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HomeMy WebLinkAboutMarch 2020 TAC Meeting_Draft PresentationDevelopment of Sustainable Management Criteria for Ukiah Valley Groundwater Basin March 11, 2020 Ukiah Valley Basin Groundwater Sustainability Agency Technical Advisory Committee Meeting DRAFT DRAFT Agenda ◼GSP Development: technical work update ◼Sustainability Goal ◼Review of Sustainable Management Criteria (SMC) ⚫What will our process look like? ◼Current Groundwater conditions: Water Quality ⚫How can we set SMC for water quality? ◼Current conditions: Subsidence ⚫How can we set SMC for Subsidence? 2 Group discussion Group discussion Group discussion DRAFT Agenda ◼GSP Development: technical work update ◼Sustainability Goal ◼Review of Sustainable Management Criteria (SMC) ⚫What will our process look like? ◼Current Groundwater conditions: Water Quality ⚫How can we set SMC for water quality? ◼Current conditions: Subsidence ⚫How can we set SMC for Subsidence? 3 Group discussion Group discussion Group discussion DRAFT ◼MODFLOW updates ⚫Newton Solver (NWT) →needed for GSFLOW coupling. ⚫Unsaturated zone flow (UZF) →needed for GSFLOW coupling. ⚫Initial calibration →refined hydraulic properties and water budgets prior to coupling with GSFLOW. ⚫Review CLSI continuous well data →Inform temporal water-level trends Integrated model updates 4 DRAFT ◼PRMS updates ⚫Inclusion of ponds →improved representation of SW diversion timing. ⚫Review CLSI tributary stream gage data →Informs wet/dry behavior of tributaries. ⚫Updated irrigation patterns based on previous meeting was implemented and will be used for the Ag Package. Integrated model updates 5 Groundwater Surfae Water Groundwater Surface Water Groundwater Surfae Water 996 3005 1362 3074 2357 6079 11.8%35.6%16.1%36.4%27.9%72.1% 208 395 96 455 304 850 18.0%34.3%8.4%39.4%26.3%73.7% No Frost Protection With Frost Protection Total Grapes Pears DRAFT ◼GSFLOW updates ⚫Migrating MODFLOW and PRMS to GSFLOW executable ⚫Acquisition of GSFLOW Ag. Package from USGS →Currently reviewing workflow and capabilities. Integrated model updates 6 DRAFT ◼Leverage local expertise to inform development of “interconnected surface water” SMC ◼1st Meeting 2/24/2020 ⚫Definitions of a “healthy” and “unhealthy” surface water system ⚫Identifying existing studies and data sets ⚫Options for prioritizing monitoring locations and data collection ⚫Develop a plan for future SW Working Group meetings Surface Water Working Group update 7 DRAFT TSS and continuous measurements 8 ◼First round of wells are identified. ◼Agreements are being pursued. ◼First visit to be made late March and instrumentation begin in April. DRAFT TSS and continuous measurements 9 DRAFT TSS and continuous measurements 10 DRAFT Agenda ◼GSP Development: technical work update ◼Sustainability Goal ◼Review of Sustainable Management Criteria (SMC) ⚫What will our process look like? ◼Current Groundwater conditions: Water Quality ⚫How can we set SMC for water quality? ◼Current conditions: Subsidence ⚫How can we set SMC for Subsidence? 11 Group discussion Group discussion Group discussion DRAFT Overview of GSP Structure A GSP has five chapters: 1.Introduction 2.Plan Area and Basin Setting 3.Sustainable Management Criteria 4.Projects and Management Actions 5.Plan Implementation 12 DRAFT Initial Exploration of a Sustainability Goal Key SGMA text (GSP Emergency Regulations 354.24) “Each agency shall establish in its Plan a sustainability goal for the basin that culminates in the absence of undesirable results” 13 DRAFT Initial Exploration of a Sustainability Goal 1.If groundwater is sustainably managed in Ukiah Valley, what has it achieved and what does it look like? 2.What does the worst-case scenario look like in Ukiah Valley if groundwater is not managed sustainably? 3.Give us your perspective but also think about how others view the issue? 