Articles : Are Spillways Working

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Muskies and Spillways:
Are the Barriers Working?
By: Steven James Rusteberg

About seven years ago I came to the conclusion that muskellunge were attracted to current. Hundreds of expensive, adult muskellunge were escaping from the lakes where they were intentionally stocked, and into streams where they could cause great damage to themselves and their new environment. After making their way through the spillways, they would either die in the shallow creek bed below, or become victims of their own circumstance in the hot summer sun. Other muskellunge would find themselves in foreign bodies of water, were they could feed on the native species causing a potential food chain catastrophe.

Through a campaign created by local fishing clubs, such as Muskies Inc., and with the help of the Department of Natural Resources, some of our Illinois lakes have become protected by experimental fish barriers. Over the past few years these barriers have helped keep the muskies out of the spillways and in the lakes were they were intended to live. Now that these barriers have been in place for several years, the time has come to evaluate the effectiveness of the different styles that were built.

Shabbona Lake

Shabbona has had a spillway barrier for quite sometime. The device consists of netting fastened to the bottom of the lake on posts. The netting is then attached to buoys on the surface of the water. The design allows it to be lowered and raised by a crank on the shore. The netting remains at the surface level as the lake drains and fills. In the first few years of its existence, I had worries about its effectiveness. Every year during the late fall the netting would be lowered below the waters surface, so that ice and it’s destructive power would not damage it. My problem was not with the lowering of the net in the late fall, but with the ability of the IDNR (and the Park) to get the net back up in the spring. For some time in the spring of 1999 and 2000, the net did not take a high priority. I also had concerns about its design. The netting rested on the surface of the lake. If a muskellunge had the natural tendency to jump the spillway, wouldn’t these fish follow the current and jump the net too?

Over the last few years the Quad County Chapter of Muskies Inc. has netted Indian Creek below the spillway, just as they did before the barrier was erected into place. They have turned up only a few fish in the creek, leading us to believe that the spillway barrier has done its job effectively.

Muskie guide Duane Landmeier has said, “Muskie fishing on this lake has never been better!” He believes that the lack of spring floods in cooperation with the barrier has lead Shabbona Lake back to its numbers and trophy status.

The net has had it run in with repairs, however. The IDNR has been out several times to repair damage to posts and netting. The barrier is at best “high maintenance.” Design flaws and ice have caused this barrier to malfunction several times probably allowing fish to escape, however, a partially working net is better than no net at all. Occasionally muskie get caught in this netting causing mortality to the fish. This hasn’t seemed to be a major problem. Most people fell that the sacrifice of a few fish is worth the many that could be lost if the barrier didn’t exist. Overall I give the design a “C-“ and it’s effectiveness a “B+”. The barrier has not been challenged with a major flood but seems to be doing its job when functioning properly.

Evergreen Lakes Experimental Structure

Lake Evergreen, located fifteen minutes north of Bloomington, has experimented with a chain link fence below the spillway. Local lake authorities are very hesitant to attach anything permanent to the dam structure. Spillway barrier supporters, along with the help of the Central Illinois Chapter of Muskies Inc., acquired permission to assemble this fence below the fall, which would contain the muskie in the spillway and its tail-waters. The fence traps muskie below the spillway and doesn’t allow them to continue further down stream. The muskie and other fish all gather below in the spillway itself and a small portion of creek, so that later the IDNR can Electro-shock them up and put a majority of them back in the lake.

This system is a temporary fix for a reoccurring problem, but better than having nothing. Some people speculate that almost one-third of a lakes muskie population can go over the spillway in one flood. This fence will contain the muskie so that later they can be collected and put back in their rightful environment. The fence also protects fish populations in down-steam waters from suffering the effects of a muskies predatory nature on waters that shouldn’t have the species in it to begin with.

One of the major problems with this type of barrier is that often time’s shallow spillways can become oxygen depleted during the summer months. Warm water and this lack of oxygen can kill off everything in the spillway in a short period of time if fish are not collected regularly. There is also a lesser issue of poaching that takes place with these enormous populations of fish in such a small area. This became a serious problem in Shabbona’s tail-water is the mid-1990’s to the point where the park had to close the tail-waters to fishing. Poachers were snagging adult fish trapped in the shallow water of the stream.

