The purpose of in-drain sediment chemistry monitoring is to detect whether selenium levels in San Luis Drain sediments are approaching the California Department of Health Services criterion for hazardous waste. The monitoring of the selenium in sediments, coupled with flow and water quality information from the inlet (A) and outlet (B) sites, will also help to assess whether there is an influx or outflux of selenium between the sediment and the water column. Sediment samples will be analyzed for selenium and Total Organic Carbon (TOC).