paleontological resources. No known archeological or historic resources are located along San Luis Obispo Creek where construction or earth-moving activities are proposed. However, riparian corridors were typically a desirable feature to prehistoric peoples for camps, villages, and procurement areas. Although no cultural resources were detected or have been recorded from the project site, it is still possible that subsurface archaeological materials may be present. It is remotely possible that such materials could be encountered during site preparation and construction. This potential impact is considered less than significant with mitigation because the City would take the following measures to ensure that subsurface sites are not accidentally destroyed. Section 15064.5 of the State CEQA Guidelines provides direction for dealing with archaeological sites that are found during construction. The following are mitigation measures described in the CEQA guidelines: ARCH-1: If archaeological sites (artifacts of stone, bone, or shell, glass, or ceramics) were found during construction, the contractor would stop all work immediately within 100 feet of the find and consult a qualified archaeologist for an immediate evaluation of the find. If the find were determined to be an important archaeological resource, the City in consultation with the State Historic Preservation Officer would develop appropriate treatment measures. Contingency funding and a time allotment sufficient to allow recovery of an archaeological sample would be made available by the contractor. Construction work may continue on other parts of the site while archaeological mitigation takes place. ARCH-2: In the event that any human remains are discovered or recognized in any location other than a 1 dedicated cemetery, no further excavation or disturbance will occur at the site or in any nearby area J reasonably suspected to overlie adjacent human remains until: to the coroner of the county in which the remains are discovered has been informed and has determined that no investigation of the cause of death is required;and o if remains are of Native American origin: ■ the descendants from the deceased Native Americans have made a recommendation to the landowner or the person responsible for excavation work, for means of treating or disposing of, with appropriate dignity, the human remains and any associated grave goods as provided in California Public Resources Code Section 5097.98, • or the Native American Heritage Commission has been unable to identify a descendent or the descendant has failed to make a recommendation within 24 hours after being notified by the commission. 6. ENERGY AND MINERAL RESOURCES. Would theproject: a) Conflict with adopted energy conservation plans? --X-- b) Use non-renewable resources in a wasteful and inefficient manner? c) c) Result in the loss of availability of a known mineral resource that would be of value to the region and the residents of the X CrrY OF SAN LUIS Osispo 17 INITIAL STUDY ENVIRO C IST 2002 r Issues, Discussion and Suppr I Information Sources sources r 'tally Potential y ss ran No scant Significant Significant Impact Issues Unless Impact ER # Mitigation Incorporated JState? The proposed project would not result in the loss of availability of a known mineral resource or recovery site. No impact would occur. 7 7. GEOLOGY AND SOILS Would theproject: a) Expose people of structures to potential substantial adverse 7 effect`s;including risk of loss, injury or death involving: X I. Rupture of a known earthquake fault, as delineated in the most-recent Alquist-Paolo Earthquake Fault Zoning Map issued by the State Geologist'for the area,or based on other X 7 substantial evidence of a known fault? II. Strong seismic ground shaking? --X-- IIISeismtc related groun(I-fatluie,includtng liquefaction --X-- I� Landslides or mudf lows b) Result Result in substantial soil erosion or the loss of;topsoil? X-- .c) Be-located on a geologic unit or soil that is unstable,or.that J would become.unstable as a result of they. roject,and potentially resul(in.dnordffsitedandsltdes,lateral-s'0readi subsidence; . X ltquefiiction,:or-coll apse d) .Be located on expansive soil as defined m Table 18 1=B of the Uniform Building Code{d99 ),creating substantial risks tollfe . X-- >' or.pro J The project site is located in the southern portion of the Coast Range geomorphic province which extends from the Oregon border to the Santa Ynez River.The province comprises a structurally complex northwest-southeast-trending set of ranges and valleys and is characterized by similarly trending faults and fold axes. Lithologies are complex and range in age from 7 Mesozoic to Holocene periods. San Luis Obispo Creek has its headwaters in the Santa Lucia Range that separates the coastal margin from the Salinas Valley. The Santa Lucia Range exemplifies the complex geology of the Coast Range and has a core of Mesozoic rocks: Franciscan Complex in fault contact with Jurassic metavolcanics and serpentinite, Jura-Cretaceous interbedded shaletclaystone with minor sandstone, and Cretaceous interbedded sandstone and shale. Mid- to late-Tertiary marine sedimentary rocks and volcanic rocks overlie the Mesozoic rocks. The soils in the Santa Lucia Range are generally residual soils and recent alluvial soils composed of clayey materials and are expected to be moderately expansive.Residual soils developed in place on consolidated bedrock and are usually shallow(12- 18 inches deep) soils found on steep slopes with frequent rock outcrops. Most of these soils tend to be sandy or cobbly loams with a moderate runoff potential.Recent alluvial soils are found in the stream and river bottoms and are mostly sand and silts. 