Clean Water Program

Fourteen monitoring stations have been established within the study area from which to assess changes in conditions from pre-project conditions (Table 4.1). These stations, labeled A through N, are located within the SLD (A and B), Mud Slough (C, D, E, and I), Salt Slough and the wetland channels (F, J, K, L, and M), and the San Joaquin River (G, H, and N).

Table 3.1 outlines the monitoring plan objectives and the tasks which are intended to address each objective. The monitoring plan is designed as a working document. The results of the monitoring effort will be reviewed on a regular basis to determine whether modifications to the tasks are necessary. Such modifications might include reduction or expansion of the sampling effort.

The following are the working hypotheses underlying the monitoring plan objectives.

Sediment samples have been collected quarterly by USBR since August 1993 for selenium and boron analysis from two monitoring locations within the SLD (Check 2 and Check 10); from each of the primary stations in Mud Slough (Stations C, D, and E); from Salt Slough (Station F), and annually from the backwater site (Station I). Separate samples of the top and bottom sediments were taken at three locations across the channel. The samples taken on the channel transect were composited.

Previous research studies have shown that dissolved concentrations of trace elements such as boron and selenium occur at elevated levels in tile drainage water (Presser and Barnes, 1984, 1985; Shelton and Miller, 1988).

Monitoring programs have been conducted in the project area by a number of agencies and their contractors since 1985 in support of research activities and water delivery operations. These agencies and contractors include the CVRWQCB, USGS, USBR, GWD, Lawrence Berkeley National Laboratory (LBNL), CDFG and Summers Engineering. A task group, made up of representatives from these agencies, was formed to develop a monitoring plan for the GBP.

Table 1.2 summarizes the GBP findings and commitments which were developed as part of the UA, EA, Supplemental EA, and FONSI. The table is divided into the following categories: physical, water quality, biological/ecosystem, sediment, human health/environmental justice, historical/Indian trust, drainage management, and construction.