The lakes were formed about 20,000 years ago by the movement of glaciers creating depressions in the otherwise flat landscape.
Originally deeper, a drought about 8000 years ago caused a drop in water level which in turn increased the saline concentration of
the water. The resulting combination of shallow depth and increased salinity make Reed Lake an ideal wetland for migratory birds.
The shallow depth means that the lake thaws and warms quickly in the spring and when this warmth is coupled with the moderate
salinity of the lake it produces large hatches of aquatic invertebrates which act as an important food source for migratory birds as
they stopover to fuel up.
Reed Lake is filled by runoff from surrounding fields which enters the lake via creeks. There is no outflow; inflow is balanced by water
loss due to evaporation. Although rare, the lake can completely dry up during severe drought conditions.
Reed Lake, along with neighboring Chaplin Lake and Old Wives Lake cover a combined area of over 100,000 acres (42,000 hectares).
They form one of the most important wetland sites in all of North America for migratory birds; with hundreds of thousands of
waterfowl and shorebirds visiting annually.
Reed Lake is classified as a wetland. Wetlands result from glacial activity and create oxygen, break down pollution in water, filter
groundwater, reduce erosion and control floods by holding water and releasing it slowly. They also provide vital habitat for wildlife.
