Groundwater Sustainability Agency

ASGSA Advisory Committee Special Meeting Greenfield Civic Center 599 El Camino Real Greenfield, CA 93927 Special Meeting Agenda January 8, 2020 3:00 P.M. Your courtesy is requested to help our meeting run smoothly. Please follow the following rules of conduct for public participation in the meetings: · Refraining from public displays or outbursts such as unsolicited applause, comments or cheering. · Any disruptive activities that substantially interfere with the ability of the Agency to carry out its meeting will not be permitted, and offenders will be requested to leave the meeting. PLEASE TURN OFF CELL PHONES AND PAGERS 1. PUBLIC COMMENTS REGARDING ITEMS ON THE AGENDA – A three-minute time limit may be imposed on all speakers. 2. APPROVAL OF MINUTES OF THE NOVEMBER 13, 2019 MEETING 3. CONSIDER RELEASING THE REVISED ARROYO SECO GROUNDWATER SUSTAINABILITY AGENCY (ASGSA) GROUNDWATER SUSTAINABILITY PLAN CHAPTER 6 TO THE PUBLIC FOR COMMENT AND POSTING ON THE ASGSA WEBSITE a. Report b. Public Comments c. Committee – Review / Comments / Action 4. CONSIDER ARROYO SECO GROUNDWATER SUSTAINABILITY AGENCY GROUNDWATER MONITORING PLAN AND PROVIDE STAFF DIRECTION a. Report b. Public Comments c. Committee – Review / Comments / Action 5. RECEIVE GENERAL MANAGER’S REPORT AND OTHER ITEMS a. Report b. Public Comments c. Committee – Review / Comments / Action 6. ADJOURNMENT In compliance with the American With Disabilities Act, if you need special assistance to participate in this meeting, please contact the City Clerk at (831) 674-5591. Notification 48 hours prior to the meeting will enable the City to make reasonable arrangements to ensure accessibility to the meeting (CFR 35.102-35.104 ADA Title II). ********************************************************************************* This agenda is duly posted outside City Hall and on the City of Greenfield web site  ASGSA Advisory Committee Meeting Minutes, November 13, 2019 Those in attendance: Committee members Tim Frahm, Allan Panziera, Michael Griva, Roger Moitoso, John Huerta, Nancy Isakson, Travis Cochrane and General Manager Curtis Weeks. 1. Public Comments: none 2. Approval of Minutes of the October 9, 2019 meeting: Action: John Huerta motion to approve minutes with; Roger Moitoso seconded it; and motion passed. 3. Review of ASGSA GSP Chapter 6. Curtis gave an overview of Chapter 6 and development of the GSP and Gus Yates was on the conference line to provide an overview and answer questions. Gus presented each section of Chapter 6 and the Advisory Committee discussed each section. The following are items that the Committee agreed needed revision and asked Curtis and Gus to work on the revisions, and have ready for review at the next Committee meeting. The Committee requested that the revised draft Chapter 6 be sent to them prior to the next meeting so they could have time to fully review. Revisions: Mgmt Action #1: * Add and highlight language to work/collaborate with others to participate in the HCP and any Drought Operations Plan * Work with other/organizations to operate reservoirs to benefit of fishery resources and landowners -- and consider 'winter release' scenario Mgmt Action #2: * reframe irrigation element to support changes that are occurring; focus on existing good practices 1 * Work with others to provide education in areas that need assistance where there is over spray, wind-control timing of sprinklers with windy conditions, * highlight urban water softeners * development of partnership on irrigation efficiency Mgmt Action #3: * point to existing program initial by city to connect small systems into their water system * revise to include alternatives to bottled water * continue to work with city to improve rural domestic water quality Mgmt Action #4: * 6.5.1-- add "and its tributaries" * need to look at 'wild and scenic' designation * seek opportunities to protect watershed * Tim said he would look at revising language on this and sending to Curtis * need to look at not including those lands of private property (when putting in certain protections) ----------------------- 4. DWR Grant: Curtis gave an update on the status of submitting the Grant and his and Tim’s discussions with Gary and Donna of the SVBGSA regarding the Grant. Curtis is following up with Gary to get a copy of the SVBGSA’s grant. 5. Co-ordination Agreement with SVBGSA: Curtis gave an update on the status of a co-ordination agreement. He said he has asked to meet with 2 the Executive Committee of the SVBGSA in January and then meet with the ‘larger’ facilitated group to provide an overview of the ASGSA and a co- ordination agreement, what it would do/mean to both the SVBGSA and the ASGSA. 6. General Manager’s Report: Curtis said he was going to look at the November and December board and committee meeting dates and would send an email as to the meetings. He said that he is still working on getting the extraction reports the committee had said they wanted Gus to use rather than the land use basis. Meeting adjourned Respectfully Submitted, Nancy Isakson 3 6 PROJECT AND MANAGEMENT ACTION DETAILS Groundwater conditions in the ASGSA area benefitting from the Arroyo Seco River are sustainable. The ASGSA area near the Salinas River with potential undesirable results are associated with 1) excessive water-level declines during droughts, and 2) gradual, long-term increases in groundwater salinity. ASGSA has developed several management actions to address those issues. To be consistent with terminology used in other Salinas Valley GSPs, “management action” in this GSP refers to policies and planning/feasibility studies that do not involve construction of new infrastructure. The term “projects” refers to activities that require new or modified infrastructure. Per SGMA Regs §354.44, the basic description of what the action is and how it would be implemented is followed by a checklist of specific characteristics, such as circumstances triggering its implementation, timetable, cost, etc. Following the selected management actions is a review of the list of specific potential actions SGMA requires “where appropriate”. 6.1 GENERAL PROVISIONS All of the actions are policies or feasibility/planning studies. None of them are contingent on exceedances of minimum thresholds or other triggers, which is to say that ASGSA intends to initiate and probably complete all of them during the first 5-year GSP implementation period. Public notice of implementation is therefore provided by this GSP. One management action (Management Action 4) might be delayed in order to obtain grant funding and might be terminated if initial analysis indicates that permitting would be infeasible. Management of groundwater extractions is not included as an action because it is unnecessary in the ASGSA area. Current levels of groundwater extraction—or more specifically, consumptive use—are sustainable. 