Draft Monitoring Special Study Plan

Delta Estuary (Bay–Delta Plan), as amended through 2006, the State Water Resources Control Board (State Water Board) set salinity objectives for the interior southern Delta. In Water Right Decision 1641 (D-1641), as part of the implementation of the 1995 Bay–Delta Plan, the California Department of Water Resources (DWR) and U.S. Bureau of Reclamation (Reclamation) were assigned partial responsibility for meeting these objectives, including maintaining Specific Conductance (EC) levels at three monitoring stations (Interagency Stations No. C-6, C-8, and P-12) in the interior southern Delta waterways (Figure 3-1)1. In 2018, the State Water Board adopted amendments to the Bay–Delta Plan. Per the 2018 Bay-Delta Plan amendments, DWR and Reclamation are working to develop a Monitoring Special Study (MSS).

This document serves as the study plan for the MSS and identifies three goals, consistent with section B(1)(iv) of the 2018 Bay–Delta Plan. Since early 2021, using best-science practices, DWR and Reclamation have been soliciting input from participating agencies and working with State Water Board staff to design technical studies to accomplish the following goals.

1) Characterize the spatial and temporal distribution and associated dynamics of water level, flow, and salinity conditions in the southern Delta waterways.

2) Identify the extent of low- or null-flow conditions and any associated concentration of local salt discharges.

3) Inform the development of a Long-Term Monitoring and Reporting Plan that will:

a. Assess attainment of the salinity objective in the interior southern Delta; and
b. Include long-term monitoring and reporting protocols, including specific compliance monitoring locations in, or monitoring protocols for, the three river segments that comprise the interior southern Delta salinity compliance locations.