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Resolution 2448l 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 RESOLUTION NO. 2448 A RESOLUTION OF THE BOARD OF DIRECTORS OF SOUTH TAHOE PUBLIC UTILITY DISTRICT APPROVING NEGATIVE DECLARATION FOR SOUTH TAHOE PUBLIC UTILITY DISTRICT EMERGENCY RETENTION BASIN SEALING SYSTEM BE IT RESOLVED by the Board of Directors of South Tahoe Public Utility District: 1. The Board finds on the basis of its review and consideration of the Environmental Assessments for the Emergency Retention Basin Sealing System Project, the Preliminary Design Reports, all Comments received and Responses thereto and modi- fications incorporated into the Project after consideration of said Assessments, Reports, Comments and Responses, that there is no substantial evidence that the Project will have a significant effect on the environment. 2. Based upon said finding the Board approves the negative declaration circulated, a copy of which attached hereto and made a part hereof. PASSED AND ADOPTED by the Board of Directors of South Tahoe Public Utility District at a regular meeting on the 17th day of December, 1987, by the following vote: AYES: Directors Mason, Olson, Jones, Sinclair, Walker ABSTAIN: None NOES: None ABSENT: None ATTEST: Robert Mason, Chairman of Board South Tahoe Public Utility District Pat A. Mamath, Clerk of Board South Tahoe Public Utility District October, 1987 NEGATIVE DECLARATION TO WHOM IT MAY CONCERN: Pursuant to the California Environmental Quality Act of 1970, the State Guidelines and South Tahoe Public Utility District Guidelines, the South Tahoe Public Utility District has made an Initial Study of possible environmental impacts of the following described project: Applicant: South Tahoe Public Utility District Application: Emergency Retention Basin Sealing System Location: Northeast of intersection of Black Bart Avenue and Pioneer Trail Description of Proposed Project: The project is the modification of the existing South Tahoe Public Utility Districts (STPUD) 56 million gallon (MG) emergency retention basin (ERB) at Black Bart Avenue, north of Pioneer Trail. The modifications to the ERB are proposed as a long -term solution to existing odor problems and to reduce 99% of the leakage from the pond. The emergency retention basin is located one and one half miles south of the STPUD treatment plant near the corner of Black Bart Avenue and Pioneer Trail. (See Figures A and B.) The land on which the basin is located is a parcel 39.255 acres in size and is currently leased by STPUD from the U.S. Forest Service. STPUD is negotiating with the Forest Service to trade the ERB site for other property owned by the STPUD. The ERB has a current capacity of just over 56 million gallons and is used to store wastewater in the event that the wastewater treatment plant cannot treat the influent flow due to: storm flows in excess of plant capacity; power failure; treatment plant upset or equipment failure; and /or export system failure. A 1986 report prepared by Culp Wesner and Culp recommended an ultimate total emergency storage capacity of 75 MG. This recommendation was based on the events during a 1986 storm in which wastewater was spilled from the treatment plant into Heavenly Valley Creek due to inadequate storage volumes. Additional analyses by Culp Wesner and Culp indicated that an 18 MG basin would be adequate to handle 90 percent of the plant's emergency storage needs. NEGATIVE DECLARATION October, 1987 Page 2 of 6 A Preliminary Design Report for the Emergency Retention Basin Sealing System and an Environmental Assessment (EA) were prepared which evaluated three scenarios for altering the present 56 MG. ERB based on these documents, STPUD has selected a combination of the alternatives as the project. STPUD is the lead agency pursuant to the California Environmental Quality Act; TRPA is the Lead Agency pursuant to the Bi -State Compact. The project consists of dredging the existing ERB of accumulated sludge by means of building a temporary access road into the pond for trucks and equipment. The sludge will then be hauled out of the Lake Tahoe Basin. A safety levee 12 feet high will be built to divide the basin in half with flow pipes connecting the two sides. A lining will cover the bottom and sides of the modified ERB consisting of a 40 mil minimum thickness geomembrane of high density polyethylene (HDPE). A system for washing down the ERB after each discharge using a filtered secondary effluent system is to be installed. Facilities, including 6 inch PVC piping and freezeless yard hydrants, will be tied into the existing 16 inch high pressure line that runs from the plant to the ERB. Portable hoses will be connected to the perimeter hydrants for manual washdown of the ERB sides and bottom. Construction of the total project is expected to last four months. See Figure C for proposed layout. MITIGATION MEASURES INCORPORATED IN THE PROJECT The following mitigation measures, as recommended in the Alternative Analysis EA, have been incorporated into the project design. Geology/ Seismicity Construction of the retention basin shall meet all local, state, and federal seismic safety standards. Soils STPUD shall provide compensation for excess land coverage in compliance with the requirements of TRPA. Construction will be completed in compliance with the TRPA grading ordinance; the project shall incorporate Best Management Practices into the design of the berm slope stabilization and the contractor shall comply with Best Management Practices during construction. NEGATIVE DECLARATION October, 1987 Page 3 of 6 Air Quality In Compliance with 3cction 90 of the TRPA codc of ordinenccs, a $80.00 air quality mitigation fec will be 1(" paid. Compliance with state vehicle emission control standards will be required for all diesel equipment. Machinery will be kept in the best working condition. Application of odor control measures (e.g., lime) during initial drying and sludge removal shall be investigated in the final design stage of the project, and the recommended measures implemented. Drainage Construction shall be completed in compliance with the TRPA