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HomeMy WebLinkAbout2020 Oct 14 TAC MeetingDRAFT Ukiah Valley Groundwater Sustainability Plan Development Update October 14, 2020 Ukiah Valley Basin Groundwater Sustainability Agency Technical Advisory Committee DRAFT ◼Outreach Meetings Update ◼GSP Writing and Review: ⚫Review and commenting of draft Chapter 2 and schedule for next deliverables ⚫Revised proposed schedule for chapter delivery and review ◼Sustainable Management Criteria and Monitoring Network Design: Chronic Lowering of GW Levels and SW depletion ◼Future Scenarios Outline DRAFT ◼Outreach Meetings Update ◼GSP Writing and Review: ⚫Review and commenting of draft Chapter 2 and schedule for next deliverables ⚫Revised proposed schedule for chapter delivery and review ◼Sustainable Management Criteria and Monitoring Network Design: Chronic Lowering of GW Levels and SW depletion ◼Future Scenarios Outline DRAFT Status Update ◼Public meeting ⚫September 29th (Zoom in English and Spanish). Recordings are available on County’s YouTube account ◼Tribal meeting ⚫October 19th 6-8 PM. Agenda and Presentation will be posted soon. ◼Stakeholder interviews ⚫1-on-1 interviews: 2nd half of October. Interviews started with Sonoma Water and we will be scheduling further calls with them for future scenarios. ⚫PVP working group meeting: September 30th. ◼TSS and instrumentation ⚫Streamgage installation and well instrumentation trips postponed due to fires and air quality/temperature but will happen this week. ⚫Drilling sites were approved by the School District. DRAFT ◼Outreach Meetings Update ◼GSP Writing and Review: ⚫Review and commenting of draft Chapter 2 and schedule for next deliverables ⚫Revised proposed schedule for chapter delivery and review ◼Sustainable Management Criteria and Monitoring Network Design: Chronic Lowering of GW Levels and SW depletion ◼Future Scenarios Outline DRAFT GSP Writing and Review ◼Content review is the main focus of the review and commenting process at this stage Missing Subsection Delivery (By the End of month) Jurisdictional Areas and Land Use: Small water districts’ information to be filled November 2020 Water Resources Monitoring and Management Programs: We need feedback November 2020 County Zoning Plan October 2020 GW contamination, cleanup, and migration: We need your feedback November 2020 Impacts on GDEs Will be written as we progress (Feb 2021) Updated CommPlan (Notice and Communication)November Board Meeting Change in GW Storage Will be written as we progress (Feb 2021) Identification of Interconnected Surface Water Systems Will be written as we progress (Feb 2021) Identification of Groundwater-dependent Ecosystems Will be written as we progress (Feb 2021) Water Budget January 2021 Modeling Appendix January 2021 Water Quality Appendix November 2021 DRAFT GSP Writing and Review Proposed schedule to deliver the next chapters and subsections: ◼Chapter 3: Sustainability Management Criteria ⚫Individual SMCs will be delivered as they are planned. Ex. Water Quality and Subsidence SMC will be delivered by the end of Oct 2020 ◼Chapter 4: Projects and Management Actions ⚫Planned to be done and delivered by Apr-May 2021 ◼Chapter 5: Plan Implementation ⚫Planned to be delivered by June 2021 ⚫Will be most likely delivered as part of the draft GSP rollout DRAFT ◼Outreach Meetings Update ◼GSP Writing and Review: ⚫Review and commenting of draft Chapter 2 and schedule for next deliverables ⚫Revised proposed schedule for chapter delivery and review ◼Sustainable Management Criteria and Monitoring Network Design: Chronic Lowering of GW Levels and SW depletion ◼Future Scenarios Outline DRAFT Sustainability Indicators ✓✓ ◼Most can be linked to groundwater levels ◼Criteria set for one can affect others DRAFT SMCs within the Context of SGMA and GSP Goal: Sustainable Management of Basin Operate within Sustainable Yield Not Experience Undesirable Results Set Quantitative Criteria Implement Projects and Management Action SM C s DRAFT Establishing SMCs Picture Sourced from Corning Subbasin Presentation DRAFT SMCs Initial Design Process: ◼For each sustainability indicator: Narrative statement describing conditions that GSA wants to avoid Sets the stage for developing quantitative