14 DRAFT Examples of Sustainability Goals from Other GSPs 15 ◼Mid-County Santa Cruz GSP: ⚫Manage the groundwater Basin to ensure beneficial uses and users have access to a safe and reliable groundwater supply that meets current and future Basin demand without causing undesirable results to: ➢Ensure groundwater is available for beneficial uses and a diverse population of beneficial users; Protect groundwater supply against seawater intrusion; ➢Prevent groundwater overdraft within the Basin and resolves problems resulting from prior overdraft; ➢Maintain or enhance groundwater levels where groundwater dependent ecosystems exist; ➢Maintain or enhance groundwater contributions to streamflow; ➢Support reliable groundwater supply and quality to promote public health and welfare; DRAFT Examples of Sustainability Goals from Other GSPs 16 ◼Mid-County Santa Cruz GSP (cont.): ⚫Manage the groundwater Basin to ensure beneficial uses and users have access to a safe and reliable groundwater supply that meets current and future Basin demand without causing undesirable results to: ➢Ensure operational flexibility within the Basin by maintaining a drought reserve; ➢Account for changing groundwater conditions related to projected climate change and sea level rise in Basin planning and management; ➢Do no harm to neighboring groundwater basins in regional efforts to achieve groundwater sustainability. ◼Salinas GSP: ⚫The goal of this GSP is to manage the groundwater resources of the 180/400- Foot Aquifer Subbasin for long-term community, financial, and environmental benefits to the Subbasin’s residents and businesses. This GSP will ensure long-term viable water supplies while maintaining the unique cultural, community, and business aspects of the Subbasin. It is the express goal of this GSP to balance the needs of all water users in the Subbasin. DRAFT Agenda ◼GSP Development: technical work update ◼Sustainability Goal ◼Review of Sustainable Management Criteria (SMC) ⚫What will our process look like? ◼Current Groundwater conditions: Water Quality ⚫How can we set SMC for water quality? ◼Current conditions: Subsidence ⚫How can we set SMC for Subsidence? 17 Group discussion Group discussion Group discussion DRAFT GSP: Monitoring and Managing Sustainability Sustainability Indicators Mo n i t o r i n g Measurable Objective (MO) Minimum Threshold (MT) modified from Ca DWR 2016 Triggers DRAFT Review of Sustainable Management Criteria Components ◼Undesirable Results ◼Minimum Thresholds ◼Measurable Objectives ◼Sustainability Goal Measurable Objective Threshold Undesirable Results DRAFT EXAMPLE DRAFT Review of Sustainable Management Criteria Components ◼Undesirable Results ⚫Must be “Significant and Unreasonable” ⚫Statement that describes conditions that we do not want to happen ⚫Defined for each sustainability indicator ◼(e.g. groundwater levels, groundwater quality, etc.) Measurable Objective Threshold Undesirable Results DRAFT EXAMPLE DRAFT Review of Sustainable Management Criteria Components ◼Minimum Thresholds ⚫Anything worse is considered an “undesirable result” ⚫The lowest a basin can go without something significant and unreasonable happening to groundwater Measurable Objective Threshold Undesirable Results DRAFT EXAMPLE DRAFT Review of Sustainable Management Criteria Components ◼Measurable Objectives ⚫A management target that provides a usable buffer for use during droughts, etc. ⚫Establishes the upper targeted boundary for basin management ⚫Should provide a reasonable margin of operational flexibility 22 Measurable Objective Threshold Undesirable Results DRAFT EXAMPLE Operational flexibility DRAFT ◼Begin development of Sustainable Management Criteria (SMC) for the Ukiah Valley Groundwater Basin, a key SGMA requirement ◼Review/ensure broad understanding of SGMA concepts ⚫Sustainability