6.2 MANAGEMENT ACTION 1: RESERVOIR REOPERATION 6.2.1 Description of Action Reoperation of Nacimiento and San Antonio Reservoirs could prevent a recurrence of the exceptionally low groundwater levels that occurred in the ASGSA area near Salinas River (not influenced by Arroyo Seco River) during the latter part of the 2012-2016 drought. Those low levels resulted from three consecutive years without major reservoir releases and caused undesirable results for well operators (a reduction in well output) in that particular area. The prolonged lack of surface flow also caused undesirable impacts on riparian vegetation and possibly on steelhead migration. By changing the timing of major releases before and during droughts, it may be possible to avoid limiting those releases for more than two consecutive years. The reservoirs are owned and operated by MCWRA pursuant to an appropriative water right permit issued by SWRCB. The permit was last updated in 2008, when terms were added implementing the steelhead flow prescription developed in 2007 by NMFS. ASGSA does not have the direct authority to Arroyo Seco DRAFT Groundwater Sustainability Plan 1 Todd Groundwater modify reservoir operation, and MCWRA does not have the authority to alter the flow prescription and certain other aspects of reservoir operation, including the flood pool reservation in San Antonio Reservoir and San Luis Obispo County’s use of its 17,500 AFY entitlement to Nacimiento yield. MCWRA has some discretion in managing releases for downstream groundwater recharge and diversion at the SRDF, which collectively comprise most of the water released from the reservoirs. The groundwater recharge and diversion at the SRDF are considered part of the Salinas Valley Water Project (SVWP) and landowners within the Zone 2C assessment district pay assessment in order to receive these benefits pursuant to the Prop. 218 vote for the SVWP. This management action consists of collaborating with the MCWRA and other interested parties to evaluate potential reoperation scenarios to ensure the sustainability of the lands near Salinas River within the ASGSA and to prevent the undesirable results that occurred during the recent drought. MCWRA committed itself to embarking on such a process in the 2018 update to its Nacimiento Dam Operation Plan: “A Drought Contingency Plan describing reservoir operations will be incorporated into this document after such a plan is developed in collaboration with NMFS, other regulatory agencies, and stakeholders, reviewed by the Reservoir Operations Advisory Committee, and adopted by the Agency Board of Directors.” This management action could be implemented in conjunction with an interagency effort to develop a habitat conservation plan for steelhead. NMFS withdrew its biological opinion for steelhead in 2019, but the flow prescription remains in MCWRA’s water rights permit. It is our understanding that MCWRA is in the initial steps of developing a habitat conservation plan to replace the biological opinion. The ASGSA could be a participant in the HCP process. Three examples of reoperation strategies that could potentially avoid consecutive years without major reservoir releases are: • Increase the amount of annual reservoir carryover storage in normal and wet years so that more storage is on hand at the start of a drought. This could decrease the amount of water released for recharge and SRDF diversions in normal/wet years in order to increase the amount released during droughts and potentially affect the special benefits paid by Zone 2C landowners. • Develop quantitative operational criteria that differentiate “surplus” water from non-surplus water. SWRCB recently affirmed that MCWRA’s water rights permit only allows surplus flow to be stored in the reservoirs, which is flow not needed to replenish groundwater downstream of the reservoirs (SWRCB 2019). Two moderate inflow events were retained in the reservoirs in January and March 2016 that downstream groundwater users assert were not surplus flows. If those natural flows had been passed through the reservoirs the exceptionally low groundwater levels that occurred that year might have been avoided. The 2018 Nacimiento Dam Operation Plan does not mention the issue of surplus water or pass-through of natural inflows under certain circumstances. • Implement the Winter Release Scenario developed by the Salinas Valley Water Coalition, which would release water as needed to maintain a flow of at least 155 cfs in the Salinas River near Spreckels whenever flow at the Arroyo Seco near Soledad gauge is greater than 173 cfs. Arroyo Seco DRAFT Groundwater Sustainability Plan 2 Todd Groundwater These strategies are not mutually exclusive, and others are possible. A quantitative analysis tool will be essential to support any discussion of reservoir reoperation. This typically is a reservoir operations model. One was developed by consultants, known as Salinas Valley Integrated Groundwater Simulated Model (SVIGSM) to support evaluation of the Salinas Valley Water Project, but it might not be available. Reservoir operations are reportedly included in a large hydrologic model of the Salinas River, reservoirs and groundwater basin being developed by the U.S. Geological Survey. That work is still in progress, however, and the availability and usability of the final model is uncertain. In order to apply “best available science” to the analysis of reoperation scenarios, this management action includes working with the MCWRA to improve existing models or developing new ones to simulate reservoir operations and groundwater-surface water interactions along the Salinas River. 6.2.2 Expected Benefits This management action will benefit the measurable objectives for water levels and interconnected surface water. Specifically, the benefits of reservoir reoperation are 1) maintaining an adequate discharge rate for wells near the Salinas River throughout drought periods by avoiding excessively low groundwater levels, 2) reducing the mortality of riparian trees along the Salinas River to some amount less than occurred by the end of 2016, and 3) increasing steelhead migration opportunity to above the amount that occurred during 2012-2016, possibly providing an additional year of reproductive success. The above benefits would be regional in scope. The water-level benefits would occur throughout the Upper Valley and Forebay Subbasins, and the vegetation and fish benefits would apply to the entire length of the Salinas River. Developing up-to-date, publicly available and reasonably user-friendly reservoir operations analysis tools would benefit MCWRA, NMFS, GSAs, consultants, environmental groups and others involved in water resources management in the Salinas Valley. 6.2.3 Circumstances for Implementation Evaluation and development of reservoir operations analysis tools are underway. ASGSA intends to initiate coordination with MCWRA as soon as possible. 6.2.4 Legal Authority ASGSA has the authority to conduct investigations (Water Code §10725.4), such as this investigation of reservoir reoperation. It can request but not mandate that MCWRA participate in a joint evaluation of reoperation strategies. MCWRA has the authority—within the constraints of its water rights permits—to modify the scheduling of releases for groundwater recharge and SRDF diversions. 6.2.5 Implementation Schedule Evaluation and adoption of a revised reservoir operation plan could take 1-2 years of meetings, technical analysis, environmental review and public process. If reoperation for ASGSA purposes is subsumed into a larger habitat conservation planning process, the schedule could stretch to 3 years. 6.2.6 Estimated Cost The estimated cost for participating in quarterly interagency meetings and intervening e-mail exchanges is $30,000 per year. The initial cost to enhance or develop modeling tools is estimated to be $30,000. If Arroyo Seco DRAFT Groundwater Sustainability Plan 3 Todd Groundwater ASGSA continues to provide modeling services for the interagency group, the cost would rise accordingly. Thus, the total cost for a 2-year effort would be on the order of $90,000-$120,000. 