LAKE BERRYESSA WATERSHED SANITARY SURVEY UPDATE FINAL REPORT JUNE 2013 PREPARED BY ARCHIBALD CONSULTING FOR NAPA COUNTY DEPARTMENT OF PUBLIC WORKS AND SOLANO COUNTY WATER AGENCY CONTENTS 1.0 Introduction ....................................................................................................................................... 1-1 2.0. Water Treatment Plants.................................................................................................................... 2-1 2.1 Lake Berryessa Resort Improvement District............................................................................... 2-1 2.2 Napa Berryessa Resort Improvement District ............................................................................. 2-3 3.0. Contaminant Sources ........................................................................................................................ 3-1 3.1 Recreational Use of Lake Berryessa ............................................................................................. 3-1 3.1.1 Background ........................................................................................................................ 3-1 3.1.2 Current Recreational Facilities at Lake Berryessa ............................................................... 3-6 3.1.3 Boater Education Efforts .................................................................................................. 3-12 3.1.4 Summary .......................................................................................................................... 3-13 3.2 Wastewater Treatment Facilities............................................................................................... 3-14 3.2.1 Wastewater Treatment Facilities in the Upper Putah Creek Watershed ......................... 3-15 3.2.2 Wastewater Treatment Facilities Serving Communities near Lake Berryessa .................. 3-18 3.2.3 Wastewater Treatment Facilities Serving Resorts and Recreation Areas near Lake Berryessa ................................................................................................................. 3-29 3.2.4 Wastewater Facilities on Lake Berryessa ......................................................................... 3-36 3.2.5 Summary .......................................................................................................................... 3-36 3.3 Agriculture/Pesticide Use .......................................................................................................... 3-37 3.3.1 Lake County...................................................................................................................... 3-37 3.3.2 Napa County .................................................................................................................... 3-39 3.3.3 Summary .......................................................................................................................... 3-40 3.4 Hazardous Materials Spills ......................................................................................................... 3-41 3.5 Wildfires .................................................................................................................................... 3-42 4.0 Water Quality..................................................................................................................................... 4-1 4.1 Microbiological Contaminants ..................................................................................................... 4-1 4.1.1 Lake Berryessa Resort Improvement District Coliform Data and Treatment Requirements .................................................................................................................... 4-1 4.1.2 Napa Berryessa Resort Improvement District Coliform Data and Treatment Requirements .................................................................................................................... 4-3 4.2 Turbidity ...................................................................................................................................... 4-3 4.3 Organic Carbon ............................................................................................................................ 4-3 4.4 Comparison to Maximum Contaminant Levels ............................................................................ 4-6 4.4.1 Lake Berryessa Resort Improvement District Constituents Exceeding Maximum Contaminant Levels ......................................................................................................... 4-10 4.4.2 Napa Berryessa Resort Improvement District Constituents Exceeding Maximum Contaminant Levels ......................................................................................................... 4-11 5.0 Findings and Recommendations ........................................................................................................ 5-1 5.1 2001 Findings and Recommendations ......................................................................................... 5-1 5.2 2013 Findings and Recommendations ......................................................................................... 5-6 5.2.1 Recreational Use of Lake Berryessa ................................................................................... 5-6 5.2.2 Wastewater Treatment Facilities ....................................................................................... 5-7 5.2.3 Agriculture/Pesticide Use ................................................................................................... 5-8 5.2.4 Microbiological Contaminants ........................................................................................... 5-9 6.0 References ......................................................................................................................................... 6-1 i FIGURES 2-1 LBRID and NBRID Water Service Areas ........................................................................................... 2-2 3-1 Lake Berryessa Watershed ............................................................................................................. 3-2 3-2 Recreational Facilities at Lake Berryessa ........................................................................................ 3-7 3-3 Location of Middletown WWTF ................................................................................................... 3-16 3-4 Location of Hidden Valley Lake Water Reclamation Facility......................................................... 3-17 3-5 Location of LBRID WWTF .............................................................................................................. 3-18 3-6 Location of Berryessa Wines WWTF............................................................................................. 3-21 3-7 Location of Spanish Flat WWTF .................................................................................................... 3-22 3-8 Location of NBRID WWTF ............................................................................................................. 3-24 3-9 Location of Turtle Rock WWTF ..................................................................................................... 3-26 3-10 Location of Capell Valley Mobile Home Park WWTF .................................................................... 3-27 3-11 Location of Circle Oaks WWTF ..................................................................................................... 3-28 3-12 Location of Reclamation WWTF ................................................................................................... 3-32 3-13 Location of Pleasure Cove WWTF ................................................................................................ 3-34 3-14 Location of Markley Cove WWTF ................................................................................................. 3-35 3-15 Acreage Devoted to Wine Grapes in Lake County ........................................................................ 3-37 3-16 Usage of Glyphosate and Copper Pesticides in Lake County ........................................................ 3-38 3-17 Usage of Glyphosate Pesticides in Napa County .......................................................................... 3-40 3-18 Usage of Copper Pesticides and Simazine in Napa County ........................................................... 3-40 4-1 Monthly Median Total Coliforms at the LBRID WTP Intake ............................................................ 4-2 4-2 Monthly Median E. coli at the LBRID WTP Intake ........................................................................... 4-2 4-3 Monthly Median Total Coliforms at the NBRID WTP Intake ........................................................... 4-4 4-4 Monthly Median E. coli at the NBRID WTP Intake .......................................................................... 4-4 4-5 Turbidity at the LBRID WTP Intake ................................................................................................. 4-5 4-6 Turbidity at the NBRID WTP Intake ................................................................................................ 4-5 4-7 TOC Concentrations at the LBRID WTP Intake ................................................................................ 4-6 4-8 TOC Concentrations at the NBRID WTP Intake ............................................................................... 4-6 4-9 Aluminum Concentrations at the NBRID WTP Intake ..................................................................