Sierra Valley Board Presentation 3/18/2019 Advancing Groundwater Sustainability in Sierra Valley: Key Messages from the Sierra Valley Groundwater Study and the GSP Planning Grant Effort P.A.M. Bachand, Ph.D. 1 ; S.M. Bachand, MS, ME, PE 1 ; K. Burt 1 and S. Carlton, PG, CHG 2 1 Bachand & Associates 2 Carlton Hydrology Sierra Valley Groundwater Management District Board Meeting Monday, Mar 18, 2019 at 6:00 pm Golden West Restaurant, Loyalton, CA B A C H A N D & A S S O C I A T E S Sustainable Water Resources 1 2‐Year Feather River Land Trust Project BACHAND & ASSOCIATES Sustainable Water Resources Goal and Partners Project • Goals • Groundwater Study • Promoting groundwater sustainability • Irrigation efficiency study in Sierra Valley through better • Groundwater Sustainability understanding groundwater conditions and considering potential Plan (GSP) Planning Grant solutions • Project Partners and Collaborators • Helen Dahlke, UC Davis • Thomas Getts, UC Cooperative Extension Plumas – Sierra County • Kristi Jamason 2 Philip Bachand, Bachand & Associates, philip@bachandassociates.com 1
Sierra Valley Board Presentation 3/18/2019 Presentation Outline • Groundwater Report Highlights • Sustainable Groundwater Management Act (SGMA) Considerations • Groundwater Sustainability Plan (GSP) and Planning Grant BACHAND & ASSOCIATES Sustainable Water Resources 3 Groundwater Report Highlights BACHAND & ASSOCIATES Sustainable Water Resources • Results • Data Gaps and Uncertainty BACHAND & ASSOCIATES Sustainable Water Resources 4 Philip Bachand, Bachand & Associates, philip@bachandassociates.com 2
Sierra Valley Board Presentation 3/18/2019 Shallow Groundwater (GW) Levels (Spring 2015) and Pumping, GVE 1998 ‐ 2016 GVW Notes: 1. GV = Grizzly Valley Fault 2. Arrows show direction of groundwater flow 3. GW contours estimated from well data based on fitting algorithms Total Pumping, 1998 – 2016 Circles show amount of pumping by Township Section BACHAND & ASSOCIATES Sustainable Water Resources 5 Shallow and Deep Groundwater (GW) Total Pumping, 1998 – 2016 Response to Groundwater Pumping by BACHAND & ASSOCIATES Sustainable Water Resources Township Section, 1998 ‐ 2016 A) Shallow Groundwater Levels (Spring 2015) B) Deep Groundwater Levels (Spring 2015) • Deep GW most affected by pumping • Static GW level in deep wells below GVE static GW levels in GVW shallow wells • GW depression represents cumulative response to GW pumping and flow dynamics • Most pumping east of GVW 6 Philip Bachand, Bachand & Associates, philip@bachandassociates.com 3
Sierra Valley Board Presentation 3/18/2019 Decline in deep groundwater from 1980 to BACHAND & ASSOCIATES Sustainable Water Resources 2015 (Spring Measurements) 7 Recharge Response Deep GW BACHAND & ASSOCIATES Sustainable Water Resources from 2017 Wet Year 8 Philip Bachand, Bachand & Associates, philip@bachandassociates.com 4
Sierra Valley Board Presentation 3/18/2019 Sustainable Yield Estimates (1989 – 2017) – Groundwater Pumping Rates during Years with Declining, Stable and Increasing Groundwater Levels BACHAND & ASSOCIATES Sustainable Water Resources 8000 Groundwater Pumping (Acre‐Ft/Year) Median 25%-75% 7000 6,447 GW Pumping (ac-ft/yr) 5,972 6000 5000 3,941 4000 3000 2000 Declining GW Stable GW Increasing GW > - 2ft +/- 2 ft > + 2 ft Annual GW Change (ft/year) 9 Sources of Current and Future Uncertainty BACHAND & ASSOCIATES Sustainable Water Resources • Geologic, e.g., • Flow paths and flow timing to aquifer • Basin stratigraphy and sediment deposition • Characterization of basin faults • Hydrology; e.g., • Evapotranspiration (e.g. basin, forests) and effects of climate change and future management • Recharge rates and effects of climate change on precipitation, effects of future upland and lowland management, and opportunities from reservoir re‐ operation • Current and future rainfall and snowfall spatial distribution • Limited set of monitoring wells • Pumping record data (e.g. completeness, accuracy, QAQC) 10 Philip Bachand, Bachand & Associates, philip@bachandassociates.com 5
