Big Sioux River Water Quality

The Public Works Environmental Division monitors the water quality and conditions along the Big Sioux River and Skunk Creek in the Sioux Falls area. Surface water samples are collected weekly at four locations along the Big Sioux River and one Skunk Creek location. 

South Dakota state law establishes beneficial use classifications for surface waters of the state. The classifications determine the minimum quality at which the surface waters of the state are to be maintained and protected. The chart below provides the beneficial use classifications related to the Big Sioux River Watershed in the greater Sioux Falls area. Water quality criteria for each beneficial use is noted in the associated Administrative Rule. (Per South Dakota Administrative Rule 74:51:01:42)

Designated Beneficial Use

Designated Water Body(s)

Link to Administrative Rule

(1)Domestic water supply waters

Big Sioux River


(5)Warmwater semipermanent fish life propagation waters

Big Sioux River


(6) Warmwater marginal fish life propagation waters

Skunk Creek


(7) Immersion recreation waters

Big Sioux River


(8) Limited contact recreation waters

Big Sioux River & Skunk Creek


(9)Fish and wildlife propagation, recreation, and stock watering waters

Big Sioux River & Skunk Creek


(10) Irrigation waters

Big Sioux River & Skunk Creek


The Environmental Division collects data for pH, temperature, dissolved oxygen (DO), Escherichia Coli bacteria (E. Coli), biological oxygen demand (BOD), ammonia (NH3), nitrate (NO3), and total suspended solids (TSS). Data is available for review and download in the Surface Water Quality Monitoring Dashboard.

Please note some test results may not be immediately available. E. Coli is only monitored May through September.

Surface Water Quality Monitoring

Surface Water Quality Monitor Image