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Science Review of Report “On Estimating Net Delta Outflow (NDO): Approaches to Estimating NDO in the Sacramento-San Joaquin Delta”

Transmittal Letter from Dr. Cliff Dahm to the State Water Resources Control Board (October 5, 2016)

 

An Independent Peer Review Report for the Delta Science Program on the DWR Report “On Estimating Net Delta Outflow (NDO): Approaches to Estimating NDO in the Sacramento-San Joaquin Delta (September 30, 2016)

 

 

Background:

The State Water Resources Control Board (State Water Board) is currently undertaking a four-phased process to develop and implement updates to the Bay-Delta Plan and flow objectives for priority tributaries to the Delta to protect beneficial uses in the Bay-Delta watershed. The Bay-Delta Plan identifies beneficial uses of Bay-Delta waters, water quality objectives for the reasonable protection of those beneficial uses, a program of implementation for achieving the water quality objectives and an associated surveillance and monitoring program. 

 

Phase 1 of the review of the Bay-Delta Plan is focused on southern Delta water quality and San Joaquin River flows. Phase 2 (Comprehensive Review) is focused on other changes that may be needed to update the remainder of the Bay-Delta Plan in order to protect beneficial uses, including fish and wildlife beneficial uses.  One of the important parameters affecting fish and wildlife beneficial uses is Delta outflows (net Delta outflow).
 

The State Water Board has requested the assistance of the Delta Science Program to obtain a peer review of the report provided by DWR in response to a request for a technical analysis of appropriate methodologies for determining net Delta outflow as a regulatory parameter in the Bay-Delta Plan. 

 

Charge to the Independent Review Panel

The charge to the panel provides the purpose, background, regulatory context, initial list of documents, and specific questions for the panel to start the review process. It provides the direction and context for the review.

 

Review Panel Members:

 

Review Materials:

DWR. 2016. On Estimating Net Delta Outflow (NDO): Approaches to estimating NDO in the Sacramento-San Joaquin Delta.

 

Additional Background Materials:

California Department of Water Resources. (1995). Estimation of Delta Island Diversions and Return Flows. DWR.

 

California Department of Water Resources. (2001). Methodology for Flow and Salinity Estimates in the Sacramento-San Joaquin Delta and Suisun Marsh.

 

California Department of Water Resources. (2015). Current Full Dayflow Documentation. Retrieved November 2, 2015, from Dayflow: An Estimate of Daily Average Delta Outflow:

 

California Department of Water Resources. (2015). Dayflow Data. Retrieved November 2, 2015, from Dayflow: An Estimate of Daily Average Delta Outflow.

 

California Department of Water Resources. (2015). Methodology for Flow and Salinity Estimates in the Sacramento-San Joaquin Delta and Suisun Marsh. Sacramento: Department of Water Resources.

 

Davids Engineering, Inc. (2012). Remote Sensing: Consumptive Use Analysis. Retrieved November 2, 2015, from Davids Engineering, Inc.

 

Denton, R. a. (1993). Antecedent Flow-Salinity Relations: Application to Delta Planning Models.

 

Kadir, T. (2006). Estimates for Consumptive Water Demands in the Delta using DETAW. DWR.

 

Kimmerer, W. a. (1992). An estimate of the historical position of 2 ppt salinity. Managing freshwater discharge to the San Francisco Bay. Page 33 of EPA Report:

Liang, L., & Suits, B. (2015). Annual Report, Chapter 3. Estimating the Impact of Groundwater on Delta Channel Depletions. DWR.

 
Russ T. Brown and Anne Huber, I. I. (2015, February 17). Relationships between Measured X2 and Equivalent Outflow (cfs) and Salinity (EC) during Low-Flow Conditions. DSM2 User Group Meeting.

 

Kimmerer, W. (2004). Open Water Processes of the San Francisco Estuary: From Physical Forcing to Biological Responses. San Francisco Estuary & Watershed Science 2(1).

 

Medellín-Azuara, J. and Howitt, R. E. (2013). Comparing Consumptive Agricultural Water Use in the Sacramento-San Joaquin Delta. Center for Watershed Sciences, University of California, Davis.

 

George, M. P. (2015). Comparative Study of Methods for Determining Consumptive Use of Water in the Delta. SWRCB Office of the Delta Watermaster.

 

State Water Resources Control Board (Sept 2015). Letter to Mark Cowin, Director of DWR: Request for Information and Technical Assistance in Updating Delta Outflow Objective.

Coequal goals

The Delta Stewardship Council was created in legislation to achieve the state mandated coequal goals for the Delta. "'Coequal goals' means the two goals of providing a more reliable water supply for California and protecting, restoring, and enhancing the Delta ecosystem. The coequal goals shall be achieved in a manner that protects and enhances the unique cultural, recreational, natural resource, and agricultural values of the Delta as an evolving place." (CA Water Code §85054)