Consider Development of a Recommendation to the Board of Directors on an Agreement with the United States Geological Survey to Calibrate the Carmel River Basin Simulation Model


Meeting Date:

January 20, 2016





Dave Stoldt,




General Manager





Prepared By:

Larry Hampson




SUMMARY:   District staff and consultants have developed a database and several modules needed for completing an integrated groundwater-surface water GSFLOW model for the Carmel River Basin.  Formal calibration is required needed before the model can be used in several planning efforts currently underway.  Staff consider the United States Geologic Survey to be best equipped to perform this calibration as the USGS developed the software that runs the model.  Exhibit 4-A describes the proposed scope of work, which is estimated to cost up to $50,000. 


RECOMMENDATION:   The Committee should review the draft scope of work between the District and the USGS and provide a recommendation to the Board and staff concerning contracting with the USGS for model calibration.


DISCUSSION:  At their August 19, 2013 meeting, the Board of Directors approved expending up to about $128,000 to develop a computer simulation model of the Carmel River Basin that would replace the Carmel Valley Simulation Model (CVSIM), which had been used for water supply planning purposes and is obsolete.  The new model will be used to simulate instream flow needs for steelhead and to model different water supply options.


Staff and consultants will complete the model development in the second quarter of 2016, at which time the model requires calibration in order to be used with several planning efforts currently underway including:


·         Wildlife Conservation Board Streamflow Enhancement Grant program – MPWMD applied for funds to complete the Instream Flow Incremental Method Study, which will use results from the basin model to evaluate effects on steelhead habitat

·         SWRCB Stormwater Grant Program Application – MPWMD is cooperating with Monterey Regional Water Pollution Agency to develop a Stormwater Resource Management Plan for the Carmel River Basin that can use model output to describe stormwater availability

·         Los Padres Dam Long-Term Plan – model output will be used in evaluation management options for the dam

·         Upstream Passage Study at Los Padres Dam – model output will be used in characterizing expected flows over the Los Padres Dam spillway

·         Sediment Management plan at Los Padres Reservoir – model flows can be used as the hydraulic component for a detailed sediment transport model to simulate changes to the river channel downstream of Los Padres Dam from changes in the bedload

·         Water Availability Analysis – the model would be the basis of determining water availability for a Change Petition to the State Water Resources Control Board involving the District’s water rights Permit 20808B

·         Sustainable Groundwater Management Act – Carmel Valley Alluvial Aquifer (CVAA): the model can be used to evaluate proposed management actions for the CVAA

·         Salinas River and Carmel River Basins Study – the model would be used in evaluating the effects of climate change on river flow

·         Drought Contingency Plan – future droughts can be simulated using the model



4-A      Proposal for Calibrating the Carmel River GSFLOW Model using PEST