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Item 5 - EA of City Capital Improvement Project AGENDA REPORT SUMMARY ~ I INITIATED BY: Honorable Mayor and Members ~~e Cit,Y Council James L. Bowersox, City Man~ ' John D. Fitch, Assistant City Manager ~~ I~, "LM Reba Wright-Quastler, Director of Planning Service~ JU'Je 4, 1996 Environmental Assessment of a City of Poway Capital Improvement Project that proposes Rattlesnake Creek Drainage Improvements 300 linear foot extension of the Rattlesnake Creek drainage box culvert south of Poway Road TO: FROM: DATE: SUBJECT: ABSTRACT This report presents the results of the environmental analysis of a City capital improvement project that proposes channel and drainage improvements on Rattlesnake Creek in association with the new library site. (' ENVIRONMENTAL REVIEW Through the environmental initial study process it was revealed that the proposed project may have a significant effect on the environment, but that this effect can be mitigated by project related mitigation measures. FISCAL IMPACT A total of $700,000 has been allocated from the 1995-96 Redevelopment Agency Capital Improvement Program for the Library Site Drainage Improvements. ADDITIONAL PUBLIC NOTIFICATION AND CORRESPONDENCE Public Notice'was published in the Paway News Chieftain and mailed to all property owners residing within 500 feet of the project area. RECOMMENDATION Based on the discussion of the potential environmental impacts contained in this report, it is reconvnended that the City Council issue a mitigated Negative Dec larat i on for the Rattlesnake Channel Improvements. ACTION / . \CITYV'LANNING\R.t.l-'O/ol' \LHUtARY. SUM ,)1 -'-' JUN 4 1996 IT~M 5 AGENDA REPORT CITY OF POWAY INITIATED BY Honorable Mayor and Members of the City Council James L. Bowersox, City Man~ John D, Fitch, Assistant City Manager J..\1l Reba Wright-Quastler, Director of Planning Services~~ Jim Lyon, Assistant Planner II TO: FROM: DATE: June 4, 1996 SUBJECT: Environmental Assessment of a City of poway Capital Improvement Project that proposes Rattlesnake Creek Drainage Improvements 300 linear foot extension of the Rattlesnake Creek drainage box culvert south of Poway Road BACKGROUND On February 16,1995, the City Council selected the old Western Lumber site located on Poway Road as the location for the new poway City Library. The entire site is within the 1 OO-year floodplain and a portion is within the 100 year floodway of Rattlesnake Creek. The main channel of Rattlesnake Creek borders the northwest corner of the library parcel. The existing channel does not have the capacity'to pass the flood water that can be delivered to the property by the existing storm drain facilities crossing poway Road. To build on the site, the building pads must be elevated above the 1 OO-year floodplain and additional drainage improvements must be constructed. A consultant was selected to prepare concept channel designs that would be capable of carrying the storm waters and would expand the developable acreage of the site. The design alternatives ranged from an open natural channel to a completely enclosed box culvert. On May 23, 1995 the City Council selected Alternative D, that proposed a combination of a reinforced concrete box culvert and a natural open channel. The box culvert would extend past the library building pad then open to an expanded width natural earthen channel. This option reduced the flood risk to the library and made available additional land that could be considered in the development of the library site plan, Proiect Descriotion The project proposes a 300 linear feet exiension of the a concrete box culvert that originates from under Poway Road, The reinforced concrete box consists of three twelve foot wide by eight foot high barrels, At the southern terminus of the box culvert the existing channel will be recontoured to create a 50 foot wide channel bottom with slopes that vary between one and one-half percent to three percent. Concrete interlocking erosion control blocks are to be placed on both sides of the transition area exiending approximately 70 feet down the channel. A similar pattern will be placed as the southern end of the creek as the channel narrows and enters the Poway Community Park. The 280 feet in between the block sections will be an open earth channel. JUN 4 1996 ITEM 5 2 of 17 Agenda Report June 4, 1996 Page 2 FINDINGS State and Federal laws dictate that there shall be no net loss of wetland habitat. A biological consultant was selected to evaluate the potential impacts that the box culvert and the expanded channel would have on the wetland habitat associated with the existing channel. In summary, the report concluded that the proposed project would impact 0.2 aces of wetland habitat. However, the creation of the 50 foot