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The Long Lake Watershed:
What’s a Watershed? 

A watershed is an area of land that drains all the streams and rainfall to a common outlet such as the outflow of a reservoir, mouth of a bay, or any point along a stream channel. 


THE LONG LAKE WATERSHED IS 7,619 ACRES! It spans Orono, Medina and Long Lake!

The watershed consists of all the surface water--lakes, streams, reservoirs, and wetlands--and all the underlying ground water. Larger watersheds contain many smaller watersheds. It all depends on the outflow point; all of the land that drains water to the outflow point is the watershed for that outflow location. 

Watersheds are important because the streamflow and the water quality of a lake or river are affected by things, human-induced or not, happening in the land area "above" the river-outflow point. ( 

The Facts:

  • Five of the 7 lakes in the watershed are identified by the MCPA as "impaired for excess nutrients" (the other two have not been tested)

  • DNR Fish monitoring shows "high" mercury levels (i.e., in excess of established state safety limits for consumption) 

  • Blue Green Algae and Ecoli in Long Lake have led to several beach closures over the summer months

  • Water quality in Long Lake is currently rated "D" by the MPCA

  • Long Lake and Tanager Lake water quality only "partially supports swimming" due to high phosphorus levels and pollution (per MPCA)

  • Nutrient loading caused by internal loading in School and Holy Name Lakes exceed 50% 

  • The upper Long Lake watershed impacts the middle watershed and flows into the lower watershed - and it all ends up in Lake Minnetonka.  We are all connected!

Why does Watershed health matter to you?

Watersheds directly affect water quality, whether it's for drinking or recreation. For example, algae blooms from fertilizer runoff draining into water harm watershed health, as do mercury and lead seeping into the water supply due to pollution. As states and cities try to find new sources of uncontaminated drinking water, keeping watersheds healthy becomes increasingly vital to finding clean water. [source: Environmental Protection Agency]. 

Unhealthy watersheds affect wildlife. The polluted water supply that results can become harmful to humans. Aquatic life quickly suffers the effects of watershed pollution, while new pollutants introduced into ecosystems alter wildlife habitats. This reduces biodiversity by eliminating some species and introducing new, invasive ones that destroy the native species. That, in turn, can affect the food chain, from microbial organisms that feed birds and animals to fish that feed humans. ( 

The Long Lake Watershed 

In the Long Lake Watershed, we count over 7,619 acres, many streams and creeks, and seven large lakes. Our watershed outflow point is Tanager Lake – a small bay or lake on Lake Minnetonka. Everything in our watershed passes through the various lakes (from School and Holy Name to Wolsfeld to Dickey to Lydiard to Long Lake), into the streams, wetlands and underlying aquifer, and into Tanager Lake, where the water eventually ends up in Lake Minnetonka.

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