Indicators ⚫Undesirable Results ⚫Measurable Objectives, Triggers, Thresholds, Interim Milestones ⚫Overarching Sustainability Goal ◼Introduce/discuss a proposed SMC development process ◼Describe and initially discuss key sustainability indicator: Water Quality Today’s Objectives DRAFT Related SGMA Activities that Inform Sustainable Management Criteria ◼Understand the basin setting: ⚫Hydrogeologic conceptual model ⚫Current and historical conditions ⚫Estimated water budget ⚫Potential management areas ◼Inventory existing monitoring programs and evaluate and build potential representative monitoring points ◼Engage interested parties (i.e. beneficial uses and users of groundwater) DRAFT ◼Assess which of the six sustainability indicators are applicable for the Ukiah Valley Groundwater Basin ◼Develop narrative (qualitative) descriptions of what constitutes significant and unreasonable conditions (i.e. locally unacceptable conditions) ◼Translate narrative descriptions into quantitative values = undesirable results and minimum thresholds ◼Determine desirable conditions = measurable objectives ◼Set interim milestones in order to achieve measurable objectives ◼Define an overarching sustainability goal Proposed SMC Development Process DRAFT Advisory Committee to propose SMC for each undesirable result (UR) Which undesirable results are controversial? What thermometer looks like? Technical team will summarize existing data and describe options Proposed SMC Development Process DRAFT ◼GOAL:Ukiah Valley Sustainable Management Criteria developed ⚫Issues around each topic (indicator) identified and explored ⚫Interests of beneficial uses and users considered ⚫Measurable objectives, triggers, thresholds, and interim milestones defined ⚫Buy in to overarching sustainability goal ◼Technical GSP pieces complete (e.g. hydrology) ◼Groundwater management responses developed if triggers or thresholds are crossed (next phase of work) ◼Stakeholder communication and engagement throughout entire process Culmination of Process and Next Steps DRAFT Preliminary SMC Development Schedule March 2020 •Sustainability goal •Water Quality SMC: Build thermometer, what’s healthy/what’s unhealthy May 2020 •Water quality SMC: Refine discussion as needed, focus on scenarios and actions, close on the thermometer •Subsidence SMC: Build the thermometer, what’s healthy and what’s unhealthy →quick discussion •SW depletion SMC: terrestrial GDEs →Build thermometer, what’s healthy/what’s unhealthy July 2020 •SW depletion SMC: SW/GW interactions→Build thermometer, what’s healthy/what’s unhealthy DRAFT Questions and Comments DRAFT Agenda ◼GSP Development: technical work update ◼Sustainability Goal ◼Review of Sustainable Management Criteria (SMC) ⚫What will our process look like? ◼Current Groundwater conditions: Water Quality ⚫How can we set SMC for water quality? ◼Current conditions: Subsidence ⚫How can we set SMC for Subsidence? 30 Group discussion Group discussion Group discussion DRAFT SUSTAINABLE MANAGEMENT CRITERIA –WATER QUALITY 31 DRAFT Outline ◼What do we need to do? ◼Water Quality Regulatory Framework ◼Technical Approach, gathered data, and information ◼Example Sustainable Management Criteria development process 32 DRAFT What will we need to do? ◼What to measure ◼Where to measure ◼When to measure ◼Who will measure ◼What is healthy vs. unhealthy for our basin? 