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. The first step taken in the development of a monitoring program for the GBP was the creation of a matrix which described both past and on-going monitoring of flow and water quality in the Grassland Subarea. This matrix (Table 2.1) was expanded to include sediment sampling and was included in both the 1993 and 1995 monitoring plan documents (USBR, 1993; USBR, 1995). The matrix identified monitoring locations common to the various agencies, identified any overlap of monitoring activities, and located sites that may have been monitored in the past, but where there was no current data collection activity. It was agreed early in the process of developing the monitoring program for the Grassland Subarea that the program should "piggy-back" on existing monitoring programs and research activities to the greatest extent possible, since this would provide the longest data record at individual sites, and would reduce the overall cost of the program. To the extent that existing sites were not adequate or non-existent in certain monitoring locations, it was deemed necessary to establish new sites.

From among the many pre-existing or newly established sites, the sites were designated as either "primary sites" or "secondary sites." Primary sites are monitoring locations at which monitoring of one or several media takes place that are considered necessary to accomplish the goals and objectives of the monitoring program for the GBP. These sites are designated with a "P" in Table 2.1. Site B, at the discharge point of the SLD, is the site at which compliance monitoring for selenium loading takes place. Stations labeled "secondary sites" and designated with a "S" in Table 2.1 are stations that are not essential for accomplishing the objectives of the GBP and are not part of the GBP monitoring program. They are listed because they provide information that may be useful in data interpretation and for research purposes in the future. Many of the secondary sites have been monitored intermittently and some have been eliminated.

The matrix in Table 2.1 provides a summary of the primary and secondary water quality monitoring sites in the proposed project area, organized according to the agency responsible for data collection, along with the sample station identification labels used by each agency. Figure 2.1 provides locations of primary monitoring sites with relative locations to major structures and transportation system. Table 2.1 also lists both the frequency of collection and the period of record for the flow, temperature, pH, water quality and sediment data at the primary sites collected to date. Where data collection is ongoing at a particular site no end date is shown under the period of record column in Table 2.1. The last column of the matrix indicates intended use of the data collected at each site.

Table 2.2 provides a summary matrix of biological sampling programs in the proposed project area. The matrix indicates the agencies responsible for the monitoring programs and the site identification codes at each site. The matrix is divided into columns for recent, current and proposed sampling of plants, invertebrates and fish. The use of the data and the period of record is provided in the two adjacent columns on the right side of the matrix.