7 Data for the liquefaction potential or project area soils are limited; however, the cohesive nature of much of the area soils is expected to limit the potential for liquefaction in major earthquakes. Although the region is seismically active, with a history of recorded earthquakes as far back as 1830, the occurrence of ground rupture and offset is rare. There is no evidence that the proposed project is located on,or in the immediate vicinity of, an identified active fault. a) Implementation of the project would not increase the exposure to or risk of geologic hazards; the project would not result in the creation of new development that would expose people or structures to seismic risks, including liquefaction and landslides. b) Implementation of the project would not result in long-term increases in erosion and soil loss. Slope set-back,riparian planting, and biotechnical bank stabilization methods (components of the proposed project) would reduce long-term erosion and soil loss. JTemporary impacts from construction-related activities would result in disturbance of the ground surface. ��A CrrY Of SAN LUIS Oetspo 18 INITIAL STUDY ENVIRC, LIsT 2002 Issues, Discussion and Suppo Information Sourcessoar«s r it Pot enun ly ss tan o S,�_.tcant Significant Significant Impact ER # Issues Unless Impact J Mitigation Inco orated Construction activities would expose disturbed and loosened soils to erosion from rainfall, water and wind. Soil erosion is the process by which soil particles are removed from the land surface by wind, water, or gravity. Most natural erosion occurs at slow rates; however, the rate increases when the land is cleared or altered and left disturbed. Construction activities remove the protective cover of vegetation that could result in localized accelerated wind and water erosion. The proposed project includes riparian re-vegetation; however, short-term increases in soil erosion would occur due to construction activities. The following mitigation measures are recommended to reduce possible soil erosion effects during construction to a less-than-significant effect: GEO-1: Implement erosion and sediment control plan The City of San Luis Obispo would require construction contractors to prepare an erosion and sediment control plan that identifies BMPs to reduce erosion of disturbed soils during construction activities. The goal of the plan would be to minimize wind and water erosion and transport of sediments during construction.The plan would include measures for containing hazardous materials associated with construction equipment(e g. diesel fuel, oils, solvents), and would describe the location and schedule for BMPs at each project site. The construction engineer would prepare the plan before construction activities begin. The following measures would be considered in the plans to minimize erosion and.sedimentation: o Erosion control methods shall include: 1) temporary measures, such as flow diversion, temporary ditches, and silt fencing; 2) permanent measures such as rock drop structures, coir logs, erosion control fabrics, and straw wattles; and 3) revegetation measures,including hydro-seeding and planting within the riparian zone o Flows in the watercourse shall be contained or routed to bypass excavation activities o Surface disturbance of soil and vegetation would be kept to a minimum; existing access and maintenance roads would be used wherever feasible o The project applicant shall be responsible for ensuring that all contractors are aware of all storm water quality protection measures,and for the implementation of such measures I o Channel excavation work should be avoided during the wet season (normally October 15 to April 1"`), and such work shall be stopped before pending storms, and all disturbed areas stabilized using temporary protection measures o Any stockpiled.soil would be placed and sloped so that it would not be subject to accelerated erosion o Discharge of all project-related materials and fluids into the creeks would be avoided to the extent possible by using hay bales or silt fences, constructing berms or barriers around construction materials,or installing geofabric in the area of disturbance a o After ground-disturbing activities are complete, all graded or disturbed areas would be t covered with protective material such as mulch, or re-seeded with native plant species. The plan would include details regarding seeding material,fertilizer,and mulching c-d)The proposed project is not located on a geologic unit or soils that are unstable or that would become unstable as a result of the project. Soil expansion index measurements are required to determine the presence of expansive soils at the project site. Even if expansive soils are present, the proposed project does not include the construction of any Istructures that would cause substantial risk to life or property. H. HAZARDS AND HAZARDOUS