wide channel would create the potential for a 0,5 acre freshwater marsh (wetland) habitat, thereby complying with the no net loss policies. Disturbance of the wetland habitat will require the acquisition of a (1601) Streambed Alteration Agreement with the Department of Fish and Game, a letter of compliance with the Army Corps of Engineers (404) Nationwide Permit, and a 401 Water Quality Certification for the Regional Water Quality Control Board. ENVIRONMENTAL REVIEW In accordance with the California Environmental Quality Act (CEQA) an environmental initial study was conducted to determine if any significant environmental impacts would occur as a result of the proposed project. The study was based on a comparison of existing conditions with the proposed improvements described in the project description and construction drawings. The environmental assessment documentation concludes that the project will not have a significant effect on the environment because mitigation measures have been incorporated into the project that minimizes potential significant environmental impacts to a level of less than significant. The following paragraphs discuss the main environmental issue, POTENTIAL ENVIRONMENTAL EFFECTS AND PROPOSED MITIGATION MEASURES Through the environmental initial study process it was revealed that the proposed project may have a significant effect on the environment, but that this effect can be mitigated by project related mitigation measures, FLORA/FAUNA The section of Rattlesnake Channel impacted by the proposed project was surveyed for biological resources in February 1996. The report noted that much of the channel and adjoining slopes were void of vegetation as a result of a gasoline/diesel spill that had previously contaminated the project area. Four types of plant communities were identified during the survey; Freshwater Marsh, Freshwater Seep, Giant Reed Wetland and Ruderal Vegetation. Twenty two plant species were identified on the project site, of which 15 were non-native. None of the plant species identified in the study are considered significant. Fourteen animal species were observed on or flying above the site. All animal species noted are common and are often seen in urban and lor disturbed habitats. 3 of 17 JUN 4 1996 ITEM 5 Agenda Report June 4, 1996 Page 3 Potential Project Impact The project will impact 8,500 square feet (0.2 acre) of wetland habitat comprised of 1,620 square feet (.04 acre) of Freshwater Marsh, 6,370 square feet (.15 acre) of Freshwater Seep and 490 square feet (.01 acre) of giant reed disturbed wetland. In addition 8,500 square feet (.2 acre) of waters of the U,S, and approximately 10,890 square feet (.25 acre) of ruderal vegetation will be impacted. The project is located in an area designated as disturbed/developed and outside of the preserve area in the Poway Subareas Habitat Conservation Plan and the MSCP Plan. No local or regional wildlife corridors are identified in the vicinity. The elimination of The 0.2 acre of Freshwater Marsh! Freshwater Seep and giant reed wetland is not considered significant and will not further fragment any larger habitat. Mitigation Measures It is anticipated that the Freshwater Marsh/Freshwater Seep will return to the channel naturally, especially due to the upstream seed source, The expanded 50 foot wide channel will generate the potential for 0.5 acre of similar wetland habitat. To encourage riparian species, it is recommended that at a minimum 1 and 5 gallon willow shrubs be planted on the banks during the rainy season, Given that riparian species do not currently exist, this is considered a enhancement action and not a mitigation requirement and therefore does not require a monitoring program. FISCAL IMPACT A total of $700,000 has been allocated from the 1995-96 Redevelopment Agency Capital Improvement Program for the Library Site Drainage Improvements. PUBLIC NOTIFICATION AND CORRESPONDENCE Public Notice was published in the Poway News Chieftain and mailed to all property owners residing within 500 feet of the project area, RECOMMENDATION Based on the discussion of the potential environmental impacts contained in this report, it is recommended that the City Council issue a mitigated Negative Declaration for the Rattlesnake Channel Improvements. ATTACHMENTS: A. Zoning & Location Map B. Negative Declaration C. Initial Study E:'CITY'PLANNING'REPORT'UBAARY AGN " 0< \ I 'J"\..\N Y. I qq G; TTC./1-i 5 z < U ..) < a: < .... PRO>.JEC-T :!>.Te. I- (,) Ul l- e :> o NEW LIBRARY SITE fRA. VA EY ELEMENTARY SCHOOL OS CITY OF POW A Y CP([~ POWAY COMMUNITY PARK IT EM: E.NVII~.o~MeN~ r-.__ ~ 1'-'\5"NT @ SCALE , TITLE: Zot>l11ol4 C L..C.l::Al\~ MAP I WA ATTACHMENT A ~ of 17 JUN 4 1996 CITY OF POWAY DON HIGGINSON. Mayor MICKEY CAFAGNA. Deputy Mayor SUSAN CALLERY, Councilmember BOB EMERY, Councilmember BETIY REXFORD. Councilmember CITY OF POWAY NEGATIVE DECLARATION 1. Name and Address of Applicant: City of Powav. 