grading ordinance; the project shall incorporate Best Management Practices into the design of the berm slope stabilization and the contractor shall be required to follow Best Management Practices during construction. Water Quality Proper design and rigorous quality control during the final design and construction phase will reduce potential damage to the proposed High Density Polyethylene material. STPUD, Lahontan and TRPA will monitor the installation fo the liner. The Design Engineer will prepare an operations and maintenance manual for the operators of the ERB to limit potential damage to the lining material. Strict adherence to the operation and maintenance manual shall be required by STPUD. STPUD is required to monitor water and report the monitoring data to Lahontan. Flora, Fauna, and Fisheries All construction and on -site improvements shall be conducted in accord with adopted Best Management Practices. Noise Powered equipment and vehicles used during construction phases and for site maintenance will be equipped with adequate mufflers and /or enclosures at all times. Construction activities or equipment with noise levels in excess of 50 CNEL or threshold single event levels will be limited to the hours of 8 a.m. to 6:30 p.m. Due to the limited period available for sludge drying and construction, during which the ERB cannot be used, it is proposed by STPUD that the hours of operation be expanded NEGATIVE DECLARATION October, 1987 Page 4 of 6 to daylight hours. A three week period is anticipated to be required for use of the heavy equipment. Risk of Upset and Safety The contractor, his employees and the operators of the ERB shall comply with the operations and maintenance manual provided by the design engineer. Regular inspections by STPUD and Lahontan shall be made of the ERB. The ERB shall be maintained and operated in compliance with Conditions of Waste Discharge Permits and Safety of Dam Permits. Scenic Resources Plantings of trees and shrubs along the existing fence line to screen the ERB from nearby urban developments shall be installed in compliance with Best Management Practices. Cultural Resources In the event that any cultural or historic resources should be uncovered during construction, all work will be stopped and an evaluation of the resource shall be conducted by a qualified professional in compliance with state and TRPA regulations. NEGATIVE DECLARATION October, 1987 Page 5 of 6 Findings: It has been found that this project, as described herein and the Environmental Assessment " " October 1987, will not have a significant effect on the environment and an environmental impact report (EIR) is therefore, not required by the California Environmental Quality Act. A brief statement of reasons supporting such findings is as follows: 1. The environmental impacts associated with the proposed modifications to the ERB are short -term construction - related impacts which will occur within the existing ERB. No significant irreversible impacts associated with the project have been identified. 2. The project will not significantly alter the potential impacts from a seismic event on the existing earthen berm. The interior berms will be engineered to withstand liquefaction in a seismic event. 3. The soils in the existing basin were significantly altered by construction of the existing ERB. The transfer of soils for the addition of another levee within the existing basin is not significant. 4. Fifteen years of sludge material from the ERB will be removed and deposited outside the Lake Tahoe Basin. 5. No project allows the continuation of odor problems currently associated with the ERB. The project mitigates this problem. The project may result in temporary odor problems during the drainage and sludge removal operations. Odors may also occur during the period of time when the ERB has been drained and prior to its washdown. Specific plans for odor control will be addressed in the final design. The project provides a washdown system to minimize sludge accumulation and reduce the major source of odors. Sludge will be returned to the head of the treatment plant and retreated. 6. The project will result in the worst case addition of 8 automobile trips per day resulting in a small but incremental increase in pollutant loading in the Lake Tahoe Basin. STPUD is to pay a $80.00 mitigatisa fee.J 7. Lining of the ERB is being performed to reduce or eliminate the existing leakage of water into soils and groundwater. 8. During the construction phases of the project, noise from construction activities will dominate the noise environment in the immediate area. Construction NEGATIVE DECLARATION October, 1987 Page 6 of 6 activities will be temporary and will occur between 8 am and 6:30 pm. 9. The project will result in a slight increase in traffic to the project site for maintenance. During a normal use period there will be 1 trip per day. During draining and cleaning there will be an estimated 10 trips per day and during a non -use period there will be no trips to the site. The worst -case of 10 trips per day is an increase in ADT of 0.1 percent on Black Bart Avenue and 0.05 percent increase on Pioneer Trail. The increase in ADT is not considered to be significant. Any person may object to dispensing with such EIR or respond to the findings herein. Information relating to the proposed project is on file in the following locations: South Tahoe Public Utility District P.O. Box AU South Lake Tahoe, CA Tahoe Regional Planning Agency P.O. Box 1038 Zephyr Cove, Nevada 89448 -1038 QUAD Consultants 2530 J Street, Suite 302 Sacramento, CA 95816 City of South Lake Tahoe 1052 Tata Lane South Lake Tahoe, CA El Dorado County Library 1000 Rufus Allen Blvd. South Lake Tahoe, CA Any person wishing to examine or obtain a copy of that information or this document, or seeking information as to the time and manner to so object or respond, may do so by inquiring at said offices during regular business hours. A copy of the Initial Study and Environmental Assessment are attached hereto. Dated this 23rd day of October, 1987. South Tahoe Public Utility District 1275 Meadow Crest Drive, South Lake Tahoe, CA 95705