MONTEREY PENINSULA WATER
MANAGEMENT DISTRICT
MEMORANDUM
DATE: January
25, 2010
TO: Darby
Fuerst, General Manager
FROM: Andrew
M. Bell, District Engineer
SUBJECT: Summary
of MPWMD Investigations of Desalination Projects to Serve the Monterey Peninsula
Area
SUMMARY
Starting
in 1990, MPWMD has investigated a number of desalination projects, with intake
facility sites ranging from the Moss Landing Harbor
to the north to Carmel
River Beach
to the south. This memorandum summarizes
the sites that have been considered, and the studies conducted and documents
prepared to evaluate options for serving the Monterey Peninsula
area from desalination projects.
DISCUSSION
In
1990, due to slow progress of the New Los Padres Dam and Reservoir Project, the
District undertook a review of non-dam alternatives. Based on review of 97 water supply options,
seawater desalination was determined to be the most promising alternative. The first study of desalination potential was
conducted by Boyle Engineering. Boyle’s
initial report, issued July 17, 1991 and titled “MPWMD Desalination Feasibility
Study,” reviewed seven sites from Moss Landing on the north to Carmel River. See Attachment 1 for a list and
locations of these sites. The resulting
recommendations of this study were to conduct more detailed evaluations of two
sites, the Monterey Regional Water Pollution Control Agency (MRWPCA) site and
the Moss Landing site.
Geotechnical
studies of seawater or “saline groundwater” intake wells at three locations were
conducted by District consultant Staal, Gardner & Dunne. These three locations are the Marina County Water
District (now Marina Coast Water District) Wastewater Treatment Facility in Marina (February 1991 report), the Monterey Sand Company
site in Marina (February 1992 report), and Sand City
(February 1992 report).
Although
the MRWPCA and Moss Landing sites were recommended by Boyle, these further
investigations resulted in selecting Sand
City as an additional
promising alternative. The desired capacity
of what was termed a “near-term project,” which represented a project that
could be completed while the dam and reservoir project proceeded, was
determined to be a 3 million-gallon-per-day (MGD) plant operated seasonally to
produce 2,000 acre-feet per year (AFY).
In March 1992, District consultant James M. Montgomery Consulting
Engineers issued a report titled “MPWMD Desalination Preliminary Design, Final
Report.” This report provides
preliminary design and estimates of capital costs for a 3 MGD project at these
three sites.
The
Sand City site was ultimately selected as
being the most promising, and a Draft EIR was issued on a 3 MGD project
producing 2,000 AFY in April 1992 (Draft EIR, Near-Term Desalination Project,
by EIP Associates). A more extensive geotechnical
feasibility study was then conducted on intake facilities at the Sand City
site, and the report on this study by Staal Gardner & Dunne was issued in
September 1992. The Final EIR on the Sand City
project was issued in December 1992. The
District issued a call for bids for final design, construction, and operation
of the project pending final approval of the project and its funding by a vote
of Peninsula residents. Unfortunately the vote, held in June 1993,
failed.
In
2002, the Board directed staff to investigate the feasibility of a desalination
project located within the District boundary that could produce up to 8,400
AFY. The District retained engineering
consulting firm Camp Dresser & McKee and environmental consulting firm
Jones & Stokes Associates (JSA) to conduct project studies. Conclusion of the engineering studies for a
7.5 MGD project producing 8,400 AFY are presented in the March 2003 CDM report
titled “Monterey Peninsula Water Supply Project Alternatives, Final Phase 1 Technical
Memorandum.” A report titled “Board
Review Draft EIR” prepared for the project by JSA was issued in December
2003. This document reviewed a project
with intake facilities located in Sand
City just north of the
Monterey Beach Hotel, and three alternative plant sites. The locations of these facilities are shown
in Attachment 2. The Board elected not to proceed with this
project.
In
January 2008, the Board directed staff to re-initiate the evaluation of a
desalination project in Sand City and former Fort Ord. In the meantime, the City of Sand City had
gained approval of its brackish water desalination project with intake
facilities located in the area where intake facilities were proposed for the
8,400 AFY project. The updated
evaluation of a project in this area, presented in an August 2008 report by JSA
and CDM titled “MPWMD 95-10 Project Constraints Analysis,” concluded that the Sand City
area was no longer available, but that there is the possibility of a project
with intake facilities located in the southern portion of former Fort Ord. A subsequent study of the feasibility of a
project in this area was conducted by Martin B. Feeney, Consulting
Hydrogeologist. Findings of Mr. Feeney’s
studies are in his November 2009 report titled “MPWMD 95-10 Desalination
Project Hydrostratigraphic Investigation” and were provided to the Board for
the December 14, 2009 meeting. The
report concluded, based on review of logs of existing wells and results of a
number of soil borings drilled in what is now the Fort Ord Dunes State Park,
that a project with intake facilities constructed in this area would be
infeasible due to the absence of a continuous low-permeability layer that would
prevent the project from impacting the Seaside Groundwater Basin. Mr. Feeney recommended that the District
“terminate further investigation of this project at this juncture.”
CONCLUSION
Since
the early 1990s, the District has investigated a large number of desalination
projects and sites in locations ranging from Moss Landing on the north to Carmel River
Beach on the south. No project site that would be both
technically and economically feasible appears to exist within the MPWMD
boundary. Desalination projects
currently under review that could serve the District as part of California
American Water’s (CAW) Coastal Water Project would have intake facilities
located north of the District boundary, just north of Reservation Road (Regional
Project and North Marina Project) and at Moss Landing (the site initially
proposed by CAW as part of the Coastal Water Project).
Attachment
1 page II-6 and Figure 1 – Desalination Sites
Considered, from Boyle Engineering July 17, 1997 report, MPWMD Desalination Feasibility Study
Attachment
2 Figure ES-1 – Location of HDD Wells and
Collection Pipelines, from Jones & Stokes, December 2003 report, Board Review Draft, MPWMD Water Supply
Project, Draft EIR
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