Kandiyohi Co. lake levels drop in an extremely vigorous return to normal levels
SPICER -- Water levels swelled to near record peaks in Kandiyohi and surrounding counties this summer, inflicting significant damage to lake shorelines and ditch banks.
At its peak on Aug. 15, the water in Green Lake was only one-half foot from the all-time high experienced in late July of 1986. The water was lapping at the underneath grid work of the bridge crossing the lake's outlet, and close to flooding the roadway as it had in 1986, according to Ethan Jenzen, an area hydrologist with the Minnesota Department of Natural Resources in Spicer.
Big Kandiyohi and other lakes in the southern half of the county saw some of the worst shoreline erosion ever, in some cases necessitating emergency work to protect residences.
Just over two months later, Green Lake and many other major water basins in the county are back to normal levels for autumn, something that hasn't been seen since 2009.
Water levels on Green Lake and Lake Wakanda have dropped by two feet, bringing them to normal fall levels. The Minnesota River at Morton is flowing at roughly 1,200 cubic feet per second, normal for this time of year but roughly one-eighth the flow of 8,000 cubic feet per second recorded on Aug. 15.
Rarely has the drop to "normal'' happened so quickly, Jenzen said. "It's like somebody shut the valve off, shut the faucet,'' he said.
Precipitation levels in the summer were anywhere from 150 to 175 percent of normal: From July 1 through Aug. 15, 10.5 inches of rain fell in central Kandiyohi County.
Since then, precipitation has been 25 to 50 percent of normal, with as little as 1.5 inches to 2.5 inches recorded in the region.
The groundwater table is also dropping to normal levels as the dry conditions provided the opportunity for water in-flows and out-flows to equilibrate, according to Jenzen.
Last summer saw unprecedented demands to county and state agencies for help in dealing with the erosion and flooding problems caused by the above-normal precipitation. Along with excessive rainfall amounts, high humidity slowed evaporation. While difficult to quantify, Jenzen said there's lot of anecdotal evidence suggesting that we experienced windier conditions too, which served to aggravate shoreline erosion problems.
The excess moisture also washed more sediment and nutrients into area waters, feeding large algae blooms.
Only time will tell whether the dry conditions will persist but Jenzen cautions that we have seen extremes like this not too long ago. The record high water levels experienced in 1986 were matched by record low levels in the drought of 1988.