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Kings Subbasin community residents and GSA leaders gather for groundwater discussion in Riverdale

Panelists discuss complexity of the nearly 1 million acre service area

June 10, Riverdale – A community discussion on groundwater and the Sustainable Groundwater Management Act (SGMA) highlighted the complexity of the groundwater Subbasin that covers nearly 1 million acres and gave attendees a better understanding of how groundwater quality will be monitored in the Kings Subbasin.

GSA leaders representing five Kings Subbasin GSAs participated in a panel discussion, emphasizing the feat to coordinate and map out groundwater conditions in a Subbasin that includes 7 GSAs. Panelists included Gary Serrato, Executive OfficerNorth Kings GSA; Matt Hurley, General ManagerMcMullin Area GSA; Steven Stadler, Administrator , James Irrigation District GSA; Mark McKean, ChairNorth Fork Kings GSA; Chad Wegley, AdministratorKings River East GSA; and Ronald (Ronnie) Samuelian, Kings Subbasin Coordinator and Principal EngineerProvost & Pritchard Consulting Group.

Panelists discussed their plans to monitor water quality as it relates to groundwater pumping. Under SGMA, GSAs are required to ensure water quality degradation resulting from groundwater pumping is not significant and unreasonable. The Kings Subbasin GSA leaders emphasized water quality concerns are localized and must be individually looked at due to high variability; there is no one-size-fits-all management tool or threshold for the Subbasin.

Panelists also noted the GSAs will be looking for changes in trends, not one-time spikes in water quality measurements, to determine if there is a water quality concern that needs to be addressed. The GSAs have outlined a network of wells that will be used to monitor water quality moving forward. In many cases this well network is similar to the network used by existing water quality regulating programs, such as the Irrigated Lands Regulatory Program that monitors nitrates for irrigated agriculture.

Additional workshop topics included an overview of SGMA, groundwater conditions in the Kings Subbasin, and why it is important for rural communities to participate in groundwater planning. The workshop was hosted by the Kings River Conservation District in association with Self-Help Enterprises.

Our water needs a budget

Water is scarce. Sustainability of the resource we all depend on requires balanced inputs and outputs. Whether SGMA is the compulsion or not, responsibly managing water demands a budget.

In the Kings Subbasin we’re working to balance an overdrafted water “account”. The North Fork Kings GSA, along with the six other GSAs in the Kings Subbasin, is required by SGMA to bring its account into balance by 2040.

A water budget, required in the Groundwater Sustainability Plan (GSP),  provides valuable insight for those managing our water. It informs current conditions and will measure impact of the North Fork Kings GSA’s upcoming sustainability efforts.

The budget tracks water inputs and outputs to calculate the change in groundwater storage in the service area. A negative groundwater storage indicates overdraft.

Groundwater Storage = Inputs – Outputs

Sustainability can be achieved by increasing water supply (inputs) and/or decreasing water demand (outputs). The GSP will define how the North Fork Kings GSA plans to balance its estimated 50,300 AF of annual overdraft. The GSA can increase its inputs, decrease its outputs, or a combination of both through projects and management actions. For example increasing inputs through flood water capture off the Kings River in wet years can offset irrigation outputs, bringing the budget closer to balance.

Inputs are water sources, and can include additional surface water, precipitation, estimated groundwater pumping, and groundwater inflow. Outputs are water uses, and can include irrigation, municipal, residential, and industrial uses, as well as groundwater outflow. The North Fork Kings GSA is committed to prioritizing supply side solutions for sustainability.

Water Budget Diagram

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A water budget is a key component of the Groundwater Sustainability Plan (GSP), and will be included in the draft document scheduled for public review beginning in July.

Stakeholders invited to FOX26 SGMA Town Hall

Stakeholders in the North Fork Kings GSA are invited to take place in the upcoming KMPH FOX26 live Town Hall: Groundwater Sustainability Act. Board Chair, Mark McKean, will represent the agency and its co-sponsor MAGSA as a panelist for the event.

The Town Hall will take place this Thursday, May 23 from 6:00-7:00 pm. Stakeholders are invited to join the audience in-person at the Clovis Veterans Memorial District, 808 4th St., Clovis, CA, or watch from the comfort of their homes. The event will air live on FOX26 from 6:00-7:00 pm and will be streamed live on KMPH.com and the FOX26 mobile app.

Panelists include:

  • Mark McKean, North Fork Kings and McMullin Area GSAs
  • Gary Serrato, North Kings GSA
  • Johnny Amaral, Friant Water Authority
  • Mario Santoyo, San Joaquin Valley Water Infrastructure Authority
  • Thomas Esqueda, California Water Institute

The panel will be moderated by news reporter Rich Rodriguez. Viewers will be able to submit questions for the panel using a special text number.

