WATER SUPPLY PLANNING COMMITTEE
DISCUSSION ITEM
2.	OVERVIEW OF SEASIDE BASIN ADJUDICATION
Meeting Date:		September 10, 2019	Budgeted:	N/A
From:		David J. Stoldt	Program/
		General Manager	Line Item No.:	N/A
Prepared By:		David J. Stoldt	Cost Estimate:	N/A
General Counsel Approval: N/A
Committee Recommendation: N/A
CEQA Compliance: Action does not constitute a project as defined by the California Environmental Quality Act Guidelines section 15378.

SUMMARY:  With the addition of several new Board members, it is an appropriate time to review the Seaside Groundwater Basin adjudication.

Description of the Seaside Basin

The Seaside Basin underlies the Cities of Seaside, Sand City, Del Rey Oaks, Monterey, and portions of unincorporated county areas, including the southern portions of Fort Ord, and the Laguna Seca Area. Generally, the Seaside Basin is bounded by the Pacific Ocean on the west, although it is recognized that the aquifer extends offshore under the seafloor, the Toro Park area on the east, Highways 68 and 218 on the south, and the northern boundary of the basin follows a groundwater flow divide separating groundwater flowing toward the Salinas Valley from groundwater flowing toward the coastal subareas of the Seaside Basin. Flow divides are hydraulic features that develop between two centers of concentrated pumping. The divide acts like a ridge in the regional water-level surface much like the way a topographic ridge separates two surface watersheds. The Seaside Basin consists of subareas, including the Coastal subarea and the Laguna Seca subarea in which geologic features form partial hydrogeologic barriers between the subareas. The Seaside Basin is shown in Exhibit 2-A. While there is some disagreement over the depiction of its boundaries, the red outline is what applies to the adjudication and was adopted by the State Department of Water Resources at the request of the District as a basin boundary adjustment under the Sustainable Groundwater Management Act (SGMA) in early 2016. The different boundary demarcations are discussed below.

DWR Boundary: The California Department of Water Resources (DWR) Bulletin 118 (2003) boundaries were mapped by the DWR as part of a statewide effort. The Seaside Groundwater Basin is characterized as a sub-basin (basin number 3-4.08) contained in the Salinas Valley Groundwater Basin. The Seaside Groundwater Basin was included based on the similarity of depositional environments between the Seaside and Salinas Valley Groundwater Basins. The DWR defined the northeast boundary along the mapped boundary of the 180/400 foot aquifer subbasin (basin number 3-4.01) in the Salinas Valley proper; the western and southeastern boundaries were defined roughly on the extent of Quaternary sand dune deposits.

Seaside Basin Adjudication Boundary: The Adjudicated Basin Boundary was delineated by the court in the final decision (filed March 2006). The Adjudicated Boundary is based on reconnaissance-level hydrogeologic data from a U.S. Geological Survey report (Muir, 1982).

Seaside Basin Update “Yates” Boundary: An updated boundary of the Seaside Basin was developed in a report prepared by Yates and others (2005). This investigation included updated hydrogeologic information and more focused fault mapping. The boundary also recognizes the groundwater flow divide between the Seaside and Salinas Valley Groundwater Basins.

MPWMD believes the Adjudicated Basin Boundary is a better representation of the Seaside Groundwater Basin than the DWR boundary, but the “Yates” boundary actually represents more recent and accurate data about the basin.

The Seaside Groundwater Basin consists of a sequence of three aquifers that overlie the relatively impermeable Monterey Formation. The lowermost or deepest aquifer is the Santa Margarita aquifer, the middle aquifer is the Paso Robles aquifer, and the uppermost or shallowest aquifer is the Dune Sands aquifer. The Paso Robles and Santa Margarita aquifer are the principal water-producing aquifers in the basin. The aquifers in the basin have been folded and faulted resulting in varying thicknesses and depths across the basin. The Seaside Basin has traditionally been subdivided into several subbasins and subareas for hydrologic analyses. These divisions reflect a combination of hydrogeologic and jurisdictional boundaries. A hydrogeologic boundary created by the Laguna Seca Anticline (an upward fold of rock layers) divides the basin into northern and southern subbasins. Each of the two subbasins is further divided into coastal and inland subareas.

Total Usable Storage Space in the Coastal and Northern Inland Subareas is 31,770 acre-feet. Total Usable Storage Space in the Laguna Seca Subarea is 20,260 acre-feet. Total Usable Storage Space in the entire Seaside Groundwater Basin is 52,030 acre-feet.

The Adjudication

Cal-Am filed the action which initiated adjudication August 14, 2003. The defendants were the City of Seaside, the City of Monterey, the City of Sand City, the City of Del Rey Oaks, Security National Guaranty, Inc., Granite Rock Company, D.B.O. Development Company No. 27, Muriel E. Calabrese 1987 Trust, Alderwoods Group (California), Inc., Pasadera Country Club, LLC, Laguna Seca Resort, Inc., Bishop, McIntosh & McIntosh, and The York School, Inc. A decision was entered March 2006 and was amended in February 2007 to allow Cal-Am to combine its production from the Coastal Subareas and Laguna Seca Subarea in determining its compliance with its assigned production allocation.

