Several sampling techniques will be used to collect samples, including grab, time and depth integrated. The techniques used at each location are summarized on Table 4.3.1. Because of the remoteness of the region and the staffing limitations, an auto-sampler will be used to collect time-composite samples and samples that must be collected more than once per week.

Grab samples will be collected using a stainless steel sampling device. This device is a 6-foot pole with a cage at one end which holds the sampling bottle. Grab samples will be collected from the stream bank. This technique will be used for samples collected at a frequency equal to or less than once per week.

Depth integrated samples will be collected by accessing the center of the channel and collecting a depth integrated sample from mid-stream. Depth integrated sampling will be utilized at sites with parameters which may not be evenly mixed in the channel (e.g. sediments). This technique will be used for sites requiring total suspended solids (TSS) characterization.

Time composite samples will be collected using a Sigma auto-sampler. Either a 4-day composite (1 subsample per day) or a daily (2 subsamples per day) composite will be collected. Samples must be taken at a greater frequency than once per week because water quality objectives for selenium are based on a 4-day average for Mud Slough (north) and the San Joaquin River at Crows Landing.