HomeMy WebLinkAboutItem 09h - Purchase of Cyclic Water from Main San Gabriel Watermaster
STAFF REPORT
PUBLIC WORKS SERVICES DEPARTMENT
DATE: October 7, 2025
TO: Honorable Mayor and City Council
FROM: Paul Cranmer, Public Works Services Director
By: John Corona, Utilities Manager
SUBJECT: PURCHASE OF 2,351.92 ACRE-FEET OF IMPORTED CYCLIC STORAGE
WATER FROM THE MAIN SAN GABRIEL BASIN WATERMASTER IN THE
AMOUNT OF $2,387,198.80
CEQA: Not a Project
Recommendation: Approve
SUMMARY
The City of Arcadia gets a major portion of its drinking water supply from the Main
San Gabriel Groundwater Basin (“Main Basin”). The remaining demand is met by City
wells that pump a fixed amount of groundwater from the Raymond Basin. Arcadia
has a Cyclic Storage account with the Main Basin that can be used to store
supplemental Replacement Water for later use. The City has the opportunity to pre-
purchase imported water that has been made available through the Upper San
Gabriel Valley Municipal Water District (“Upper Water”) for $1,015 an acre-foot. This
rate is $100 an acre-foot less than Replacement Water that is typically purchased.
This water will be used to satisfy demands for Fiscal Year 2025-26, with any remaining
water to be used at a later date. By pre-purchasing at a lower rate, the City and its
customers will save approximately $235,000 in water costs.
It is recommended that City Council approve the purchase of 2,351.92 acre-feet of
Imported Cyclic Storage Water from the Main San Gabriel Basin Watermaster, in the
amount of $2,387,198.80.
BACKGROUND
In 1973, an overproduction of water from the Main Basin resulted in a stipulated
judgment that created the Main San Gabriel Basin Watermaster. The Main San
Cyclic Water Purchase from the Main San Gabriel Watermaster
October 7, 2025
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Gabriel Basin Watermaster is a nine-person board appointed by the Los Angeles
County Superior Court that administers and enforces the provisions of the Main San
Gabriel Basin Judgment. This Judgement established water rights and responsibilities
for the efficient management of the quantity and quality of the Main Basin.
This is accomplished, in part, by the Main San Gabriel Basin Watermaster
determining the total amount of water that can be pumped from the Main Basin each
year, free from a Replacement Water assessment; this amount is referred to as the
Operating Safe Yield. The Operating Safe Yield was set at 160,000 acre-feet. The City
of Arcadia’s annual share of the Operating Safe Yield is 4.23%, or 6,769.68 acre-feet.
Pumping more water than the amount established for a given year is allowed;
however, the City must then purchase Replacement Water to recharge the
groundwater basin. For context, one acre-foot is approximately the size of an entire
football field buried in one foot of water.
DISCUSSION
The Main San Gabriel Basin Watermaster has set the cost for Replacement Water at
$1,115 an acre-foot for Fiscal Year 2025-26. However, to encourage water agencies
to purchase available water from the State Water Project, the Watermaster is offering
a reduced rate of $1,015 per acre-foot, if purchased before January 1, 2026. Pre-
purchasing 2,351.92 acre-feet of additional imported supplemental water will save
the City approximately $235,000.
The advantages of pre-purchasing imported supplemental water and storing it in the
City’s Cyclic Storage Account are two-fold. First, it ensures that water is delivered to
the Main Basin, which helps maintain higher groundwater levels than if the water
was purchased as Replacement Water. Second, the water is purchased at a lower
rate and can be credited toward the City’s Storage account for up to five years. With
Replacement Water costs increasing annually, the savings will grow over time.
ENVIRONMENTAL ANALYSIS
The proposed action does not constitute a project under the California
Environmental Quality Act (“CEQA”) under Section 15061 (b)(3) of the CEQA
Guidelines, as it can be seen with certainty that it will have no impact on the
environment.
Cyclic Water Purchase from the Main San Gabriel Watermaster
October 7, 2025
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FISCAL IMPACT
Sufficient funds have been budgeted in the Fiscal Year 2025-26 Water Operations
Budget for the purchase of Imported Cyclic Storage Water. No General Funds are
necessary for this purchase, and pre-purchasing this water at the reduced rate will
save the City approximately $235,000.
RECOMMENDATION
It is recommended that the City Council determine that this action does not
constitute a project under the California Environmental Quality Act (“CEQA”); and
approve the purchase of 2,351.92 acre-feet of Imported Cyclic Storage Water from
the Main San Gabriel Basin Watermaster, in the amount of $2,387,198.80.