MATERIALS. Would theproject: a) ` Create a significint1aiard to the public or the`environrnent _}{__ Crry OF SAN LUIS Owspo 19 INrrlAL STUDY ENVIRON HMisT 2002 Al llatomiVIM I k Issues, Discussion and Sup Ig Information Sources Sources mitally Potentially Lcss Than No ,nificant Significant Significant impact Issues Unless Impact 1 ER # Mitigation Inc orated J though the routine use,transport or disposal of hazardous materials? b) Createa significant hazard to the public or the environment through seasonably foreseeable upset and accident conditions 1 involving the release of.hazardous materials into the X environment? c) trait hazardous emissions or handle.hazardous or acutely hazardous materials,substances, or waste'within one-quarter }{__ mile-of an existing or proposed school? d) Expose,-:people or structures to existing sources of hazardous 1 emissions or hazardous or acutely hazardous materials, substances,or waste? e) Be located on a site which is included on a•list of•hazaidous materials sites.compiled pursuant to Govemnment Code-Section 1 65962:3 and;as asesal(;it would creafe a sigritfica it}iazard`to X the•public or'the environment? f) ' For a project located within an airporfland'use plan,of within 1two miles'of a public airport,would the project result in a safety --X-- hazard for.the.people residing or working-in the.project area? g), "Impair mplementationbf,oFphysicsllj,i"n'tdifere�witlt;'-the adopted emergency response plan or emergency evacuation X-- plari? '• h) Expose people or structures to a sij;n>ficant,iiskrof lose,injury, orileath involving wild]and fires,inCluding'where vildlands are X- adjacentlo urbanized.areas onwhere residents are. ntOrnixed With wildlands? a-b)The proposed project does not include any components that entail the routine transport, use,or disposal of hazardous material. No releases of hazardous materials or substances would occur during the implementation of the proposed project. c-d)Potential impacts from temporary emissions due to construction equipment activities are addressed in Section 3,Air Quality. Other hazardous emissions or the handling of hazardous or acutely hazardous materials, substances, or waste are not predicted to result from the implementation of the project. The project site is not located on a hazardous materials site; it is not located within an airport land use plan area, or within two miles of a public use airport; it is also not located within the vicinity of a private airstrip. g) Implementation of the proposed project would not interfere with an adopted emergency response/evacuation plan. h) Implementation of the proposed project is not expected to increase the risk of wildfires in the project vicinity. 9. HYDROLOGY AND WATER QUALITY. Would theproject: aj .•Violate any water quality standards or waste discharge requirements? X b) Substantially deplete.groundwater supplies or interfere substantially with groundwater recharge such that there would be a net deficit in aquifer volume or a.lowering of the local groundwater table level(eg.The production rate of preexisting X nearby wells would drop to a level which would not support existing land uses for which permits have been granted)? c) Create or contribute runoff water that would exceed the capacity of existing or planned storm-water drainage systems or provide __X__ substantial additional sources of polluted runoff. d) Substantially alter the existing drainage pattern of the site or area in a manner that would result in substantial erosion or X- 1 Crrr OF SAN Luis Oetspo 20 INITIAL STUDY ENVIq� -�r A {`CKLIsT 2002 ATTACHMENT Issues, Discussion and Suppol , Information Sources sources F ally Potentially Less Than No Significant Significant Significant Impact Issues Unless Impact ER #1 Mitigation loco orated siltation onsite or offsite? e) Substantially alter-the existing.drainage pattern of the site or area in•aananner.thatwodld result-in substantial flooding onsite __X__ or offsite? T f) Place•housirigwithina 100-yearflood hazard area as mapped on a Federal'F1ood.Hazard Boundary or Flood Insurance Rate Map or other flood;bazard defined iah map? 1 g) Place within-a.100-year flood hazard area structures that would impede or redirect flood flows? X h). Otherwisesubstantiall Ati adewater quality? 1 a) The proposed project would not violate any water quality standards or waste discharge requirements. b) The proposed project does not require additional water supplies that could deplete existing groundwater supplies. c) The proposed project would not create or contribute runoff water that would exceed the capacity of existing or planned storm-water drainage systems or provide substantial additional sources of polluted runoff. d) The restoration project proposes to create new stable channel bed and banks along the existing channel centerline. Excavation above the dam (to be partially removed under the proposed project) and engineered fill below the dam will create a consistent slope throughout the project reach and allow Steelhead access to headwaters above the dam. This channel restoration does change the existing drainage pattern through the site; however, Iona-term impacts are predicted to be beneficial. Under existing conditions, the project reach downstream of the dam is experiencing significant bank erosion. Erosion mechanisms