SMC metric Define Appropriate Geographic Area DRAFT SMCs Initial Design Process: ◼For each sustainability indicator: Define Appropriate Geographic Area •Analysis and written interpretation of the information, data, and rationale used to set the MTs •Describe the relationship between each SI’s own MTs and with other Sis’ MTs •How MTs would avoid impacts to adjacent basins •How they impact beneficial uses and users •How state, local, and federal standard relate to MTs. •Monitoring network designed to measure MTs. DRAFT •Undesirable results occur when conditions related to any of the six SIs become significant and unreasonable. •Will be used by DWR to determine whether the sustainability goal has been achieved. •It should be defined based on MTs. GSA has significant flexibility. •But it should be clear how impacts to beneficial uses and users were considered. SMCs Initial Design Process: ◼For each sustainability indicator: Define Appropriate Geographic Area DRAFT SMCs Initial Design Process: ◼For each sustainability indicator: Define Appropriate Geographic Area •Quantitative goals that reflect the basin’s desired groundwater conditions. •Should be set to provide a margin of operational flexibility between MT and MO to accommodate droughts, climate change, projects, etc. DRAFT Potential Paths to Sustainability DWR, 2016, Sustainable Management Criteria BMP DRAFT SMC at Representative Monitoring Point Maintain Sustainability for the next 30 years DWR, 2016, Sustainable Management Criteria BMP DRAFT Monitoring Networks ◼Why is it important? ⚫Measures progress toward the achievement of any management goal ⚫Sustainability criteria are defined based on the components of the monitoring network ◼May be different for each sustainability indicator ◼Must have sufficient temporal frequency and spatial distribution to: ⚫demonstrate short-term, seasonal, and long-term trends in basin conditions ⚫demonstrate progress toward achieving measurable objectives ⚫monitor impacts to the beneficial uses or users of groundwater ⚫monitor changes in groundwater conditions relative to Mos and MTs ⚫quantify annual changes in water budget components DRAFT Monitoring Networks: Density and Extent De t e r m i n i n g F a c t o r s Aquifer Characteristics GW pumpage and use Impacts to BUs Fluctuation and variability Proximity to projects or adjacent basins Multi-SI monitoring Access and safety “There is no definitive rule for the density of groundwater monitoring points needed in a basin.” UVGB: 59 sq miles DRAFT Monitoring Networks: Density and Extent Aquifer I Aquifer II Aquifer III “There is no definitive rule for the density of groundwater monitoring points needed in a basin.” DRAFT Representative Monitoring Points ◼A series of RMPs or a single RMP may be adequate to characterize a management area or basin. ◼RMPs should demonstrate similar levels, trends, and seasonal fluctuations to the surrounding monitoring wells in their represented area. The complete monitoring network is represented by black dots. DRAFTExisting and Planned Monitoring Network for Chronic Lowering of Groundwater Levels ◼GW levels will at least be collected in mid-October and mid-March. Frequency should be increased/adjusted based on the factors discussed. ◼Monitoring data must be sufficient and able to: ⚫map GW depressions, recharge areas, inside and along basin boundaries. ⚫determine changes in storage. ⚫demonstrate the interconnectivity between shallow GW and SW bodies ⚫map the effects of management actions ⚫characterize conditions and monitor adverse impacts as they may affect the beneficial uses and users identified within the basin. ◼Wells should be dedicated groundwater monitoring wells, preferably, with known construction information.The selection of wells should be aquifer- specific and wells that are screened across more than one aquifer should be avoided where possible. DRAFTExisting and Planned Monitoring Network for Chronic Lowering of Groundwater Levels ◼We want to rely on existing CASGEM and what we drill and/or instrument. We need to discuss with MCRCD and analyze the wells in detail. From our initial assessments: ⚫Existing: Max 50 CASGEM wells currently, 2 multi-depth wells (7 total) 40 have well depth and screen interval