For many years, the floods of 1993 were used as the yardstick to gauge the flood waters in Central Iowa. Then the floods of 2008 were used to define what could happen in many parts of Iowa. Perhaps these flood events are no longer "two hundred year floods," but have become and will be more common? Many will blame global warming, or climatic change. What has changed since 1961 or 1929? Both years were also used as a yardstick to gauge flood events.
I like to consider myself a scientist of sorts. My personal studies have directed me towards the quest for truth and harmony in my understanding of scientific things. Like many others, the desire to define and understand things is nagging. The unexplained and things taken on faith are not comforting to people like us. There has to be an explanation for what has happened, and will most likely happen again.
Remember when the good people of the great state of Iowa rose to the occasion when then president Nixon announced to the world we can feed the world's hungry? Iowans stepped up to the task. Trees were removed from the fence rows and field perimeters. The Corps of Engineers worked with communities and the state to straighten out certain waterways. More tillable land, and decades of record crops was the result.
As the landscape was changed, and farmers were able to plant fencerow to fencerow, so did the dynamics of how water flowed across the land. Now when it rains, the runoff is directed through tiling and straightened waterways to the major arteries so the water can more easily be directed away from the precious tillable acres. Gone are some of the natural barriers and meandering cricks which slowed, absorbed, and softened the impact of an infrequent deluge on the great rivers. The Iowa, Cedar, Wapsipinicon and other rivers now see more frequent and extreme rises as a result of such engineering.
Because of past flooding, dikes were built around large expanses of land that once served as a buffer for floodwaters; the water still has to go someplace. So the dikes and levies serve to protect certain areas but force the swollen river water farther downstream to become the problem of other people.
It isn't hard to get a grasp on what happens if you just analyze the events in our area, and the effect on the Iowa River after a heavy rainfall.
The water, which once was slowed by fencerow buffers and snaking cricks is funneled to that great river as efficiently as possible. Heavy rains in Hardin and Marshall County are soon flowing in the Iowa River. In the past, if river water overflowed the banks near Marshalltown, many hundreds of acres were covered by several inches of water. All of the area North of Main Street in Marshalltown and West of the confluence of Lynn Creek with the river was prone to flooding. The entire neighborhood around Sharon Avenue and what was once known as Sloppy's Acres would go under water; sometimes just inches, but occasionally the flood waters could be measured in feet.
So Marshalltown decided to engage the help of the Corps of Engineers to design and build a levy to protect what had historically been river bottom land, and a buffer for flood waters. Once the levy was built, with Lynn Creek straightened into nothing more than a ditch, Marshalltown was reasonably safe from rising waters. Unusually heavy rains in the area were quickly directed to the great river and kept the community out of harms way. Heavy rainfalls in Northern Marshall and Hardin counties were no longer a threat to the flood plain which once was. The water and the problem were directed farther down stream.
With all of that buffer area removed from the equation in Marshall County, Tama County and the city of Tama became the next victim of the ravages of the swollen Iowa River. Water which was choked down by artificial measures upstream increasingly became a crisis for Tama County.
After too many floods, the City of Tama decided they too needed a levy to protect property from the ravages of the swollen Iowa River. The city has been protected now from the floodwaters which once filled hundreds of acres of bottom land. Yet another buffer was removed from the equation. The swollen river was kept in its banks and forced to carry the load farther downstream.
Chelsea then became the brunt of the floodwaters Marshalltown and Tama kept from their city limits. What once had been infrequent flooding has escalated into more frequent and severe flooding for the city. It will not get better, but will only get worse as man tiles yet more acres, removes yet more vegetative buffers, and continues the mission to confine the great rivers and keep their community from harms way.
While a problem might have been solved for Marshalltown and Tama, both communities only pushed their problem off to their neighbors to the south-Chelsea, Marengo, Iowa City, Columbus Junction.
I am not the expert to solve the problem. However, the solution is probably similar to one which the State of Florida is now undertaking to restore the Everglades back to their original state.
Modifications to the ecosystem similar to what we have seen in Iowa have been made to the rivers and watershed for the Everglades. Now they are spending billions of dollars to restore those systems back to the way they were before man began meddling.
Until next time-
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In to the Wind and this column are copyright 2005 - 2013 Mike Gilchrist. Readers, feel free to contact me at firstname.lastname@example.org via email, or write to me at P.O. Box 255, Toledo, IA 52342