generally consist of toe scour and geotechnical sloughing. The proposed channel restoration will allow bank slopes to be re-graded to a slope of 3H:1 V, and engineered fill to be _ placed downstream of the dam to bring channel bed slopes to a consistent grade. This will increase bank stability throughout the lower segment,and, in the long-term,reduce erosion and/or siltation onsite Proposed construction activities, including excavation and grading, would result in the disturbance of the ground surface, temporarily increasing erosion rates and, potentially, sediment discharge rates to creeks. Effects on water quality during construction,such as increased turbidity, are short-term and would not result in substantial decline in existing water quality in the watershed. Channel modification activities would be followed by various re-vegetation/ bank stabilization techniques to minimize discharge of sediment-laden stormwater from entering the Creek. These techniques include: bank slope erosion control blankets and riparian re-vegetation to stabilize the ground surface after construction. This temporary impact is considered less-than-significant with mitigation. Mitigation procedures discussed in previous sections would also be implemented to further reduce temporary construction impacts: SI0-3: Limit in-channel construction activities to the summer low-precipitation period B104: Ensure that turbidity does not substantially increase during construction GEO-1:Implement erosion and sediment control plans e) Implementation of the proposed project would not increase flooding potential onsite and off site, and would not increase the rate or amount of surface runoff. 1 f-g)The proposed project would not place housing within a 100-year flood hazard area, and it would not place structures within a 100-year flood hazard area that would impede or re-direct flood flows. The gradient control low rock weirs (0.3 in (1 ft) high) to be installed into the Creek serve to stabilize channel bed elevations and create scour pool habitat for aquatic organisms. 10. LAND USE AND PLANNING-Would theproject: J JN;J CRY OF SAN LUIS OBISPD 21 INITIAL STUDY ENVIRONI[F.PaO.limiGC isT 2002 ATTACH , M7 Issues, Discussion and Suppc Information Sources so ces sally Potentially Less Than No S._ ..tcanl Significant Significant Impact Issues Unless Impact 1 ER k Mitigation Inco orated 1 a) Conflict with applicable land use plan, policy, or regulation of __X__ an agency with jurisdiction over the project adopted for the purpose of avoiding or mitigating an environmental effect? b) Physically divide an established community? __X__ 1 c) Conflict with any applicable habitat conservation plan or natural community conservationplans? --X-- 1 The proposed project site is located within the San Luis Obispo Planning Area of the County of San Luis Obispo. The area surrounding the project site is designated Rural Residential. This designation is applied to sites unsuitable for agriculture with lots ranging from seven to 50 acres. 1 a)The proposed project would be implemented on existing public land owned by the City of San Luis Obispo; therefore, it will not result in the division of an established community. b)The proposed project does not conflict with any applicable land use plan, policy, or regulation of any agency with jurisdiction over the project. 1 c) Implementation of the proposed project would not conflict with any applicable habitat conservation or natural community conservation plans. 1 11.NOISE. Would the project result in: a) Exposure of people to or generation of"unacceptable"noise Jeve(s as iiefint i by the Santniis"Obispo General Plan"Noise Element or general noise leyels to excess of standards' X establisted m the Noise Ordinance? b} As ubstantial terrlporaiy,penodic ..permanent increase iii nm$ient noise levels in the project'yicmily above levels.exisfing —X-- J without the project? c) Exposure of persons to ongenerati'on of.excessive groundborne vibratiomor groundborne noise levels? --X-- d) For a_project located within an airport land-use plan,or within two.mile.s of a-public airport or public use airport,would the Fro ecf ezPo-s.e people residing ar w6ild rthgne roJe"ct area to g excessi Ve itpise'levels? 1 The proposed project would not result in the generation of long-or short-term noise or the exposure of people to long-or short-tens noise levels exceeding local noise thresholds. The proposed project would result only in the generation of temporary noise,most likely lasting less than 2 months.No permanent impact would occur. Temporary project-related noise would occur from use of construction equipment and construction activity. Noise levels in construction areas would increase and noise-sensitive land uses, such as residences, located near the construction area could be affected. The effect of increased noise levels would be diminished because most construction activity is expected to take place during daylight hours when noise levels are generally the highest and people's tolerance is the highest. The proposed channel restoration project would not be located within an airport land use area or near a private airstrip. The project does not involve locating noise-sensitive land uses near active airports.No impact would occur. 