The Department of Water Resources (DWR) measures flow at a number of stations along the San Joaquin River, including Newman, which is located within the GBP area. The DWR also measures flow in Salt Slough at Lander Avenue. These DWR stations (B00470 and B07375) are at the same location as two proposed primary stations (F and G).

The Salt Slough and Mud Slough sites (Stations D and F) were monitored by the USGS until 1994. Responsibility for data collection at these sites was then assumed by the San Joaquin River Management Program (SJRMP) Water Quality Subcommittee. Maintenance was performed by the DWR and the USGS. In March 1996, the USGS resumed operation of these sites. Dataloggers, cellular telephones and sensors for stage, EC and temperature were installed at each site during September 1995. The USGS has also been charged with rehabilitating a previously abandoned gauging station at Crows Landing under a recently signed contract with USBR. This station is currently reporting stage, EC and temperature. Flow is being calculated using a recently established rating curve for the site. The SJRMP Water Quality Subcommittee is utilizing data from the Crows Landing, Mud and Salt Slough sites, as well as other sites, to produce water quality forecasts for EC in the San Joaquin River at Vernalis.

Other flow monitoring within the Grasslands is performed jointly by Summers Engineering and the GWD as part of the GWTF. Much of the flow monitoring performed at these sites is for water accounting purposes and for scheduling of water deliveries.

The most intensive study of flow, water quality and sediment selenium in recent years in a single conveyance within the GWD was conducted during 1994 and 1995 by LBNL on the Agatha Canal within the GWD (Quinn et al, 1995). Data were collected at two locations on the Agatha Canal in this study, the objective of which was to determine the mechanisms responsible for selenium in-transit losses within the Grasslands canal systems. The acoustic Doppler flow monitoring equipment used in this LBNL study has been moved to Site B on the SLD.