13325 Civic Center Drive. Powav. CA 92064 2. Brief Description of Project: Environmental Assessment of the Citv of Powav Capital Improvement Proiect that proposes Rattlesnake Creek Drainaae Imorovements that includes a 300 linear foot extension of the existina drainaae box culvert south of Powav Road. widenina of an additional 300 linear foot section of the channel. landscaoina and aradina necessary to accomplish the proiect. 3. In accordance with Resolution 83-084 of the City of Poway, implementing the California Environmental Quality Act of 1970, the City af Poway has determined that the above project will not have a significant effect upon the environment. An Environmental Impact Report will not be required. 4. Minutes of such decision and the Initial Study prepared by the City of Poway are on file in the Department of Planning Services of the City of Poway. 5. This decision of the City Council of the City of Poway is final. Contact Person: Jim Lvon Phone: (619) 679-4290 Approved by: Date: Reba Wright-Quastler, Ph.D., AICP E:\CITY'PlANNINGIREPORT\l.IBRARY,NEG 6 of 17 . :.,. ,~. : City Hall Located at 13325 Civic Center Drive Box 789, Poway, California 92074-0789 . (619) 748-6600. ATTACHMENT B I I 695-1400~ lailing Address P 0 JUN 41996 ITEM 5 , DATE: APPLICANT: PROJECT: CITY OF POWAY INITIAL STUDY ENVIRONMENTAL CHECKLIST Aoril 28,1996 City of Powav Rattlesnake Creek Drainaae Imorovements PROJECT LOCATION: Southeast corner of Powav Road and Tarascan Drive. Powav CA 92064 I. ENVIRONMENTAL IMPACTS (Fact-based explanations of all answers are required on attached sheets.) YES MAYBE NO 1. Soils and Geoloav, Will the proposal have significant impacts in: or 17 a. Unstable ground conditions or in changes in geologic relationships? _1- b, Disruptions, displacements, compaction, or burial of the soil? -1L_ c. Change in topography or ground surface contour intervals? -L d. The destruction, covering, or modification of any unique geologic or physical features? _1- e. Any potential increase in wind or water erosion of soils, affecting either on- or off-site conditions? _1- f. Changes in erosion, siltation, or deposition? _1- g. Exposure of people or property to geologic hazards such as earthquakes, landslides, mudslides, ground failure, or similar hazards? _1- ATTACHMENT C JUN 4 1996 ITEM 5 YES MAYBE lliL 2, Hvdroloav, Will the proposal have significant impacts in: a, Changes in currents, or the course in direction of flowing streams, rivers, or ephemeral stream channels? - - ---2L. b, Changes in absorption rates, drainage patterns, or the rate and amount of surface water runoff? -A-_ c. Alterations to the course or flow of flood waters? -A-_ d, Change in the amount of surface water in any body of water? _-A- e. Discharge into surface waters, or any alter- action of surface water quality? _-A- f. Alteration of groundwater characteristics? _-A- g. Change in the quantity of groundwaters, either through direct additions, or with- drawals, or through interference with an aquifer? Quality? _-A- Quantity? _-A- h. The reduction in the amount of water other- wise available for public water supplies? _-A- i. Exposure of people or property to water related hazards such as flooding or seiches? _-A- 3. Air Qualitv. Will the proposal have significant impacts in: a. Constant or periodic air emissions from mobile or indirect sources? _-A- Stationary sources? _-A- b, Deterioration of ambient air quality and/or interference with the attainment of appli- cable air quality standards? _-A- c. Alteration of local or regional climatic conditions, affecting air movement moisture or temperature? _-A- 8 of 17 J UN 4 1996 ITEM 5 , YES MA YBE ~ 4. Flora, Will the proposal have significant results in: a. Change in the characteristics of species, including diversity, distribution, or number of endangered species of plants? _ ---X- b. Reduction of the numbers of any unique, rare, or endangered species of plants? ---X- _ c, Introduction of new or disruptive species of plants into an area? _ ---X- d. Reduction in the potential for agricultural production? _ ---X- 5, Fauna. Will the proposal have significant results in: a. Change in the characteristics of species, including diversity, distribution, or numbers of any species of animals? _ ---X- b, Reduction of the numbers of any unique, rare, or endangered species of animals? ---X- _ c. Introduction of new or disruptive species of animals into an area, or result in a barrier to the mitigation or movement of animals? _ ---X- d. Deterioration or removal of existing fish or wildlife habitat? _ ---X- 6, Poculation. [Will the proposal] have significant results in: a. [Will the proposal] alter the location, distri- bution, density, diversity, or growth rate of the human population of an area? _ ---X- b, [Will the proposal] affect existing housing, or create a demand for additional housing? - - --X- 9 of 17 JUN 4 1996 ITEM 5 7, Socio-Economic Factors, Will the proposal have significant results in: a. Change in local or regional socio-economic characteristics, including economic or commercial diversity, tax rate, and property values? 