information, 48 have well depth 8 wells are screened in multiple aquifers or we are not 100% certain 25 Aquifer I: 4 Redwood Valley, 2 Southern Drainage, 14 Southern Ukiah, 5 Central Ukiah 9 Aquifer 2: 4 Redwood Valley, 2 Central Ukiah, 3 Southern Ukiah 6 Aquifer 3: 3 Redwood Valley, 3 Central Ukiah ⚫To be drilled: 3 approved: 1 layer 1 Redwood Valley, 1 Layer 1 and 1 multi-layer in southern Ukiah May add 1 multi-layer in Redwood valley and up to 2 in Central Ukiah (1 may be multi-layer) DRAFT SMC: Chronic Lowering of Groundwater Levels ◼All SMCs are interrelated ◼Consider basin conditions. We know we have gaps and model will be used later but we have to start somewhere and revise. ◼There is no wrong approach if justified by best available scientific and local knowledge ◼Remember the process: 1.Draft significant and unreasonable condition narrative 2.Set Minimum Thresholds at each RMP 3.Determine undesirable results as a combination of MTs 4.Set Measurable Objectives at each RMP with operational flexibility 5.Identify projects and management actions and assess their effectiveness 6.Iterate 1 to 5 based on new information and model simulations 7.Define path and interim milestones DRAFTSMC Development: 4. Determine Undesirable Results ◼A GSA can prove sustainability by avoiding Undesirable Results ◼Decide how to combine Minimum Thresholds into Undesirable Results ◼Considerations ⚫Impacts on beneficial users. ⚫What are the types of mitigations that can be enforced? ⚫What projects and management actions will be needed? ◼Iterative process: ⚫How does this undesirable result affect beneficial uses and users of groundwater? ⚫How does this undesirable result affect land use and property interests? ⚫Does the undesirable result adequately characterize conditions that are significant and unreasonable? DRAFT Example Significant and Unreasonable Condition Narrative from Other GSPs regarding LOWERING GROUNDWATER LEVELS ◼Cuyama Valley Basin Significant and unreasonable reduction in the long-term viability of domestic, agricultural, municipal, or environmental uses over the planning and implementation horizon of this GSP. ◼Salinas Valley Basin –180/400 ft Aquifer Public and stakeholder input identified historically low groundwater elevations as significant and unreasonable. •Are at or below the lowest observed groundwater elevations. •Cause significant financial burden to local agricultural interests. •Interfere with other sustainability indicators. ◼Santa Cruz Mid-County Basin A significant number of private, agricultural, industrial, and municipal production wells can no longer provide enough groundwater to supply beneficial uses. DRAFT As a reminder about sustainability indicators… •Measur able Objective: Goal that we want to strive for. •Minimum Thr eshold: Quantitative value reflecting what is significant and unreasonable.The line we don’t want to cr oss. DRAFT Sustainability Indicators: Examples from other GSPs Mid County Santa Cruz ◼Minimum thresholds: set based on the groundwater elevation required to meet the typical overlying water demand in the shallowest well in the vicinity of the RMP (no less than 30 ft below historical levels). Demand is calculated based on an experimental worksheet from Kansas Geological Survey. ◼Measurable objectives: the 75th percentile of historical groundwater elevations for the period of record of each monitoring point. ◼Interim milestones: Since the measurable objectives effectively represent current conditions, IMs were set at the same elevations as measurable objectives. DRAFT Sustainability Indicators: Examples from other GSPs Cuyama ◼Measurable objectives: set equal to the measurement taken closest to (but not before) January 1, 2015 and not after April 30, 2015. ◼Minimum thresholds: defined different regions and took the following approaches based on the regions: 1.The MT was calculated by subtracting 5 years of groundwater storage from the MO, which was calculated by finding the groundwater level declines during the 2013 -2018 drought. 