Water Forum Agreement and Groundwater in the Sacramento Region:
Recognizing that the groundwater basin underlying Sacramento supplies over half the water used in the Sacramento region, the Groundwater Element of the Water Forum Agreement sets out specific recommendations designed to protect the viability of this resource for both current and future users. Among the most important of these were recommendations on the sustainable yields and groundwater management governance structures for the three Sacramento groundwater subbasins.
• Sustainable yield is defined as the amount of groundwater that can be safely pumped from the groundwater basin over a long period of time while maintaining acceptable groundwater elevations and avoiding undesirable effects such as increased pumping costs, accelerated movement of underground pollutants, etc.
• Recommendations for a groundwater management governance structure in the North Area of the County (i.e., in the area between the American River and the Sacramento - Placer County boundary) were spelled out in the Water Forum Agreement to some detail. These recommendations were subsequently implemented by Sacramento County and the Cities of Citrus Heights, Folsom and Sacramento and led to the creation of the Sacramento North Area Groundwater Management Authority (now know as the Sacramento Groundwater Authority).
• With regard to groundwater management governance in other areas of Sacramento County, the Agreement recommended: “…Discussions involving all parties interested in the negotiation of groundwater management arrangements in the [Central] area and the [Galt or South] area will continue. These discussions, employing the principles of interest-based negotiation, are part of a public process designed to provide all community interests the opportunity to participate in tailoring a groundwater management plan to fit each area’s unique circumstances.”
Starting in 2002, stakeholders of the Central groundwater basin began a process of groundwater management planning and development of a governance structure. That effort resulted in the adoption of the Central Sacramento County Groundwater Management Plan in February 2006 and creation of the Sacramento Central Groundwater Authority in August 2006. Efforts to create a governance structure in the South Basin are currently underway with the creation of the South Area Water Council for negotiation of a governance structure and completion of a groundwater management plan by end of 2008 or early 2009.
Groundwater Basin Descriptions:
In Sacramento County, the Water Forum Agreement divided the Sacramento groundwater basin into three subbasins, North, Central, and South (Galt), as shown in the above figure. The boundaries indicated in the figure represent political and hydrogeologic boundaries that were considered in the groundwater negotiation process. In many cases, the boundaries of the subregions of the regional groundwater model were used providing the somewhat jagged appearance.
A subbasin is loosely defined as a hydrogeologic region that can be managed independently of adjoining groundwater subbasins. In the case of Sacramento, the Cental Basin is one basin that best fits this definition with the American, Cosumnes and Sacramento Rivers providing boundaries that minimize effects of groundwater activities in the Central Basin in the two adjoining groundwater subbasins. The North and South Basins have at least one hydrogeologic boundary such as a river or the Sierra Neveda foothills. They also share political boundaries with adjacent counties, requiring coordination of on-going and proposed activities that might affect groundwater in other counties.
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North Area -- 131,000 acre-feet
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Central Area -- 273,0000 acre feet
North Subbasin:
The political delineation of the North Basin governance structure lies north of the American River and extends to Sacramento/Placer and Sacramento/Sutter County lines. The actual hydrogeographic expanse of the North Basin is much larger and extends further north to the Bear and Yuba Rivers. The Water Forum Agreement's long term average sustainable yield determination for the North Basin is 131,000 Acre-Feet per year (AF/year).
Groundwater Management Implementation Summary:
The Sacramento Groundwater Authority (SGA) has and will continue to partake in groundwater management activities that meet the Water Forum co-equal objectives and the objectives of the membership agencies.
The objectives are as follows:
-Facilitate implementation of regional conjunctive use
-Mitigate conditions of regional groundwater overdraft
-Replenish groundwater extractions
-Mitigate groundwater contamination migration
-Monitor groundwater elevations and quality
-Develop relationships with State and Federal agencies
A number of specific activities for meeting the groundwater management objectives have been identified.
These activities include:
-Development of a groundwater monitoring and data collection collation system referred to as the Data Management System (DMS).
-Development of a system of economic incentives and disincentives for encouraging the operational modifications required to implement the regional conjunctive use program.
-Development of a regional groundwater banking and exchange/surface water transfer program based on the Water Forum Agreement and the regional conjunctive use program.
-Coordination of quality groundwater protection programs (e.g., the Drinking Water Source Assessment Program – DWSAP).
-Development of a comprehensive outreach and education program to keep the public and regional stakeholders apprised of the activities of the SGA.
Central Subbasin:
The political delineation of the Central Basin lies south of the American River, east of Interstate 5 and the Sacramento River, and north of the southern boundary of the Omochumne-Hartnell Water District and the Cosumnes and Mokelumne rivers. The eastern boundary of the Central Basin is approximately 5 to 6 miles west of the Sacramento County-El Dorado County boundary where the Sierra Nevada foothills begin to rise up from the Central Valley floor. The actual hydrogeographic delineation of the Central Basin along the southerly boundary is the approximate centerline of the Cosumnes River/Deer Creek flood plains. However, because the Omochumne-Hartnell Water District (OHWD) straddles both sides of the flood plain, a decision was made in the Water Forum Agreement to include the OHWD entirely within the Central Basin. As the South Basin negotiation process begins, it is very likely that the OHWD could belong to both the Central Basin and the South Basin.