6.3 MANAGEMENT ACTION 2: SALINITY MANAGEMENT STUDIES 6.3.1 Description of Action Gradual, long-term increases in groundwater salinity in the Salinas River area were identified as unsustainable. Parts of the ASGSA area already have groundwater salinity high enough to impair crop growth or restrict crop selection. The highest existing TDS concentrations derive from natural sources (brackish groundwater entering the basin from the Pancho Rico Formation along the northeast side of the Salinas Valley). However, evaporation and transpiration of irrigation water adds significant amounts of additional salt to the basin when salts are flushed below the root zone by rainfall recharge or excess applied irrigation water. Another potential source of salt loading is self-regenerating water softeners, which are probably common in Greenfield given the high hardness of the municipal water supply. This management action consists of completing a water softener management study and collaborating with other groups and agencies to accelerate the implementation of agricultural technologies and practices that decrease salt loading to groundwater and adapting to gradual long-term increases in salinity. The agricultural strategies would be potentially applicable throughout California. ASGSA’s role in this management action would be to actively seek participation in regional or statewide efforts. Management Action 2A: Water Softener Management Study. A residential self-regenerating water softener typically adds about 40 pounds of salt per month to the household wastewater stream. This salt passes through the wastewater treatment process. Treated effluent from the City of Greenfield wastewater treatment plant is percolated via ponds near the Salinas River northeast of the City. Those ponds are upgradient of the City of Soledad, which means that salt loading from water softeners in Greenfield adds to the salinity of the municipal water supply in Soledad and other down-gradient cities and towns. Cartridge-type water softeners are an alternative to self-regenerating water softeners. Ion exchange is by means of a resin that stays in the water softener tank. A service company periodically replaces a used cartridge with a fresh one. The used cartridges are regenerated offsite where the resulting brine discharge is not a problem (such as discharging to an ocean outfall). This study will commence with an inventory of water softener use in Greenfield based on the salinity of influent to the wastewater treatment plant, estimates of salt sales from local vendors and interviews with residents and local officials. If the salt load is significant, the availability and cost of cartridge-type water softeners will be ascertained. A plan for adopting an ordinance prohibiting self-regenerating water softeners will be prepared and provided to the City Council for possible adoption. Ordinances passed by Los Angeles County Sanitation District and the requirements of AB1366 (2009) will be used as guidelines. If the Greenfield salt load is significant, this suggests that other municipalities may be similarly contributing to salt loading. A subsequent appropriate action is to encourage King City public works personnel and the City Council to implement a similar water softener conversion program, which would decrease ambient salinity of groundwater flowing into the ASGSA area. Arroyo Seco DRAFT Groundwater Sustainability Plan 4 Todd Groundwater Management Action 2B: Collaboration on Reducing Agricultural Salt Loading and Adapting to Higher Groundwater Salinity. Agricultural activities tend to increase groundwater salinity, particularly where groundwater is the source of irrigation supply. Typically, the largest salt load is not from an addition of dissolved minerals but from evaporative concentration of applied irrigation water, which removes pure water and leaves dissolved minerals behind. Those minerals remain in the soil and are periodically flushed downward below the root zone by rainfall or excess applied irrigation water (the “leaching fraction”). This relatively high-TDS recharge water eventually migrates downward to the aquifer strata tapped by wells. The water gets pumped again, applied for irrigation and subjected to a second round of evaporative concentration. Salinity can continue to increase until it reaches an equilibrium determined by the rates and salinities of other sources of recharge and the magnitudes of other outflows from the system. Application of fertilizers and gypsum to agricultural fields are additional inputs of dissolved minerals associated with agriculture. Long-term increases in groundwater TDS concentration in the San Joauin Valley have averaged about 1 mg/L per year over the past century (Hansen and others, 2018). Groundwater salinity in the ASGSA area has not exhibited a statistically detectable increase over the past 60 years (see Appendix E), but current and future agricultural activities will continue to increase groundwater TDS to a level that will likely become detectable and to some extent problematic. Improvements in irrigation application efficiency decrease salt loading without reducing water available to crop roots. Evaporation of sprinkler spray and from bare soil are examples of irrigation inefficiencies that contribute to salt loading. Salinas Valley growers have improved irrigation efficiency over the past 25 years, largely by converting from spray or furrow irrigation to drip irrigation. The increase in vineyard acreage has contributed to this improvement in overall irrigation efficiency because that crop is always drip-irrigated (except for frost protection). However, vegetable crops still account for 78 percent of total irrigation water use in the Forebay Subbasin (MCWRA, 2017). An example of possible future improvements in irrigation efficiency would be more widespread use of low-evaporation sprinklers, such as the low-energy precision applicator (LEPA) type of linear move sprinklers. By emitting water at low pressure with large droplets just above the crop canopy, this irrigation method decreases overall irrigation water use and salt loading and even more dramatically decreases energy use (with attendant reductions in greenhouse gas emissions and grower cost). In addition to reducing salt loading, adaptation to rising groundwater salinity is a reasonable salinity management strategy. This would consist of developing salt-resistant varieties of crops grown in the ASGSA area. Groundwater salinity increases gradually, and the pace of agricultural research might be able to keep up with it. Developing salt-tolerant crop strains through traditional breeding or biotechnology would allow continued production of the vegetable crops for which the Salinas Valley climate is particularly well suited. However, the pace of progress depends partly on research priorities and funding. ASGSA is not a logical agency to fund and lead crop research efforts, but it could reasonably collaborate with other agricultural interests to promote and fund additional research. ASGSA’s commitments under this management action are: 1) Work with MCWRA, cooperative extension specialists and others to provide grower education regarding irrigation efficiency best management practices. 