When Water Supply is Scarce, Management Actions can Mitigate Overdraft

There are only two ways to achieve sustainability and eliminate groundwater overdraft for the North Fork Kings service area: increase water supply, primarily through project development and reduce water demand, primarily through management actions. The NFKGSA Board is emphasizing increasing water supply with the understanding there are hurdles to overcome.

The preliminary project list continues to be updated and contains recharge projects that would yield an estimated annual average of approximately 50,000 acre feet per year based on historic floodwater availability. The seven Kings Subbasin GSAs have reached agreement on an initial overdraft amount for the entire Kings Subbasin of 122,000 acre feet. The North Fork Kings GSA estimated amount of the 122,000 acre feet is 50,300 acre feet. 

The amount of overdraft that cannot be overcome with increasing the water supply will need to be overcome with management actions that reduce water demand.  Demand reduction through management actions will likely need to be initiated within 5 – 10 years if project development isn’t progressing as needed.

Management Actions are programs and policies that will aid the GSA in achieving sustainability primarily through water demand reduction measures and improving data monitoring.  A suite of potential management actions will be presented in the GSP that could be implemented at the GSA level or landowner level. The GSA may not want to dictate management actions at the landowner level, what works for one landowner may not work for another and economic impacts must be considered.

Below are potential management actions that will be considered in the GSP and the estimated time for implementing those actions.

Management Actions for the 2020-2025 Timeframe


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Management Actions for the 2025-2030 Timeframe


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Management Actions for the 2030-2040 Timeframe

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Discussions and the development of the management actions details will begin after the adoption of the GSP in January 2020.

Proposed project would recharge an estimated 15,000 AF annually in the North Fork Kings GSA

A portfolio of solutions will be considered to achieve sustainable groundwater under SGMA. Projects and management actions can work in tandem to augment water supply and reduce water demand, stabilizing groundwater levels. The North Fork Kings GSA Board’s first priority is implementing projects to increase water supply in the service area. The North Fork Regional Recharge Project introduced by Kevin Johansen, Provost & Pritchard, aligns with that priority. The project is in early conceptual stages.

Three groundwater recharge basins with estimated annual recharge capacity of 15,000 AF (acre-feet) are included in the project scope, leveraging suitable recharge conditions in the GSA’s northeast region. The average annual cost per AF of recharge is $160 according to preliminary project cost estimates. The project includes two new basins and expansion of an existing Laguna Irrigation District basin. An additional component needed is improvement and expansion of Liberty Canal to increase current carrying capacity and secure water delivery.

Surface soil type, absence of clay layers, and groundwater flows at project sites are highly conducive to recharge that benefits the entire GSA’s service area. The bulk of surface soils at proposed sites are coarse sands and sandy loam, ideal for percolation into the groundwater aquifer below. And although much of the GSA is underlain with clay layers, the northeast region is absent of these layers. Because groundwater generally flows east to west in the GSA, the groundwater recharged by the project would flow into the rest of the service area. This includes to disadvantaged communities of Lanare and Riverdale where soil type and clay layers are unsuitable for recharge projects.

(click map images to enlarge)

To help cover project cost, the North Fork Kings GSA is pursuing grant funding through Integrated Regional Water Management (IRWM) Prop 1 Implementation funds. A pre-application was sent to the Kings Basin Water Authority for review and if selected, will compete for funding from a pool of $12.7 million for the Tulare Kern Funding Area.

Preliminary Overdraft Number for NFKGSA Released

The seven Kings Subbasin GSAs have reached agreement on an initial overdraft amount for the Kings Subbasin of 122,000 acre feet. The North Fork Kings GSA estimated amount of the 122,000 acre feet is 50,300 acre feet. The North Fork Kings GSA  Board has already identified potential projects to begin correcting the target overdraft amount by the SGMA sustainability deadline of 2040.

There are two basic ways to achieve sustainability and eliminate overdraft: increase water supply or reduce water demand. The Board’s first priority is to increase water supply, but there are hurdles for this course of action within the North Fork Kings area including availability and frequency of additional water; all Kings River water is allocated through a water rights schedule; and the service area has physical constraints for recharge including soil types and a limited distribution system.

The map below (click map to enlarge) shows the general soil types in the North Fork Kings GSA. The green areas in the eastern portion of the GSA are sandier soils and more conducive for recharging the aquifer. The western portion has heavier clay soils that are more impermeable and consequently poor for recharge.

Although the eastern part of the service area has better soils for recharge, it lacks a distribution system. Therefore, infrastructure needs to be constructed to deliver water to any future recharge projects that may be built. The map below (click map to enlarge) represents significant surface water features in the North Fork Kings GSA.

