St Croix Flowage

Water Quality

One measure of a lakes health is the trophic state, which relates to the amount of algae in the water. The average summer trophic state for the last 5 years was 44 (Mesotrophic) and was determined using chlorophyll data. For a Reservoir lake, this is considered Excellent.

St Croix Flowage was monitored by volunteers between 1994 and 2020. Volunteers monitor water clarity with a black and white Secchi disk. Some also collect water samples, which are sent to the State Lab of Hygiene to be analyzed. Volunteers are the source of the majority of Wisconsin's lake water quality data, and their dedication is greatly appreciated. Additional monitoring has been done through projects funded in part by DNR Aquatic Invasive Species Grants. Reports and graphs featuring data collected by volunteers, DNR staff and others can be viewed below.

Water Quality Reports and Graphs

Station Name	Station ID	Map	Max Year	Reports
Saint Croix Flowage - The Narrows	163299	Map	2020	Details
Saint Croix Flowage - True Deep Hole	10031157	Map	2020	Details
St Croix Flowage - Main Basin - Site B - Nr Wilcox Island	163236	Map	2020	Details
St Croix Flowage - N Wilcox Island - Site C	163387	Map	1995	Details
St Croix Flowage - Near Dam	163298	Map	1994	Details
St Croix Flowage - Near Dam Deep Hole Site A	163235	Map	2020	Details
St Croix Flowage - St Croix Flowage	164017	Map	1979	Details
St. Croix River - - Gordon Flowage	214	Map	1970	Details