2017 WATERSHED SANITARY SURVEY & SOURCE WATER ASSESSMENT UPDATE Littlerock Reservoir and Lake Palmdale Watersheds B&V PROJECT NO. 197191 served. PREPARED FOR Palmdale Water District 18 DECEMBER 2017 ©Black & Veatch Holding Company 2017. All rights re Palmdale Water District | 2017 WATERSHED SANITARY SURVEY & SOURCE WATER ASSESSMENT UPDATE Table of Contents EXECUTIVE SUMMARY ......................................................................................................................................... 1 ES.1 OVERVIEW .................................................................................................................................................. 1 ES.2 BACKGROUND ............................................................................................................................................. 1 ES.3 STUDY AREA ............................................................................................................................................... 1 ES.4 PROJECT OBJECTIVES .................................................................................................................................. 1 ES.5 DELINEATION OF CONTRIBUTING AREAS .................................................................................................... 2 ES.6 WATER SUPPLY INFRASTRUCTURE .............................................................................................................. 2 ES.6.1 Groundwater ..................................................................................................................................... 3 ES.6.2 Littlerock Reservoir and Dam ........................................................................................................... 3 ES.6.3 Lake Palmdale .................................................................................................................................. 3 ES.6.4 Palmdale Ditch ................................................................................................................................. 3 ES.6.5 Palmdale Water Treatment Plant (WTP) .......................................................................................... 3 ES.7 INVENTORY OF POTENTIALLY CONTAMINATING ACTIVITIES ...................................................................... 5 ES.7.1 Littlerock Reservoir........................................................................................................................... 5 ES.7.2 Lake Palmdale .................................................................................................................................. 5 ES.7.3 Wildlife/Domestic Animals ................................................................................................................ 5 ES.7.4 Dumping/Vandalism.......................................................................................................................... 5 ES.7.5 NPDES Permittees ............................................................................................................................ 5 ES.7.6 Wildfire ............................................................................................................................................. 5 ES.7.7 Review of Spills ................................................................................................................................. 5 ES.7.8 Underground Storage Tanks ............................................................................................................. 6 ES.7.9 Recreation ......................................................................................................................................... 6 ES.7.10 Animals ............................................................................................................................................. 6 ES.7.11 Population and Development ............................................................................................................ 6 ES.7.12 Traffic ................................................................................................................................................ 7 ES.7.13 Dumping ............................................................................................................................................ 7 ES.8 SUMMARY OF PREVIOUS SANITARY SURVEYS ............................................................................................ 7 ES.9 WATER QUALITY REVIEW ........................................................................................................................... 7 ES.9.1 Turbidity ............................................................................................................................................ 7 ES.9.2 Total Coliform and E. coli ................................................................................................................ 7 ES.9.3 Other Parameters .............................................................................................................................. 8 ES.9.4 Regulatory Discussion ...................................................................................................................... 8 ES.9.5 Regulatory Compliance ..................................................................................................................... 8 ES.10 MANAGEMENT ACTIVITIES REVIEW ............................................................................................................ 8 ES.11 SOURCE PROTECTION OPPORTUNITIES ........................................................................................................ 8 1.0 INTRODUCTION .............................................................................................................................................. 1 1.1. BACKGROUND ............................................................................................................................................. 1 1.2. STUDY AREA ............................................................................................................................................... 1 1.3. PROJECT OBJECTIVES .................................................................................................................................. 2 1.4. REPORT ORGANIZATION .............................................................................................................................. 2 2.0 DELINEATION OF CONTRIBUTION AREAS ............................................................................................ 4 2.1. OVERVIEW .................................................................................................................................................. 4 2.2. LOCATION AND EXTENT .............................................................................................................................. 4 2.3. TOPOGRAPHY AND HYDROLOGY ................................................................................................................. 4 2.4. PRECIPITATION ............................................................................................................................................ 4 2.5. LAND USE ................................................................................................................................................... 4 3.0 WATER SUPPLY INFRASTRUCTURE ........................................................................................................ 8 3.1. OVERVIEW .................................................................................................................................................. 8 BLACK & VEATCH ii Palmdale Water District | 2017 WATERSHED SANITARY SURVEY & SOURCE WATER ASSESSMENT UPDATE 3.2. LITTLEROCK RESERVOIR AND DAM ............................................................................................................ 8 3.3. PALMDALE DITCH ....................................................................................................................................... 9 3.4. CALIFORNIA AQUEDUCT TURNOUT ........................................................................................................... 11 3.5. LAKE PALMDALE ...................................................................................................................................... 11 3.6. LESLIE O. CARTER WATER TREATMENT PLANT ........................................................................................ 12 4.0 UPDATE OF POTENTIALLY CONTAMINATING ACTIVITIES .......................................................... 13 4.1. OVERVIEW ................................................................................................................................................ 13 4.2. INVENTORY METHODS .............................................................................................................................. 13 4.3. SUMMARY OF WATERSHED ACTIVITIES AND CHANGES ............................................................................ 13 4.3.1. NPDES Permit and Waste Discharge Requirement Holders ............................................................... 14 4.3.2. Wildfire ................................................................................................................................................ 14 4.3.3. Review of Spills .................................................................................................................................... 16 4.3.4. UST, LUST, and SLIC Sites ................................................................................................................