2) Actively identify and collaborate with growers, other water management agencies, irrigation equipment designers and vendors and agricultural extension specialists to refine and implement Arroyo Seco DRAFT Groundwater Sustainability Plan 5 Todd Groundwater  irrigation methods and practices that increase irrigation efficiency and decrease salt loading to groundwater. 3) Actively identify and collaborate with other agencies, grower groups and researchers to promote additional research aimed at developing salt-resistant crop strains. 6.3.2 Expected Benefits This management action will benefit the measurable objective for groundwater quality. Improving irrigation efficiency would have three benefits: decreased groundwater salinity, increased water use efficiency and decreased greenhouse gas generation. Promoting research to develop salt-tolerant strains of crops grown in the ASGSA area would increase the long-term viability of local agriculture by maintaining good crop yields and a broad range of crops that can be grown. Eliminating the salt load from self-regenerating water softeners would decrease ambient groundwater salinity downgradient of the Greenfield wastewater treatment plant. If half of the homes in Greenfield have self-regenerating water softeners using 40 pounds per month of salt, converting those to cartridge- type softeners would decrease the TDS concentration of municipal wastewater by about 350 mg/L. This would amount to 444 tons per year of avoidable salt loading. Reducing the TDS concentration of municipal recycled water would also greatly increase its potential reuse for irrigation. Because the Greenfield wastewater treatment plant is in the northeastern corner of the ASGSA area, most of the benefits would be to groundwater users to the north, notably the City of Soledad. If outreach to King City results in similar measures there, ambient groundwater salinity would be reduced in the southeastern part of the ASGSA area, near the Salinas River, where existing salinity concentrations are highest. 6.3.3 Circumstances for Implementation ASGSA is committed to completing the water softener study and irrigation efficiency collaboration efforts. No conditions need to be met prior to initiating them. 6.3.4 Legal Authority ASGSA has the authority to conduct studies (Water Code §10725.4). Pursuant to AB1366, cities have the authority to ban self-regenerating water softeners provided certain findings are made and the RWQCB concurs. 6.3.5 Implementation Schedule The water softener study will be completed during the first 5-year GSP implementation period. If the results indicate significant benefits and reasonable cost-effectiveness of converting from self- regenerating to cartridge-type water softeners, active implementation will be pursued during the second 5-year period. 6.3.6 Estimated Cost The cost of the water softener study is estimated to be $12,000. A commitment of 1 day per week of ASGSA staff time to engage in coordination activities related to grower education, irrigation technology refinement and crop salt tolerance research would cost roughly $20,000 per year. The total cost for the first five-year implementation period would be $112,000. Arroyo Seco DRAFT Groundwater Sustainability Plan 6 Todd Groundwater 6.4 MANAGEMENT ACTION 3: IMPROVE RURAL RESIDENTIAL WATER QUALITY 6.4.1 Description of Action Rural residents supplied by on-site domestic wells are more likely to have poor-quality water because the quality is rarely tested, unregulated and usually from relatively shallow aquifers that typically have lower-quality water. Strategies for mitigating this situation include: • Buying bottled water for drinking. • Installing point-of-use under-counter reverse osmosis (RO) units at the kitchen sink to provide drinking water. • Extend the City’s municipal water supply system to serve nearby rural residences. In recent years, the City has extended water service to some nearby rural residences, and its water master plan includes expansion of the municipal service area to new development around the perimeter of the existing urban area (Wallace Group, 2016). This management action consists of educating rural residents about common groundwater quality issues and options for obtaining safe and aesthetic potable water in their homes. 6.4.2 Expected Benefits This management action does not exactly address the measurable objective for water quality but does improve beneficial uses. None of the strategies has a beneficial or adverse impact on groundwater quality, but all of them improve potable water quality at rural residences. The dissolved minerals removed by RO units are returned to the groundwater basin via the septic system, resulting in no net change in groundwater quality. 6.4.3 Circumstances for Implementation Rural homeowners may purchase bottled drinking water or install an RO unit at any time. Many RO units are readily available in home improvement stores and online. The City’s Water Master Plan already intends to expand the distribution system. No further action is necessary, but service to more outlying could be considered. 6.4.4 Legal Authority ASGSA has the authority to make non-binding recommendations of any kind. Homeowners do not need a permit to install an RO unit. 6.4.5 Implementation Schedule The timing of bottled water purchases or installation of an RO unit is up to the rural resident. The Water Master Plan includes a schedule for expanding the municipal potable water supply distribution system. 6.4.6 Estimated Cost Under-counter RO units typically cost several hundred dollars. Handy homeowners can do their own installation. Otherwise, a plumber can do the installation in 1-2 hours, at prevailing rates. Bottled water is ubiquitously available in local markets at a range of prices. Arroyo Seco DRAFT Groundwater Sustainability Plan 7 Todd Groundwater 6.5 MANAGEMENT ACTION 4: OPPOSE NEW DAMS ON THE ARROYO SECO 6.5.1 Description of Action This action consists of adopting a policy to actively oppose construction of new dams on the Arroyo Seco River and its tributaries. The action also recommends support of State or Federal designations for the Arroyo Seco River which disallow dams or disallow activities which modify the Arroyo Seco River’s natural hydrograph or which disallow degradation of water quality/flow beyond current baseline. Activities associated with this management action include participating in local, regional and state-level water planning processes to oppose any new dams in the Arroyo Seco watershed and or advocacy for appropriate protective designations, such as wild and scenic status for the river. The U.S. Forest Service recommended federal wild and scenic designation in a 2005 study, but Congress has not yet acted on the recommendation (Ventana Wilderness Alliance, 2019). This management action would likely entail monitoring the planning processes via the internet, participating in interagency meetings to develop a steelhead Habitat Conservation Plan, reviewing and commenting on draft planning documents and/or environmental compliance documents prepared by other agencies, seeking funding for watershed protection efforts, and occasionally attending meetings for planning processes led by other agencies. 