Update on the Status of Hydrogeological Work in the Tule Subbasin - PowerPoint PPT Presentation

Update on the Status of Hydrogeological Work in the Tule Subbasin in Support of SGMA Compliance May 3, 2018 Prepared for: Eastern Tule Groundwater Sustainability Agency

Presentation Overview  Short History of Our Involvement in the Tule Subbasin  Work Conducted to Date  Hydrogeological Conceptual Model  Preliminary Detailed Water Budget  Preliminary Estimate of Sustainable Yield  Work in Progress – Groundwater Flow Model  Next Steps

Ultimate Objective – Basin Sustainability Sustainable Yield: The maximum quantity of water, calculated over a base period representative of long-term conditions in the basin and including any temporary surplus, that can be withdrawn annually from a groundwater supply without causing an undesirable result.

Best Management Practices Source: California Department of Water Resources Best Management Practice Framework, Dated December 2016

Study Area

Data for the Analysis are Stored in a Database that Includes:

Sources for the Data Have Included:  Deer Creek Tule River Authority  Tule River Association  California Statewide Groundwater Elevation Monitoring Database (CASGEM)  California Department of Water Resources (DWR)  Cities and Agencies within the Tule Subbasin  Kern County Water Agency  Tulare Lake Bed Coordinated Groundwater Management Plan  United States Geological Survey (USGS)

Wells in the Database More than 1,000 Wells in the Groundwater Level Database More than 9,000 Driller’s Logs Records

Cross Sections (A-E) B’ E’ E A A’ C’ C B

Cross Section Along C- C′

Shallow Aquifer Confining Layer Santa Margarita Fm Deep Aquifer 1,200 – 2,300 ft bgs 1,200 ft bgs

1998 Groundwater Contours – Shallow Aquifer

Historical Groundwater Level Trends – Shallow Aquifer

Surface Geology Cross Section

Outflow Change in Storage Inflow I ss + I mb + I pr + I str + I rf + I ar - O ss + O et + O p = ∆ S I pr O ss O et I str I rf O p I mb Modified from USGS PP 1766

Tule Subbasin Surface Water Budget Inflow

Tule Subbasin Surface Water Budget Outflow

Tule Subbasin Groundwater Budget Inflows

Tule Subbasin Groundwater Budget Inflows/Outflows Approx. Average Annual Overdraft: -118,000 acre-ft/yr Approx. Cumulative Change in Storage: -2,350,000 acre-ft

Tule Subbasin Preliminary Sustainable Yield Estimate Annual Average Sustainable Yield: 257,725 acre-ft/yr 0.54 acre-ft/acre

Work in Progress  A Groundwater Flow Model of the Subbasin is Being Developed (BMP-5)  Refine the Preliminary Water Budget  Refine the Estimate of Sustainable Yield  Develop Water Budgets Specific to Each GSA  Identify Key Well Locations  Assess the Impact of Neighboring Basins on the Tule Subbasin Sustainable Yield  Preparing a Basin-Wide Monitoring Plan

What is the Schedule for Making Model Results Available to the GSAs? Present Preliminary Model Model Analyze Future Results: Calibration Basin Projections Subbasin Sustainable Yield Mar – Apr 2018 • May – Aug 2018 GSA Groundwater Budgets • Identification of Key Wells • August 2018 Refine Monitoring Locations Present Draft Prepare Surface Monitoring Plan with Authorize Water, Recommended Preparation of Groundwater and Prioritization for the Subbasin Land Subsidence Monitoring Monitoring Plan Monitoring Plan Features/Locations March 2018 April – August 2018 August 2018

Questions