Establishing Log Check Dams for Gulley Erosion in Central IL
On Sunday, March 23, 2025, I was a part of a demonstration showing the use of log check dams in Brimfield, IL. Two landowners have been implementing this practice for up to 10 years in multiple drainages on their properties, which border each other.
A log check dam is a very crude structure built from logs cut 2-3 feet long, ideally 3-10 inches in diameter. These logs are stacked in an eroded gulley, parallel to the flow of water. Many examples of log check dams elsewhere seem to be built with the logs running perpendicular to the flow of water. These landowners have found that placing the logs parallel with the flow of water allows for some porosity in the dam, which lets water trickle through, but captures sediment upstream of the dam.
Initially, the landowners brought us around their property to show us examples of log check dams they made in the past. One of the dams was built 10 years ago, and has captured an astonishing amount of sediment. While we had no way to measure the amount of sediment captured, I was able to dig in the creek bed just upstream from the dam into new sediment at least 2 feet deep, and the landowner claims the check dam was around 6 ft tall when originally constructed. I was quite amazed at how well these dams have proven to work over the years.. Here is a photo of the 10 year old log check dam.
After touring some of the old log check dams on the property, we got all of our gear on and filled the chainsaws with fuel, eager to build a check dam of our own. The spot we chose to install 3 log check dams was a seriously eroded ditch, which originated at a 10 inch pipe outflow. This 10” pipe runs underground up to the end of a cul de sac, which captures water from a neighborhood about 3 acres in size. The problem here is that the pipe ends and runs directly onto 6-10 inch rocks, where ideally the water would slow down and percolate into the ground. However, over time, the water has found a path around the rocks and created a ravine that is around 200 ft long and 5-6 feet deep in some sections, severely eroded of course. I can think of at least 100 neighborhoods in Peoria that mirror this exact drainage set up.
We started cutting 3 ft sections of deadwood that was already on the forest floor and making a pile to begin constructing the dams. With 5 people, we installed 3 moderate sized log check dams in 2 hours. Here is a picture of the most eroded part of the ravine in which we installed a dam.
From trial and error, the landowners observed that building the dam all the way to the top of the gulley is not ideal. In large rain events, there needs to be an area for water to flow over the dam. We constructed all of these dams about ¾ of the way to the top of the gulley. It’s also important to build the dams with a low point in the center, so if water does need to flow over the top, it will flow in the center and not cut around the sides.
Two Birds With One Stone – Timber Stand Improvement and Log Check Dams
As we were working, my forestry trained mind was ticking and I was seeing a way to solve problems that I hadn’t thought of before. I suppose I need to explain some typical forest problems we deal with here.
On the majority of forests in Illinois, mesophytic tree species like Elm, Hackberry, and Maple have grown up to dominate the understory of Oak-Hickory type forests, mostly because of the lack of forest disturbance (Fire, Timber harvest, etc). These mesophytic tree species are shade tolerant, meaning they have no problem growing up under a completely shaded understory. The trees that benefit wildlife and habitat the most (Oaks, Hickories), are very shade intolerant. The common situation here in Central IL forests is that a mesophytic understory ends up replacing the oak-hickory overstory and does not allow enough light to the forest floor for oaks and hickories to regenerate. This leads to a very low diversity, crowded forest, with almost no understory growth. No understory growth leads to less plants actively growing on streambanks, less plants leads to more soil erosion. This is a very common cycle in Central IL. One of the most common forestry practices conducted here is called Timber Stand Improvement (TSI). Timber Stand Improvement involves thinning trees, and a lot of invasive species removal but I will leave the invasive talk out for now. When conducting Timber Stand Improvement, a forester will often prescribe a certain volume of trees that need to be removed to open up sunlight to the forest floor and to improve species composition. Most trees that end up being culled, or removed, are elms, hackberries, and maples within the 2-10” diameter class. After a TSI treatment has been completed, there’s often an unsightly looking forest floor for a few years. Many of these trees that were cut are just left to rot on the forest floor. It can be similar to playing a game of sticks and ladders trying to navigate your way through a mess like this, but don’t worry, the wildlife do love the cover and woody browse that this provides.
What I’m getting at with all that forestry talk is that I see a huge opportunity for a solution to clean up the forest floor after TSI has been conducted. You can simply cut up the trees you have felled into 3 feet sections and begin establishing log check dams on your property local to the site, or haul the wood to an adjacent gulley if there isn’t one present.
Long Term Solution?
As much as I loved seeing these log check dams in action, and actually constructing one of my own. I do worry about the longevity of these structures. Certainly we know that the dams are efficient up to 10 years, but that is not without some maintenance. The landowners stated “As logs in the dam decay and the dam lowers itself, we have simply added more logs to the top of them”. This sounds like a simple operation to me, especially if there’s already trees on site that need to be cut. Longer than 10 years? We don’t have any data on this as of now, but we have started a monitoring program with these landowners to see how they look long term.
I am seriously curious about the amount of sediment captured and ways to attain reputable data from these dams. We took measurements on the 3 dams we constructed, including total height, width, distance from each other, and size of watershed. We will come back periodically and remeasure the height from the streambed to gauge how much sediment has accumulated. We can then use a volume formula to crudely calculate the volume of sediment captured between each check dam. My team and I are thinking of ways to implement a long term, standardized measuring system on these check dams. Let us know if you have any suggestions, or would like to construct log check dams on your property. We’d love to help.