6.5.2 Expected Benefits This management action would benefit the measurable objectives for water levels, water quality and interconnected surface water. Groundwater users in the ASGSA receive significant water supply and quality benefits from the unregulated flow regime of the Arroyo Seco. It supplied more groundwater recharge to the ASGSA area during the 2012-2016 drought than did the regulated Salinas River. The salinity of Arroyo Seco water is also low, and recharge from the Arroyo Seco River has created a region of high-quality groundwater that covers most of the ASGSA area. In addition, there are very significant environmental benefits to maintaining the Arroyo Seco River in a natural state. The Arroyo Seco River is recognized as a Class 1 Recovery stream for threatened South-Central Coast Steelhead. It is the largest unregulated tributary to the Salinas River and is relatively close to the coast. As a result, it has the greatest potential for sustaining steelhead populations in the Salinas River watershed. 6.5.3 Circumstances for Implementation The ASGSA Board may pass this policy at any time. No prior conditions need to occur prior to implementing this action. 6.5.4 Legal Authority This management action consists of advocacy in the context of public proceedings. No special authority is required. 6.5.5 Implementation Schedule This management action would be implemented as needed on an ongoing basis. The level of activity would likely be sporadic. If an HCP process gets underway, it would be reasonable to assume that it might last three years. 6.5.6 Estimated Cost The estimated cost for staff or consultant time to monitor and participate in the planning activities of other agencies is $10,000 per year. Active participation in a steelhead HCP process would be largely Arroyo Seco DRAFT Groundwater Sustainability Plan 8 Todd Groundwater covered by the cost for Management Action 1, but it could entail an additional $10,000 per year if additional experts are supported. 6.6 ADDITIONAL GSP ELEMENTS Water Code §10727.4 requires that a GSP “shall include, where appropriate” the following list of potential management actions. Many of them are inherited from groundwater management plan requirements pursuant to AB3030. The applicability and utility of each action for ASGSA area sustainability are described below. a) Control of saline water intrusion. Intrusion is not an issue in the ASGSA area because of its inland location. b) Wellhead protection areas and recharge areas. The concept of wellhead protection areas originated with the 1986 Amendments to the federal Safe Drinking Water Act (SDWA). The California Department of Health Services (DHS), Division of Drinking Water and Environmental Management subsequently incorporated wellhead protection into its Drinking Water Source Assessment Program (DWSAP). Permitting of a new public water supply well requires that a DWSAP be completed, which is the responsibility of the permit applicant. Thus, wellhead protection is already implemented through an existing regulatory program that applies to the ASGSA area. Recharge area protection is a resource management strategy of the California Water Plan. Its focus is on localized, high-rate percolation from stream channels or off-channel recharge basins. This GSP includes two management actions involving management and enhancement of recharge. The reservoir reoperation management action would change the timing of percolation from the Salinas River. The Arroyo Seco winter recharge management action would evaluate the feasibility of increasing recharge at moderate rates by applying water diverted from the Arroyo Seco in winter to agricultural fields where conditions are favorable for percolation. c) Migration of contaminated groundwater. Local contamination of groundwater by human activities is regulated by the State and Regional Water Quality Control Boards, which mandate clean-up actions. The Regional Water Quality Control Board also enforces the Irrigated Lands Regulatory Program, which is designed to reduce nitrate contamination from excess fertilizer applications to negligible levels. The City of Greenfield’s municipal water system is subject to the requirements for providing water below the primary (such as nitrate) and secondary (such as TDS) maximum contaminant levels to its customers. This GSP includes management actions to address groundwater salinity, which is elevated over broad areas due to natural sources and irrigation and may affect growers. d) A well abandonment and well destruction program. Well construction and destruction are regulated by Monterey County Health Department (see Section 2.2.2.5 “Permitting of Well Construction and Destruction”). No additional management actions are needed. e) Replenishment of groundwater extractions. This element is covered by Management Action 1: Evaluate Reservoir Reoperation. By changing the timing of recharge from the Salinas River, that Arroyo Seco DRAFT Groundwater Sustainability Plan 9 Todd Groundwater  management action would prevent undesirable results during droughts. Recharge would also be increased by Management Action 4: Enhance Arroyo Seco Winter Recharge. f) Implementing conjunctive use or groundwater storage. Surface water in the Arroyo Seco and Salinas Rivers are already conjunctively used with groundwater in the ASGSA area. Other than reservoir reoperation (Management Action 1), no further action is needed to achieve full sustainability. g) Well construction policies. See item (d) above. h) Measures addressing groundwater contamination cleanup, groundwater recharge, in-lieu use, diversions to storage, conservation, water recycling, conveyance and extraction projects. These activities are not needed or are already managed by existing agencies and programs: cleanup of contaminated groundwater (State and Regional Water Quality Control Boards), , conservation (see the LEPA sprinkler feasibility study in Management Action 2), water recycling (not needed at present; salinity constraints), conveyance and extraction projects (not needed). i) Efficient water management practices. The LEPA sprinkler feasibility study in Management Action 2 would improve agricultural water use efficiency. j) Efforts to develop relationships with state and federal regulatory agencies. Reservoir reoperation analysis (Management Action 1) will entail close interaction with MCWRA. ASGSA will be interacting with the Central Coast Regional Water Quality Control Board regarding water softener issues and effective implementation of the ILRP program for nitrate reduction for the small number of rural residents not served by the City’s water system.. ASGSA intends to participate with the National Marine Fisheries Service in developing a Habitat Conservation Plan for steelhead trout if or when that effort gets underway. k) Review of land use plans. The City of Greenfield already reviews regional land use plans. l) Reduced impacts on groundwater dependent ecosystems. As discussed in Section 4.9 “Interconnected Surface Water”, GDEs in the ASGSA area are sustainable with respect to groundwater. No specific action is needed at this time to reduce impacts on groundwater dependent ecosystems. Arroyo Seco DRAFT Groundwater Sustainability Plan 10 Todd Groundwater 5 MONITORING NETWORK DETAILS 5.1 INTRODUCTION The objective of the monitoring program described in this chapter is to demonstrate whether sustainability is being achieved or maintained and whether beneficial uses and users of groundwater are being impacted. It identifies variables to be measured, monitoring sites, monitoring protocols, and the frequency of measurement necessary