Surface Water Quality of the Big Sioux River Watershed

The Big Sioux River has the following designated beneficial uses established by the State of South Dakota: Domestic Water Supply, Warmwater Semipermanent Fish Life, Warmwater Marginal Fish Life, Immersion Recreation, Limited Contact Recreation, Fish and Wildlife Propagation, and Irrigation. The State of South Dakota has established Water Quality Criteria (WQC) to protect this water body for these designated uses. Skunk Creek is a major contributor to the flow and overall character to the water quality of the Big Sioux River in Sioux Falls, however, the Skunk Creek does not have the same designated uses as the Big Sioux River.

The Public Works Environmental Division monitors the conditions along the Big Sioux River as well as Skunk Creek in the Sioux Falls area. Monitoring data for Dissolved Oxygen (DO), Escherichia Coli bacteria (E. Coli), and Total Suspended Solids (TSS) is available for public review. The water quality criteria for each of these parameters are outlined below. To view data on each segment of the river that is monitored, find the parameter of interest and then select either historic data or recent month’s data.

Stormwater Outfall Monitoring

Stormwater Outfall Monitoring

Big Sioux River Water Quality Criteria (WQC)

Parameter Recent Historic Criteria Unit Special Conditions
Dissolved Oxygen (DO)

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 > 5.0 mg/L daily minimum
Escherichia coli (E. Coli)

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 < 126 /100 mL geometric mean based on a minimum of 5 samples obtained during separate 24-hour periods for any 30-day period
 < 235 in any one sample
Total Suspended Solids (TSS)

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 < 90 mg/L 30-day average
 < 158 mg/L daily maximum

 

Skunk Creek Water Quality Criteria (WQC)

Parameter 

Criteria 

 Unit  Special Conditions
 Dissolved Oxygen (DO) > 5.0 mg/L daily minimum
 Escherichia coli (E. Coli) < 630 /100 mL geometric mean based on a minimum of 5 samples obtained during separate 24-hour periods for any 30-day period
< 1178 /100 mL in any one sample
 Total Suspended Solids (TSS) < 90 mg/L 30-day average
< 158 mg/L daily maximum