UPDATE ON Los Padres Dam Alternatives Study


Meeting Date:

January 23, 2017





Dave Stoldt,




General Manager





Prepared By:

Larry Hampson




SUMMARY:   The California Department of Fish and Wildlife (CDFW) and the National Marine Fisheries Service (NMFS) recently provided comments on the proposed set of alternatives for Los Padres Dam (LPD) (see attached Exhibits 2-A and 2-B for comments and Exhibit 2-C for a description of the alternatives).  There are some key statements from the agencies that staff wish to discuss with the Committee including the following.


CDFW states:


“Alternative 4a [dam raise] – this causes a sustained loss of upstream habitat, has less operational flexibility, is likely to have greater fish passage difficulties and is more expensive.”


Alternative 4c & 4d [new dam downstream] – These eliminate additional spawning and rearing habitat, cause additional downstream and upstream passage problems and come at a high cost. Department will not permit nor contribute funds to a new dam.”


NMFS states:


“We … request that alternatives 4a, 4c, and 4d be removed from further consideration.”


RECOMMENDATION:   The Committee should review comments by the two agencies and consider providing direction to staff.




As part of the scope of work to develop a long-term plan for management of Los Padres Dam, the Water Supply Committee had requested that a dam raise and an expanded reservoir be included in the alternatives to be analyzed.  Alternative 4a and 4b are similar with Alternative 4a being a permanent dam raise of about 10 feet and Alternative 4b being installation of a 10-foot high rubber dam.  Both alternatives would result in an estimated increase in storage capacity of just under 600 acre-feet (AF).  The rubber dam is favored by both agencies over a permanent dam raise because of the operational flexibility for raising and lowering the water surface.  This would reduce impacts to spawning and fish passage as compared to a permanent dam raise.


The Committee had also directed staff to include an alternative to build a larger reservoir.  Alternatives 4c and 4d involve building a new dam about 2,600 feet downstream of the existing dam at the same site as the proposed New Los Padres Dam.  Depending on what elevation the spillway is set at, a new dam could result in a storage capacity ranging from 3,000 AF to a little over 7,500 AF.


Both CDFW and NMFS strongly object to including an alternative that would result in a new dam on the river.


Attached as Exhibit 2-D is a new agreement between California American Water, NMFS, and the State Coastal Conservancy regarding a set of activities Cal-Am must carry out while SWRCB Cease and Desist Order 2016-0016 remains in effect.  Several of the activities involve work at Los Padres Dam, including completing the dam alternatives study.



2-A      CDFW comments

2-B      NMFS comments

2-C      Draft Alternatives Descriptions

2-D      MOA between CAW, NMFS, and Conservancy