North Fork Kings GSA preliminary project list contains nine groundwater recharge projects yielding an estimated annual average of approximately 20,000 acre feet per year. Additional projects will need to be identified to alleviate the overdraft amount. If water supply tactics are not sufficiently successful to eliminate the 50, 300 acre feet overdraft number then management actions to reduce water demand will need to be implemented.

Increasing data-driven groundwater management is needed under SGMA; DWR technical services can support that effort

At the October 24th Board Meeting the North Fork Kings GSA Board approved to submit an application for Technical Support Services from the CA Department of Water Resources (DWR) in a move to solve data gaps in the monitoring network. Services available through DWR include the installation of dedicated monitoring wells and video logging to gather construction information on existing wells among others.

Sustainability mandates under SGMA necessitate data-driven groundwater management. A Groundwater Sustainability Plan requirement, the monitoring network is a key data gathering component for establishing and monitoring sustainability goals in the North Fork Kings GSA. Data collected from the network of monitoring wells must be reported annually to DWR; the data will also be an important metric for the North Fork Kings GSA to measure the impacts and results of future projects and management actions on groundwater levels within the service area.

Current groundwater condition insights are drawn from existing monitoring programs including CASGEM (California Statewide Groundwater Elevation Monitoring) and GAMA (Groundwater Ambient Monitoring and Assessment Program), but increased data capacity is needed to sufficiently monitor sustainability progress and ensure the GSA is achieving its mitigation targets.

The GSAs technical consultant, Kevin Johansen of Provost & Pritchard recommends a network density of 2-3 monitoring wells per township. Because of the hydrogeologic variability of the area, which includes multiple clay layers, a confined aquifer, and an unconfined aquifer (unconfined aquifer exists in the absence of clay layer), sufficient network density is important in the North Fork Kings GSA.

The map pictured below illustrates current gaps in the North Fork Kings GSA monitoring network. (Please note the image is a DRAFT.)

North Fork Kings GSA Well Network and Data Gaps

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Both existing and newly established dedicated monitoring wells will be used to fill gaps and achieve the recommended network density. To qualify for the monitoring network a well must be accompanied by a Well Completion Report, a document outlining the construction information such as depth and perforated intervals. Because it can be time-consuming work to obtain and match reports with the appropriate well, the GSA plans to take advantage of the Technical Support Services offered by DWR for the installation of dedicated monitoring wells pending application approval.

The well monitoring network will ultimately be the data collection tool providing insight into the trajectory toward sustainable levels of groundwater in the North Fork Kings GSA. The Technical Support Services offered by DWR can help efforts of the GSA to sufficiently monitor groundwater levels.

Project discussions begin as GSP elements progress

At the September 26th Board Meeting technical consultant Kevin Johansen, Provost & Pritchard, presented potential Groundwater Sustainability Plan (GSP) concepts and management actions for consideration. The list included projects across six broad categories: conjunctive use (the combined use of surface water and groundwater), surface water, land management, groundwater use restrictions, water conservation, and “other”.

Conjunctive use projects may include groundwater recharge by means of dedicated basins, injection wells, unlined canals or intentional on-farm recharge. The preliminary list also included supply-side solutions that focus on acquisition of surface water or building additional storage and conveyance. An innovative supply-side solution that made the list: internal surface water trading among growers within the GSA.

On the demand side, land management solutions aim to decrease the amount of water needed. Solutions to achieve this may include land purchase and fallowing by the GSA from willing landowners, or incentives for landowners to convert to less water-demanding crops.

The projects presented are not an exhaustive or definite list, but rather concepts that require further exploration for consideration. Economic constraints will be a key factor in identifying projects that lessen the burden of reaching State-mandated sustainability as the GSA moves toward developing a more detailed project roadmap.

Board selects preferred methodology for recommendation to Kings Subbasin coordinated effort, indicates accuracy is a priority

At the August 1, 2018 North Fork Kings GSA Special Board Meeting, Kevin Johansen of Provost&Pritchard briefly reviewed the alternative methodologies considered for allocating the estimated 206,000 AF of annual groundwater overdraft within the Kings Subbasin. The North Fork Kings GSA Board moved to select its preferred methodology for recommendation to the Kings Subbasin coordination group. The coordination group must still reach an agreement on the methodology that will be used by the entire subbasin.

Below are the five alternative methodologies to determine groundwater overdraft allocation:

Methodology 1: equal subbasin overdraft distribution by GSA acreage

Methodology 2: storage change only within boundaries of individual GSA

Methodology 3: storage change plus groundwater boundary flows between GSA’s

Methodology 4: storage change plus groundwater boundary flows between GSA’s, including historical flow patterns

NEWIteration 4A: same as methodology 4, except an adjustment is made for aquifer thickness caused by declining water levels, and uses bookend years of 1999 and 2011 to determine current groundwater flow conditions

NEWIteration 4B: same as iteration 4A, except rather than bookend years, averages data from multiple years between 1999 to 2011 to determine current groundwater flow conditions (thus, more data is used in the calculation than in iteration 4A)

Methodology 5: water budget concept: utilizes calculated water demand, and assumes demand not met by surface water delivery/precipitation is met by groundwater pumping

Click here to read our previous post for more detail on the methodologies, including their benefits and shortcomings. 

