The Monitoring Plan provides for sediment chemistry samples on annual and quarterly sites in the SLD. The purpose of monitoring the annual sites is to provide an intensive sampling of the SLD to provide an indication of whether sediments are accumulating selenium towards hazardous waste criterion levels (minutes of Sediment Task Group meeting, February 22, 1996). The annual sites are located in four reaches of the SLD, with three sites (beginning, mid-point, and end defined by accessibility) chosen to characterize each of four selected reaches of the SLD between the inlet and the terminus. These four reaches are: a. between Checks 17 and 18; b. between Checks 14 and 15; c. between Checks 10 and 11; and, d. between Checks 1 and 2. These locations were selected because of the unique characteristic of the SLD or adjacent lands in the area that might have an impact on the sediments (Nigel Quinn, pers. comm.). The reach between checks 17 and 18 was chosen because it is close to agricultural land; 14 and 15 for adjacent wetlands; 10 and 11 had previous data collection points so that a comparison might be made to prior data; and the SLD between 1 and 2 has had a seasonal wet and dry cycle for the past several years.

In addition to the four annual sites, quarterly sampling of sediment chemistry will occur at two sites within the Drain. These sites are:

Site A - a location immediately upstream of the inflow, selected to characterize the SLD sediments prior to the introduction of drainage water;

Site B - chosen for its location near the terminus, available power, and other related monitoring activities.

Together, the annual (4 sites) and quarterly (two sites) sampling of sites within the Drain will provide cost-effective and representative information about sediment chemistry of the SLD.