Meeting Date:

January 17, 2018





David J. Stoldt,


Water Supply Projects


General Manager

Line Item No.:





Prepared By:

Suresh Prasad

Cost Estimate:



General Counsel Review:N/A

Committee Recommendation:The Administrative Committee reviewed this item on January 17, 2018 and recommended _____________________.

CEQA Compliance:This action does not constitute a project as defined by the California Environmental Quality Act Guidelines Section 15378.


SUMMARY:†† There are two pending efforts to model the Seaside Groundwater Basin for which District funding will be required: Geochemical Modeling and Recalibration and Updating of the Basin Model.Each is summarized below.On August 21, 2017, the MPWMD Board authorized for this work, however, the cost estimates are now higher than the previously authorized amount.


Geochemical Modeling:There are potential changes in groundwater quality as a result of the introduction of new sources of water to the Seaside Basin from the Monterey Peninsula Water Supply Project (MPWSP.)In its original form, wells from the Seaside Basin draw from ďancientĒ water that has resided for many years, as well as some natural replenishment from precipitation.Since 1998, Aquifer Storage and Recovery (ASR) has injected Carmel River water for later recovery.With the expected completion of the MPWSP in a few years, Pure Water Monterey water and desalinated water will be injected in the basin for later recovery.The potential interactions of these various sources of water needs to be investigated in order to ensure the long-term integrity of the basin.For example, a few years ago, arsenic concentrations in groundwater in Orange County spiked in a transient fashion later determined to be linked to injection of reverse osmosis water manufactured by the Orange County Water District Groundwater Replenishment Project.The geochemical model to be developed will examine the interactions of the different water types and the aquifer mineralogy.Such a modeling effort is expected to cost up to $70,000 and should be cost-shared by the District, Monterey One Water, and California American Water Company.A cost-sharing arrangement will be determined to share the costs of this effort.If each party, was responsible for 1/3rd of the estimated cost, the Districtís share would be $23,333.The District will also be responsible for its portion of the Pure Water Monterey cost (75% of 33% of the cost), an additional $17,500 would be required, for a total of $40,833.Additional contingency of $4,167 is also requested. Previous Board action authorized $30,000 for this effort.


Recalibration and Updating of the Basin Model:The Seaside Basin Watermaster is considering recalibrating and updating its Seaside Groundwater Basin Model in 2018. The Model was developed for the Watermastcr by its consultant, HydroMetrics WRI, and was provided to Pure Water Monterey for use in performing modeling studies for the Pure Water Monterey groundwater replenishment project.The Watermaster has asked that the District and Monterey One Water participate in cost-sharing.Such a modeling effort is expected to cost $54,370 and should be cost-shared by the District and Monterey One Water.The cost sharing proposed by the Watermaster would have the Watermaster pay 50% of the costs ($27,185), the District cover 25% of the costs directly ($13,593), as well as the Districtís portion of the Pure Water Monterey cost (75% of the other 25% of the cost $10,195), for a total of $23,788.Additional contingency of $4,212 is also requested.Previously the Board action authorized $18,170 for this effort.


Adequate funds for both studies have been identified in the adopted Fiscal Year 2017-18 budget.


RECOMMENDATION:Staff recommends that the Committee recommend Administrative Committee approval of a not-to-exceed amount of $45,000 for the Districtís share of geochemical modeling in FY 2017-18 and an amount not-to-exceed $28,000 for the Districtís share of recalibration and updating the basin model.On August 8, 2017, the Water Supply Planning Committee voted 3 Ė 0 to recommend approval.On August 21, 2017, the Board authorized for this work at no-to-exceed cost of $50,000.