8. b, Will project costs be equitably distri- buted among project beneficiaries, Le., buyers, taxpayers, or project users? Land Use and Plannina Considerations, Will the proposal have significant results in: a. A substantial alteration of the present or planned land use of an area? b. A conflict with any designations, objectives, policies, or adopted plans of any govern- mental entities? 9, c. An impact upon the quality or quantity of existing consumptive or non-consumptive recreational opportunities? TransDortation. Will the proposal have significant results in: a. Generation of substantial additional vehicular movement? b. . Effects on existing streets, or demand for new street construction? c. Effects on existing parking facilities, or demand for new parking? d. Substantial impact upon existing transpor- tation systems? e. Alterations to present patterns of circu- lation or movement of people and/or goods? Alteration to or effects on present and potential water-borne, rail, mass transit, or air traffic? Increases in traffic hazards to motor vehicles, bicyclists, or pedestrians? f. g. lO or " YES MAYBE till ....lL _ -X... _ -X... _ -X... _ -X... _ -X... _ -X... _ -X... _ -X... _ -X... _ -X... _ -X... JUN 4 1996 ITEM 5 YES MAYBE tiQ.. 10, Cultural Resources, Will the proposal have significant impacts in: a, A disturbance to the integrity of archaeo- logical, paleontological, and/or historical resources? _ _......L 11. Health. Safetv. and Nuisance Factors. Will the proposal have significant results in: a. Creation of any health hazard or potential health hazard? _ ......L b, Exposure of people to potential health hazards? _ ......L c, A risk of explosion or release of hazardous substances in the event of an accident? _ ......L d. An increase in the number of individuals or species of vector or parthenogenic organisms or the exposure of people to such organisms? _ ......L e, Increase in existing noise levels? _ ......L f. Exposure of people to potentially dangerous noise levels? _ ......L g. The creation of objectionable odors? _ ......L h. An increase in light or glare? _ ......L 12. Aesthetics, Will the proposal have significant results in: a. The obstruction or degradation of any scenic vista or view? _ ......L b, The creation of an aesthetically offensive site? _ ......L c, A conflict with the objective of designated or potential scenic corridors? _ ......L II or 17 JUN 4 1996 ITEM 5 ~:2 of 1"7 JUN 4 1996 ITEM 5 YES MAYBE .tiO- 15. Mandatorv Findinas of Sianificance. a. Does the project have the potential to degrade the quality af the environment, substantially reduce the habitat of fish or wildlife species, cause a fish or wild- life population to drop below self- sustaining levels, threaten to eliminate a plant or animal community, reduce the number of restrict the range of a rare or endangered plant or animal, or eliminate important examples of the major periods of the California history or prehistory? -~ b. Does the project have the potential to achieve short-term, to the disadvantage of long-term, environmental goals? (A short- term impact on the environment is one which occurs in a relatively brief, definitive period of time while long-term impacts will endure well into the future,) -~ c. Does the project have impacts which are individually limited, but cumulatively considerable? (Cumulatively considerable means that the incremental effects of an . individual project are considerable when viewed in connection with the effect of past projects, and probable future projects. ) -~ d. Does the project have environmental effects which will cause substantial adverse effects on human beings, either directly or indirectly? -~ II. DISCUSSION OF ENVIRONMENTAL EVALUATION (Le" of affirmative answers to the above questions plus a discussion of proposed mitigation measures.) SEE ATTACHED PAGES 13 of 17 JUN 4 1996 ITEM 5 III DETERMINATION D ~ D On the basis of this initial evaluation: I find the proposed project COULD NOT have a significant effect on the environment, and a NEGATIVE DECLARATION will be prepared. I find that although the proposed project could have a significant effect on the environment, there will not be a significant effect in this case because the mitigation measures described on an attached sheet have been added to the project, A DECLARATION WILL BE PREPARED. I find the