2.The MT was calculated by taking the total historical range of recorded groundwater levels and used 35% of the range. This 35% was then added below the MO. ◼Interim milestones: were set to equal the MT in all incremental years between 2020 and 2040. DRAFT Sustainability Indicators: Examples from other GSPs Greater Kaweah ▪Minimum thresholds: set at water level projections for 2040 using same trend in GW levels from 2006 to 2016, which represents a more current trend, the recent groundwater pumping patterns and the historic five-year drought (2012-2016). ▪Measurable objectives: The intersection of the groundwater level projection and 2030, a point midway through the implementation period, was selected as the measurable objective for each well. ▪Interim milestones: were established in 2025, 2030, and 2035 to measure progress at these time intervals regarding groundwater level trends. DRAFTSMC Development: 4. Determine Undesirable Results ◼Example: Undesirable result is defined as 3 wells falling below MTs. Both pictures show undesirable result. However, left is still managed sustainably. DRAFT Looking at UVGB Based on our limited information we guessed they are screened in the first aquifer, but we need to investigate DRAFT Looking at UVGB DRAFT Looking at UVGB DRAFT Looking at UVGB DRAFT Aquifer I ◼Trends: No significant trend can be seen in any region other than seasonal fluctuations. No declines. ◼Data: Long-term data is scarce. ◼Monitoring Network: We propose to include all newly- drilled wells plus a subset of wells instrumented with continuous monitoring (pending agreement) for monthly or quarterly monitoring/reporting (between 6 to 8 wells). ◼Data Gaps: Some areas in the basin do not have any wells that should be noted. ◼RMPs: We initially (at least for this discussion) suggest choosing the shown RMPs for the three regions in the basin. We recommend switching these RMPs to the newly drilled wells as soon as enough data is collected, probably in the first 5 years. DWR Well 392962N1232047W001 Ukiah Valley-1 DWR Well 15N12W08L001M Ukiah Valley-10a DWR Well 391096N1231677W001 DRAFT Looking at UVGB DRAFT Aquifer II ◼Trends: Relatively declining trends in southern Ukiah Valley. Stable otherwise. ◼Data: Long-term data is not available. ◼Monitoring Network: We propose to include all newly- multi-screened drilled wells plus a subset of CASGEM wells (pending agreement) for quarterly to biannual monitoring/reporting (between 4 to 6 wells). ◼Data Gaps: Some areas in the basin do not have any wells that should be noted. ◼RMPs: We initially suggest all chosen CASGEM wells to be used as RMPs. We recommend switching these RMPs to the newly drilled wells as soon as enough data is collected, probably in the first 5 years. DRAFT Looking at UVGB DRAFT Aquifer III ◼Trends: Redwood Valley shows insignificant inclining trend. Central Ukiah is stable. ◼Data: Long-term data is not available. ◼Monitoring Network: We propose to include all newly-multi-screened drilled wells plus a subset of CASGEM wells (pending agreement) for quarterly to biannual monitoring/reporting (between 2 to 4 wells). ◼RMPs: We initially suggest all chosen CASGEM wells to be used as RMPs. We recommend switching these RMPs to the newly drilled wells as soon as enough data is collected, probably in the first 5 years. ◼Data Gaps: Some areas in the basin do not have any wells that should be noted. DRAFT Setting Sustainable Criteria ◼Consider: ⚫UVB does not suffer from chronic lowering of GW levels, water levels are relatively stable ⚫Seasonality is very important ⚫This SI is most likely affected by SW Depletion and GDEs ⚫Operational flexibility is very important due to seasonal changes and stable conditions ⚫Aquifer-specific and region-specific criteria must be set ◼Discuss and decide: ⚫Is there a need for defining hydrogeologic zones or management areas? ⚫What is the most suitable method(s) applicable to UVB ⚫Trend may not be appropriately applicable to all zones in UVB DRAFT Proposed Possible Approaches ◼Minimum Thresholds: ⚫For declining trends, project GW levels in 2042 and set that as MT. ⚫Minimum historical measurement. ⚫Levels close to January 1, 2015 minus a percentage of the seasonal variation or historical range. ⚫Average historical level minus the maximum continuous multi-year drawdown due to droughts ◼Measurable Objective: ⚫Average of historical measurements ⚫The 75th percentile of historical GW levels for the period of record. ⚫The