Welcome! GSP WORKSHOP August 15, 2019 | Online Webinar
SESSION 1 Chapter 2 - Plan Area
SGMA Overview Date: August 13, 2019 Presented by: Randy Hopkins and Lynn Groundwater
LIVE POLL
What is the Sustainable Groundwater Management Act (SGMA)? • Comprehensive legislation to manage groundwater to sustainable levels – Adopted in 2014 – Gives local public agencies ability to form Groundwater Sustainability Agencies (GSAs) to comply with SGMA – Local public agencies mean those with water supply, water management, or land use responsibilities within the groundwater basin – Water Code §10721(n) – Counties are backstop to local agencies – State will intervene if locals and counties fail
SGMA Recap • Establishment of GSAs by 2017 • GSP Development by 2020 • Annual Reports • 5-Year GSP Updates • Groundwater Sustainability by 2040 Provost & Pritchard Consulting Group
Process Kings Subbasin Coordination Present to Present to Develop TAC Board Documents Collect Data, Reports,& Information Provost & Pritchard Consulting Group
What the GSP Does • Documents historic and current conditions – Groundwater Levels – Groundwater Quality – Water Budgets • Defines Path Forward – Identifies Measurable Objectives & Minimum Thresholds – Defines potential Projects and Management Actions Provost & Pritchard Consulting Group
What the GSP Does NOT Do • Require immediate pumping restrictions • Require changes to crops • Require land use changes • Require mandatory fallowing Provost & Pritchard Consulting Group
Kings Subbasin Provost & Pritchard Consulting Group
MAGSA Provost & Pritchard Consulting Group
GSP Requirements GSP Outline • Executive Summary • Introduction • Plan Area • Basin Setting • Sustainable Management Criteria • Monitoring Network • Projects and Management Actions to Achieve Sustainability • Plan Implementation • References and Technical Studies • Appendices
SESSION 2 Chapter 3 – Basin Setting
Historic Water Conditions- Spring 1997 Provost & Pritchard Consulting Group
Current Water Conditions- Spring 2017 Provost & Pritchard Consulting Group
Water Level Change
Water Level Change
Water Level Change
Water Level Change
Overdraft Mitigation Target Storage Change 16,000 AF/yr GW Inflow 91,700 AF/yr Historic GW Inflows (16,600) AF/yr Overdraft Mitigation Target 91,100 AF/yr Provost & Pritchard Consulting Group
Current Water Budget Description Volume (AF) Supply Average Year Wet Year Dry Year 1) Surface Water for Irrigation 1,900 6,200 0 2) Surface Water for M&I 0 0 0 3) Groundwater Pumping for Irrigation (Private Wells, calculated/estimated) 0 0 0 4) Groundwater Pumping for Irrigation (Private Wells, unknown) 290,200 243,600 320,800 5) Groundwater Pumping for M&I (Agency Wells) 0 0 0 6) Groundwater Pumping for M&I (Private Wells) 2,600 2,600 2,600 7) Precipitation 92,700 131,098 65,901 8) Spill Inflows 2,000 3,500 0 9) Other Supply: 0 0 0 Total Supply 389,400 386,998 389,301 Provost & Pritchard Consulting Group
Current Water Budget pp y , , , Demand Consumptive Use 10) Evapotranspiration met by Applied Water 232,000 199,800 253,100 11) Evapotranspiration met by Effective Precipitation 52,000 84,200 30,900 12) Evapotranspiration of M&I 1,300 1,300 1,300 13) Other Consumptive Use: 0 0 0 Consumptive Subtotal 285,300 285,300 285,300 Provost & Pritchard Consulting Group
Current Water Budget p Groundwater Recharge 14) Groundwater Inflow 153,000 153,000 153,000 15) Deep Percolation of Irrigation Water 61,700 53,111 67,280 16) Deep Percolation of Precipitation 8,800 22,400 0 17) Deep Percolation of M&I Water 1,300 1,300 1,300 18) Seepage of Channels & Pipelines 0 0 0 19) Seepage - Reservoirs 400 400 400 20) Urban Stormwater - Recharge 0 0 0 21) Local Streams/Rivers - Recharge 16,700 12,000 25,000 22) Groundwater - Intentional Recharge 0 0 0 23) Other Recharge: 0 0 0 GW Recharge Subtotal 241,900 242,211 246,980 Provost & Pritchard Consulting Group
