Groundwater Water Budget Requirements 11/13/2019 - PowerPoint PPT Presentation

. Groundwater Water Budget Requirements 11/13/2019 PETALUMAVALLEYGROUNDWATER.ORG 1

September – November 2018: 1.0 Introduction- Initial Draft and Advisory Committee Review Complete 2.0 Description of Plan Area - Initial Draft and Advisory Committee Review Complete Petaluma Valley December 2018 – December 2019: GSP Section 3.0 Basin Setting 3.1 Hydrogeologic Conceptual Model - Initial Draft provided to Advisory Development Committee May 2019 3.2 Current and Historical Groundwater Conditions Initial Draft provided to Advisory Working Schedule Committee September 2019 3.3 Water Budget 3.4 Management Areas Bring Drafts of Sections 1 through 3 to GSA Board for Input: Hold Public Workshop on Sections 1 through 3 January 2020 – December 2020 4.0 Sustainable Management Criteria 5.0 Proposed Monitoring Program Bring Drafts of Sections 4 and 5 to GSA Board for Input: Hold Public Workshop on Sections 4 and 5 January 2021 – December 2021 6.0 Projects and Actions 7.0 Implementation Plan Bring Completed Draft Entire GSP to GSA Board for Input: Hold Public Workshop(s) on Complete GSP PETALUMAVALLEYGROUNDWATER.ORG 2

Water Budgets GENERAL WATER BUDGET COMPONENTS AND SGMA REQUIREMENTS 11/13/2019 SONOMAVALLEYGROUNDWATER.ORG 3

SGMA Water Budgets CA CCR §354.18 & Best Management Practices document Three water budgets for GSP: 1. Historical conditions 2. Current conditions 3. Projected conditions over the 50-year planning and implementation horizon Water budget must include: ◦ Inventory of all inflows (supply) and outflows (demand) ◦ Summary of both surface water and groundwater budgets ◦ Evaluation of changes of groundwater in storage ◦ Estimation of groundwater overdraft (if applicable) ◦ Estimation of sustainable yield

Summary of Typical Surface Water Budget Components SURFACE WATER INFLOWS SURFACE WATER OUTFLOWS • Stream inflows from outside of basin • Streambed recharge to groundwater • Overland runoff (from precipitation) • Direct stream diversions • Groundwater discharge to streams • Evaporation (often negligible or hard to compute) • Irrigation return flows

Summary of Typical Groundwater Budget Components GROUNDWATER INFLOWS GROUNDWATER OUTFLOWS • Deep percolation of precipitation • Groundwater pumping (agricultural, urban, domestic) • Streambed recharge to groundwater • Groundwater discharge to streams • Deep percolation of applied irrigation water • Subsurface outflows to adjacent basins (or irrigation return flows) • Septic system return flows • Riparian and crop evapotranspiration • System loss return flows • Subsurface inflows

Water Budget Diagram From: Water Budget BMP, California Department of Water Resources, 2016

Groundwater Modeling GENERAL INFORMATION ON HYDROLOGIC MODELS APPROACH FOR USING MODELING FOR GSP 11/13/2019 SONOMAVALLEYGROUNDWATER.ORG 8

What is a Hydrologic Model? Models are a mathematical approximation of physical processes underground Models are powerful tools that integrate measured and observed hydrologic data and provide estimates within data gap areas Models organize and synthesize multiple related activities and hydrologic processes ◦ Groundwater pumping ◦ Rainfall and recharge Discretized hypothetical aquifer system. ◦ Evapotranspiration (Modified from McDonald and Harbaugh, 1988) ◦ River flows ◦ Groundwater flow and fluxes 9

Groundwater Flow Model – USGS (under review) Integrated Hydrologic Model • Climatically driven agricultural demands • Streamflow simulation • Incorporation of surface water diversions • Recycled Water deliveries • Representation of land use trends and changes Example Model Uses • Estimate hydrologic budget • Identify recharge areas • Evaluate water-resource management strategies • Evaluate climate-change impacts • Evaluate effects of changes in land-use

Typical Model Outputs – Overall Water Budgets Exam ample f from S Sonoma V a Valley M Model

Typical Model Outputs – Detailed Budget Components Exam ample f from S Sonoma V a Valley M Model SONOMAVALLEYGROUNDWATER.ORG 12

Historical water budget Historical calibrated Model Current water budget GSP Modeling Process Flow Include climate change and projected urban growth/land use changes Baseline future water budget Projected Model with Develop projects and actions projects and actions Yes Projected future water Develop SMCs Are SMCs met? budget No 11/13/2019 SONOMAVALLEYGROUNDWATER.ORG 13

Discussion/Questions? 11/13/2019 SONOMAVALLEYGROUNDWATER.ORG 14