measurement taken closest to but not before January 1, 2015. DRAFT Southern Ukiah Valley -15N12W34Q001M (Aquifer I) MO DTW- Year-round (ft) DTW– Low Season(ft) DTW– High Season(ft) Average of historical -26 -33.3 -18.9 75th percentile of historical range -34 -34.8 -22.1 March 25, 2015 -23.5 MT DTW (ft) Trend -36 Historical Min -37.2 Fall 2015 minus 25% of average historical range -39.6 Fall 2015 minus 25% of maximum seasonal range -39.6 Fall 2015-maximum continuous drawdown 39.3 DRAFT Southern Ukiah Valley -15N12W34Q001M (Aquifer I) 44 MO DTW-Year- round (ft) DTW– Low Season(ft) DTW– High Season(ft) Average of historical -21.8 -24.9 -18.9 75th percentile of historical range -24.9 -26.3 -20.5 March 25, 2015 -20.3 MT DTW (ft) Trend -25 Historical Min -30.1 Fall 2015 minus 25% of average historical range -31.6 Fall 2015 minus 25% of maximum seasonal range -31.6 Fall 2015-maximum continuous drawdown 33.2 DRAFT Redwood Valley -392962N1232047W001 (Aquifer I) 45 MO DTW-Year- round (ft) DTW– Low Season(ft) DTW– High Season(ft) Average of historical -13.6 -18.6 -9.2 75th percentile of historical range -15.5 -16.9 -10.3 March 25, 2015 -12 MT DTW (ft) Trend +5.64 Historical Min -57.8 (-17.4) Fall 2015 minus 25% of average historical range -19.3 Fall 2015 minus 25% of maximum seasonal range -19.3 Fall 2015-maximum continuous drawdown -22.6 392962N1232047W001 DRAFT Southern Ukiah Valley –UV-29a (Aquifer II) 46 MO DTW-Year- round (ft) DTW– Low Season(ft) DTW– High Season(ft) Average of historical -18.5 -15 -22 75th percentile of historical range -22.5 -22.5 -16.5 April 15, 2016 -13.745 MT DTW (ft) Trend -53.5 Historical Min -22.5 Fall 2016 minus 25% of average historical range -22.2 Fall 2016 minus 25% of maximum seasonal range -22.1 Fall 2016-maximum continuous drawdown -24.5 Ukiah Valley-29a DRAFTChronic Lowering of Groundwater Level Undesirable Result ◼Decide how to combine Minimum Thresholds into Undesirable Results ◼Iterative process: ⚫How does this undesirable result affect beneficial uses and users of groundwater? ⚫How does this undesirable result affect land use and property interests? ⚫Does the undesirable result adequately characterize conditions that are significant and unreasonable? DRAFT Groundwater Level Interim Milestones ◼Determines the path to sustainability and if the GSP is in compliance. ◼Is set in 5-year increments. ◼Possible approaches: ⚫If trend is used, interim milestones can be extrapolated. ⚫If GW levels are stable, interim milestones can be set at or close to MO with a trend that provides operational flexibility. ⚫Cuyama set milestones at equal to MT for all increments presumably not to fall out of compliance. DRAFT ◼Outreach Meetings Update ◼GSP Writing and Review: ⚫Review and commenting of draft Chapter 2 and schedule for next deliverables ⚫Revised proposed schedule for chapter delivery and review ◼Sustainable Management Criteria and Monitoring Network Design: Chronic Lowering of GW Levels and SW depletion ◼Future Scenarios Outline DRAFT Future Scenario Survey: Future Baseline ◼In order to generate a representative future baseline scenario, we need to form a 50-year period from the basin’s historical record. What would be the most representative 50-year baseline? Major Comments: ◼Last 50-years may be the least conservative because id does not take into account the most recent period. 25 is a bit of a middle ground. ◼Either 25-50 year periods are fine but we should look at how the water years are assigned with the Gamma Distribution. DRAFT Future Scenario Survey: Climate change here ◼Do you agree with using the DWR recommended approach to conduct the climate change simulations for the Ukiah Valley Basin GSP? If not, please provide your suggestion while also considering that additional time and budget needed to conduct different approaches may become significant. Major Comments: ◼A transient method would be more appropriate for evaluating potential impacts to Lake Mendocino and surface water flows in the main stem Russian River. ◼Include additional climate change simulations as may be available to the consultants and deemed relevant for this basin. DRAFT Future Scenario Survey: Changes to PVP ◼There is an expectation that PVP operations would change during the