San Benito County Water District Annual Groundwater Report

San Benito County Water District Annual Groundwater Report 2020 Todd Groundwater Maureen Reilly, PE Iris Priestaf, Ph. D

Agenda • Introduction: 2020 at a glance • Geographic Area • Basin Conditions • Water Use • Looking Ahead

2020 at a glance • Generally stable conditions Ø Ø Slightly below normal rainfall –water levels declined CVP allocation: USBR Water Year March 2019 - February 2020 March 2020 - February 2021 Agriculture 75% 20% M&I 100% 70% • Total water use stable Groundwater is 54 percent of supply in Zone 6 Ø Recycled water at 1 percent Ø • Monitoring and data are being evaluated for SGMA

Geographic Area Annual Report focuses on Zone 6 GSP and future Annual Reports address North San Benito Groundwater Basin

Basin Conditions: Groundwater Levels Monitoring network being improved • 100 wells • Continue to add new wells

Change in Levels 2019 to 2020

Groundwater storage decreased slightly in 2020 25 000 20 000 Annual Change in Stoage (AFY) 15 000 10 000 5 000 0 (5 000) (10 000) San Juan Hollister West Tres Pinos Pacheco Northern Hollister East Southern Hollister East Bolsa SE Bolsa (15 000) (20 000) (25 000) (30 000) 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Annual Zone 6 Water Use by Source 60 000 Agriculture Groundwater Domestic & Municipal Agricultural Domestic & Municipal 50 000 Recycled Water • Increased M&I demand for CVP • Groundwater use was 54 percent of total supply • Recycled water decreased slightly last year • Ag recycled water use up to 170% since 2016 40 000 Water Use (AFY) Total water use remained at about 38, 000 acre-feet 30 000 20 000 10 000 0 88 990 992 994 996 998 000 002 004 006 008 010 012 014 016 018 020 19 1 1 2 2 2 2 2 1 2 Water Year

Volume of Percolation, afy, 1994 -2020 12 000 San Benito River Tres Pinos Creek Arroyo de las Viboras Arroyo Dos Picachos Pacheco Creek Santa Ana Creek Hollister Ponds 8 000 6 000 4 000 2 000 96 19 97 19 98 19 99 20 00 20 01 20 02 20 03 20 04 20 05 20 06 20 07 20 08 20 09 20 10 20 11 20 12 20 13 20 14 20 15 20 16 20 17 20 18 20 19 20 20 95 19 19 94 19 CVP Percolation AFY 10 000 Increased CVP percolation into off-stream basins

GSP Overview Management / Plan Components Plan Development Management Actions / Monitoring Policy Components Technical Components Sustainability Criteria Management Areas / Water Budgets Hydrogeologic Conceptual Model / Groundwater Data Compilation / Data Management System Plan Area / Institutional Setting

Future Annual Reports • SGMA Annual Reports require items already included in the District Groundwater Report: • • Monitoring data stored in a Data Management System General information about basin Detailed description of groundwater levels Surface water supply by use

Future Annual Reports • SGMA Annual Reports also require: • • • Details on groundwater use Groundwater extractions and a map Total water use for the entire basin Change in storage maps for the entire basin Cumulative change in storage from the model Description of progress towards implementing the plan.

Future Annual Reports

Increased analysis and tracking ØNeed a new method to assess groundwater pumping across basin ØAnnual update and application of the model ØWill require more time to prepare annual report

Outlook • Below to near average (? ) rainfall and below normal CVP (? ) but groundwater available in storage • SGMA supports enhanced monitoring and management • GSP to be completed by January 2022, the first SGMA Annual Report is due April 2022.

Recommendations • Groundwater Charges Zone 6 – Ø Ø $13. 55 /AF for agricultural $40. 55 /AF is recommended for M&I • Groundwater Production and Replenishment – Ø Focus replenishment on areas that still show lower water levels • Proceed with SGMA Prepare a GSP by 2022 Ø Prepare Annual Reports to satisfy SGMA requirements Ø

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