12. POPULATION AND ROUSING. Would the ro'ect: a) Induce substantial population growth in an area, either directly (for example by proposing new homes or businesses) or indirectly (for example, through extension of roads or other _X infrastructure)? b) Displace substantial numbers of existing housing or people necessitating the construction of replacement housing X•- elsewhere? �a CITY OF SAN LUIS Osispo 22 INITIAL STUDY E.NVIROCt�Sli CFl1�LlsT 2002 t 11 ATTACHMENT Issues, Discussion and Supp g Information Sources Sources nuauy Potentially Lessrhan No significant Significant Significant Impact 1 ER # Issues Unless Impact Mitigation Inc orated The Upper San Luis Obispo Dam Removal Project would not induce substantial growth in the Cuesta Grade area or displace housing units or people. All facets of the project take place on public land. 7 13. PUBLIC SERVICES. Would the project result in substantial adverse physical impacts associated with the provision,or need,of new or physically altered government 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: a) Fire protection? --X-- •b) Police protection? --X-- •c) ` Schools? •d) Parks? _X e) Roads Roads and other transportation infrastructure? 'f1 Otherpublic facilities? The project vicinity is primarily a rural, low population density area. The proposed project would not result in the increased police or fire services, or involve the construction of facilities that would cause significant environmental impacts to schools, parks,or other public services. 14.RECREATION. Would theproject: )_ Increase the use of existrng neighborhood or rbgtonal parks or other-reCreationti facilities such that substantialphysieal ;:`3eY novation of ttie faci]ity wouhi`occur or ba°acce7erafed� `r s;' b) lnbludexecreational facilifies or require the construction or expansion of recreational facilities,which might•have:an'adverse _ h sical effect on the environment? The proposed project does not include a recreational or public access component. Implementation of the project will not affect recreational use or facilities in the project vicinity. Land uses within the project vicinity are primarily rural residential and agricultural. 15. TRANSPORTATION/TRAFFIC. Would the ro ect a),, CauSezn tncrea'se antraffic wlttch�s+substarit tn�reliCton to tier: �.. •C _X_ exr'sttngtraffit'lbadandcapacgyoffhestrebt*sten3n r H z b) Ekzceed;.etther ridt+nt3ual or cumulatively,a legel of$eiwice Y, standard rstablished bythe:ootinty congesdtinmanagement agency..ffor'designatedxoads and highways? gid) Substantially increase hazards due to design'feattrres(e g sharp curves or dangerous intersections)or inoompauble,uses-(e g __X__ farm equipment)? ` d) Result in inadequate emergency access? Jl e) Result in inadequate parking capacity onsite or offsite? —X --X-- f) Conflict with adopted policies supporting alternative transportation(e.g. bus turnouts,bicycle racks)? __X-- g) Conflict with the with'San Luis Obispo County Airport Land Use Plan resulting in substantial safety risks from hazards,noise, __X__ or a chane in air trafficpatterns? a-b)The proposed project would not cause long-term increased traffic loads, nor would it cause a long-term level-of- service standard to be exceeded. During construction, truck traffic to and from the site will increase; however, these traffic impacts will be temporary and therefore less-than-significant. Mitigations concerning equipment emissions are taA CtrY OF SAN Luis OBispo 23GIT INRIAL STUDY ENYIRO LIST 2002 Issues, Discussion and Suppc 1 Information Sources Sources iauy P t u. n _Zt No :. .,cam Significant Signi ficam Impact ER I Issues Unless Impact Mitigation Inco orated described in Section 3, Air Quality. J c-d)The proposed project would not result in a change in air traffic patterns, increased hazards because of design features J or incompatible use,inadequate emergency access or inadequate parking capacity. f)The proposed project would not conflict with adopted programs supporting alternative transportation. 1 16. UTILITIES AND SERVICE SYSTEMS. Would the ro'ect: a) Exceed wastewater`reaiment:rgquiretnents'of the applicable Regional Witei ty`• X g Qiiali Contrd]$oard? b) Require orrresult in the'construction or expansion of new water treatment,Waste.wat1.er„treatme1.'7nti or.stonh drainage facilities,the construction of w"tiich coup cause`significant environmental X” .1 effects? •1 c). .Have sufficient w'ater:supplies:available:to.serve the project from existing emgllements andzresouices,onare new and }{__ expanded 4aterlesourecsateeded?. :d) Result in a determinatron;by the wastewater tceatment;provider which:serva�ormay serve the-pro3ect that tt has adequate capacity to serve.fhe pro�eof s projected d'i Mand and°addition to X the providers extsttng commitment. e):; Be served by a Iatidfll avith"suffictentpermitted capacityYo accommodate the;project's soltd waste disposal needs? X- f3 'Comply with federal state,and Inca]statutes and regulations .related#osolid waste-?_ £.�;: .._<. .:: . . .',,:,,'• :_ :,: .. :: X-- 1 The proposed channel restoration project would not increase demand for wastewater, water supply, or solid waste facilities. It would not exceed wastewater treatment requirements of the Central Coast Regional Water Quality Control Board. 