implementation period of the GSP. This scenario, or a set of scenarios, would simulate how those changes would impact the basin and the beneficial uses. Major Comments: ◼All respondents say it is helpful and we can run Sonoma Water scenarios. ◼No diversion, partial (winter only) diversion, and run of the river scenario should be run. ◼Everybody agrees it would not be immediate, responses from 5 to 15 years. ◼Everybody thinks we should combine it with other scenarios, including climate change, fish flow habitat, DRAFT Future Scenario Survey: Changes to PVP ◼A PVP Scenarios working group was convened and different approaches were discussed. ◼It was suggested that LWA conducts bookending scenarios to gauge the impacts to the extent possible. ◼Final 3 scenarios that were agreed upon are: ⚫Removal of the dam and no additional flows (worst-case scenario) ⚫No change ⚫Run of the river ◼All scenarios will be set up to happen in 15 years ◼Difficult issue is to estimate appropriate flows from CVD and PVP for different scenarios. DRAFT Future Scenario Survey: Changes in Land Use and Ag ◼There is a general expectation that cannabis cultivation would grow in the basin. This scenario would simulate such changes and how they might affect the water resources and beneficial uses within the basin. Major Comments: ◼Majority of respondents say it is not helpful/maybe helpful or not sure. ◼Review Upper Russian River/Lake Mendocino Reliability report. ◼Increased utilization of water rights in 20 years may cover for these scenarios. DRAFTFuture Scenario Survey: Urban expansion, population growth, and increase in demand ◼These three changes are codependent and will happen to some extent according to historical trends. This scenario would show the extent of the changes and how they would impact the basin, its water resources, and beneficial uses. Major Comments: ◼Majority of respondents say it is a helpful scenario. ◼Review Upper Russian River/Lake Mendocino Reliability report. ◼Not everyone agrees on the trend or if historical trends are representative. ◼Combine with PVP, land conversion, and climate change. DRAFT Future Scenario Survey: Recharge projects ◼There has been a consensus among TAC members on implementing recharge projects in the future. This scenario would simulate possible recharge projects and how they would impact the basin. Major Comments: ◼Majority of respondents say it is a helpful scenario. ◼Scale and location answer did not converge. ◼Step-wise and in small steps was emphasized for when it may happen. ◼Combine with PVP, RW, Ag land conversion, and climate change. DRAFTFuture Scenario Survey: Changes in Lake Mendocino Release ◼Changes in Lake Mendocino releases are expected to happen due to FIRO and other regulatory measures. This scenario would simulate how these changes would impact the basin. Major Comments: ◼Majority of respondents say it is a helpful scenario. ◼Most say to coordinate with Sonoma to the extent feasible. ◼Step-wise and in small steps was emphasized for when it may happen. ◼Combine with PVP, RW, Ag land conversion, and climate change. DRAFT Future Scenario Survey: Recycled Water ◼City of Ukiah has been implementing its Recycled Water project and is scheduled to expand it in the near future. This scenario would simulate the impacts of increased Recycled Water use within the basin. Major Comments: ◼Majority of respondents say it is a helpful scenario. ◼Follow the City’s plan. DRAFTScenario What we are required to have What we have now or planned as a default to have Proposed Improvements (may or may not be feasible) What is nice and ideal to have (mostly are not feasible) Future Baseline A 50-year representation 50-year repeat of historical baseline (could be changed to two 25-year) Coordinate with Sonoma Water to use the same arrangement A 50-year period that best represents the hydroclimate conditions and captures future expectations Climate Change Capture impacts of climate change using best available science and knowledge 2 DWR provided climate period analyses 2030 & 2070 Transient simulation of 50- year period using one GCM/RCP/Downscaling method scenario used in Sonoma basins A catalogue of transient simulations using all or many of the 20 GCM/RCP scenarios DWR used