to evaluate changes in the sustainability indicators for all six categories of undesirable results. The monitoring program must be capable of “collecting sufficient data to demonstrate short-term, seasonal and long-term trends in groundwater and related surface conditions” (GSP Regulations §354.34(a)). For this GSP, the program for each indicator reflects whether the changes of concern are slow and gradual (such as increases in ambient groundwater salinity) or episodic (such as drought- related water-level declines). Most types of data needed to monitor sustainability are already being collected by other agencies on an ongoing basis. ASGSA does not wish to duplicate those efforts, but only supplement them where needed. Furthermore, ASGSA does not wish to store information in a local database that is already maintained in and available from the source agency’s database. For that reason, ASGSA’s data management system only stores new data collected by ASGSA and data required to be submitted electronically as part of the annual reporting process to DWR. Table 5.1-1 lists monitoring data that were used to prepare this GSP and that will be used in the monitoring program. Some of them are needed to develop the water balance but do not directly measure sustainability indicators. The data can be accessed from source agencies each year to prepare annual reports and every five years to update the GSP. 5.2 MONITORING FOR WATER LEVELS MCWRA’s existing water-level monitoring program includes 42 wells in and near the ASGSA area, at the locations shown in Figure 5.2-1. These are the wells used to define minimum threshold water levels (see Table 4.4-1). MCWRA’s monitoring network has several shortcomings that need to be remedied to achieve a program adequate for SGMA. Monitoring program enhancements to remedy the shortcomings are described below: 5.2.1 Public Availability of Data Except for the three CASGEM well locations, water level data collected by MCWRA are confidential pursuant to MCWRA Ordinance Nos. 3663, 3696 and 3717. ASGSA will remedy this limitation during the first year of implementation by contacting the owners of private wells measured by MCWRA and asking permission to make the data public. If a significant number of well owners decline, ASGSA will seek cooperative well owners in nearby locations to maintain a similar density and geographic coverage of measured wells. Arroyo Seco GSP ADMINISTRATIVE DRAFT 1 January 3, 2020 5.2.2 Geographic Data Gaps MCWRA measures only one well in the upper part of the Arroyo Seco Cone (well 19S/06E-11C01). The steep water level gradient in that area is poorly defined and is where most of the storage fluctuation in the ASGSA area occurs. ASGSA will fill this data gap by seeking three existing wells in that region (probably one in the lower end of the Arroyo Seco Canyon and two in the upper-cone area). The general regions for additional wells are circled in Figure 5.2-1. Insofar as possible, monitoring sites will be consistent with standards described in GSP Regulations §352.4(c) or the necessity of the site will be explained. 5.2.3 Interconnected Surface Water Gaps Except for the three CASGEM well sites, wells monitored by MCWRA are water supply wells screened at least tens of feet and commonly hundreds of feet below the water table. Shallow monitoring wells that measure the true water table elevation are needed near the Arroyo Seco and Salinas River channels to support conclusions regarding when and where groundwater is hydraulically connected to surface water. During the first five-year GSP implementation period ASGSA will install two shallow wells next to each waterway at locations where interconnection is likely (see general locations on Figure 5.2-1). 5.2.4 Measurement Frequency and Season The CASGEM wells have data loggers that record water levels every 15 minutes. MCWRA measures water levels at five other locations monthly. All of the other wells are measured annually in November or December. Those annual data were sufficient to identify transient water-level declines that caused undesirable results in the evaluation of groundwater conditions in Chapters 3 and 4. Annual data would continue to suffice for that purpose. However, GSP Regulations explicitly require at least semi-annual measurements that coincide with the seasonal low and high water levels (§354.34(c)(1)(B)). MCWRA (2015) identified August as the month when the annual minimum water level typically occurs and December or January or February as the most common month for the annual high water level. ASGSA will meet with SVBGSA and MCWRA in the first year of GSP implementation to coordinate the timing of measurements and to determine whether MCWRA can change and/or add measurement dates in the ASGSA area. If not, ASGSA staff will make the additional measurements needed for SGMA compliance; ASGSA measurements will be consistent with MCWRA protocols (MCWRA, 2015). 5.2.5 Well Construction and Reference Point Elevations MCWRA has well depth information for about 80 percent of the monitored wells in the ASGSA area. GSP regulations state that well depth and screened intervals should be known for all wells included in a monitoring program (§352.4(c)(1)(D)). While desirable, this information is not necessary for water-level monitoring in the ASGSA area because the basin is a single aquifer unit in the area and because water levels from the existing network were adequate to identify undesirable results in Chapters 3 and 4. The three CASGEM nested well sites near the Arroyo Seco provide information regarding vertical gradients near that waterway, and the new riparian zone water table monitoring wells will provide additional similar information. The regulations also state that reference point elevations should be measured to the nearest 0.5 foot or less or use the “best available information” (§352.4(a)(4)). Reference point elevations of wells in MCWRA’s existing program are mostly estimated from digital elevation models with lower accuracy (particularly given that reference points for measuring water levels are often one or more feet above the ground). While desirable, more precise surveyed reference point elevations are not necessary in the Arroyo Seco GSP ADMINISTRATIVE DRAFT 2 January 3, 2020 ASGSA area because the total change in water level across the area is usually 50 feet and because undesirable results are defined by changes in water levels over time at individual wells rather than gradients between wells. 5.2.6 Monitoring Protocols MCWRA follows CASGEM protocols for making water level measurements (MCWRA 2015). Those same protocols will be used for any measurements made by ASGSA. Those protocols do not fully address the problem of residual drawdown from recent pumping when water supply wells—especially irrigation wells—are measured. ASGSA will investigate possible additional procedures for determining the amount of time since a well was last operated. 5.2.7 Nexus with Sustainability Criteria The minimum threshold and measurable objective for water levels are defined in terms of measured water levels at the wells included in the monitoring program. Semiannual measurements at those wells will reveal whether the minimum threshold is exceeded, which occurs when 15 percent or more of the monitored wells have water levels below the December 2015 water levels. 