1. Decide MOs “Healthy” range 2. Decide trigger levels: “warning” 3. Decide minimum threshold: “critical unhealthy” level DRAFT Water Quality Regulatory Framework Clean Water Act Porter-Cologne Act EPA Regulations State Plans Basin Plans •Water Quality Objectives •Permits •TMDLs Federal (Surface Waters)State (Surface and GW) Laws Regulations, Plans and Policies Implementation DRAFT Water Quality Responsibilities U.S. Congress State Legislature EPA Headquarters State Water Resources Control Board Regional Water Quality Control Boards Federal State Laws Regulations Implementation DRAFT SGMA Requirement ◼§345.28 (c) (4) Degraded Water Quality. “The minimum threshold for degraded water quality shall be the degradation of water quality, including the migration of contaminant plumes that impair water supplies or other indicator of water quality as determined by the Agency that may lead to undesirable results. The minimum threshold shall be based on the number of supply wells, a volume of water, or a location of an isocontour that exceeds concentrations of constituents determined by the Agency to be of concern for the basin. In setting minimum thresholds for degraded water quality, the Agency shall consider local, state, and federal water quality standards applicable to the basin.” DRAFT ◼What is a “significant and unreasonable undesirable result” ◼Monitoring & Metrics: ⚫Review and approve shortlist of constituents to be included in the GSP ⚫Are we still missing existing data? ⚫Review existing and potential future groundwater quality monitoring network programs available to be used in GSP ◼Review and discuss options to set SMC for the shortlisted constituents ⚫Thresholds ⚫Measurable objectives ⚫Projects and management actions Our Focus now: provide recommendations on SMC for Water Quality DRAFT Existing Groundwater Quality Monitoring Programs and Networks ◼Public water supply wells ⚫Monitored regularly for key water constituents ◼State small public water supply wells ⚫Monitored regularly, but less frequent than PWS wells for some water constituents ◼Domestic wells ⚫Only sporadic monitoring, if any ◼Agricultural/irrigation wells ⚫Only sporadic monitoring, if any ◼Monitoring wells ⚫At contamination sites to guide/assess remediation 38 DRAFT Existing Water Quality Data Repositories ◼SWRCB GAMA Groundwater Information System ◼County environmental health department ◼Public water supply systems ◼USGS (NWIS) ◼U.S. EPA (STORET) ◼California DWR ◼California DPR 39 DRAFT What is already included in GAMA ◼The Department of Pesticide Regulation (DPR) ◼Department of Water Resources (DWR) ◼GAMA -Domestic Wells ◼GAMA –Special Studies ◼GAMA –Priority Basin Project ◼Monitoring Wells (Water Board Regulated Sites) ◼Public Water System Wells (State Water Board - Division of Drinking Water) ◼U.S. Geological Survey (USGS) National Water Information System 40 DRAFT California Water Quality Regulations pertinent to Groundwater in Ukiah Valley ◼North Coast Basin Plan Water Quality Objectives refer to the Title 22 Regulations for MUN use, but add criteria for Bacteria, Radioactivity, and Taste and Odors. No Groundwater objectives DRAFT California Water Quality Regulations pertinent to Groundwater in Ukiah Valley Maximum Contaminant Levels (MCLs) to protect drinking water ◼Primary MCLs –e.g. Nitrate ◼Not-to-exceed standards to protect human health ◼Secondary MCLs –e.g. Iron ◼Non-enforceable guidelines to achieve consumer acceptance (e.g. taste, odor, or color) ◼May have a range of acceptable values (e.g. Recommended, Upper, Short Term) Notification Level (NL) for Boron set by California Division of Drinking Water DRAFT Ukiah Valley: Data Selection and Approach to Create preliminary list of Constituents ◼MCL, Basin Plan water quality objective, or human health-related level exists for the constituent ◼Consider only data from the last 30 years ◼Focus on water quality parameters confirmed by multiple measurements ◼Constituent either (a) shows exceedances of a threshold, (b) shows a strong likelihood of exceeding a threshold, or (c) is commonly addressed in other GSPs. 43 DRAFT Ukiah: Data Selection and Approach ◼Databases pulled from ◼Groundwater Ambient Monitoring and Assessment Program (GAMA) ◼California Integrated Water Quality System (CIWQS) ◼Total number of wells ◼629 wells with water quality data ◼384 wells with water quality data from 1990-2020 ◼Parameters ◼207 unique analytes ◼Time period (earliest to latest) ◼11/11/1950 –11/25/2019 DRAFT Chemicals of Concern: Examples ◼Screen parameters down to a reasonable number for further analysis and for setting minimum thresholds and measurable objectives ⚫Boron ⚫Iron ⚫Manganese ⚫Nickel ⚫Nitrate ⚫Specific Conductance ⚫Other Basin-specific analytes ? 