August 14, 2019 Paso Robles Subbasin Groundwater Sustainability Plan VOLUME 1 Chapter 1. Introduction to Paso Robles Subbasin Groundwater Sustainability Plan Chapter 2. Agencies’ Information Chapter 3. Description of Plan Area Chapter 4. Hydrogeologic Conceptual Model Chapter 5. Groundwater Conditions Chapter 6. Water Budgets Prepared for: Paso Robles Subbasin Cooperative Committee and the Groundwater Sustainability Agencies DRAFT DRAFT Paso Robles Subbasin GSP 1 August 14, 2019 TABLE OF CONTENTS ABBREVIATIONS AND ACRONYMS ........................................................................................................ vii REGULATIONS CHECKLIST FOR GSP SUBMITTAL ................................................................................ x DEFINITIONS .............................................................................................................................................. xv 1 INTRODUCTION TO PASO ROBLES SUBBASIN GROUNDWATER SUSTAINABILITY PLAN ........ 1-1 1.1 Purpose of the Groundwater Sustainability Plan ....................................................................... 1-1 1.2 Description of Paso Robles Subbasin ......................................................................................... 1-1 2 AGENCIES’ INFORMATION ................................................................................................................. 2-1 2.1 Agencies’ Names and Mailing Addresses ................................................................................... 2-1 2.2 Agencies’ Organization and Management Structure .................................................................. 2-2 2.2.1 City of Paso Robles GSA ..................................................................................................... 2-2 2.2.2 Paso Basin - County of San Luis Obispo GSA .................................................................... 2-2 2.2.3 San Miguel Community Services District GSA ..................................................................... 2-2 2.2.4 Shandon - San Juan GSA .................................................................................................... 2-2 2.3 Authority of Agencies ................................................................................................................... 2-3 2.3.1 Individual GSAs ................................................................................................................... 2-3 2.3.2 Memorandum of Agreement for GSP Implementation ......................................................... 2-5 2.3.3 Coordination Agreements .................................................................................................... 2-5 2.3.4 Legal Authority to Implement SGMA Throughout the Plan Area .......................................... 2-5 2.4 Contact Information for Plan Manager ........................................................................................ 2-5 3 DESCRIPTION OF PLAN AREA ........................................................................................................... 3-1 3.1 Paso Robles Subbasin Introduction ............................................................................................ 3-1 3.2 Adjudicated Areas, Other GSAs, and Alternative Plans ............................................................ 3-1 3.3 Other Jurisdictional Areas ........................................................................................................... 3-1 3.3.1 Federal Jurisdictions ............................................................................................................ 3-1 3.3.2 Tribal Jurisdiction ................................................................................................................. 3-4 3.3.3 State Jurisdictions ................................................................................................................ 3-4 3.3.4 County Jurisdiction .............................................................................................................. 3-4 3.3.5 City and Local Jurisdictions ................................................................................................. 3-4 3.4 Land Use ........................................................................................................................................ 3-7 3.4.1 Water Source Types ............................................................................................................ 3-9 3.4.2 Water Use SectorsDRAFT ............................................................................................................. 3-11 3.5 Existing Well Types, Numbers, and Density ............................................................................. 3-13 3.6 Existing Monitoring Programs ................................................................................................... 3-17 3.6.1 Groundwater Level Monitoring ........................................................................................... 3-17 3.6.2 Groundwater Quality Monitoring ........................................................................................ 3-19 3.6.3 Surface Water Monitoring .................................................................................................. 3-21 3.6.4 Climate Monitoring ............................................................................................................. 3-21 3.7 Existing Management Plans ....................................................................................................... 3-25 3.7.1 Groundwater Management Plan (2011) ............................................................................. 3-25 3.7.2 San Luis Obispo County Master Water Report (2012) ....................................................... 3-25 3.7.3 San Luis Obispo County Region Integrated Regional Water Management Plan (2014) .... 3-26 3.7.4 Salt and Nutrient Management Plan for the Paso Robles Groundwater Basin (2015) ....... 3-26 3.7.5 City of Paso Robles Urban Water Management Plan (2016) ............................................. 3-27 DRAFT Paso Robles Subbasin GSP ii August 14, 2019 3.8 Existing Groundwater Regulatory Programs ............................................................................ 3-27 3.8.1 Salinas River Live Stream Agreement (SWRCB, 1972) ..................................................... 3-27 3.8.2 Groundwater Export Ordinance (2015) .............................................................................. 3-27 3.8.3 County of San Luis Obispo Water Demand Offset Ordinance (2015) ................................ 3-28 3.8.4 Agricultural Order (RWQCB, 2017) .................................................................................... 3-28 3.8.5 Water Quality Control Plan for the Central Coast Basins (SWRCB, 2017) ........................ 3-29 3.8.6 Requirements for New Wells ............................................................................................. 3-30 3.8.7 Title 22 Drinking Water Program (SWRCB) ....................................................................... 3-30 3.9 Monitoring and Management Programs with GSP ................................................................... 3-30 3.9.1 Incorporation into GSP....................................................................................................... 3-30 3.9.2 Limits to Operational Flexibility .......................................................................................... 3-31 3.9.3 Conjunctive Use Programs ................................................................................................ 3-31 3.10 Land Use Plans ........................................................................................................................ 3-31 3.10.1 City of Paso Robles General Plan (2011) .......................................................................... 3-31 3.10.2 San Luis Obispo County General Plan (2014) ................................................................... 3-32 3.10.3 Camp Roberts Joint Land Use Study ................................................................................. 3-35 3.10.4 Land Use Plans Outside of Basin ...................................................................................... 3-36 4 HYDROGEOLOGIC CONCEPTUAL MODEL ....................................................................................... 4-1 4.1 Subbasin Topography and Boundaries ....................................................................................... 4-1 4.2 Soils Infiltration Potential ............................................................................................................. 4-5 4.3 Regional Geology .......................................................................................................................... 4-7 4.3.1 Regional Geologic Structures ............................................................................................... 4-7 4.3.2 Geologic Formations Within the Subbasin .......................................................................... 4-17 4.3.3 Geologic Formations Surrounding the Subbasin ................................................................ 4-18 4.4 Principal Aquifers and Aquitards............................................................................................... 4-21 4.4.1 Alluvial Aquifer ................................................................................................................... 4-26 4.4.2 Paso Robles Formation Aquifer .........................................................................................