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ITEM: |
ACTION ITEMS |
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24. |
REVIEW PROCEDURE AND
TIMELINE FOR CONDUCTING A FEASIBILITY STUDY OF INCREASING THE HEIGHT OF THE
EXISTING LOS PADRES DAM TO INCREASE ITS WATER STORAGE CAPACITY |
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Meeting Date: |
April 21, 2008 |
Budgeted: |
No |
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From: |
Darby Fuerst, |
Program/ |
N/A |
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General Manager |
Line Item No.: |
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Prepared By: |
Andrew M. Bell |
Cost Estimate: |
N/A |
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General Counsel Approval: N/A |
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Committee Recommendation: N/A |
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CEQA Compliance: N/A |
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SUMMARY: The purpose of this item is for the Board to receive
a staff report regarding procedure and timeline for conducting an evaluation of
the feasibility of increasing the height of the existing Los Padres Dam, or of
otherwise increasing the capacity of Los Padres Reservoir. The purpose of the project would be to create
additional storage capacity in the reservoir so that stored water could be
released to increase streamflow in the
RECOMMENDATION: The Board should receive staff’s presentation, ask questions, and open the meeting to the public for comment. The Board should then decide whether to direct staff to issue requests for proposals to consulting firms for completing the needed engineering, geotechnical, and environmental studies to evaluate the feasibility of increasing the storage capacity of Los Padres Reservoir, and to determine the timeline for doing so.
BACKGROUND: At the February 28, 2008 Board meeting, the Board approved a request by Director Brower to direct staff to prepare, for review at a future Board meeting, a report regarding the feasibility of increasing the height of the existing Los Padres Dam.
The existing Los Padres Dam,
constructed in 1948 and 1949 by California Water and Telephone, a predecessor
of California American Water (CAW), is an embankment dam (zoned earthfill)
approximately 150 feet high. It is
located on the
Increasing the height of the dam would require extensive engineering, geotechnical, and planning efforts. In order to evaluate the technical feasibility of this project, the District would need to retain experts in dam construction and rehabilitation. A summary of factors to consider is provided in Exhibit 24-A, a memorandum report by District Engineer Andrew Bell.
A location map of the area of the dam and reservoir is provided in Exhibit 24-B. This is a figure from the 1998 Draft Supplemental EIR for CAW’s proposed Carmel River Dam and Reservoir Project, which was a new, higher concrete gravity dam to be located approximately one-half mile downstream of the existing dam and a reservoir with a capacity of 24,000 acre-feet. Exhibit 24-B shows the “Existing Wilderness Boundary” and the “Proposed Los Padres National Forest Boundary Adjustment,” which would be an addition of approximately 140 acres (Parcel B) to the Ventana Wilderness in exchange for removing approximately 23 acres (Parcel A). An increase in the elevation of the existing spillway of five feet or more would cause the reservoir to extend into the Ventana Wilderness along Danish Creek near its mouth. This would require either a land exchange similar to that shown in Exhibit 24-B or other arrangement acceptable to the U.S. Forest Service and other entities with interests in wilderness areas.
Two alternatives to increasing the height of Los Padres Dam that could be considered are described in Exhibit 24-A: (1) sediment that has accumulated in Los Padres Reservoir could be removed; and (2) an inflatable dam could be installed in the existing spillway and raised to create additional storage space when it is deemed safe to do so.
The conclusion of the staff report (Exhibit 24-A) is as follows:
“Increasing the height of Los Padres Dam, or otherwise increasing the storage capacity of Los Padres Reservoir, would require extensive engineering, geotechnical, environmental review, and project planning efforts. In order to evaluate the technical feasibility of this project, the District would need to retain expertise in dam construction and rehabilitation, in environmental impacts of such a project, and most likely in fish passage biology and engineering. MPWMD staff members are not qualified to make such determinations. The timelines and costs for such studies would require staff to developing scopes of work for the desired studies, obtain proposals from consultants, and analyze the proposals.”
IMPACT TO DISTRICT STAFF/RESOURCES: If the Board decides to proceed with feasibility investigations of increasing the storage of Los Padres Reservoir, the initial tasks by Planning & Engineering Division staff would be to issue requests for proposals to obtain formal scope of work, cost, and timeline from engineering, geotechnical and environmental impact consultants to complete the needed evaluations. Once funds are authorized and agreements are executed, staff would administer the contracts and oversee the consultants’ work. These are work efforts not currently anticipated by the Planning & Engineering Division, and they would impact the Division staff’s current highest priority, which is to process the existing backlog of approximately 60 Water Distribution System permit applications and pre-applications that have been received by the District.
There would be a significant direct financial impact to the District if consultant services were retained to conduct the feasibility investigations. At its December 10, 2007 meeting, the Board approved a “pay-as-you-go” approach as an alternative to financing the $1.7 million estimated cost to complete the Seaside Basin Phase 1 ASR Project, which will reduce the District’s general operating reserve below the Board’s 5% minimum for the next 12 to 24 months. Since the District would have insufficient reserves to pay for the additional environmental and engineering work required to conduct feasibility studies of increasing the storage capacity of Los Padres Reservoir, the Board would need to either temporarily borrow the amount from one of the District’s designated reserves such as the Flood/Drought Reserve, or do some other type of short-term borrowing. In either case the funds would need to be recovered by a User Fee increase to cover the engineering and environmental consultant costs for feasibility investigations of increasing the storage capacity of Los Padres Dam and Reservoir.
EXHIBITS
24-A April 7, 2008 Memorandum Report by Andrew M. Bell, MPWMD District Engineer
24-B Figure 2-2. Location Map - Proposed
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