17.MANDATORY FINDINGS OF SIGNIFICANCE. a) <Does the^pro3eet hale thepotentialito,degrade he quality.of.the :.environment,s I -.N ";' ,,I ,educe,the fiab1if�af vfx ish nr wtldhfe �..,specie ,causes fishyorvav}ldltfepopulafion io,$rop below.self susta>mrig ieveis;tl}teaten to eliminate a ]an�Aiaruma`1 :, ! 1 ` i} a e StY r i 'commuruty,teducP tha$nuaibErt)rtrestnetatklen �eoaarenr endangered,plant;orlanmtal orh mina[ mgot#ant examples , the ma or enpi3saf G iltf iota histbr dr rehtsto 7�' b) Does the project have impacts that ai e indidually llmiteii but'. cumulayvely considerable?:'('tCumulatively considerable" means that thedricrementsl effects bf a proleet are considerable' when viewed in connectionwith the effects,of ihelpast projects, X 1 the effects of other current projects;and the effects of probable futureprojects) c) Does the project have environmental effects which will cause substantial adverse effects on human beings,either directly or X__ indirectly? Eheproposed project a) Though the proposed project has the potential, in the short-term, to have significant impacts on biological resources, geology/soils resources, and hydrology/water quality, implementation of mitigation measures identified above will 1 t.� CITY OF SAN Luis Owspo 24 INITIAL STUDY ENVIRO C IST 2002 "WVint RCHMENT 2 �- Sources Poa.__.�Ily Potentially Less Thanfues, Discussion and Supportly Information Sources Significant Significant Signifcantt Issues Unless Impact ER # Mitigation Inco orated ensure that the quality of the environment will not be degraded. The project components,including biotechnical bank stabilization, the creation of new stable low-flow channel bed and banks, rock weir installation and riparian revegetation, will increase the quality of the environment in the project area and prevent the potential for future bank erosion. 1 b) Cumulative impacts from the proposed project will be beneficial in the long-term. Partial removal of the dam would ensure that the historic gradient control functionality of the dam would be retained while providing greater migratory access for the federally threatened Central Coast Steelhead to headwaters habitat suitable for rearing and spawning. Accordingly, cumulative impacts to watershed aquatic habitat quantity and quality and water quality conditions will most likely be positive. c) The development of the project as proposed would not cause any substantial adverse environmental effects on human beings either directly or indirectly. All potentially adverse environmental impacts which may be associated with the proposed project will be mitigated to a level of less than significant through the implementation of the mitigation measures identified above. J J J 7 7 CrrY OF SAN LUIS OBISPO 25 INITIAL STUDY ENVIROLIST 2002 Issues, Discussion and Supl ig Information Sources Sources `ntially f%1.fAMAW01a No ,,ificant Significant Significant Impact Issues Unless Impact 7 ER # Mitigation Inca orated 18. EARLIER ANALYSES. �t •Earlier.analysis may be,used where, pursuant to the tiering, program EIR, or other CEQA process, one or more effects have been adequately analyzed`in an earlier EIR or Negative Declaration. Section 15063 (c) (3) (D). In this case a discussion should,identify the following items: a) Earlier analysis used.-identify earlier analyses and state where they are available for review. J b) Impacts adequately addressed. Identify which effects from the above checklist were within the scope of and adequately analyzed in an earlier document pursuant to applicable legal standards, and state whether such effects were addressed by mitigation measures based oni the earlier analysis. ] c) Mitigation measures. :For effects that are "Less than Significant with Mitigation Incorporated," describe the mitigation measures which:wereJncorparated or refined from the earlier document and the extent to which:they address site-specific Conditions of 1h6 prOject., -• 19. SOURCE REFERENCES 1. City of San Luis Obispo. 1994. San Luis Obispo General Plan.Community Development Department.August 1994. 2. State of California Department of Transportation. 1995. Route 101/Cuesta Grade Improvements Project Draft Environmental Impact Statement/Report. San Luis Obispo County,CA. 5-SLO-101,P.M. 32.3/35.5 3. U.S.Fish and Wildlife Service, 1997. Guidance on site assessment and field surveys for California Red-Legged Frogs.February 1997.Ventura,California. ] 4. California Department of Fish and Game,2002.California Natural Diversity Database. Special status wildlife and (ant species search results for the San Luis Obispo and Lopez Mountain quadrangles,California. 5. California Department of Fish and Game, 1994.Amphibian and Reptile Species of Special Concern in California, ] Coast Range Newt. 6. Jennings,M.R. and M.P.Hayes, 1994.Amphibian and reptile species of special concern in California. California Department of Fish and Game,Sacramento. 