MINNEAPOLIS (WCCO) — Strong storms rolled through Minnesota Sunday night and dumped two to four inches of rain across the Metro. That water raised parts of the Mississippi River seven inches and some sections of Minnehaha Creek about two and half feet.
So, why do the water levels go so high?
According to the U.S. Geological Survey, Minnehaha Creek rose 2.5 feet at the measuring station at Hiawatha Station in Minneapolis Sunday night into Monday morning. Given all of the twists and turns of Minnehaha Creek, the amount of water is also measured in volume. The volume of the Creek went from 20-30 cubic feet per second, to 270 cubic feet per second at the Hiawatha Station as well.
“We’re in the Minnehaha creek subwatershed, so all of the water that falls on Minneapolis, Edina, Hopkins, Saint Louis Park, Minnetonka and areas of Wayzata and Plymouth all of that flows into Minnehaha Creek,” said Laura Domyancich, project and land technician with the Minnehaha Creek Watershed District. “So all of that land area that got 2.5 inches is flowing into Minnehaha Creek.”
The amount of runoff that enters into the bodies of water can vary due to a number of circumstances.
“A lot that depends on how much rain we’ve gotten in the past few weeks,” said Domyancich. “If our wetlands are totally full of water, we’re going to get more storm water runoff because they’ll have less ability and capacity to store water.”
Nearby hard surfaces also matter. The more heavily populated areas near Minnehaha Creek also put more discharge into the water.
Size and depth can make a difference as well. For example, White Bear Lake rose 2.5 inches Sunday night compared to 2 inches at Lake Minnetonka. But, the watershed for the smaller White Bear Lake is twice the size of the lake. The watershed for Lake Minnetonka is five times the size of the lake.