Greater Kaweah GSA Board Meeting www.GreaterKaweahGSA.org Monday, - PDF document

6/10/2019 Greater Kaweah GSA Board Meeting www.GreaterKaweahGSA.org Monday, June 10, 2019 APPROVAL OF MINUTES 1

6/10/2019 SUBBASIN & GSP ACTIVITIES Kaweah Subbasin Activities • Subbasin Basin Setting Components Report – Nearing completion of incorporating clean up comments • Numerical Model – GSI completed Base Run Scenarios – GSI currently running scenarios with Projects and Management Actions • Draft Coordination Agreement discussions are ongoing. • Completion of SkyTEM study 2

6/10/2019 Kaweah Subbasin Activities (cont.) • DMS funds from GSP grant to be reallocated to Basin contract • Upcoming Management Team Committee meeting agenda to include: – DMS update and walk-through – Groundwater Quality suggested approach presentation by Richard Meyerhoff (GEI) – Prop 68 funding discussion – Public Review Drafts of GSPs – change management and response to comments approach. – Preliminary modeling results SkyTEM Investigation Objectives 1) Develop a 3D hydrogeological framework to assist in water resources management. 2) Produce maps of aquifer materials along the flight lines 3) Locate potential Managed Aquifer Recharge (MAR) areas along the flight lines 4) Provide information to identify optimal drilling locations for production, monitoring, and test wells 3

6/10/2019 SkyTEM Helicopter AEM Operation Generator Usually 2-3 Flights/day Generator Totaling about 180-250 line-miles/day Approx. 100’ – 150’ above ground Along-Line Data Density Approximately Every ~ 10 ft SkyTEM In Field QA/QC Abraham et al., 2016 4

6/10/2019 SkyTEM: Kaweah As Flown Flight Lines SkyTEM: Boreholes Near Flight Lines Blue dots- 440 Borehole with lithology only Yellow dots-52 Borehole with lithology and geophysical log 5

6/10/2019 SkyTEM: Interpretation of the Profiles Flight Line SkyTEM: Interpretation of the Profiles Water Table Flight Line 6

6/10/2019 SkyTEM: Example Fence Diagram Visalia Tulare N SkyTEM: Depth to Top of Basement 7

6/10/2019 SkyTEM: Depth to Top of Corcoran Clay SkyTEM: Thickness of Corcoran Clay 8

6/10/2019 SkyTEM: Recharge Potential Based on Results Poor Resistivity Greater than 25 ohm-m is optimal Good ITEM 3: SkyTEM Recommendations 1. Additional AEM mapping with high density block flights would allow for improved hydrogeologic framework for identifying recharge areas, managed aquifer recharge sites and estimating groundwater in storage and hydrogeologic boundary identification. 2. Siting new boreholes used for water quality and water quantity should use the results from this survey and future surveys to optimize locations. 3. Aquifer characteristic studies such as aquifer tests and other methods should be planned using the data from this study to optimize location for studies and observation- production well installation. 4. Improved geophysical bore hole logs will benefit current and future studies. This logging should use calibrated equipment for best results. 9

6/10/2019 1. Summary of Base Run Scenarios 1. Average Hydrologic Conditions 2. Historical Conditions 3. Historical Conditions, backwards Order 1. Base Run Scenario 1 - 3 Future No Project Scenarios 1) Future “No Project” Scenarios – Current water budget conditions modified by climate data and forecasts of supply and demand. – Forecasts future groundwater levels for comparison against minimum thresholds 10

6/10/2019 1. Base Run Scenario 1 - 3 Future No Project Scenarios Future “No Project” Scenarios 1. Base Run Scenario 1 Average Conditions 1) Average Hydrology 11

6/10/2019 1. Base Run Scenario 2 Historical Conditions 2) Historical Hydrology 1. Base Run Scenario 3 Historical Conditions - Backwards 3) Historical Hydrology in reverse order 12

6/10/2019 2. Results of Base Scenarios 3. Projects and Management Actions Future Management Actions Only: Pumping Reductions Future Management Actions Only: Pumping Reductions + Projects 13

