CMSCWD Water Monitoring Trends + Recommendations
Square Lake has exceptional water quality and clarity within the metropolitan area. This is demonstrated by the Metropolitan Council’s Lake grades, which are consistently reported as an A for Square Lake. This lake grade is based on annual measurements of nutrients and clarity.
Square Lake has been a high priority for protection by the Carnelian Marine St Croix Watershed District since its inception. The district collects annual water quality monitoring data to make management decisions for the lake. Water monitoring records for Square Lake go back to 1993. Over that timeframe Square Lake has seen a trend of declining water clarity. However, over the last ten years (2010-2019), the transparency of Square Lake has an improving trend. This improving trend is likely the result of all the work that has occurred by landowners and the CMSCWD over the last couple of decades on Square Lake.
Mike Isensee, Administrator of the CMSCWD said “We do not think the transparency trend over 38 year is alarming, especially since we are seeing improvements over the past decade, but it will require actions from landowners to continue the improving trends we have seed over the last decade.”
To identify potential areas of erosion and nutrient input the district developed a “Pollutant Hotspots” map of high potential sediment and phosphorus loading to the lake. The district is seeking to work with landowners in the red areas to consider voluntary conservation practices. Watershed Map — Carnelian-Marine-St Croix Watershed District (cmscwd.org)
Some of the most important actions landowners can take to protect and improve water quality on Square Lake are:
Maintain or restore native shorelines (which have less erosion and support more beneficial nutrient consuming native critters);
Reduce stormwater directly flowing into the lake (which carries excess nutrients and sediment);
Manage terrestrial invasive species such as buckthorn within the shoreland zone sloping to the lake (buckthorn reduces and eventually eliminates native herbaceous ground cover which leaves exposed soils to erode into the lake (it also drops nutrient rich leaves into the water very lake in the year which can lead to phosphorus pulses without organisms to process it);
Restore and maintain native plant communities within the watershed, especially near lake shoreland areas.
Landowners interested in meeting with a professional shoreland or landscape restorationist are encouraged to contact the Washington Conservation District for a free site visit. http://www.mnwcd.org/site-visit-signup-form
