Base flow is measured at Sites 1, 2, 3, and 4a.  We hope to take two measurements a year at each of these locations, the first one between May 15 and June 15 and the second one between Aug 15 and September 15.  Base flow condition will be determined by 3-4 days of "flat line" flow at the USGS Flow Monitoring Site at County Road F.

Click here for Base Flow Data.

Base flow is determined by measuring the flow at specific points (for example at 3 meter intervals) along a cross section of the stream that has been measured for water depth. This data is then entered into the computer and flow is computed.

Base flow is important because impervious surfaces created by development will inhibit water from infiltrating into the ground as it did prior to development.  Over time this will draw down the groundwater elevation, which in turn affects spring activity, which feeds the river.  In short the river's base flow will decrease over time if springs aren't replenished by infiltration; which is why base flow is a key indicator to monitor.

A good measurement of the overall flow of the Kinnickinnic can be found at the USGS Flow Monitoring Site at County Road F (just upstream of where the Kinnickinnic empties into the St. Croix River).