The Sacramento Central Groundwater Authority's (SCGA) groundwater management plan identifies available water supplies to meet the total water demands of users within the basin. Water supplies include surface water, groundwater, and recycled water. Water demand is a result of rural, agricultural, private industrial, environmental, and urban activities. Demand reduction can be accomplished through water conservation measures identified in the WFA.
Groundwater Management Implementation Summary:
Water supplies have been quantified in some detail in the SCGA's groundwater management plan. Availability and reliability of surface water is dependent on the particular contract or water right and the hydrologic year type (e.g., wet or dry years). Based on existing and projected contract and water right entitlements, the total surface water supply available to the Central Basin is approximately 333,656 AF/year. The Water Forum Agreement's long term average sustainable yield determination for the North Basin is 273,000 Acre-Feet per year (AF/year).
A goal of the SCGA is to ensure a viable groundwater resource for beneficial uses including water for adjacent purveyors, agricultural, agricultural residential, industrial, and municipal supplies that support the WFA’s co-equal objectives of providing a reliable and safe water supply and preserving the fishery, wildlife, recreational, and aesthetic values of the lower American River. In addition, this GMP partakes in the enhancement of maintaining ecological flows in the Cosumnes River.
The SCGA has introduced two unprecedented negotiated programs: the Well Protection Program and the Groundwater Contamination Monitoring and Collaboration Program.
The Well Protection Program stems from the need to protect domestic and agricultural irrigation wells. Protection of existing privately owned wells is of fundamental importance to the stakeholders of the Central Basin. As part of this program, a trust fund will be put in place to cover costs of deepening or replacing any existing well that provides water for agricultural or domestic use that may be impacted by future development. The trust fund revenue will be generated from a fee assessed on every new building permit and permit to drill a new well. The fee is estimated to be less than $100 per single family home.
The Groundwater Contamination Monitoring and Collaboration Program is focused on maintaining a clear line of communication between the designated Responsible Parties for groundwater contamination clean-up activities and private well owners. The program encourages the use of remediated groundwater in urbanized areas to keep the groundwater in the basin. This program also envisions the Regional Water Quality Control Board requiring designated Responsible Parties to survey private wells within 2,000 feet of any identified contamination plume. Assistance will also come from the Sacramento County Environmental Management Department (EMD). EMD is encouraged to exercise the strictest vigilance to ensure that all permitting requirements are enforced and that, if requirements are not met, EMD will undertake whatever rigorous enforcement actions are effective.
South Subbasin:
Most water use in the South Basin depends on groundwater. Apart from the City of Galt, whose public water system is supplied completely by groundwater, commercial agricultural operations and agricultural-residential homeowners are all self-supplied pumpers. An unusually large proportion of the residents of the South Basin occupy agricultural-residential (ag-res) parcels of 2 – 10 acres, each of which has its own well and septic system. The County recognizes six ag-res communities that lie outside the Urban Services Boundary established under the General Plan. They comprise the residential base for most of the area lying between the City of Galt at southeastern corner of the basin and Rancho Murieta in the northeastern corner. To narrow the scope of the governance strucuture to a manageable area, and for purposes of groundwater management planning to be undertaken by the South Area Water Council, the planning area will likely consist of that portion of the Cosumnes subbasin within the southern portion of Sacramento County (South Basin). There is an overlap area with the Central Basin boundaries on the north and west, as those boundaries have been defined in the Sacramento Central Groundwater Authority charter. This will be explored further in the section. The large portion of the Cosumnes subbasin that extends south of Dry Creek (the Sacramento/San Joaquin County boundary) to the Mokelumne River in San Joaquin County, and the other part extending into Amador County in the Sierra Nevada foothills are also excluded only because there are either separate efforts already taking place in these regions or stakeholders are not ready to negotiate as part of the framework setup for the South Area Water Council.
Groundwater Management Implementation Summary:
The Water Forum Agreement's long term average sustainable yield determination for the South Basin is 115,000 Acre-Feet per year (AF/year). Another important element of the Water Forum Agreement relating to the South Basin is a commitment that a 15,000 acre-feet portion of the Central Valley Project contract supply of the Sacramento Municipal Utility District would be assigned for agricultural use in the South basin once a governance structure is formed. Upon completion of the negotiation process and the formalization of a governance structure and adopted groundwater management plan, the South Basin will likely move forward with programs similar to those in the North and Central Basins with more of a focus on the Cosumnes River corridor. Updates to this process will be posted here as well as on the South Area Water Council's web site once in operation.
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Groundwater Basin Map