7 Attachments: Project Description for Upper San Luis Obispo Dam Removal Project _� �J CITY OF SAN LUIS OBISPO 26 1NrrIAL STUDY ENVIRD.yAJAT f LiECKLIST 2002 ATTACHMENT 2 1 Upper San Luis Obispo Creek Danz Removal Project J J JPrepared for (and currently under review by): J City of San Luis Obispo J 900 Palm Street San Luis Obispo, CA 93401 J Prepared By: Questa Engineering Corporation 1220 Brickyard Cove Road, Suite 206 ® P. O. Box 70356 Point Richmond, California 94807 (510) 236-6114 Job# 20137 1 April 12, 2002 r 1 I J J a C11-30 Upper San Luis Obi. „Creek Dam RTTA� MENT 2 City of San Luis Obispo NATURE OF ACTIVITY Introduction The upper San Luis Obispo Creek dam is a non-functional water diversion structure built by the City of San Luis Obispo in the late 1800's as part of the city's original water supply. This facility captured water from San Luis Obispo Creek and diverted it into a pipeline, which conducted that water plus water from the nearby Hansen and Gularte Creeks to reservoirs nearer the City. This system was abandoned in the 1950's and has not functioned since that time. San Luis Obispo Creek contains a viable population of southern steelhead (077corhynchus mykiss irideus) and enhancement of this population is a high priority locally. While San Luis Obispo Creek is relatively unobstructed to fish passage for much of its length, its upper reaches are blocked by an abandoned water supply dam located approximately 550 m (0.3 miles) upstream of the Old Stagecoach Road bridge. The reservoir behind the 4m (13 ft) high dam is filled with sediment. The dam constitutes a significant barrier to the movement of steelhead and other native fishes in this area. The purpose of the proposed project is to: 1) restore steelhead access to the upper reaches of San Luis Obispo Creek 2) create stable channel bed and banks 3) improve in-stream habitat Site Description The site is located above the Creek's crossing of Highway 101 near the base of Cuesta Grade, at the northern end of the San Luis Obispo Creek watershed (Figure 1). The project has a watershed area of approximately 6.5 sq. km (2.5 sq. miles). About 1.3 km (0.8 miles) of U.S.G.S. blue line (perennial) stream are located above the site, in addition to other intermittent tributary streams flowing into the Creek. To the west of the channel, a steep hill slope abuts the dam. To the east, the slopes are much flatter_ The stream channel downstream of the dam is characterized by significant bank erosion and undercut banks, while the grade control provided by the dam has prevented significant bank erosion from forming upstream of the structure. Vegetation at the site is primarily characterized by oak woodland. However, some riparian trees are present near the stream channel, especially upstream of the dam, where several large willow and cottonwood trees have colonized the sediment stored in the old reservoir. Two tributaries enter San Luis Obispo Creek just above the dam. The larger enters from the east about 25 m (82 ft) above the dam. If the dam were removed, flow in this tributary would be large enough that grade control would have to be provided to prevent the tributary from eroding upstream and threatening Old Stagecoach Road. The smaller tributary is actually a gully that has been stabilized by the dam. Some bedrock is present BLOCK 18: NATURE OF ACTIVITY C11-31 t ATTACHMENT 2 _. Upper San Luis Obi_, .-Creek Dam Removal Project City of San Luis Obispo within the gully; however, if the dam were entirely removed, the gully would continue to degrade, likely destabilizing a large hillslope area to the west of the dam. Project Description The proposed project would provide fish passage past the existing dam structure through the partial removal of the dam (Figure 2). The project also entails the construction of a new channel with the installation of low rock weir drop structures to replace the grade stabilizing function of the existing dam. The total length of affected stream channel within the grading footprint would be approximately 105 m (345 ft). The bottom width of the new channel would be about 3 m (10 ft). About 130 m (425 ft) of San Luis Obispo Creek and about 35 m (115 ft) of an un-named tributary would be temporarily dewatered during project construction. Construction access would be from the west, as shown in Figure 3. Partial Dam Removal • A 6-meter (20-ft) wide, 1.6 m (5.2 ft) deep notch within the center section of the dam would be removed. Most of the structure would be retained to provide long- term stability. (See Cross Section B-B' in Figure 2). • The maximum height of the cut slope would occur immediately upstream of the dam and would be just under 4 m (13 ft). • The remaining dam section would form a gradient control drop structure. Rock Weir Gradient Control • The new channel would be stabilized by low rock weir structures with a drop height of 0.3 in (1 ft), each 6.0 m (20 ft) apart. Eighteen rock,weirs would be installed in the main channel, and 3 smaller rock weirs would be installed in the tributary. • The structures would be constructed of large rocks placed across the channel in a "U' shape, with the open end of the "U' facing downstream. They would focus flow into the center of the stream channel, creating valuable pool habitat and providing a resting place for migrating fish and sufficient water depth for them to accelerate prior to jumping to the next pool. • Anchor rocks would be placed below the weir structures and at their edges to prevent scour from causing their failure. • The weirs would be keyed into the streambank or anchored to bedrock using metal cable. Rock weirs are generally accepted to have benefits in addition to the fish passage that they provide. They create pool habitat at the bottom of each weir, and increase the natural sorting of stream