Sierra Valley Board Presentation 3/18/2019 SVGMD Wells CASGEM Well Subset used in GW report Uncertainty Example • Affects predicted groundwater elevations using contouring programs Well Selection and Density • Affects adaptive management decisions with Effects on Data increased uncertainty about cause (e.g. pumping Interpretation and Decision rates) and effect (i.e., resulting groundwater Making elevation changes) 11 Uncertainty Example Climate Change Considerations • Affects estimates of precipitation amount and type due to upward migration of snowline • Greater uncertainty north of Tahoe • Affects estimates of precipitation frequency within seasons and through years BACHAND & ASSOCIATES Sustainable Water Resources 12 Philip Bachand, Bachand & Associates, philip@bachandassociates.com 6
Sierra Valley Board Presentation 3/18/2019 Uncertainty and Adaptive Management BACHAND & ASSOCIATES Sustainable Water Resources • Total Sierra Valley Water Budget approximately 250,000 AF annually • Sustainable Yield in the 5000 – 6500 AF range in Eastern Valley • 2 ‐ 3% error in Water budget equivalent to total Sustainable Yield • Water budget error likely around 10 – 30% due to propagation of error in calculations • Best solution to act on direct measures (e.g. groundwater levels, subsidence, water quality) • Better data – • Constrains effects spatially and temporally • Informs on strategies and actions for adaptive management 13 Key SGMA Considerations BACHAND & ASSOCIATES Sustainable Water Resources • Undesirable Results • Process and Timeline • State Water Board Intervention 14 Philip Bachand, Bachand & Associates, philip@bachandassociates.com 7
Sierra Valley Board Presentation 3/18/2019 Achieving Sustainable Yield and Avoidance of Undesirable Results (DWR 2017) BACHAND & ASSOCIATES Sustainable Water Resources Reduction Lowering of GW Levels Seawater Intrusion of GW Storage Depletionof Water Quality Degradation Land Subsidence Interconnected Streams 9 15 Achieving Sustainable Yield and Avoidance of Undesirable Results (DWR 2017) BACHAND & ASSOCIATES Sustainable Water Resources The amount of usable water Needs sufficient density that remains in an aquifer to characterize depends on soil texture, groundwater and inform stratigraphy and on adaptive actions groundwater levels. Reduction Lowering of GW Levels Seawater Intrusion of GW Storage • Is GW pumping causing Commonly refers to A well designed GW contaminants to network should be stream and shallow migrate. established in areas groundwater • Sufficient to assess where subsidence interactions. Artesian impacts to beneficial uses wells likely will be conditions are or and users, and to evaluate considered if linked to believed to be management. occurring. groundwater declines. Depletionof Water Quality Degradation Land Subsidence Interconnected Streams 9 16 Philip Bachand, Bachand & Associates, philip@bachandassociates.com 8
Sierra Valley Board Presentation 3/18/2019 Phase 1: BACHAND & ASSOCIATES Sustainable Water Resources GSA Formation and SGMA Process and Timeline Coordination 2014 – 2017 Phase 2: Phase 4: GSP Preparation and Phase 3: Implementation and Submission GSP Review and Reporting Evaluation • DWR funding, facilitation • Annual Reporting and technical support • • 2‐year initial review GSP 5‐year assessments • GSP development period and re‐evaluation: • GSP define thresholds, • • Corrective actions Alternatives triggers, projects and • Inadequate GSP leads resubmitted management actions • to intervention Interim milestones • GSP January 2022 • GW Sustainability submittal 2022 ‐ 2025 2022 ‐ 2042 2017 – 2022 17 State Water Board (Board) Intervention BACHAND & ASSOCIATES Sustainable Water Resources Local Agency Qualification Interventions • Qualifies as probationary: • Board will allow agencies time to correct issues that led to probation • fails to form a GSA, • fails to develop an adequate sustainability plan, • Board will develop an interim plan if local • fails successfully implement plan. agencies cannot fix the issues, which will include – • When Board designates a basin probationary • directly manage groundwater extractions, • All extractors must file extraction reports • contain corrective actions, (unless specifically excluded by the Board). • Contain timeline to basin sustainability • May require meters to measure extractions • Contain a monitoring plan to validate • May require additional reporting effectiveness of actions 18 Philip Bachand, Bachand & Associates, philip@bachandassociates.com 9
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