Water level data from wells in the Seaside Basin have been collected for more than 40 years. In the ten years prior to the adjudication, water levels in the Santa Margarita aquifer had declined 20 feet from approximately 5 feet above sea level to 15 feet below sea level. During the 42-year period December 1960 through December 2002, water levels had dropped from approximately 50 feet above sea level to 10 feet below sea level. Similarly, groundwater levels in the eastern end of the Laguna Seca Subarea for a 13-year period from 1989 through 2001 in the Santa Margarita (SM) aquifer had declined about 25 feet from 230 feet above sea level to 205 feet above sea level, with seasonal fluctuations throughout the period of analysis. Current data shows levels in the Laguna Seca subarea continue to drop.

Two hydrogeologic assessments of the Seaside Groundwater Basin were prepared for the adjudication proceedings and form the factual basis for the determination by the Monterey County Superior Court (Case No. M66343) that the Seaside Groundwater Basin is in overdraft. The first report, Hydrogeologic Assessment of the Seaside Groundwater Basin, prepared for California American Water by CH2M Hill, is dated January 2004, and is referred to as the "CH2M Hill Report". The second report, Seaside Groundwater Basin: Update on Water Resource Conditions, prepared for the District by Eugene B. (Gus) Yates, Martin B. Feeney, and Lewis I. Rosenberg, is dated April 14, 2005 and is referred to as the "Yates Report". Both reports developed annual water budgets for the Seaside Basin to estimate the safe yield of the basin. Specifically, the CH2M Hill Report estimated that the safe yield for the basin ranged from 2,581 acre-feet per year (afy) to 2,913 afy and the Yates Report estimated that the safe yield for the basin was 2,880 afy. Based on these estimates and then-recent basin extractions of approximately 5,600 afy, both reports concluded that the basin was in overdraft. That conclusion was confirmed in the adjudication decision which established a "Natural Safe Yield" for the Seaside Basin of 3,000 afy.

Accordingly, the current restrictions are needed to balance outflows and inflows within the basin, prevent further declines in water levels, and reduce the risk of seawater intrusion.

To achieve the Natural Safe Yield, pumpers were expected to reduce pumping in steps every three years through 2021. The required reductions in pumping are not borne by all pumpers. Initially, only "Standard Producers" or pumpers exercising appropriative water rights are required to reduce their production. "Alternative Producers" or pumpers exercising overlying water rights are required to reduce their production only when the Standard Producers' production has been reduced to zero acre-feet per year and additional reductions are required to reach the natural safe yield of the subarea. The Standard Producers include California American Water and the Seaside Municipal Water System. Alternate Producers include landowners of individual parcels and jurisdictions such as Sand City, Seaside, and Monterey County.

As part of its Well Registration and Reporting Program, the District maintains a list of registered well owners that derive their source of supply from the Seaside Groundwater Basin that are within the District boundaries. Note that there are some wells within the Seaside Basin that are outside the District boundaries and, if di minimis, are not tracked or regulated by the District. Larger wells in the basin, but outside the District, are monitored by the District on behalf of the Watermaster.

The District didn’t always regulate the Laguna Seca Subarea and began initial public outreach to explain the proposed change to the definition of the Monterey Peninsula Water Resource System (MPWRS) to include the Northern Inland and Laguna Seca Subareas in May 2008. District staff met with representatives from affected Property Owner and Management Associations during the summer of 2008, to discuss the proposed change and its implications. In addition, District staff and counsel participated in several settlement discussions with the Hidden Hills Subunit Ratepayers Association (HHSRA) during this period. District Ordinance No. 135 that changed the definition of the MPWRS to include the entire Seaside Basin, including the Northern Inland and Laguna Seca Subareas, went into effect on October 22, 2008.

The Watermaster

A Watermaster was established for the purposes of administering and enforcing the provisions of the Decision and any subsequent instructions or orders of the Court. The Watermaster consists of thirteen (13) voting positions held among nine (9) representatives. California American, Seaside, Sand City, Monterey, and Del Rey Oaks shall each appoint one (1) representative to Watermaster for each two-year term of Watermaster. The Landowner Group shall appoint two (2) representatives to Watermaster for each two-year term of Watermaster. The MPWMD shall have one (1) representative and the MCWRA shall have one (1) representative. The representatives elected to represent the Landowner Group shall include one (1) representative from the Coastal Subarea and one (1) representative from the Laguna Seca Subarea. The California American representative shall possess three (3) voting positions; the. Seaside, MPWMD, and MCWRA representatives shall each possess two (2) voting positions; and every other representative shall

posses one (1) voting position.

The 2018 Annual Report of the Watermaster, attached as Exhibit 2-C, provides a good overview of the activities of the Watermaster.

EXHIBITS

2-A Seaside Basin Boundaries

2-B Other Useful Figures

2-C 2018 Annual Report of the Watermaster (Several Appendices Excluded)

The full report may be found at:

http://www.seasidebasinwatermaster.org/Other/2018%20Annual%20Report.pdf

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