CVD Releases Best available science and information: forecast appropriate releases for each scenario Historical and future baseline using hard input measured by gages Using Sonoma ResSim or program and its outputs: requires matching climate data and diversions Coupled GSFLOW with ResSim or modified ResSim/Program with our data to produce accurate releases PVP PVP outputs based on reasonable possibilities to assist with setting SMCs and developing management actions Historical/future baseline input to basin from gages + worst case scenario of no inputs Using Sonoma ResSim and its scenarios for outputs: requires matching climate data and diversions Compatible ResSim for run- of-the-river and climate change scenarios with GSFLOW Overall for future scenarios Best available science and accurate representation of basin and possibilities to develop SMCs and MAs We are reliant on historical inputs and need to find a reasonable way to produce CVD and PVP future outputs To always couple CVD releases and mostly climate change scenarios based on what Sonoma has produced Compatible CVD and PVP release data with hydroclimate data we use in GSFLOW for all scenarios Can be fit in our current budget Depending on input data and conditions may be doable or may be time- consuming and not feasible Would add a month or more of work It will be long and most probably infeasible DRAFT Future Scenarios Discussion ◼Ideal scenarios (purple tasks) are not required but very nice to have. They could be run for the GSP in a longer horizon, ex. for the next interim milestone but will not be feasible to conduct for this round of GSP submittal. ◼With the current timeline, we will be able to probably conduct 1 or maybe 2 orange/red tasks and still successfully submit the GSP in time. ◼Orange tasks’ feasibility heavily depend on the type of input data available and the fit it provides into the model. If taken on, we may need to accept some uncertainty due to simplifications to be able to succeed. DRAFTSMC Introduction -Depletion of Interconnected Surface Waters ◼The minimum threshold metric for depletion of interconnected surface waters shall be a rate or volume of surface water depletions caused by groundwater use that has adverse impacts on beneficial uses of the surface water and may lead to undesirable results. ◼Minimum Threshold established for depletions of interconnected surface water shall be supported by the following: ⚫The location, quantity, and timing of depletions of interconnected surface water. ⚫A description of the GW and SW model used to quantify surface water depletion. ◼GSP Regulations allow GSAs to use groundwater elevation as a proxy metric for any of the sustainability indicators when setting minimum thresholds and measurable objectives. ⚫The GSP must demonstrate that there is a significant correlation between groundwater levels and the other metrics. DRAFTSMC Development: 1. Significant and Unreasonable Conditions ◼What to Consider: ⚫Who is impacted? ⚫What is the impact? Monetary and non-monetary nature of impacts? ⚫Spatial and temporal extent of the impact Example Beneficial Users Potential Impact Recreation Aquatic habitat Riparian habitat •Reduced flow •Loss of habitat •Loss/limitation of recreational potential DRAFT What is a Groundwater-Dependent Ecosystem? ◼Ecosystems that rely on surface expression of groundwater ⚫Springs ⚫Perennial wetlands ⚫Rivers that are receiving groundwater ◼Ecosystems that rely on subsurface presence of groundwater ⚫phreatophytes 63 ‘wetlands’ ‘vegetation’ DRAFTConsideration of GDEs as Groundwater Users for Developing SMC 64 From: TNC 2018 DRAFTWhere are we with regards to GDEs? ◼We used TNC’s map as a starting point for identification of GDEs and discussed in the GW/SW Working Group ⚫Consensus was that the map is not accurate ⚫We need your feedback in correcting the map ◼We presented a satellite imagery approach to assess GDEs. We are working based on that methodology and will present results. 