Sometime this fall, probably soon, White Bear Lake will reach its lowest level on record -- lower than the mark it reached only two years ago.
But the course of the shrinking lake can't be entirely blamed on this summer's drought.
It also involves a man-made threat to one of the metro area's brightest jewels, and other lakes like it: the use of underground water for lawn watering, bathing and drinking.
Since 1980, growing communities in the northeast metro have more than doubled the volume of water they pump from the Prairie du Chien aquifer beneath them, pulling water from White Bear Lake and other lakes nearby, according to Perry Jones, a U.S. Geological Survey (USGS) hydrologist.
Jones just completed a two-year study of groundwater-surface water interactions, which found that since about 2003, White Bear continued to drop even in wet periods -- a significant new trend. One reason: The city of White Bear Lake and nine surrounding communities pumped 2.6 billion gallons of water from the Prairie du Chien aquifer in 1980, but 6 billion in 2008. Most of that has been for residential use, while industrial and commercial use, including golf course watering, remained steady. The study found that it would take annual rainfall 4 inches above normal just to stop the lake's shrinkage.
White Bear and the surrounding lakes and streams are particularly prone to shrink quickly due to pumping because the sandy soil beneath them allows surface water to drain readily into the aquifer. White Bear Lake, in particular, is deep enough to have an easy exchange with the aquifer.
As a result, shoreline residents will have to continue dragging their docks hundreds of yards to reach water -- or trying to find them in tall brush -- while swimmers at the main public beach encounter a steep drop off at what used to be a long, shallow walk-in, and dozens of slips at the downtown marina remain vacant, with mud having replaced boats.
"I'm thinking White Bear Lake is reaching a 'new normal,'" said Molly Shodeen, a metro-area hydrologist for the Minnesota Department of Natural Resources.