5.3 MONITORING FOR GROUNDWATER STORAGE Groundwater storage is correlated with groundwater levels but refers to a volume of water. It is not measured directly but calculated as the difference between total inflows and total outflows in the water budget. The monitoring program for groundwater storage consists of updating the annual water budget for the ASGSA area each year and reporting the estimated net change in storage. 5.3.1 Monitoring Protocols Updating the annual storage change estimate involves repeating the calculations described in Section 3.3 “Water Budget Information” using current-year data. Data for precipitation, evapotranspiration, land use, stream flow and municipal pumping will be obtained from agencies that monitor those variables. The data will be processed through the rainfall-runoff-recharge model and the groundwater flow model to obtain an estimate of net change in groundwater storage over the year. Agricultural pumping is one of the largest items in the water budget. Operators of wells with discharge pipes three or more inches in diameter are required to measure their annual production and report it to MCWRA. Data for individual users are confidential, but MCWRA can publish summaries of aggregated data. The groundwater model requires pumping information by well. ASGSA will meet with MCWRA during the first year of GSP implementation to arrange procedures for using and reporting the pumping data. For the purposes of this section, pumping data need not be reported, only the net change in groundwater storage as an annual value. Thus, model output for storage change can be made public without revealing the individual pumping data that goes into the model. Calibration of the groundwater model raised questions about the accuracy of MCWRA’s agricultural pumping data. There was a marked discrepancy between pumping estimated from crop water demand prior to the early 1990s and pumping reported by well owners since then. Similar discrepancies between expected and measured pumping have been found in other basins, such as in northern San Benito County (Todd Groundwater, 2015). To address this potential data gap, ASGSA will approach MCWRA during the first year of GSP implementation to explore options for confirming data accuracy, such as by independent meter audits or comparison with field-scale, remotely-sensed evapotranspiration data. It is Arroyo Seco GSP ADMINISTRATIVE DRAFT 3 January 3, 2020 worth noting that the draft GSP for the 180/400-Foot Subbasin makes a similar statement: “A potential data gap is the accuracy and reliability of reported pumping rates. SVBGSA will work with MCWRA to evaluate methods currently in place to assure data reliability.” 5.3.2 Nexus with Sustainability Criteria The ASGSA area is sustainable with respect to groundwater storage as long as water levels do not fall chronically below their minimum thresholds. The minimum threshold is defined as 58,800 AF of cumulative storage decline during a drought, which is the simulated decline during 2013-2015 (see Section 4.5 “Groundwater Storage”). The annual storage change estimates from the monitoring program will be compared with this threshold. 5.4 MONITORING FOR SEAWATER INTRUSION Seawater intrusion is not an issue in the ASGSA area because of its inland location. Therefore, seawater intrusion will not be monitored. 5.5 MONITORING FOR SUBSIDENCE Subsidence will be monitored using the digital maps of cumulative subsidence since 2015 stored on DWR’s SGMA Data Viewer website. It is assumed that DWR will continue to compile updated subsidence maps at least annually. 5.5.1 Monitoring Protocols ASGSA will annually download updated raster maps of InSAR data showing cumulative subsidence since 2015 from the SGMA Data Viewer website (https://sgma.water.ca.gov/webgis/ ?appid=SGMADataViewer#landsub ). Pixels in the ASGSA area will be evaluated for colors indicating high cumulative subsidence and color contrasts indicating high local differential subsidence. 5.5.2 Nexus with Sustainability Criteria The cumulative subsidence shown on the InSAR maps is the variable used to define the sustainability criteria. No additional calculations are necessary. Pixel values will be compared with the minimum threshold criteria: more than 10 percent of pixels in the image for spring of the current year are more than 1 ft lower than in the May 2015 image, or at least five pairs of pixels within one mile of each other exhibit a local gradient greater than 0.001. 5.6 MONITORING FOR WATER QUALITY The water quality monitoring program presented here is designed to track trends and comply with SGMA requirements. However, no management actions are contingent on whether minimum thresholds are exceeded. As explained in Section 4.8.2 “Minimum Threshold”, ambient water quality takes decades to respond to changes in loading. Consequently, water quality over the next several decades is more likely to deteriorate than improve regardless of what management actions are taken in the near future. Furthermore, some wells already exceed the minimum thresholds for nitrate or salinity, which are the two major constituents of concern. Accordingly, this GSP will immediately implement management actions to reduce salt loading and adapt to elevated salinity, regardless of measured concentrations. Arroyo Seco GSP ADMINISTRATIVE DRAFT 4 January 3, 2020 5.6.1 Monitoring Protocols ASGSA will annually retrieve water quality data collected by the Irrigated Lands Regulatory Program for wells in the ASGSA area. Those data can be accessed from the SWRCB Geotracker website (https://gamagroundwater.waterboards.ca.gov/gama/gamamap/public/ ). The ILRP agricultural orders require that sampling must follow U.S. Environmental Protection Agency procedures, and samples must be analyzed at a laboratory certified by the California Department of Public Health. The exact number and locations of wells enrolled in ILRP monitoring changes over time but has been in the range of 100- 200 wells in recent years. For example, the locations of wells sampled in 2017 or 2018 are shown in Figures 4.8-1 and 4.8-2. This is a large enough number to support statistical evaluation of changes in ambient water quality. Data for nitrate and total dissolved solids will be evaluated. For nitrate, the percentage of wells with concentrations exceeding the primary drinking water MCL of 10 mg/L as N will be calculated. For TDS, the percentage of wells exceeding the Basin Plan Objective (1,145 mg/L for the “upper Forebay area” and 2,059 mg/L for the “lower Forebay area”) will be calculated. Also, net change in the median concentration since 2015 will be determined using the nonparametric Wilcoxon rank-sum test. 5.6.2 Nexus with Sustainability Criteria The percentage of wells with nitrate exceeding the drinking water MCL will be compared with the existing percentage (65%), which is the minimum threshold. The percentages of wells with TDS concentrations exceeding the Basin Plan Objective will similarly be compared with the existing percentages (21% for the upper Forebay area and 27% for the lower Forebay area), which are the TDS minimum thresholds. The final element of the TDS minimum threshold is whether there has been a statistically significant increase in median concentration since 2015. 5.7 MONITORING FOR INTERCONNECTED SURFACE WATER The sustainability criteria for depletion of interconnected surface water along the Arroyo Seco and Salinas River are defined in terms of the rate, season and frequency of percolation losses, conditioned on groundwater levels and reservoir operation. Evaluation of the criteria requires joint analysis of several monitoring data sets, all of which are collected and maintained by external agencies. 