Current Water Budget Nonrecoverable Losses 24) Groundwater - Outflow 0 0 0 25) Evaporation - Channels 0 0 0 26) Evaporation - Reservoirs & Recharge Basins 0 0 0 27) Precipitation - Evaporation and Runoff 31,900 24,500 35,000 28) Operational Spills 0 0 0 29) Groundwater - Export 18,500 1,497 27,598 30) Other Losses: 0 0 0 Nonrecoverable Subtotal 50,400 25,997 62,598 Provost & Pritchard Consulting Group
Sustainable Yield MAGSA Pumping 292,800 AF/yr GW Export 18,500 AF/yr Total GW Demand 311,300 AF/yr Overdraft Mitigation Target 91,100 AF/yr MAGSA Sustainable Yield 220,300 AF/yr Provost & Pritchard Consulting Group
Sustainability Approach Overdraft Cumulative Overdraft Year Mitigation Mitigation Mitigation % (AF) (AF) 2025 10% 9,110 9,110 2030 20% 18,220 27,330 2035 30% 27,330 54,660 2040 40% 36,440 91,100 Provost & Pritchard Consulting Group
LIVE POLL
SESSION 3 Chapter 4 – Sustainable Management Criteria Chapter 5 – Monitoring Network
Sustainable Management Criteria Groundwater Levels Groundwater Storage Water Quality Land Subsidence Depletion of Interconnected Surface Water Seawater Intrusion
Sustainable Management Criteria Terms • Sustainability Indicators • Significant & Unreasonable – We define using the following: • Minimum Thresholds Must be • Undesirable Results Addressed agreed to by, • Measurable Objectives in this and • Sustainability Goal order consistent in the GSPs of all GSAs within basin
Sustainable Indicators and Metrics This is what is monitored Subsidence Depletions Chronic Degraded All Undesirable Results Reduction Undesirable Seawater that that Lowering Water Quality, of GW Result Intrusion interferes impact Based on Exceeding indicating Migration of Storage (Significant & with surface beneficial significant & Minimum Threshold Contamination Unreasonable) land uses uses of unreasonable Plumes surface depletion water
Water Level SMC • The GSAs within the Kings Basin have defined the Undesirable Result for groundwater levels to be significant and unreasonable when either the water level has declined to a depth that a new productive well cannot be constructed, or when the water level has declined to a depth that water quality cannot be treated for beneficial use. • MAGSA defined undesirable results when 1/3 (8 wells) of the indicator wells in the monitoring network drop below the minimum threshold for two consecutive years at the same wells.
Water Level SMC
Water Level SMC Distance from 2017 Water Level to Distance from 2017 Water Level to MAGSA Well ID Measurable Objective (ft) Minimum Threshold (ft) 13‐1 31.3 100.4 13‐2 18.7 66.8 13‐3 27.0 102.7 14‐1 21.9 41.6 14‐2 25.0 83.7 14‐3 18.1 40.7 14‐4 30.7 67.5 14‐5 18.6 36.1 14‐6 24.5 72.5 15‐1 23.0 48.6 15‐2 35.9 72.2 15‐3 20.9 65.8 15‐4 14.5 47.0 15‐5 65.2 110.2 15‐6 49.5 83.7 15‐7 22.5 54.1 15‐8 19.9 100.7 15‐9 57.5 97.1 15‐10 22.4 46.7 16‐1 36.1 75.3 16‐2 57.6 120.1 16‐3 32.3 72.6 16‐4 35.3 73.6
Storage Change SMC • Estimated storage change for the Kings Subbasin -1.8 MAF • From spring 1997 to spring 2012 • An average of about -122,000 AF/yr • An undesirable result would occur if the total amount of water in storage was less than the estimated amount of groundwater in storage below the Minimum Thresholds.
Water Level and Storage Change Monitoring Network
Water Quality SMC • Undesirable results determinations will be based on the aggerated effect of: – 1) the degradation of water quality to excess of MCLs (i.e. California potable water standards) where concentrations of chemicals of concern were recent historically below MCLs; and – 2) a statistically significant increase in groundwater degradation where concentrations of chemicals of concern were recent historically above MCLs. • The occurrence of an undesirable result will be defined as 6 of the 12 representative monitoring wells having reached either of these two criteria for two consecutive years at the same wells.
Water Quality SMC Chemical of Concern California Primary MCL (mg/L unless otherwise shown) Arsenic 0.01 Chloride 500** Manganese 0.5* Sodium 50 Uranium 20 (pCi/L) Nitrate as NO3 45 Dibromo-Chloropropane (DBCP) 0.0002 1,2,3-Trichloropropane (TCP) 5x10 -6 Total Dissolved Solids (TDS) 1,000**
Water Quality Monitoring Network
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