45 Other draft GSP examples DRAFT MCLs, NLs, and WQOs for a handful of Chemicals of Concern 46 Constituent Units Applicable Regulation Regulatory Threshold Boron, Total mg/L DW Notification Level 1.0 Iron, Total µg/L Secondary MCL 300 Manganese, Total µg/L Secondary MCL 50 Nickel, Total µg/L Primary MCL 100 Nitrate mg/L as N Primary MCL 10 Specific Conductance µmhos/cm Secondary MCL 900 (Recommended) 1,600 (Upper) 2,200 (Short Term) DRAFT Background on Constituents of Concern Found in Groundwater ◼Boron –Naturally occurring element found in groundwater primarily as a result of leaching from rocks and soils containing borates and borosilicates. ◼Iron –Abundant element in the earth’s crust that is found in groundwater in its dissolved form; concentrations can be elevated due to mining operations, industrial waste, and corroding metal. ◼Nitrate –Nitrogen is very prevalent in the earth’s crust; nitrates are found in groundwater as a result of the applications of nitrate-containing fertilizers, feedlot discharges, treated and untreated sewage, and emissions from industrial processes; nitrates/nitrites affect the oxygen carrying capacity of hemoglobin, thyroid gland function, and vitamin A retention. 47 DRAFT Background on Constituents of Concern Found in Groundwater ◼Manganese –Occurs naturally as a mineral from sediment and rocks or from mining and industrial waste. ◼Specific Conductivity –The salinity of water is commonly measured indirectly as a water’s ability to pass electrical flow. Conductivity measured at –or normalized to –25º Celsius is called specific conductivity. Salinity is the total concentration of all dissolved salts in water. ◼Nickel –is naturally occurring in soil and surface water but some activities like industrialization, sewage, use of chemical fertilizer, pesticides etc. increase the concentration in environment. 48 DRAFT What will our process look like? Advisory Committee to propose SMC for each undesirable result (UR) Which undesirable results are controversial? What thermometer looks like? Technical team will summarize existing data and describe options DRAFT Who Measures and When to Measure What Monitoring Network ◼Options for GSP: A.GSA uses public supply well and contaminant site monitoring well data reported by to SWRCB under existing WQ monitoring program B.Option A PLUS expanded ambient monitoring network to address data gaps 50 DRAFT ◼What is a monitoring network? ◼Established for each sustainability indicator: ⚫Groundwater levels and quality ⚫Subsidence ⚫Surface water-groundwater interaction ◼Includes monitoring wells, stream gauges, subsidence measurements ◼Will have spatial and temporal components: ⚫How many wells and how spread out are they? ⚫How frequently are they measured? ◼Able to provide data relative to undesirable results What makes a good monitoring network? 51 DRAFT What to Measure -Constituents of Concern ◼Existing example Draft GSP screening process (i.e. how some other GSPs identified their “list”) ⚫Utilized existing Regional Monitoring Program (RMP) constituents of concern ⚫Evaluated all regulated drinking water constituents to determine only constituents with known water quality issues within the sub- basin ⚫Evaluated only a select number of water quality constituents based on review of data, local stakeholder input, and regulatory agency input ⚫All screening processes included known groundwater contamination sites and plumes 52 DRAFT