proposed project MAY have a significant effect on the environment, and an ENVIRONMENTAL IMPACT REPORT is required. DATE: ~~, SIGNATURE: '-+ C f 11 JUN 4 1996 ITEM 5 DISCUSSION OF ENVIRONMENTAL EVALUATION SOILS AND GEOLOGY The project area is underlain primarily by ~lIuvium, colluvium and artificial fills. Given that Rattlesnake Creek flows throughout the year, itlis expected that saturated material will be found in all the soil units adjacent to and immediatel~belOW Rattlesnake Creek. The existing drainage channel has a bottom width that varies fro five to fifteen feet. The top of slope width is approximately forty feet across. Constructio of the box culvert section will require grading an approximate sixty foot wide channel. Once the ox culvert is constructed, soil will be replaced and compacted along both sides and the top of ,the structure. The top of slope width of the open channel section will require grading to crea~ a 1 DO-foot span that will include a 50-foot wide channel bottom, I Mitigation: I Removal of loose, unsuitable soils will be r~quired before placement of engineered fill in all proposed fill areas. It is recommended that ~rganic matter, oversize rock and other deleterious materials be removed from the site. All porouj' surface soils and any fill soils not removed by the grading operation, shall be placed over the concrete slope reinforcement blocks to provide a medium for plant growth. Similar top soils shall be used on the banks of the earthen section of the channel to provide a suitable planting material. All grading should be conducted and monitored in accordance with the Grading Ordinance of th City of Poway HYDROLOGY Approximately 600 linear feet of Rattlesnake C eek will be directly impacted by the project with the objective to increase the carrying capacity the channel through this area. Any reduction in absorption rates created by the extension 0 the box culvert will be mitigated by the expanded channel width beyond the culvert. As noted, ttlesnake Creek flows year round with flows varying according to season. Mitigation: To provide the ability to grade and to construct ther improvements within the channel, a temporary dam and siltation basin is proposed at the be inning of the project area, Drainage waters will be pumped via a pipe around the construction ite and deposited back into the stream below the project area in order to maintain existing downstream flows. Because of the potential for encountering groundwater during the proj ct construction, the City will request in writing concurrence from the Army Corp of Enginee that the Corp issue a Nationwide Permit to cover potential groundwater issues. AIR QUALITY Potential air quality impacts from the proposed roject are associated exclusively with construction activities, as particulate matter generated fro construction vehicles would be emitted during the implementation of the project. Additionally, ust generated during grading activities could also cause temporary impacts to local air quality. Mitigation: To reduce potential adverse construction emi sion/air quality impacts it is recommended that dirt stock pile areas be sprayed with water dail or as needed to control dust, that water trucks or equivalent facilities be used to control dust during the grading process, and that construction vehicles use best available control technolog to regulate emissions. 15 or 17 JUN 4 1996 ITEM S FLORA/FAUNA The section of Rattlesnake Channel impacted by the proposed project was surveyed for biological resources in February 1996, The report noted that much of the channel and adjoining slopes were void of vegetation as a result on a gasoline/diesel spill that had previously contaminated the project area, Four types of plant communities wer.e identified during the survey; Freshwater Marsh, Freshwater Seep, Giant Reed Wetland and Ruderal Vegetation. Twenty two plant species were identified on the project site, of which 15 were non-native. None of the plant species identified in the study are considered significant. Fourteen animal species were observed on or flying above the site. All animal species noted are common and are often seen in urban and lor disturbed habitats. The project will impact 8,500 square feet (0.2 acre) of wetland habitat comprised of 1,620 square feet (.04 acre) of Freshwater Marsh, 6,370 square feet (.15 acre) of Freshwater Seep and 490 square feet (.01 acre) of giant reed disturbed wetland. In addition 8,500 square feet (.2 acre) of waters the U.S. and approximately 10,890 square feet (.25 acre) of ruderal vegetation will be impacted, The project is located in an area designated as disturbed/developed and outside of the preserve area in the Poway Subareas Habitat Conservation Plan and the MSCP Plan. No local or regional wildlife corridors are