Below are two photos of a creek and associated wetlands taken by a timelapse camera. The first photo was taken in early June, 2015 and the second photo was taken about a month later. Looking just at those two photos, you’d think nothing much was happening.
Derr Wetland in early June 2015.
Derr Wetland in early July 2015.
However, now look at the next photo, which was taken in mid-June. After some rains in early June, the stream swelled and filled much of its floodplain, and that high water lasted a couple weeks before it came back down again. The photos show how dynamic a stream and its floodplain can (and should) be.
Mid-June 2015.
The area in these photos is a restoration site that was formerly a sand pit lake left behind after gravel mining. A stream flowed into the narrow lake on one end and out the other, and the lake was surrounded by spoil piles and trees. After restoration, the site now has a couple stream channels, some adjacent wetlands, and provides wide and open habitat for a diverse number of aquatic and terrestrial animals. In addition to providing great wildlife habitat and a diverse plant community, though, the restored site also improves the floodplain functionality of this stream.
Flooding is a natural and important process, and floodplains play an essential role in that process. After big rain events, streams quickly gain water that has to go somewhere. Ideally, that water spreads out into a floodplain where it slows down and sits until it either drains into the soil or gradually is allowed to proceed downstream. When we restrict or block access of streams to their floodplains, floodwater is forced downstream in a torrent and sometimes breaks out from its restraints, causing unexpected and often catastrophic damage to property.
The 10 second timelapse video below shows (on a small scale) the kind of gentle rise and fall of water levels a functioning floodplain can facilitate. The images in the video were taken between June 3 and July 1, 2015. The water level came up fairly quickly between June 4 and 5, remained high for a couple weeks, and then dropped slowly back to where it had started. Just like it was supposed to.
(If the above video doesn’t work, try clicking on the title of this blog post to open it in a web browser and then try again. If that doesn’t work, try just following this link.)
The Prairie Ecologist 
The time-lapse really tells the story neatly!
As I drove through the Grand Prairie division of Illinois last weekend, I saw a number of signs soliciting to install drain tiles. This region of Illinois must have been dotted with wetlands or possibly have been one big wetland before drainage occurred. I am amazed the soil is still so black. As I looked at the carefully cultivated fields I wondered how much longer the organic soil will last. Cultivation catalyzes the oxidation of organic soils. Once the fertile soils have been turned into greenhouse gases what will remain for people in Illinois?
For 33 years I have soil sampled every year a number of central Nebraska high yielding irrigated corn and soybean rotated fields. All are silt loam soils in the 2 to 2.5% organic matter range. The organic matters haven’t changed in that time frame. Once soils reach a “steady state” of OM level following prairie, it is very difficult to change the OM up or down. I have also yearly soil sampled certified organic fields in a 4-5 crop rotation and the OM hasn’t changed in 25 years.
I hope the farmland in Illinois is not all in that steady state category yet. Especially after considering the following photo from Florida.
It would be interesting if measurements were taken in the Derr Wetland to see if soil organic matter increased over time.
We Northern Californians are getting some dramatic evidence of the value of floodplains. Our Coyote Creek, which was in the news recently when it destroyed property in the San Jose area, was “restricted” in many ways, and during some of our February rains fallen trees and other debris narrowed the channel even more. We wonder when and how they’ll even get it cleaned out enough to allow “normal” flow. Unfortunately it’s probably too late for Mother Nature’s floodplains to do their thing. We are in a pickle…
Along the Des Plaines River in Illinois people have used a rather innovative solution.
http://www.journal-topics.com/image_63b1e688-047e-11e3-b7b3-001a4bcf6878.html
It should not be too surprising people in the area did the above considering all the large brick buildings in Chicago were elevated using jacks after 1858 so they could put in a sewer system.