Restoration Plans Revealed For Virgin Lake
RUTHVEN For thousands of years, ever since the great glaciers retreated from the lands that now make up our state, a small lake known as Virgin Lake has been a feature south of Ruthven. However, the face of the small lake will be changing later this year and over the space of the next year. Plans call for Virgin Lake to be drained later this year as part of Iowa’s Shallow Lakes Restoration Program.
Representative of the Iowa Department of Natural Resources explained what they plan on doing to Virgin Lake during an open house held Monday, August 15, at the Lost Island Prairie Wetland Nature Center at Ruthven. Mike Hawkins, a fisheries biologist for the Iowa DNR was joined by Brian Hellyer, wildlife biologist and Doug Jahnke, Manager of the Shallow Lakes Restoration program, talked with around a dozen area residents about the process of restoring the lake.
Virgin Lake is a 220-acre basin that lies two miles south of Ruthven, which features a highly diverse shoreline along with back bays, peninsulas, and small islands. Like so many other shallow lakes in Iowa
and the upper Midwest, Virgin Lake has become unhealthy due to agricultural lands located in its watershed and an overabundance of rough fish. Together, these and other factors have resulted in turbid water in the lake and have led to the subsequent loss of the beneficial aquatic plants needs to sustain clean water and provide habitat for more desirable sport fish and aquatic wildlife.
Virgin Lake varies in depth from two feet to a maximum depth of 6.7 feet, with an average depth of 4.2 feet, according to DNR surveys conducted in 2008. There are two boat access points on the lake, one on the northeast side and one on the south edge of the lake. A concrete structure regulates the water flow out of the lake into a neighboring drainage district.
“Basically, we plan on making some minor modifications to the lake in order to drain it on a temporary basis,” Jahnke explained, “We want to get rid of the carp, get good vegetative growth back into the lake and refill and restock it with fish. But, our overall goal is to restore the water quality of the lake.”
According to Brian Hellyer, who is based at the Ruthven Wildlife Unit of the DNR, the restoration plans also call for the construction of a new water control structure featuring box culverts with stop logs to facilitate water level control, which will replace the old concrete weir control structure.
“A lot of old dams were placed on these shallow lakes in the 1800’s” noted Mike Hawkins. “They’ve led to a lot of shoreline erosion, due to a lack of vegetation and high water levels.”
The basic plan calls for a gradual draw down of the lake’s water, starting in late November of this year. “It will be metered carefully,” Hellyer said. “You can’t just rip six feet of water out and dump it. We certainly don’t want to cause anyone any problems. We don’t want to use the drainage district facilities out there any differently than we’ve used them before.”
Once the lake is drained, it would be kept dry through 2012 to allow for settling of sedimentation and the bottom of the lake and for the establishment of native aquatic vegetation. Once the aquatic growth is established, the lake would be allowed to re-fill with water.
A question was asked if the lake would become solid bulrushes and cattails after being drained.
“Virgin is going to look different,” Hellyer answered. “Bull rushes will live in three to three and a half feet of water and they will probably surround the lake for sure, but as far as how long they’ll live, that’s dependant on muskrats, natural events, things like that.”
Hawkins was asked about stocking the lake with fish once it was re-filled. “We’ll start out with yellow perch the first year, and then introduce a predator, Northern Pike,”
“The bulk of the biomass in Virgin right now is carp and buffalo head,” Hellyer noted. “That’s why we need to drain it down and re-establish the natural vegetation.”
“It’s a travesty that carp were ever brought to North America,” Hawkins added. “We’d be in a lot different situation without them as a species in our lakes.”
According to Hawkins, as Virgin is a shallow lake, there will be a possibility of winterkill once fish are reintroduced. At that point, a question was asked about deepening a part of the lake to perhaps boost fish survival.
“Deeper water is not a guarantee for fish survival,” Hawkins said. “Dredging is expensive and it’s also difficult to deal with federal government. These lakes are 13,000 years old and all of our work has to be done in accordance with federal regulations. We’ll be working with the State Archeological Survey as well, knowing the history of this area. We’re no different than anyone else.”
“You folks have some very strong ties to this lake,” Hellyer noted, “and that’s what makes it even more special to us for this restoration. That’s great that you are all here to discuss these plans and express your thoughts and concerns.”
“Our overall objective once this project is done is to leave it alone,” Hawkins said. “But, we also know that it will probably have to be done again in the future. We’ll monitor the lake after the restoration and the water quality will be the triggering factor when something needs to be done again.”
It was pointed out the costs of the restoration work were being funded through a legislative appropriation through the Shallow Lake Restoration Project, as well as from federal funding from the North American Conservation Act.
“We’re not out her inventing the wheel with this,” Hawkins said. “These projects actually begin in the Netherlands and Wisconsin and Minnesota have done several as well, with a lot of success. We’re as anxious as you folks are to see how this will turn out.”
“We hope that it will be a healthy, shallow lake when it is all done,” agreed Hellyer. “This isn’t a fix all, but it will allow the lake to fix itself quicker.”