Acknowledging that overdraft numbers will change as quality and quantity of monitoring data is made available, the Board moved to select iteration 4B as its primary preference citing its parameters and data quantity as key indicators of accuracy.

In the absence of coordinated group consensus on iteration 4B, the Board moved to select methodology 4 and 4A as alternative preferences. The difference between current estimated overdraft amounts assigned to the North Fork Kings GSA between methologies 4, 4A, and 4B is minimal, with all falling between 72,000-75,000 AF (numbers are preliminary and subject to change).

The Board’s goal is to set realistic mitigation targets and implement projects to successfully reach sustainability goals. An accurate representation of groundwater conditions will equip the GSA for that goal.

Please note that all numbers are preliminary and subject to change pending data improvements.

Board Workshop Discusses Methodologies to Determine Groundwater Overdraft Responsibility within Kings Subbasin, Among Additional GSP Topics

At the June 27, 2018 North Fork Kings GSA Board Workshop, technical consultant Kevin Johansen of Provost & Pritchard provided a detailed update on Groundwater Sustainability Plan (GSP) elements within the context of SGMA-mandated subbasin coordination. Because the State requires sustainability at the subbasin level, the seven Kings Subbasin GSAs are seeking agreement on the methodologies used to develop their individual GSPs.

The coordination group is working towards an overdraft yield estimate within the Kings Subbasin, and are seeking agreement on a methodology to assign appropriate responsibility among each GSA for that overdraft amount. Work to determine unconfined aquifer (unconfined aquifer, as opposed to confined, exists in the absence of a clay layer) storage change and groundwater boundary flows is currently underway.

Using best available monitoring well data, contour maps from the Spring of 1999 and the Spring of 2011 are used to determine aquifer storage change and boundary flows within the Kings Subbasin. Contour maps utilize groundwater elevation (feet above mean sea level) to illustrate the direction that groundwater moves. The map below (click image to enlarge) indicates groundwater elevation levels with numbers along the blue contour lines in the year 2011 in the Kings Subbasin. Water flows perpendicular to these contour lines from higher elevations to lower. The map indicates Kings Subbasin groundwater generally flows from East to West.  Please note that the elevation numbers are preliminary and subject to change pending improvements in well monitoring data.Preliminary numbers for unconfined aquifer storage change are calculated for each GSA in the subbasin using groundwater elevation data from 1999 to 2011. The subbasin as an entirety has experienced an estimated average annual storage change of 206,000 AF. Please note these numbers are preliminary and subject to change pending data improvements.

A methodology for answering the important question of how much overdraft each GSA is responsible for must be agreed upon by the seven GSAs. Johansen outlined five potential methodologies for determining the apportionment of storage change responsibility.

Methodology 1: The approach of this methodology is simply to prorate the subbasin total change in storage (the estimated 206,000 AF) amount based on GSA acreage – in other words, to equally distribute the total change amongst the GSAs by acreage. This method lacks causal explanation for change in storage.

Methodology 2: The second proposed methodology utilizes only change in storage within the boundary of each GSA. This method lacks information on groundwater flow in and out of the GSA.

Methodology 3: The third alternative takes into account the GSA’s change in groundwater storage and its groundwater boundary flows. This method looks at the estimated change in storage in a GSA, together with net boundary flow (water flowing in and water flowing out) to assign responsibility.

Methodology 4: Identical to the third method, except that it accounts for historical flow patterns and its associated benefits or losses to a GSA over a period of time.

Methodology 5: The final methodology utilizes the water budget concept. This method uses calculated water demands for each GSA depending on land use, and assumes that whatever demand not met by surface water delivery or precipitation is met by groundwater pumping.

The current goal is to coordinate amongst the seven Kings Subbasin GSAs on an agreed methodology from the list above. No formal agreement has been made, but methodology 4 represents a holistic and equitable approach in calculating distribution of overdraft responsibility. Although a key component, change in storage is not enough to assign overdraft responsibility to each specific GSA because it excludes additional causal information such as groundwater flows and historical flow impacts. Assigning responsibility is key for each GSA’s individual GSP, as it sets a target for mitigation that can be achieved by projects and management actions.

The presentation included preliminary calculations, and covered a broad range of GSP elements including Kings Subbasin Coordination outline in the above article, Water Budget, Sustainable Management Criteria, Preliminary Water Quality Characterization, Management Area Considerations, and Next Steps.

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