Characteristics of Sediments, Settleable Solids and Water Quality of Stormwater Runoff in the Minnesota River Watershed

This section of MRAP Volume III contains data collected from 1989-1992. Sediment, settleable solids, various clam species and stormwater runoff were collected from sites in the Minnesota River Basin. Settleable solids were analyzed for selected heavy metals, grain size, nitrogen, phosphorus and PCBs. Clam tissues underwent PCB and heavy metal analysis. Stormwater runoff was analyzed for nitrogen, total suspended solids and chemical oxygen demand. Settleable solids were found to contain heavy metal levels expected due to the Minnesota River Basin's geology. No PCBs were found in the settleable solids, but the samples did contain high levels of total Kjedahl nitrogen, ammonia and P-orthophosphate. These levels were higher in the upper reaches of the river. The stormwater samples demonstrated generally high levels of TSS and N-nitrates. Also, highly variable levels of total phosphorus, p-orthophosphate and N-ammonia were found in the stormwater samples. Sediment samples contained the predicted levels of heavy metals.