What Metric to Use for the “Thermometer” Options: ◼Averages ◼Medians ◼Statistical trends over time ◼Number of wells with exceedances ◼Volume fraction of groundwater basin with exceedances 53 Example MCL Example Dataset DRAFT What Metric to Use for the “Thermometer” Options: ◼Averages ◼Medians ◼Statistical trends over time ◼Number of wells with exceedances ◼Volume fraction of groundwater basin with exceedances 54 Example MCL Example Dataset DRAFT What Metric to Use for the “Thermometer” Options: ◼Average ◼Median ◼Statistical trends over time ◼Number of wells with exceedances ◼Volume fraction of groundwater basin with exceedances 55 Example MCL Example Dataset DRAFT What Metric to Use for the “Thermometer” Options: ◼Averages ◼Medians ◼Statistical trends over time ◼Number of wells with exceedances ◼Volume fraction of groundwater basin with exceedances 56 Example MCL Example Dataset DRAFT What Metric to Use for the “Thermometer” Options: ◼Averages ◼Medians ◼Statistical trends over time ◼Number of wells with exceedances ◼Volume fraction of groundwater basin with exceedances 57 Example MCL Example Dataset DRAFT What Metric to Use for the “Thermometer” ◼Example from Salinas Valley GSP ⚫Minimum Threshold =# of exceedances of drinking water standards ⚫Measurable Objective = Minimum Threshold 58 DRAFT What Metric to Use for the “Thermometer” ◼Example from Mid County Santa Cruz GSP ⚫Minimum Threshold = state drinking water standards 59 DRAFT What Metric to Use for the “Thermometer” ◼Example from Mid County Santa Cruz GSP ⚫Measurable Objectives = Multi-year trends at individual wells in network 60 DRAFT What Metric to Use for the “Thermometer” ◼Promising Options for GSP A.Threshold sets at the MCL B.Long-term trends at individual wells in network 61 DRAFT Where to Measure (monitoring network) 62 Limiting to at least 5 data points per well for illustrative purposes Data? DRAFT Groundwater Quality in Ukiah Valley Historical Conditions for the Six Constituents of Concern (COCs) 63 DRAFT Ukiah Iron 1)All wells with data within the basin (72 wells) Colors based on Primary MCL for Iron; highest measured value in well Red = Above 300 µg/L (43) Yellow = 150 –300 µg/L (20) Green = Below 150 µg/L (140) DRAFT Ukiah Iron 1)All wells with data within the basin (72 wells) 2)Restrict data to within the past 30 years (53 wells) Colors based on Primary MCL for Iron; highest measured value in well Red = Above 300 µg/L (36) Yellow = 150 –300 µg/L (17) Green = Below 150 µg/L (115) DRAFT Ukiah Iron 1)All wells with data within the basin (72 wells) 2)Restrict data to within the past 30 years (53 wells) 3)Restrict data to wells with 2 or more data points (30 wells) Colors based on Primary MCL for Iron; highest measured value in well Red = Above 300 µg/L (31) Yellow = 150 –300 µg/L (13) Green = Below 150 µg/L (101) DRAFT * Iron concentration in Well 2300606-004 in 2015 is about 15,000 µg/L. DRAFT DRAFT DRAFT DRAFT Ukiah Nitrate as N ❑All wells with data within the basin (43 wells) Colors based on Primary MCL for Nitrate; highest measured value in well Red = Above 10 mg/L (1) Yellow = 5 –10 mg/L (2) Green = Below 5 mg/L (515) ❑Nitrogen is very prevalent in the earth’s crust; nitrates are found in groundwater as a result of the applications of nitrate- containing fertilizers, feedlot discharges, treated and untreated sewage, and emissions from industrial processes; nitrates/nitrites affect the oxygen carrying capacity of hemoglobin, thyroid gland function, and vitamin A retention. DRAFT DRAFT DRAFT Ukiah Boron ❑All wells with data within the basin (15 wells) Colors based on Notification Levels demonstrated in California Division of Drinking Water; highest measured value in well Red = Above 1 mg/L (0) Yellow = Above 0.5 mg/L (2) Green = No exceedance (42) ❑Naturally occurring element found in groundwater primarily as a result