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rights to expand the existing Rosedale Banking Program beyond the existing 10,000
AFY and not acquiring the Newhall Land Semitropic Banking Program as provided in
the Semitropic/Newhall Banking Agreement. Further, reducing recycled water use to
that used in the Newhall Ranch project and the Agency’s Phase 2B-D projects.
 Scenario C: Larger supply reductions relative to the Base Scenario with larger
reductions in SWP supply reliability and additional limits on alluvium groundwater
supplies, not allowing Saugus extractions beyond the average annual quantities and
further reducing recycled water use to existing use and that supply generated by and
for the Newhall Ranch project.

The analysis shows that the Base Scenario (UWMP supplies) is fully reliable through buildout
and that Scenario A and B meets a goal of reaching a 95% reliability objective. Scenario C
would not meet that objective, however supply shortfalls occur in dry-years and could be
mitigated if the Board chose to exercise its contractual rights to expand the extraction capacity
for the Rosedale Banking program by 10,000 AFY and participated in a banking program with
10,000 acre-feet of extraction capacity, such as the Newhall Land Semitropic Banking Program,
as indicated in the 2015 UWMP in combination with other banking programs, such as an Aquifer
Storage and Recovery (ASR) program using the Saugus Formation. As shown below, with
those modifications, all of the scenarios meet a water supply reliability objective of 95%
reliability in 2050 (buildout).

On June 13, 2018, the Water Resources and Watershed Committee considered staff’s
recommendation to approve a resolution authorizing the General Manager to execute an
assignment of Buena Vista-Rosedale Rio Bravo Water Supply to the proposed Tapia
Annexation.

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