5.7.1 Monitoring Protocols To evaluate the Arroyo Seco minimum threshold for flow depletion, daily stream flow at the upper and lower gauges (site 11152000 “Arroyo Seco nr Soledad CA” and site 11152050 “Arroyo Seco blw Reliz C nr Soledad CA”) will be downloaded from the U.S. Geological Survey’s National Water Information System website (https://waterdata.usgs.gov/nwis ). See Figure 2.0-2 for those gauge locations. Diversions by CCWC from the reach between the gauges will be obtained from CCWC. During the season and flow ranges of interest (related to steelhead passage), tributary inflow to the inter-gauge reach from Reliz Creek can be assumed to equal zero. Net percolation along the inter-gauge reach will be calculated as the upper gauge flow minus CCWC diversion minus the lower gauge flow. Annual discharge at the upper gauge will also be used to determine the hydrologic year type according to the five categories (“dry” to “wet”; see Figure 3.2-1). To evaluate the Salinas River minimum threshold, daily release data for Nacimiento and San Antonio Reservoirs will be obtained from MCWRA. Those will be evaluated to confirm whether reservoir releases complied with reservoir operation requirements for pass-through of non-surplus water and releases for Arroyo Seco GSP ADMINISTRATIVE DRAFT 5 January 3, 2020 fish passage and habitat, and whether major releases were curtailed for more than two consecutive years. Daily flows in the Salinas River at the gauge “Salinas R nr Bradley CA” (site 11150500), “Salinas R a Soledad CA” (site 1151700) and “San Lorenzo C blw Bitterwater C nr King City CA” (site 11151300) will be downloaded from the USGS NWIS website. See Figure 3.1-3 for those gauge locations. Net percolation between the Bradley and Soledad gauges will be calculated as Bradley flow plus San Lorenzo flow minus Soledad flow. Groundwater levels from the water level monitoring network will be evaluated to confirm whether water levels were above the minimum threshold. 5.7.2 Nexus with Sustainability Criteria The percolation rate exceeds the minimum threshold for flow depletion along the Arroyo Seco. If the year type is “below normal”, “normal” or “above normal”, the percolation rate exceeds 200 cfs on any day during the April-June date window when flow at the lower gauge recedes through 1 cfs, and this has also occurred in any of the preceding four years. If the reservoir operation criteria were met and groundwater levels were above the minimum threshold, then the calculated net percolation loss along the Salinas River did not exceed the minimum threshold. If they were not met, it exceeded the threshold. Arroyo Seco GSP ADMINISTRATIVE DRAFT 6 January 3, 2020  Table 5.1‐1. ASGSA Monitoring Program Summary Monitored Variable Type of Measurement Locations Data Interval Data Collection Agency Database Storage Agency Notes Water levels Existing MCWRA wells Depth to water Forebay Semiannual MCWRA and/or ASGSA MCWRA Request data from MCWRA. Need to overcome confidentiality problem. Additional existing wells (3) and Depth to water ASGSA area Semiannual ASGSA or MCWRA ASGSA or MCWRA If data collection and storage delegated to MCWRA, request data annually. new shallow riparian wells (4) Groundwater storage Rainfall Rain gauge, daily total, inches Bradley, King City, Arroyo Seco Daily NCDC with local partners NCDC Download from web Mt. Diablo, Salinas North, Salinas South II Reference ET (ET0) Daily ETo, inches CIMIS Station #114 Arroyo Seco Daily CA Department of Water DWR Download from web Resources, CIMIS program Stream flow Daily average flow, cfs Arroyo Seco nr Soledad CA, Daily USGS USGS Download from web Arroyo Seco bl Reliz C nr Soledad CA, Salinas R nr Bradley CA, Salinas R a Soledad CA, Salinas R nr Chualar CA, Salinas R nr Sprackels CA CCWC diversions Diversion flow, cfs CCWC diversion weir Daily CCWC ASGSA Request data from CCWC Reservoir operations Rainfall, elevatoin, storage, release, Nacimiento and San Antonio Daily MCWRA MCWRA Request data from MCWRA spill Reservoirs Crop patterns Map of crops by field, mid‐summer ASGSA area Annual LandIQ ASGSA or SVBGSA Jointly develop and fund valley‐wide satellite‐based crop monitoring program with SVBGSA? Groundwater pumping Agricultural Well flow meters (several types) Large irrigation wells in ASGSA Monthly MCWRA MCWRA Need raw data for model. Subtotal any published data to entire ASGSA area to maintain confidentiality. Investigate accuracy of metered data with MCWRA. Municipal Monthly total pumping by well Greenfield municipal wells Monthly City of Greenfield ASGSA Request data from City. Domestic & industrial Number of residences; list of large self‐ ASGSA area Annual ASGSA ASGSA Count residences on Google Earth and multiply by Greenfield per‐residence water factor. Contact large supplied industiral/commercial users self‐supplied industrial/commercial users in Greenfield individually and request pumping data. Wastewater percolation WWTP eflluent volume, gallons Greenfield WWTP Monthly City of Greenfield ASGSA Request data from City. Subsidence Subsidence Cumulative decrease in land surface ASGSA area and surrounding Semi‐annual DWR (InSAR) DWR SGMA data website ASGSA evaluates InSAR image pixels against minimum threshold criteria. elevation since 2015 region Groundwater quality Greenfield municipal wells Specific conductance, TDS, N City of Greenfield Wells 1, 6 Annual City of Greenfield SWRCB Division of Drinking Water Download self‐monitoring data from SWRCB website. and 7 plus any future new wells Rural ag/dom wells Specific conductance, N 100‐200 wells throughout Twice per five ILRP SWRCB Geotracker database Download data from Geotracker ASGSA area years Interconnected Surface Water and GDEs Riparian vegetation Vegetation extent and vigor in Google Arroyo Seco and Salinas River Annual Google Earth and The Nature Google Earth and The Nature Examine on‐line air photos and GDE Pulse maps, and tally results. Earth and GDE Pulse maps channels in ASGSA area Conservancy Conservancy Arroyo Seco Flow loss between gauges Upper and lower gauges Daily USGS USGS ASGSA calculates flow loss based on gauged USGS flows and CCWC diversions. Salinas River Flow loss between gauges Reservoirs, Bradley and Daily MCWRA and USGS MCWRA and USGS ASGSA calculates flow loss based on USGS gauged stream flows and MCWRA reservoir releases Soledad T:\Projects\Arroyo Seco 81401\Deliverables\GSP\Monitoring_program.xlsx 1/3/2020  R. 6 E. R. 7 E. Soledad 33R02 Sal i na s Riv er 0 ( N Scale in Miles 2 05R03 03P01 02N01 09M01 09P01 14B01 18D01 T. 18 S. 15L01 15M01 14R01 22B02 22B03 19G02 22B04 24M01 24M02 20K01 27A01 19N50 27C01 25F01 29M50 28K01 34B01 34A01 35F01 35F02 32G02 Greenfield 33J02 05B02 co 01H01 Se 03H02 06P01 05J01 royo T. 19 S. 04Q01 Ar 08D01 08N01 10P01 16D01 14N02 Legend MCWRA Monitored Wells Locations for CASGEM Additional Wells Monthly Semiannual Township Range January 2020 Arroyo Seco GSA FigureP Corp., Sources: Esri, HERE, DeLorme, Intermap, increment 5.2-1GEBCO, USGS, FAO, NPS, NRCAN, GeoBase, IGN, Kadaster NL, Ordnance Document Path: Groundwater Basin Water-Level Survey, Esri Japan, METI, Esri China (Hong Kong), swisstopo, Monitoring MapmyIndia, © OpenStreetMap contributors, Community Network and the GIS User Wells