WATER SUPPLY PLANNING COMMITTEE
ITEM:		DISCUSSION ITEM
2.	ABILITY OF PURE WATER MONTEREY TO PROVIDE PROTECTIVE WELL LEVELS IN THE SEASIDE BASIN
Meeting Date:			April 5, 2021	Budgeted:	N/A
From:			David J. Stoldt	Program/	N/A
			General Manager	Line Item:
Prepared By:			David Stoldt	Cost Estimate:	N/A
General Counsel Review: N/A
Committee Recommendation: N/A
CEQA Compliance: This action does not constitute a project as defined by the California Environmental Quality Act Guidelines section 15378.

SUMMARY: There has been much discussion about protective water levels being achieved in the Seaside Groundwater Basis through the addition of water to the ground, beyond the perceived overdraft. This was raised in a letter from the Watermaster to the California Coastal Commission in August 2020. This is not a new issue, rather it has been known and talked about since 2009.

Protective groundwater elevations were determined in 2009 using the Seaside Groundwater Basin groundwater flow model and cross-sectional modeling (HydroMetrics LLC, 2009). A subsequent study in 2013 to revisit and update the protective groundwater elevations concluded that the calibrated parameters in the basin-wide model do not indicate that protective elevations should be lowered (HydroMetrics WRI, 2013). 

Both Pure Water Monterey expansion and the MPWSP desalination plant were sized taking into consideration Cal-Am’s 700 AFY in-lieu recharge, but never has either project been approached by the Watermaster until recently or sized to meet replenishment needs of the Seaside Basin, despite the known need for protective water levels (PWLs).  In fact, at the Watermaster Technical Advisory Committee meeting which preceded the Watermaster Board meeting August 7, 2013 where the second presentation was made, the Cal-Am representative stated that replenishment to meet protective water levels is not the company’s responsibility.

Further, until the past few months there has been no discussion as to how the Watermaster could afford to purchase water to achieve protective levels, especially desalination supply at over $5,000 - 6,000 per acre-foot.  Likewise, there has to date been no initiative by the Watermaster to develop the infrastructure to distribute and inject water for such a purpose.

To make a connection between the proposed desalination plant and Seaside Basin protective levels was a red herring for the Coastal Commission hearing.  For the Watermaster to state that “The MPWSP is the only possible supplemental water project before us that is capable of supplying the additional water needed to allow Watermaster to sustain PWL in the Basin” is actually an admission that the desalination plant is sized grossly over the needed capacity as a replacement supply for consumers on the Peninsula, further underscoring that the demand forecast used was inflated.  Further, it ignores that a Pure Water Monterey expansion of 2,250 AFY could also provide the needed water for such a purpose, as shown in Exhibit 2-A attached. The Watermaster has simplified the annual requirements for PWLs which would be 1,000 AFY if at inland wells, but only 850 AFY if at coastal wells.   The new 2022 AMBAG growth forecast indicates even more water available from Pure Water Monterey Expansion that could be made available for protective levels, drought reserve, or unexpected growth.

Assuming available supplies of 11,294 AF each year with Pure Water Monterey (PWM) expansion, as shown below, then over 30 years there would be additional water available of 27,931 AF or an average of 931 AF per year.

Supply Source	w/ PWM Expansion
Pure Water Monterey	3,500
PWM Expansion	2,250
Carmel River	3,376
Seaside Basin	774
Aquifer Storage & Recovery (ASR)	1,300
Sand City Desalination Plant	94
Total Available Supply	11,294

If there was concern over the viability of ASR to provide 1,300 AF per year – even though studies show that over time ASR builds up a drought reserve in average-to-wet years sufficient to handle an extended drought – then PWM expansion could first be used to build up a 5-year ASR reserve of 6,500 AF. Since there already exists 1,290 AF of ASR water in the ground another 5,210 would be required – almost the first 4 years of PWM expansion excess. The 30 years after that would yield 24,131 AF or 804 AF per year on average.

Both of these scenarios ignore that 700 AF per year becomes available in year 26 after the Cal-Am in-lieu recharge program is concluded.

EXHIBIT

2-A Calculation of Excess Water Availability under Pure Water Monterey Expansion

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