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Iowa DOT partners with Living History Farms on stream project


TreeObvious point number 1: We only have one planet.

Obvious point number 2: Humans are always doing things that impact the environment in which we live. 

Obvious point number 3: We need to be good stewards of the environment and work to minimize those impacts.

Any time a highway project is in the works, the Iowa DOT does what it can to avoid and minimize impacts to the environment. But when specific impacts can’t be avoided, a mitigation plan is developed to reduce the damage to the environment as a whole. Colin Greenan from the Iowa DOT’s Office of Location and Environment said, “When we develop a mitigation plan, our goal is to make a greater positive impact on the environment around the construction project.”

When the Interstate 35 reconstruction project in Warren County was being designed, Iowa DOT engineers realized they could not avoid impacting streams and wetlands in the area. Iowa DOT environmental specialists went to work on a plan to mitigate the impacts in the immediate construction area. Greenan said in this case, there was minimal work that could be done in the immediate area, so the Iowa DOT developed a mitigation plan to be implemented within the same watershed as the impacted water resources.

LogoHe said, “We always start off by contacting county conservation boards and other conservation-minded groups to identify opportunities to reduce impacts to the environment. We looked along the I-35 corridor for areas to complete a mitigation project. We had completed a previous mitigation project on the Living History Farms property and had a good working relationship with them. Impacted streams along I-35 and the tributary to Walnut Creek at the Living History Farms property are in similar watersheds, something we look for when we do a mitigation project.”

The banks of the stream at LHF are falling in and erosion is a real problem.

Chin-Ta Tsai, Iowa DOT mitigation design engineer who designed the project, said, “Part of our responsibility is to mitigate at least as large an area as we have impacted, but we also have to be fiscally responsible. The stream on the Living History Farms property was the right size and the improvement it needed was the same or a little greater than the impact we were having on the I-35 project, so it was a good fit. The project would benefit both organizations because it allowed us to mitigate our highway impacts and improve the Living History Farms stream at a time when the farm could not complete the project on its own.”

Greenan said the stream they identified on the Living History Farms property is in poor condition. He said, “The banks are falling in and this material was being transported offsite by the stream. When that happens, the channel gets deeper which accelerates further bank erosion.”

Another consideration for the project was timing. Greenan said, “After collaborating with farm staff, we solicited bids on the project in November so the work could be completed during the farm’s off season to lessen the disruption to their business.”

Construction should be wrapped up no later than April. 

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Iowa highway in the evening