Tremendous Value of Wetlands in the Landscape
Jim Reinartz, FOCB President
Just a couple of photographs tell a very powerful story of the role wetlands play in the attenuation of floods and the maintenance of healthy base flow in our streams. Flood prevention is one of the major ecosystem services that wetlands provide.
Over a three-day period between August 9 and 12 the Field Station recorded 11.1” of rain; I recorded the same total at my house just a mile from the south end of the Bog. 11.1” of rain over our 2,300-acre wetland is 2,125 acre-feet of water; that’s over 693 million gallons of water.
That much water is bound to be a major contribution to flooding of Cedar Creek downstream, right? Well, it would have been except the Cedarburg Bog has an amazing capacity to store and slowly release all that water. Discharging that water over a period of months prevents downstream flooding and maintains the base flow in Cedar Creek and the Milwaukee River.
August 13, after 11.1” of rain (top/left)
September 4, 22 days later (bottom/right)
Compare the photographs of the Bog’s outlet stream where it crosses County Hwy Y the day after the rain event and three weeks later. There was no question that the outlet was running hard the day after, but no flooding occurred; streamflow remained well within its banks. Three weeks later, there is still more flow than normal for this time of year, but it remains just a nice steady flow of very clean water from our wonderful wetland.
The water level in the Bog rose well over a foot with the rain event; the vegetation and peat in the Bog occupy a lot of volume so it is not just like rain falling on a lake. But the peat swells and the entire vegetation mat rises with a higher water level, so the surface doesn’t get flooded and no harm is done. Good work Cedarburg Bog!
