SWEETWATER AND LOVELAND RESERVOIRS WATERSHED SANITARY SURVEY FIRST UPDATE Final Report August 2007 ARCHIBALD CONSULTING Sweetwater and Loveland Reservoirs Watershed Sanitary Survey First Update FINAL REPORT August 2007 Technical Committee: Sweetwater Authority Pete Baranov Jane Davies Mark Hatcher George Silva Don Thomson Prepared By: Leslie Palencia, Palencia Consulting Engineers Bonny Starr, Starr Consulting PREPARED BY TABLE OF CONTENTS Page Number Executive Summary Introduction ............................................................................................................... ES-1 Objectives of the Update........................................................................................... ES-1 Key Findings and Conclusions .................................................................................. ES-1 Source Water Quality ..................................................................................... ES-1 Turbidity ............................................................................................ ES-2 Coliform............................................................................................. ES-2 Giardia/Cryptosporidium ................................................................... ES-2 Disinfection By-Product Precursors................................................... ES-2 Volatile and Synthetic Organic Compounds (VOCs and SOCs)........ ES-2 Nitrate ............................................................................................... ES-3 Selected Metals................................................................................. ES-3 Selected Minerals.............................................................................. ES-3 Plankton and Related Constituents................................................... ES-3 Arsenic/Hexavalent Chromium.......................................................... ES-4 Intake Evaluation ............................................................................................ ES-4 Robert A. Perdue Water Treatment Plant ......................................... ES-4 Turbidity............................................................................... ES-4 Microbiological Constituent Review .................................... ES-4 Disinfection By-Products...................................................... ES-5 VOCs and SOCs.................................................................. ES-6 Inorganics ............................................................................ ES-6 Giardia/Virus/Cryptosporidium Reduction Requirements..... ES-7 Watershed Contaminant Sources................................................................... ES-7 Spills ................................................................................................. ES-7 Landfills............................................................................................. ES-8 Recreation......................................................................................... ES-9 Urban Runoff................................................................................... ES-10 Wastewater ..................................................................................... ES-11 Proposed Highways and Other Developments ............................... ES-11 Homeless Encampments ................................................................ ES-12 Agriculture....................................................................................... ES-12 Fires ................................................................................................ ES-13 Topics to Consider for the 2012 Update.................................................................. ES-13 Recommendations .................................................................................................. ES-13 Section 1 – Introduction Introduction .................................................................................................................. 1-1 Objectives of the Update.............................................................................................. 1-1 Constituents and Potential Contaminating Activities Covered in the First Update........ 1-2 Description of How the First Update was Conducted ................................................... 1-4 Report Organization ..................................................................................................... 1-5 Sweetwater and Loveland Reservoirs Watershed Sanitary Survey Page i First Update – Final Report Section 2 – Watershed and Water Supply Systems Watershed Description ................................................................................................. 2-1 Precipitation....................................................................................................... 2-1 Flow................................................................................................................... 2-2 Land Use ........................................................................................................... 2-3 Population ......................................................................................................... 2-3 Land Ownership ................................................................................................ 2-4 Water Supply System................................................................................................... 2-5 Background ....................................................................................................... 2-5 Sweetwater and Loveland Reservoirs ............................................................... 2-6 Robert A. Perdue Water Treatment Plant.......................................................... 2-6 Section 3 – Source Water Quality Review Overall Water Quality Summary .................................................................................. 3-2 Selected Constituent Review ....................................................................................... 3-2 Turbidity............................................................................................................. 3-4 General Characteristics and Background ............................................... 3-4 Evaluation ............................................................................................... 3-4 Summary of Results................................................................................ 3-5 Microbial Constituents ....................................................................................... 3-6 General Characteristics and Background ............................................... 3-6 Evaluations ............................................................................................. 3-7 Total Coliform ................................................................................. 3-7 E. coli.............................................................................................. 3-9 Giardia and Cryptosporidium ........................................................ 3-11 Summary of Results.............................................................................. 3-12 Disinfection By-Product Precursors ................................................................. 3-12 General Characteristics and Background ............................................. 3-12 Evaluation ............................................................................................. 3-13 Organic Carbon ............................................................................ 3-13 Bromide ........................................................................................ 3-16 Summary of Results.............................................................................. 3-16 Volatile and Synthetic Organic Chemicals....................................................... 3-17 General Characteristics and Background ............................................. 3-17 Evaluation ............................................................................................. 3-17 Summary of Results.............................................................................. 3-19 Nitrate.............................................................................................................. 3-19 General Characteristics and Background ............................................. 3-19 Evaluation ............................................................................................. 3-20 Summary of Results.............................................................................. 3-20 Selected Metals............................................................................................... 3-21 General Characteristics and Background ............................................. 3-21 Evaluation ............................................................................................. 3-21 Sweetwater and Loveland Reservoirs Watershed Sanitary Survey Page ii First Update – Final Report Summary of Results.............................................................................. 3-23 Selected Minerals ............................................................................................ 3-24 General Characteristics and Background ............................................. 3-24 Evaluation ............................................................................................. 3-24 Summary of Results.............................................................................. 3-27 Plankton and Related Constituents