CONSIDER Receipt of Los Padres Dam and Reservoir Long-Term Strategic and Short-Term Tactical Plan


Meeting Date:

July 21, 2014





Dave Stoldt,


Augment Water Supply


General Manager

Line Item No.:    

Program 1-8-1


Prepared By:

Larry Hampson

Cost Estimate:



General Counsel Approval:  N/A

Committee Recommendation:  Water Supply Planning Committee reviewed this item on July 14, 2014 and recommended approval.

CEQA Compliance:  N/A


SUMMARY:  At their July 14, 2014 meeting, the Water Supply Planning Committee received the June 2014 - Los Padres Dam and Reservoir Long-Term Strategic and Short-Term Tactical Plan” (Los Padres Dam Plan).  The Committee recommended that the Board of Directors receive the plan, subject to further review and analysis by the Committee. 


RECOMMENDATION:  If this item is approved with the Consent Calendar, the Board will receive the “Los Padres Dam and Reservoir Long-Term Strategic and Short-Term Tactical Plan.”  The Water Supply Planning Committee will continue its review of the plan over several meetings and may make additional recommendations to the Board of Directors about the plan.


DISCUSSION:  In April 2013, the National Marine Fisheries Service (NMFS) directed California American Water (Cal-Am) to resolve fish passage issues and aquatic habitat degradation in the Carmel River associated with Los Padres Dam.  In December 2013, NMFS released the final recovery plan for South Central Coast steelhead that included a critical recovery action to improve upstream passage at Los Padres Dam and address habitat degradation or analyze the effect of dam removal.  In its 2015-17 General Rate Case application to the California Public Utilities Commission, Cal-Am requested $4.2 million to improve downstream fish passage at Los Padres Dam and $1 million to complete a detailed feasibility study to determine the ultimate fate of the dam.  The District supported both requests, but recommended that MPWMD take the lead, with assistance by Cal-Am, on completing a feasibility study for Los Padres Dam. 


If the CPUC approves Cal-Am’s request for funds, the feasibility study would be completed over a three-year period and would focus on evaluating options for improving upstream steelhead passage at Los Padres Dam, whether the Carmel River is better or worse with surface storage at Los Padres Dam, and what options exist to maintain or enhance physical existing surface storage in Los Padres Reservoir (e.g., by managing existing sediment and annual sediment inflow to the reservoir).  Also included in the studies would be an analysis of the potential geomorphic effects of a resumption or increase of the natural flow of sediment. 


In order to provide additional water supply to the Monterey Peninsula and develop a long-term strategy for Los Padres Dam, the Water Supply Planning Committee requested an investigation by the Shibatani Group.  The first draft of the Los Padres Dam Plan was reviewed by the Committee with Robert Shibatani on February 4, 2014.  The Committee and staff provided comments to the Shibatani Group and a final draft of the plan was reviewed by the Water Supply Planning Committee at their July 14, 2014 meeting.


The Committee expressed several concerns about the alternative recommended by the Shibatani Group (remove Los Padres Dam and build off main-stem storage).  Committee members believe a new dam in the Carmel River watershed would not be feasible due to community concerns and potential environmental effects if a proposed dam would impact National Forest or Wilderness areas.  The Committee focused on an alternative that would include preserving or enhancing the existing storage at Los Padres Reservoir in order to provide water for downstream users and to benefit aquatic habitat downstream of the dam.


The Los Padres Dam Plan by the Shibatani Group is one of several component studies and investigations that will be needed to fully evaluate options for Los Padres Dam.  In addition to further review of that plan by the Water Supply Planning Committee, studies needed to address the questions and recommendations made by NMFS and the Water Supply Planning Committee about the dam include:


·         Flow analyses associated with alternatives – several flow analyses involving different levels of diversions would be required in order to evaluate whether the Carmel River is better or worse with surface storage at Los Padres Dam.  Alternative scenarios would include simulation of existing conditions and Cal-Am operations; future Cal-Am operations as proposed in the Monterey Peninsula Water Supply Project; partial reservoir dredging; full reservoir dredging; reservoir enlargement; and dam removal (with future Cal-Am operations).  MPWMD is currently developing a computer model that will be able to simulate these alternatives.  The model is expected to be completed by the end of 2014 or early 2015.


·         Updated instream flow study – NMFS completed recommendations for maintaining instream flows in 2002.  A modified version of those recommendations is currently being attached by SWRCB to all new permits issued for the Carmel River.  The 2002 NMFS study does not accurately reflect significant changes in river habitat conditions and Cal-Am operations over the past 25 years.   District staff is currently working with a consultant to develop an updated instream flow analysis using the Instream Incremental Flow Method (IFIM).  A workshop to discuss the IFIM study was held April 23, 2014.  The study will likely take one to two years to complete.


The IFIM can be used to evaluate how changes in flow affect steelhead habitat and fish passage.  Alternatives being considered at Los Padres Dam would have significant effects on the flow regime in the dry season and could affect the flow regime in the “shoulder” seasons of late fall/early winter and late spring/early summer. 


·         Steelhead habitat evaluation of the Carmel River watershed – MPWMD’s 2004 evaluation of steelhead habitat in the watershed estimated that 50% of the spawning habitat in the watershed was upstream of Los Padres Dam.  Similarly, MPWMD estimated that 42% of the suitable rearing area in the watershed was above Los Padres Dam and that it was of exceptional quality due to its location within the Ventana Wilderness.  These estimates were based on habitat conditions between the 1980s and early 2000s and included the effects of unauthorized diversions.


The value of steelhead habitat both upstream and downstream of Los Padres Dam should be re-evaluated in the context of improvements to habitat in the main stem due to the removal of San Clemente Dam, stream restoration in the lower 15 miles of the river, proposed reductions in Cal-Am diversions, and any proposed gravel replenishment projects associated with sediment management at Los Padres Reservoir.  A combination study using IFIM and habitat suitability index assessments should be used to better understand the value of each reach of the river and each tributary and the potential for improvements downstream of Los Padres Dam.


In addition, MPWMD will be working with Cal-Am to install a steelhead counting device on the downstream steelhead fish passage facilities to be installed at Los Padres Dam.  Monitoring at this location will provide valuable data about how many juvenile and adult steelhead migrate downstream out of the upper watershed.


·         Yield and cost/benefits analysis – Each alternative has different economic and environmental costs as well as benefits.  These should be quantified at a preliminary level and be part of the consideration of alternatives.


·         Sediment management – Los Padres Reservoir is a more difficult and expensive site to address sediment issues than at the San Clemente Reservoir, where a unique situation allowed sediment to remain in place.  A fundamental issue with Los Padres Dam that needs to be addressed with any proposed project is both short term and long term management of sediment.  The long term average sediment inflow is about 20 AFY or the equivalent of about 2,200 tandem truckloads of sediment annually.  Sediment starvation downstream of the dam continues to degrade the river through the armoring effect (winnowing of spawning gravel) and downcutting into the riverbed.  Failure to address this degradation will compromise efforts to improve habitat for steelhead by reducing diversions and may lead to further destabilization of streambanks in the lower 15 miles of the river.



2-A      June 2014 - Los Padres Dam and Reservoir Long-Term Strategic and Short-Term Tactical Plan (Available for review at the District office or on the MPWMD web site)






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