Lake Camanche Unit 6 Wastewater Treatment Plant Improvement Project Initial Study/Mitigated Negative Declaration September 20, 2018 Prepared for: Amador Water Agency 12800 Ridge Road Sutter Creek, CA 95685 Prepared by: Stantec Consulting Services Inc. 101 Providence Mine Rd. Suite 202 Nevada City, CA 95959 Lake Camanche Unit 6 Wastewater Treatment Plant Improvement Project Initial Study/Mitigated Negative Declaration Prepared for: Amador Water Agency 12800 Ridge Road Sutter Creek, CA 95685 Prepared by: Stantec Consulting Services Inc. 101 Providence Mine Rd. Suite 202 Nevada City, CA 95959 September 20, 2018 LAKE CAMANCHE UNIT 6 WASTEWATER TREATMENT PLANT IMPROVEMENT PROJECT Table of Contents ABBREVIATIONS ......................................................................................................................... I PROJECT INTRODUCTION .............................................................................................. 1 1.1 PROJECT OVERVIEW ......................................................................................................... 1 1.2 PROJECT LOCATION ......................................................................................................... 1 1.3 PROJECT BACKGROUND ................................................................................................. 1 1.4 CEQA PROCESS ................................................................................................................ 5 PROJECT DESCRIPTION ................................................................................................. 6 2.1 PROJECT NEED AND PURPOSE ........................................................................................ 6 2.1.1 General Improvements.................................................................................. 7 2.1.2 Expanded Treatment Capacity ................................................................... 7 2.1.3 Expanded Storage Capacity ....................................................................... 8 2.1.4 Expanded Disposal Capacity ....................................................................... 8 2.1.5 Proposed Pipeline Alignment ........................................................................ 9 2.2 CONSTRUCTION ACTIVITIES AND ESTIMATED CONSTRUCTION SCHEDULE ................. 9 2.3 OPERATION ...................................................................................................................... 12 2.4 PERMITS AND OTHER AGENCY APPROVALS ................................................................ 12 ENVIRONMENTAL IMPACTS ASSESSMENT .................................................................. 14 3.1 AESTHETICS ....................................................................................................................... 14 3.1.1 Regulatory Setting ........................................................................................ 14 3.1.2 Environmental Setting .................................................................................. 15 3.1.3 Impact Analysis ............................................................................................. 18 3.1.4 Mitigation Measures ..................................................................................... 20 3.2 AGRICULTURAL AND FORESTRY RESOURCES ............................................................... 20 3.2.1 Regulatory Setting ........................................................................................ 20 3.2.2 Environmental Setting .................................................................................. 23 3.2.3 Impact Analysis ............................................................................................. 24 3.2.4 Mitigation Measures ..................................................................................... 26 3.3 AIR QUALITY AND GREENHOUSE GAS EMISSIONS ....................................................... 27 3.3.1 Regulatory Setting ........................................................................................ 27 3.3.2 Environmental Setting .................................................................................. 32 3.3.3 Impact Analysis ............................................................................................. 35 3.3.4 Mitigation Measures ..................................................................................... 41 3.4 BIOLOGICAL RESOURCES .............................................................................................. 43 3.4.1 Regulatory Setting ........................................................................................ 43 3.4.2 Environmental Setting .................................................................................. 50 3.4.3 Impact Analysis ............................................................................................. 77 3.4.4 Mitigation Measures ..................................................................................... 85 LAKE CAMANCHE UNIT 6 WASTEWATER TREATMENT PLANT IMPROVEMENT PROJECT 3.5 CULTURAL AND TRIBAL CULTURAL RESOURCES ........................................................... 95 3.5.1 Regulatory Setting ........................................................................................ 95 3.5.1 Environmental Setting ................................................................................ 100 3.5.2 Impact Analysis ........................................................................................... 109 3.5.3 Mitigation Measures ................................................................................... 113 3.6 GEOLOGY AND SOILS .................................................................................................. 120 3.6.1 Regulatory Setting ...................................................................................... 120 3.6.2 Environmental Setting ................................................................................ 122 3.6.3 Impact Analysis ........................................................................................... 124 3.6.4 Mitigation Measures ................................................................................... 128 3.7 HAZARDS AND HAZARDOUS MATERIALS .................................................................... 128 3.7.1 Regulatory Setting ...................................................................................... 128 3.7.2 Environmental Setting ................................................................................ 132 3.7.3 Impact Analysis ........................................................................................... 133 3.7.4 Mitigation Measures ................................................................................... 137 3.8 HYDROLOGY AND WATER QUALITY ............................................................................ 140 3.8.1 Regulatory Setting ...................................................................................... 140 3.8.2 Environmental Setting ................................................................................ 144 3.8.3 Impact Analysis ........................................................................................... 145 3.8.4 Mitigation Measures ................................................................................... 152 3.9 LAND USE AND PLANNING........................................................................................... 152 3.9.1 Regulatory Settings ..................................................................................... 152 3.9.2 Environmental Setting ................................................................................ 154 3.9.3 Impact Analysis ........................................................................................... 155 3.9.4 Mitigation Measures ................................................................................... 157 3.10 MINERAL RESOURCES ................................................................................................... 157 3.10.1 Regulatory Setting ...................................................................................... 157 3.10.2 Environmental Setting ................................................................................ 158 3.10.3 Impact Analysis ........................................................................................... 159 3.10.4 Mitigation Measures ................................................................................... 159 3.11 NOISE .............................................................................................................................. 160 3.11.1 Regulatory Setting ...................................................................................... 160 3.11.2 Environmental Setting ................................................................................ 162 3.11.3 Impact Analysis ........................................................................................... 166 3.11.4 Mitigation Measures ................................................................................... 173 3.12 POPULATION AND HOUSING ....................................................................................... 174 3.12.1 Regulatory Setting ...................................................................................... 174 3.12.2 Environmental Setting ................................................................................ 175 3.12.3 Impact Analysis ..........................................................................................