65 DRAFTMonitoring Network Considerations for Depletion of Interconnected Surface Water ◼The monitoring network shall be able to characterize the following: ⚫Flow conditions including surface water discharge, surface water head, and baseflow contribution. ⚫Identifying the approximate date and location where ephemeral or intermittent flowing streams and rivers cease to flow, if applicable. ⚫Temporal change in conditions due to variations in stream discharge and regional groundwater extraction. ⚫Other factors that may be necessary to identify adverse impacts on beneficial uses of the surface water. ◼Use existing stream gaging and groundwater level monitoring networks to the extent possible. DRAFTMonitoring Network Considerations for Depletion of Interconnected Surface Water ◼Establish stream gaging along sections of known SW/GW connection ⚫Location selection must account for surface water diversions and return flows. ◼Establish a shallow groundwater monitoring well network to characterize groundwater levels adjacent to connected streams and hydrogeologic properties. ⚫Network should extend perpendicular and parallel to stream flow to provide adequate characterization to constrain model development. ⚫Monitor to capture seasonal pumping conditions in vicinity-connected surface water bodies. ◼Identify and quantify both timing and volume of groundwater pumping within approximately 3 miles of the stream or as appropriate for the flow regime. ◼Establish qualitative monitoring by use of GPS survey of the timing and position along stream where ephemeral or intermittent streams cease to flow. DRAFTSMC Development: 2. Set Minimum Thresholds ◼Considerations ⚫What are the historical rates of stream depletion for different water year types? ⚫What is the uncertainty in streamflow depletion estimates from analytical and numerical tools? ⚫What is the proximity of pumping to streams? ⚫Where are groundwater dependent ecosystems in the basin? ⚫What are the agricultural and municipal surface water needs in the basin? ⚫What are the applicable State or federally mandated flow requirements? DRAFT Examples from other GSPs Mid County Santa Cruz ◼Used groundwater elevation as a proxy. ◼Significant and unreasonable depletion of surface water due to groundwater extraction, in interconnected streams supporting priority species, would be undesirable if there is more depletion than experienced since the start of shallow groundwater level monitoring through 2015. ◼Minimum thresholds were set based on the GW elevations in shallow RMPs below which significant and unreasonable depletions of surface water due to GW extractions would occur. ◼Since significant and unreasonable conditions have not occurred since 2001, minimum thresholds are based on the highest historical seasonal-low elevation during below-average rainfall years. ◼Measurable objectives at RMPs are groundwater elevations greater than the MTs by the range in seasonal-low shallow elevations over the period of record through 2015. ◼The interim milestones for Water Years 2025, 2030, and 2035 are based on the minimum model simulated groundwater elevations over Water Years 2021-2025, Water Years 2026-2030, and 2031-2035, respectively. DRAFT Examples from other GSPs Cuyama ◼Used groundwater elevation as a proxy. ◼The Undesirable Result for depletions of interconnected surface water is a result that causes significant and unreasonable reductions in the viability of agriculture or riparian habitat within the Basin over the planning and implementation horizon of this GSP. ◼Because current Basin conditions have not varied from January 1, 2015 conditions, the groundwater level thresholds will act to maintain depletions of interconnected surface water at similar levels to those that existed in January 1, 2015. DRAFT What are we doing? ◼Collecting and assessing existing data (ex. From CLSI) to understand individual tributaries better and also calibrate model. ◼Developing GSFLOW to assist with this SMC. ◼Installing transects to form a reliable monitoring network and fill the gaps. ◼Using Satellite imagery as proxy monitoring/observation to generate flow/no- flow datasets and record historical conditions. ◼Using recently published functional flow database to understand the interconnection better. DRAFT What are we doing? Ex. McNab Creek 15-minute stream gage + monitoring well head data since 2012 Magnitude and direction of gradient affects loss/gain volumes DRAFT What are we doing? Ex. McNab Creek McNab Creek 1 DRAFT Thank you! Questions?