By Steve Weisman

Since 2006, the Iowa DNR has gone about restoring lakes across the state through the Lake Restoration Program. Created by the Iowa Legislature, the goal of the program is to increase the health and safety of Iowa’s lakes, involve local communities in restoration projects and remove bodies of water from the state’s Impaired Waters list. Some of the lakes restored in Iowa have been the shallow natural lakes we find northwest and north central Iowa. The cool thing is when the restoration is completed, it’s almost like turning a switch.

At one time these natural lakes were all healthy and vibrant ecosystems that unfortunately have become degraded to the point of little use. Often devoid of plant life with very poor water quality and overrun by fish such as carp and bullheads, these former gems are often ignored and forgotten. They simply cannot handle the runoff and increased nutrients and sediments that accompany this runoff. Left alone, these lakes cannot recover and simply will stay in their poor state. Common carp add to this situation and can keep the lake in poor condition even after other changes are made. This is where this program is so important.

One of the most recent shallow lake restoration projects in northwest Iowa has been taking place at West Swan Lake located south of Gruver. However, it has taken longer than originally planned because of its size, complexity, and string of extreme weather events. This has been an extended battle.

According to Iowa DNR Fisheries Biologist, Mike Hawkins, “This has been a long project.” The first attempt was with a drawdown of the lake with the goal of having winter take care of the common carp. This normally works well with the harsh cold of Iowa winters. However, Mother Nature did not cooperate, and the mild temperatures allowed the rough fish to survive. So, an under the ice application of rotenone, a chemical that targets only fish, was completed. We then experienced the warmest winter in Iowa’s history helping some of the carp survive again! So, things were delayed until the fall of 2024.

Third time the charm

According to Hawkins, “After that unsuccessful attempt, we decided try one more time and do a rotenone open water fall application after we had gotten water levels down as far as we could.”

However, with the lake drawn down, it was impossible to use boats to apply the product to the water, and so a different technique was used. According to Mark Flammang, Iowa DNR Fisheries Biologist, “We took the opportunity to use an agricultural drone, something that to our knowledge hasn’t been used to this point for this type of application.”

Following the application, the results were excellent with a complete kill of the rough fish. The boards were put back into place so that with, hopefully, good spring rains West Swan Lake will be filled. According to Hawkins, recent rains in late March and early April have raised the lake levels by about two feet bringing the water levels to the base of the boat ramp. If timely rains continue and water begins running out of Ingham Lake, then West Swan has a good chance of attaining a full level.

Fish stocking has begun with 2,000 adult perch recently stocked. These adult perch came from South Dakota. In addition, northern pike fry will be introduced in a few weeks, followed by   bluegill and largemouth bass.

Drone potential

Following the use of the agricultural drone, Flammang sees a lot of potential for future uses, “some that haven’t even been considered at this point.” For this type of application, Flammang sees that the drone “allows us to get into locations where we can’t get a boat.” Areas such as adjacent sloughs and wetlands, which were difficult or impossible to access by boat, are now easily accessible with the drone. These are all places that common carp can avoid a renovation.

To me, this is what is most exciting: drone usage potential. Technology continues to expand. The use of the drone in this case is limited to a person calibrating and running the drone with complete precision. It’s more cost and time effective. Pretty amazing, I’d say!