6/10/2019 3. Projects and Management Actions Greater Kaweah: Kings County Water District 3. Projects and Management Actions Greater Kaweah:  GKGSA’s Target (1997-2017 Water Budget Apportioned to WAF) = 42,675 acre-feet/year  Annual Native Yield of the Basin and GKGSA = 363,784 acre-feet or 0.82 acre-feet/acre/year Possible Projects and/or Management Actions Alternatives Apportionment of Average Annual Alternatives Targets as a Percentage of Average Net Increase in Supply Minus Reduction in Annual Sustainable Yield Deficit (overdraft) Demand in Acre-Feet Alt. 2020-25 2026-30 2031-35 2036-40 Total Alt. 2020-25 2026-30 2031-35 2036-40 Total 1 0% 20% 35% 45% 100% 1 0 8,535 14,936 19,204 42,675 2 5% 25% 30% 40% 100% 2 2,134 10,669 12,803 17,070 42,675 Minimum 3 5% 20% 35% 40% 100% 3 2,134 8,535 14,936 17,070 42,675 Optimal 4 10% 20% 30% 40% 100% 4 4,268 8,535 12,803 17,070 42,675 5 10% 30% 30% 30% 100% 5 4,268 12,803 12,803 12,803 42,675 6 25% 25% 25% 25% 100% 6 10,669 10,669 10,669 10,669 42,675  Preliminary model results using projects and management actions received suggest above target outcomes for the first 10-15 years 14

6/10/2019 Sustainable Management Goal • Must be coordinated / agreed to by all three GSAs • Draft language has been circulated through various committees and GSA boards for several months with only minor revisions • Latest language changes address comments regarding water quality Combined RCC/SC Recommendation: SMCs Approach for Groundwater Storage and Groundwater Levels • The change in groundwater storage is correlated to the chronic decline in groundwater levels. Therefore, the SMCs for groundwater levels will be used as a proxy for the change in storage. • For each Representative Monitoring Site, the Minimum Threshold for Groundwater Levels would be established at the projected 2040 GWL and the Measurable Objective would be the projected 2030 GWL. – Provides 10 years of drought storage in the “worst-case scenario”. – This approach is subject to modification in order to avoid harm to EKGSA 15

6/10/2019 SMCs for Water Quality • The Basin Setting has identified existing water quality issues. However, undesirable results related directly to groundwater levels have not been observed to-date. • To re-evaluate a Minimum Threshold and Measurable Objective for each of the Constituents of Concern discussed in the Basin Setting, ongoing and future water quality monitoring will coincide with GWL measurements. – e.g. The Kaweah Watershed Coalition has begun to collect water quality samples coincidental with GWL measurements. SMCs for Water Quality • In addition to the IRLP, there are other existing programs (i.e. Title 22 Drinking Water Program) which monitor water quality and will be used to determine the occurrence of an Undesirable Result, due to the migration of existing groundwater contamination. • GEI is preparing a proposed coordinated approach to SMCs for Water Quality 16

6/10/2019 SMCs for Subsidence • The Basin Setting identifies Land Subsidence as a current condition in the subbasin. However, damage to critical infrastructure within the Kaweah Subbasin has not been observed to-date. • To establish an Minimum Threshold and Measurable Objective for subsidence, one method would use the change in storage (with respect to the SMCs for GWLs) to develop correlations between change in storage and rates of subsidence. • Another method would be to calculate the potential land subsidence, based on the change in storage, and set a land elevation for Minimum Thresholds and Measurable Objectives at the Representative Monitoring Sites. • TAC directed GEI to prepare a correlation analysis between storage and subsidence rate to establish a rate of change. GSP Development • Basin Setting Chapter – GKGSA Basin Setting Chapter to be completed with Basin Setting Components Report. The TAC has provided comments on the report, which are being reviewed and addressed. • Monitoring Network Chapter – Chapter has been revised to reflect comments and is under internal review. Discussions with other GSAs on coordinated Monitoring Network improvements to finalize Representative Monitoring Sites selection. • Sustainability Goal and Undesirable Results Chapter – In draft, to be completed with incorporation of GSAs’ feedback and approval of Undesirable Results definitions and adoption of Sustainability Goal for the Subbasin. • Sustainable Management Criteria Chapter – Draft chapter to be revised with Minimum Thresholds and Measurable Objectives, based on TAC, RCC, and SC recommendations. • Projects and Management Actions Chapter – Draft chapter under internal review, includes projects and management actions discussed so far, at committees. Follow up discussions with JPA members for input and inclusion of their projects. 17