of leaching from rocks and soils containing borates and borosilicates. DRAFT 75 DRAFT 76 DRAFT Ukiah Manganese ❑All wells with data within the basin (29 wells) Colors based on CCR Title 22; highest measured value in well Red = Above 50 ug/L (42) Yellow = Above 25 ug/L (14) Green = No exceedance (84) ❑Occurs naturally as a mineral from sediment and rocks or from mining and industrial waste. DRAFT * Manganese concentration in Well 2300606-005 in 2012 is about 2,800 µg/L. DRAFT * Manganese concentration in Well 2310003-028 in 2009 is about 1,300 µg/L. DRAFT DRAFT DRAFT Ukiah Nickel ❑All wells with data within the basin (26 wells) Colors based on CCR Title 22; highest measured value in well Red = Above 0.2 ug/L (2) Yellow = Above 0.1 ug/L (0) Green = No exceedance (139) ❑Nickel is naturally occurring in soil and surface water but some activities like industrialization, sewage, use of chemical fertilizer, pesticides etc. increase the concentration in environment. DRAFT DRAFT DRAFT Ukiah Specific Conductivity ❑All wells with data within the basin (44 wells) Colors based on CCR Title 22; highest measured value in well Red = Above 1000 mg/L (9) Yellow = Above 500 mg/L (24) Green = No exceedance (278) ❑The salinity of water is commonly measured indirectly as a water’s ability to pass electrical flow. Conductivity measured at –or normalized to –25º Celsius is called specific conductivity. Salinity is the total concentration of all dissolved salts in water. DRAFT DRAFT DRAFT DRAFT Example Dataset SMC Option A: Threshold = MCL 89 Triggers Threshold (MT) Measurable Objective (MO) DRAFT Example Dataset SMC Option B ◼Long-term (30 year) trend ⚫Is either negative (downward) ⚫Or does not increase by more than 0.1 unit-per-year over the current (1990-2020) trend 90 Triggers DRAFT Key Tasks/Needed Input ◼Think about what’s important in the valley and what we need to examine. Which are the parameters that need to be considered in this basin? Brainstorms are valuable. ◼How would you like this data to be represented? ◼We need to decide which groundwater wells to monitor. ◼We need to determine minimum threshold (maximum), trigger and measurable objectives. ◼What to measure, where, when, and who will measure (and how to measure). 91 DRAFT GOAL ◼Work on summary tables and development of SMC! 92 DRAFT Question? 93 DRAFT Agenda ◼GSP Development: technical work update ◼Sustainability Goal ◼Review of Sustainable Management Criteria (SMC) ⚫What will our process look like? ◼Current Groundwater conditions: Water Quality ⚫How can we set SMC for water quality? ◼Current conditions: Subsidence ⚫How can we set SMC for Subsidence? 94 Group discussion Group discussion Group discussion DRAFT SUSTAINABLE MANAGEMENT CRITERIA –SUBSIDENCE 95 DRAFT Subsidence of the land surface is an undesirable result for SGMA Lowering groundwater levels Reduction in storage Seawater intrusion Degraded water quality Land subsidence Surface water depletion DRAFT DRAFT Subsidence data available for Mendocino Co. InSAR satellite-derived subsidence data product is the only known dataset for Mendocino Co. to use for GSPs Data available from mid 2015- 2018 Additional 2018-2019 data expected by April 2019 DRAFT DRAFT 98 Data shown are within these two color zones InSAR-derived and calibrated to CGPS stations across CA DRAFT Subsidence data available for Mendocino Co. DRAFT Subsidence data for Ukiah Valley 99 DWR assessed that there was no documented groundwater-extraction induced subsidence of concern DRAFT DRAFT 100 Subsidence data for Ukiah Valley 2015-2018 DRAFT InSAR error from calibration and conversion is ~0.1 ft DRAFT 101 Subsidence data for Ukiah Valley 2015-2018 DRAFT InSAR error from calibration and conversion is ~0.1 ft Data display largely noise considering the range of both the data and the error are equivalent DRAFT Thank you! Questions?