Everyone lives in a watershed
WATERSHEDS are the definition geologists and other land managers are quite familiar with. Even if you live in the heart of a city like Marshalltown, you have to be at least somewhat aware of the importance of watersheds to our daily lives. A defined area of land that contributes rainfall toward one common point is a watershed. If light rains fall from the sky, the soils within a watershed act like sponges to soak up the water. Very little water runs off toward area streams. Little creeks hardly notice.
However, if a large storm with lots of rain falling in a short time frame should occur, everyone knows that creeks will rise and eventually the river level will have to respond in turn as its water levels increase. Heavy rains put too much water on the land too quickly for natural absorption into the deep pores of a soil profile. The result is runoff of the excess water, and since the laws of gravity still apply, the water has to go somewhere and that somewhere is downhill. In the process, this is a vulnerable time for soil erosion everywhere in the watershed. And we are all too familiar in Marshall County with past flood events closing major roadways for several days and the disruptions this causes.
The bulk of liquid water flows toward any waterway, rivulet or channel and stream to make little creeks into big creeks. Lots of tributaries exist along the entire length of the 300 plus mile length of the Iowa River. Each contributes their proportionate share to the river’s gathering power. On hot summer days, evaporation takes some of the surface water off the land and moves it upward into the atmosphere where it condenses as it cools. Those big fluffy clouds we look at and watch are just another type of “sponge” to hold water vapor. In fact, one small typical fluffy white cloud may be holding 16.5 tons of water.
The Iowa River watershed contains 12,637 square miles of land beginning at its source (mouth) at the Mississippi River. The water gathered to form the Iowa begins in two separate small flowages near Crystal Lake in Hancock County. As every waterway and small creek adds to the bulk of water that must be accommodated, streams and a river become larger to handle the average flow of water. Excess water at flood times overflows into adjacent low and level lying floodplain lands.
Marshall County is about at the one-half way point of this watershed. Our sub-watershed is a part of the much larger Upper Mississippi drainage. Add the Ohio River and Missouri River watersheds and now one gets an understanding of why the Mississippi River is so huge. But wait, there is more. Downstream from the mouths of the Ohio and Missouri, additional waters flow from the Arkansas-White River and additional contributions from the Lower Mississippi watershed. All of this combined flow eventually enters the Gulf of Mexico below New Orleans, La.
Locally, here are the biggest tributaries to the Iowa River. I’ll start with Minerva Creeks watershed, already mentioned, with 164 square miles of drainage. Asher Creek adds another 46.2 square miles. Burnett Creek takes another 32.4 and Rock Creek 14.8. Honey Creek begins in Hardin County and flows south into Marshall. It empties into the Iowa a bit north of Indian Bridge with 110 square miles. Going through Marshalltown is Linn Creek. This watercourse begins northwest of State Center gathering potential power as it flows east. The watershed it contains is 66.8 square miles.
There is another big tributary we know as Timber Creek. Actually there are three segments to it, the North, Middle and South and all join as one stream at a point southeast of Marshalltown. From there it travels another three miles in a northeast direction to join the Iowa about one mile west of Three Bridges County Park. The total drainage of Timber Creek is 124 square miles. Davison Creek is the last small stream to enter the river from within the county boundaries, where it begins on lands a few miles south of Le Grand. It has a watershed area of only 11.2 square miles.
One inch of rain adds 27,154 gallons of water per acre. During those times when rains fall slowly and lightly, our soils can keep up with absorption. Moderate rains events will have some runoff. Big storms, severe weather and lots of heavy rains do damage to our lands, from excess runoff from watersheds. There are things all land managers can agree on. First is doing what is workable, economic and prudent to maintain good waterways in grassy condition with capacity to slow runoff water. Buffer strips along stream courses are another option to capture surface water runoff, and its silt load, before it enters a waterway. Third, minimal tillage farming practices help the soils soak up and hold water and thereby minimize soil losses. Terraces in some places help a lot to shorten the length of slope across a farm field, thereby not allowing storm runoff to gain the power it needs to cause erosion. Soil and Water Conservation District offices have many programs and recommendations for every parcel of land.
These are big long term conservation and water quality issues in Iowa where so much of our landscape is dedicated to agriculture. How do we keep water as clean as possible for as long as possible? How do we as a society come together to work on water quality issues? Are you willing to work for and support good stewardship of our watersheds? We all need to be a part of the solution to strive for the things we can control that effect long term water quality issues. We all live in a watershed. What happens there does effect us. Will it be positive or negative? I vote for the former. It can be done. Are we willing?
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Spring time activities continue to be made available for outdoor enthusiasts. Tomorrow is the day for the Izaak Walton League’s CLAY BIRD SHOOT. Registration begins at 9 a.m. with the first shooting squads beginning at 9:30. The Ikes grounds is located two miles south of Iowa Avenue on Smith Avenue, or about two miles southeast of Marshalltown.
Wednesday, May 4, is the date for a Marshall County Conservation Board public program, the Brown Bag Brunch Birds and Blooms walk at Grammer Grove Wildlife Area. This public area is located six miles northwest of Albion. A guided hike will be lead by Diane Hall, naturalist with the MCCB. You will see lots of woodland wildflowers and hear (and see) migrating birds that have returned from southerly wintering areas. Bring your own lunch and beverage. Dress for the weather since this is a rain or shine event. One might even find a morel mushroom or two.
Wild turkey season is ongoing through May 22. More than 30 of these secretive and elusive wild game birds have been taken by Marshall County hunters so far.
Wildlife babies will soon be hatched, if not already done so, or born in the near future. White tail deer fawns will be starting to appear later in May and into early June. If you are hiking in areas where a fawn might be discovered, do not, repeat, do not consider it abandoned and attempt a “rescue.” The fawn is not abandoned. Its mother is quite aware of where her offspring is. She will take care of it. Just keep your distance and observe it but leave it alone. The same goes for baby birds and baby rabbits. People need to have a hands-off policy in these cases.
Garry Brandenburg is a graduate of Iowa State University with BS degree in Fish & Wildlife Biology. He is the retired director of the Marshall County Conservation Board. Contact him at PO Box 96, Albion, IA 50005.