identified in the vicinity. The elimination of The 0.2 acre of Freshwater Marsh/ Freshwater Seep and giant reed wetland is not considered significant and will not further fragment any larger habitat. Mitigation: It is anticipated that the Freshwater Marsh/Freshwater Seep will return to the channel naturally, especially due to the upstream seed source. The expanded 50 foot wide channel will generate the potential for 0,5 acre of similar wetland habitat. To encourage riparian species, it is recommended that at a minimum 1 and 5 gallon willow shrubs be planted on the banks during the rainy season, Given that riparian species do not currently exist, this is considered a enhancement action and not a mitigation requirement and therefore does not require a monitoring program. POPULATION The proposed channel improvement project is intended to regulate flood waters in and around the library site. As such, it will not induce direct or indirect growth of population or housing construction, Given that the site is bordered by commercial land uses and a park, the project will not impact existing housing. No mitigation measures are required because no impacts are anticipated. SOCIO-ECONOMIC The proposed channel improvement project is intended to regulate flood waters in and around the library site and will have no direct impact on commercial diversity or tax rates. The project is funded by the City of Poway Redevelopment Agency, No mitigation measures are required because no impacts are anticipated, LAND USE AND PLANNING CONSIDERATIONS The proposed channel improvements are located within commercially designated land. The channel and the areas immediately surrounding the project area are also included within the floodway or 100 year floodplain of Rattlesnake Creek. The areas where the main channel improvements are proposed lie either within the existing channel or on vacant city owned land. No mitigation measures are required because no impacts are anticipated. 16 of 17 JUN 4 1996 ITEM 5 TRANSPORTATION AJ; the proposed project provides channel improvements only, the only transportation issues would be associated with construction traffic. The project boundaries are Poway Road the Poway Community Park. Potential impacts could occur from construction vehicles arriving and existing the site, Mitigation: A traffic control plan for the project construction should be prepared by the contractor to the satisfaction of the City Traffic Engineer, who will review and approve the plan. The plan should be coordinated with the Poway Fire Department, Sheriff department, Community Services Department, the Weingart Senior Center and the Poway Unified School District. CULTURAL RESOURCES The Poway General Plan identifies the area south of Poway Road as having a high probability for archeological resources. The subject area and adjoining parcels, however, have been subject to flooding, the channel to scouring and numerous grading and construction activities associated with the development of commercial structures and parking lots. With the extensive degree and duration of different types of disturbance, no archeological resources are anticipated. No mitigation measures are required because no impacts are anticipated, HEALTH. SAFETY AND NUISANCE FACTORS The project proposes to improve the flood water carrying capacity of the channel through the project area creating a benefit to the immediate area. As a drainage facility no potential increased noise levels, odors, light or other health hazards are anticipated. The only objectionable noise and odor could come from construction activities. Mitigation for these are discussed in previous mitigation measures regarding proper maintenance of vehicle, dust control and traffic control. AESTHETICS AJ; noted in the biological study the site contain very limited vegetation, The propose project would place approximately 300 feet of the existing channel underground. Landscaping could be used to enhance surface area of this corner of the project, The remaining section of the channel will be expanded and replanted with native vegetation to restore the appearance of a natural stream channel. UTILITIES AND PUBLIC SERVICES As a floodway improvement project it will not require additional public services other than maintenance. The City's Public Service Department will maintain the channel on an annual or as need basis. No mitigation measures are required because no impacts are anticipated. ENERGY AND SCARCE RESOURCES A temporary increase in the use of fuel by vehicles and associated equipment would occur during project construction, however, this increase is not expected to be significant. No additional fuel or other resources would be used. No mitigation measures are required because no impacts are anticipated, Ii of 17 JUN 4 1996 ITEM 5