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PW1-Presentation_02072018-finalGROUNDWATER AT THE SOUTH Y FEBRUARY 7, 2018 6:00 PM – 7:30 PM CITY OF SOUTH LAKE TAHOE | COUNCIL CHAMBERS Lukins Brothers Water Company, Inc. AGENDA •INTRODUCTIONS •SOUTH Y GROUNDWATER AND WATER AGENCY OVERVIEW •CURRENT SITUATION •WATER AGENCY APPROACH TO SOLUTION •LUKINS BROTHERS WATER COMPANY •TAHOE KEYS WATER COMPANY •SOUTH TAHOE PUBLIC UTILITY DISTRICT •NEXT STEPS •QUESTIONS AND ANSWERS INTRODUCTIONS NAME TITLE AFFILIATION Richard Solbrig, P.E. General Manger Jennifer Lukins Assistant Manager Rick Robillard, P.E. Manager Ivo Bergsohn, PG, CHG Hydrogeologist Sachi Itagaki, P.E. Principal Engineer Lukins Brothers Water Company, Inc. 82% 10% 5% 1% 2% STPUD TKWC LBWC SCWS (estimated) Private (estimated) 99.8% 0.2% GROUNDWATER SURFACE WATER DRINKING WATER GROUNDWATER BASIN •TAHOE VALLEY SOUTH BASIN •SEDIMENTARY GEOLOGIC BASIN •HIGHLY PRODUCTIVE FOR GROUNDWATER •RECHARGED FROM SURROUNDING WATERSHEDS •EXCELLENT WATER QUALITY •HIGH RELIANCE ON WELLS •SUSCEPTIBLE TO CONTAMINATION WHAT IS TETRACHLOROETHYLENE (PCE)? •MANUFACTURED CHEMICAL USED FOR DRY CLEANING AND METAL DEGREASING •1970S - PEAK USE AS A DRY CLEANING SOLVENT •1980S – PROBABLE CARCINOGEN, TOXIC POLLUTANT, •DRINKING WATER MAXIMUM CONTAMINANT LEVEL (MCL) = 5 PARTS PER BILLION •IN GROUNDWATER ENVIRONMENT – DENSE NON-AQUEOUS PHASE LIQUID (DNAPL) •SINKER - HEAVIER THAN WATER •CAN BE REMOVED BY TREATMENT FOR DRINKING WATER USE. CURRENT SITUATION •PCE CONTAMINANT PLUME > 400 ACRES (SOUTH Y PLUME) •IMPAIRED BOTH PRIVATE AND PUBLIC WATER SYSTEM (PWS) WELLS •TOTAL AVAILABLE WATER PRODUCTION CAPACITY REDUCED BY 3.25 MGD (~5,000 AVERAGE CA HOUSEHOLDS) •PCE DETECTIONS •LBWC – 3 WELLS •TKWC – 2 WELLS WATER AGENCY APPROACH TO SOLUTIONS LUKINS BROTHERS WATER COMPANY TAHOE KEYS WATER COMPANY SOUTH TAHOE PUBLIC UTILITY DISTRICT LUKINS BROTHERS WATER COMPANY Initial detection over MCL Preliminary Engineering Report for water system improvements finalized Began engineering for granular activated carbon (GAC) filtration system at Well 5 location. Planning grant awarded Summer 2014 May 2015 July 2017 Construction plans and specifications nearing 90% completion California Department of Water Resources State Revolving Fund Application has been submitted for funding construction of GAC Treatment 2018/2019 Anticipated construction of GAC Facility January 2018 Submitted California Department of Water Resources State Revolving Fund Application for Feasibility study to locate potential new water sources for Lukins TAHOE KEYS WATER COMPANY PCE detected in Tahoe Keys well #2 and required to shut well down in 2009 by State of California. Exceeded maximum contaminant level (MCL) Installed granular activated carbon filtration in 2012 on well #2 to remove PCE. Limits the pumping capacity of well #2 below original capacity. 2009 2012 PCE detected in Tahoe Keys Well #1 below the state required MCL, Well will be required to be shut down if value exceeds MCL. 2016 2017 Hired engineering consultant to develop a facilities plan to address the PCE contamination and provide alternatives to deliver safe, reliable water to the Tahoe Keys water users. SOUTH TAHOE PUBLIC UTILITY DISTRICT •GROUNDWATER SUSTAINABILITY AGENCY (GSA) •PLANNING & IMPLEMENTATION •GROUNDWATER STUDIES & INVESTIGATIONS •BASIN MONITORING •DEVELOP PROJECTS/ACTIONS TO ADDRESS PROBLEMS •GROUNDWATER MANAGEMENT PLAN •BMO#1 - MAINTAIN A LONG-TERM GROUNDWATER SUPPLY •BMO #2 - MAINTAIN AND PROTECT GROUNDWATER QUALITY •OBTAIN GRANT FUNDING FOR GROUNDWATER PROJECTS •SOUTH Y FEASIBILITY STUDY OF REMEDIAL ALTERNATIVES PURPOSE : EVALUATE FEASIBILITY OF PUMPING AND TREATMENT OF GROUNDWATER UPSTREAM TO REDUCE CONTAMINATION TO DRINKING WATER WELLS DOWNSTREAM SOUTH Y FEASIBILITY STUDY Public Outreach Predesign Investigation Feasibility Study Main Elements •EVALUATION OF ALTERNATIVES FOR TREATMENT AND DISPOSAL •DEFINE FACILITY NEEDS AND ESTIMATE COSTS FOR IMPLEMENTATION •IMPLEMENTATION PLAN FOR RECOMMENDED ALTERNATIVE SOUTH Y FEASIBILITY STUDY- UPCOMING ACTIVITIES •PRE DESIGN INVESTIGATION •TEST WELL DRILLING & AQUIFER TESTING • 5TH STREET & ELOISE AVE. •DEADLINE: JUNE 2018 NEXT STEPS •COMPLETE PRE-DESIGN INVESTIGATION •CONDUCT GROUNDWATER MODELING •START FEASIBILITY STUDY •PUBLIC WORKSHOP (JUNE 2018) BREAK 10- MINUTES QUESTION AND ANSWERS