gravels by creating diverse hydraulic conditions. Also, the rock weirs can help prevent streambank erosion because they focus flow energy into the center of the channel. Cut and Fill • The project footprint area is approximately 1000 square meters. BLOCK 18: NATURE OF ACTIVITY C11-32 2 ATTACHMENT 2 Upper San Luis Ob., ,Creek Dam Removal Project City of San Luis Obispo • Approximately 400 cubic meters of material would be excavated from the channel upstream of the dam. This material would be placed as engineered fill in the channel downstream of the dam. While the cut and fill calculations done as part of the project design show fairly close balance, it is possible that some additional material may need to be imported from off-site for fill below the dam. An additional approximately 430 cubic meters of 1-2 ton rock would be placed in the stream both upstream and downstream of the dam to create the low rock weir drop structures. e The proposed project directly impacts approximately 105 m (345 ft) of the existing channel. Biotechnical Bank Stabilization Vegetation on the banks and bed of the existing channel would be removed as part of the construction process. Banks would be reconstructed at an angle not steeper than 3H:IV (except 2H:1 V where bank heights would be less that 1.5 m), but existing stable banks steeper than this angle may be retained. New slopes would be seeded with a mix of erosion control grasses and lined with biodegradable erosion control blankets. Coir logs would be placed at the toe-of-slope to prevent erosion of the toe by normal winter-time flows. Young willow poles would be staked into the erosion control fabric and through the coir logs. Over 2-3 growing periods, the willows would provide rooted bank stabilization for the new channel banks. Tree Removal Two smaller (0.3 m (1 ft) diameter) bay trees would be removed as a result of this project. Grading of banks may require shallow excavation under the dripline of approximately 5 other trees. The large (1 m (3.3 ft) diameter) cottonwood at station 1+24 would be preserved. Planting Plan The purpose of the planting plan is to replace any vegetation that will be removed as part of the proposed project. This dam removal project is essentially an enhancement project, and long-term beneficial impacts to riparian and aquatic habitats are expected. Upland trees will be replaced at a 2:1 ratio. Four bay laurel trees will be planted above the dam to replace the two that will be removed. Planting will also be done at the bank toes of the new channel. California blackberry, black cottonwoods, arroyo willows and American dogwood will be planted in coir logs and at mid- to low-banks within the creekside zone. A standard erosion control seed mix will be applied to all newly graded surfaces. Table 1 shows the proposed planting palette for the project. Where possible, cottonwoods and willows to be planted will be collected on-site. Due to the enhancement nature of this project, the planting should not be considered a mitigation measure. The planting is intended to hasten the process by which long-term riparian species establish themselves at the site. BLOCK IS: NATURE OF ACTIVITY C11-33 3 ATTACHMENT 2 Upper San Luis Obisl,. ,Creek Dam Removal Project City of San Luis Obispo Below the dam, the project entails mostly channel fill. No trees will be removed here. Minimal riparian vegetation occurs below the dam due to incised and shaded conditions of the channel. Since all trees below the dam will be preserved, and since only minimal vegetation exists there now, new planting below the dam would not be necessary if the goal of the project were only to replace lost vegetation. However, to help speed vegetation colonization, the coir logs at the toe will still be planted with the mix of species described above. Because banktop trees will likely continue to shade the site, it is anticipated that toe plantings below the dam will have a lower success rate than along sunnier areas above the dam. Certain species will have higher success rates than others, so the best way to ensure eventual vegetation establishment will be to plant the mix of species, with the understanding that those not well suited will not survive. It should not be necessary to replace unsuited species that don't survive, because the plantings that do survive will represent much better riparian vegetation than the current bare channel banks. The proposed project will result in improved fish passage and greater quality of habitat for aquatic and terrestrial wildlife. 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GRAY SHADING REPRESENTS �• j i EXTENT OF ORDINARY HIGH WATER WITHIN GRADING FOOTPRINT, BASED ON FIELD OBSERVATIONS PROJECT NOTES: MADE WINTER 2002. ~'- TOTAL AREA WITHIN PROJECT FOOTPRINT t " BELOW ORDINARY HIGH WATER: •� 690 SO M j •.' TOTAL PROJECT CUT VOLUME(ABOVE DAM): 400 CUM TOTAL FILL VOLUME: 830 CU M(SOME OF THIS IS IMPORTED MATERIAL) TOTAL FILL VOLUME BELOW ORDINARY HIGH WATER: - APPROX 200 CU.M. 10 FOOTPRINT LENGTH ALONG CHANNEL: ' , LIMIT F APPROXIMATELY 105 ��f WORK LENGTH OF CHANNEL TO BE TEMPORARILY DEWATERED: 130 M MAIN CHANNEL.35 M TRIBUTARY OI+ D"" 0410202 MOBILIZATION PLAN FIGURE "" W.L. Apprm W.- UPPER DAM REMOVAL PRO& D.Q.Na 20137_DESIGN.DWG SAN LUIS OBISPO,CA .,vw+n�w..ram.rar��,mn®raw•a o+.+nr