So far the Evergreen Lake fish barrier has been very efficient, however the real test on the stress level of the fence will be put on trial with higher water conditions. This fence does back up the water in the spillway when it gets clogged with derbies. It must be maintained periodically to prevent this backup. It seems like a good choice for lakes with dams that cant have anything attached to them. There has been some trma to fish reported as they repeatedly hit the fence in their attempt to go further downstream. Many fish rub against the fence to the point where they wound themselves.

Overall I give the design of the fence a “C-” and its effectiveness an “A-.” As long as it is maintained, and shocked regularly it is a very efficient structure. However, regular shocking trips for the IDNR can become very costly and this may become the structure downfall. If oxygen is depleted in the spillway, everything will dye. The only positive to a barrier of this nature is that it is nearly impossible for a fish to make it past this fence when it is functioning properly.

Otter Lake’s Spillway

Otter Lake has a structure assembled by the Army Corps of Engineers and divers. The netting is one-inch mesh fastened to the bottom of the lake and to all sides of the dam itself. The barrier and netting ascend about two feet above the water surface. This is a very effective deterrent to any fish that wants to try jumping for freedom. Rocks adorn the netting’s bottom to prevent erosion or anything to escape underneath it.

Dan Becker, one of the lake’s muskie experts, considers the fence to be 95% effective at keeping fish in the lake where they belong. “Sure” Dan said, “these muskie are just like mice, if there is a way in or out… they will find it. But the barrier seems to be very efficient.”

A recent problem with the barrier allowed twenty-seven adult fish to escape over the spillway. A bottom erosion matting ripped and tore a hole in the spillway netting. The hole was only open for two weeks of high water and you can see what can happen to a muskie population in that short of an amount of time. The twenty-seven fish were later Electro-shocked up in the spillway by the IDNR and returned to the lake. Some of these fish were actually tagged earlier by the IDNR with “pit tags” for individual identification. This data would have been lost had the problem with the spillway not been repaired and the fish not returned to the lake.

Overall, this is one of the most expensive contraptions the IDNR and the Army Corps of Engineers have erected to contain muskellunge in their lake of stocking origin. The cost I was told was not available, but you can assume those divers, plan layouts, and construction materials of this magnitude don’t come cheap. I give this spillway an “B“ for design and an “A” for overall effectiveness. Maybe using a netting more resistant to tears will help future designs. I think that Otter Lake's spillway barrier is one of the most efficient designs in the state.

Kinkaid Lake Spillway

Al Nutty, one of the lake's most famous muskie guides with over ten years of experience said, “Muskie fishing on Lake Kinkaid has never been so good. The fishery has been significantly better since the spillway construction”.

This spillway is constructed of one-inch bars that are two inches apart. It is virtually a fortress, with a 24” rise above the water. The barrier was constructed in November of 1998 and has been fully functional ever since. The IDNR has had very little problem with things getting caught up in the bars and cleans and maintains it on a regular basis. The structure is fastened to the spillway and, if need be, can be disassembled for cleaning or maintenance.

“Even the walleye action in the lake has picked up due to the spillway”, said Al. “The walleye action has always been best down below the spillway in past years, but the structure has allowed the lake to excel in other species as well.”

I would consider this structure one of the best in Illinois. Early fears were that the spillway barrier would back up water, or get clogged like a bath tub drain. Neither has happened. Anytime something of this nature is added on to an existing structure such as a dam of this magnitude, there are worries of down stream repercussions. It would appear that this structure is a success. Al commented that this barrier is more than 95% effective at keeping adult muskie in the lake, and is even benefiting the walleye fisherman too. I give this structure my highest rating of an “A” for design and an “A+” for effectiveness.

Illinois is well on it’s way to becoming a leading state in the construction and instillation of muskie spillway barriers. We have already saved hundreds of thousands of dollars with our experimental barriers that are now in place. I would like to be the first to say that I think the action to address this issue has been slow, but the follow through to correct this problem by our IDNR has been nothing short of noble. The IDNR has not cut corners or ignored the problem exists. Brent Manning, Steven James Rusteberg Pallo, and other staff members have brought the term “spillway management” into the vocabulary of other states and organizations. The IDNR has allowed our state to be the “guinea pig” when it comes to testing and constructing something that will allow sportsman a better experience on the water. We have won a small victory when it comes to problems such as spillway escapement. Hopefully, future designs will lead to more and better breakthroughs. I think that many Muskie Fishermen look forward to the day when all of our lakes have a spillway barrier in place.