Tuesday, January 14, 2014

High Water

A WATERWORKS Column in the Aitkin Independent Age for January 4, 2014, by Gordon Prickett


Following the extremes of summer flooding in 2012 the ACLARA lake association representatives have considered how to prepare for the next high water event. We learned a few things when the lake levels were rapidly rising back then. For instance, every developed lake, whether it has a lake level gauge or not has an elevation known as the Ordinary High Water Level (OHWL), established by the DNR. Commonly, this is the point where the natural vegetation changes from predominately aquatic to predominately terrestrial. And we learned that just 28 lakes in Aitkin County are provided every spring with a calibrated gauge where DNR staff and volunteers plan to take readings of the lake levels during summer months.

How fast the waters rise depends on the rainfall and the amount that runs off, plus the size of a lake’s “watershed.” When a lake has a large watershed it may take a few days for all the collecting streams and ditches to find their way downhill.

Each lakeshore property has its own connection and vulnerability to fast rising flood water. In the spring of 2012 when ice went out early some shore land residents placed docks and boatlifts in the water earlier than normal. When heavy rains came the docks were under water and had to be reset.

Led by Sheriff Turner, the county government acted with the approval of DNR Commissioner Landwehr to restrict boating traffic on all county lakes to slow no-wake speeds during the height of extreme high water in June and July. This measure prevented damage to vulnerable shores from wave action. Getting the word out to all boaters in the county was not simple. Problems developed when the restrictions were relaxed for part of the county, and then on certain lakes where lake elevations could be measured and high waters had receded.

Lakes that experienced unusually high water in 2012 have discussed where the “trigger elevation” above OHWL should be, that calls for slow no-wake boating until conditions return to normal. ACLARA will be cooperating with the County and with the DNR to assist in advising and informing their members during high water conditions in the future.

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