Read more about the work at Twelve Mile Lake, and other water quality successes, in Working For Clean Water, the DNR's annual watershed success story publication.
This is one lake that’s hit its stride.
Not to say things weren’t rough for a while. During its peak in the late 1990s, Twelve Mile Creek Lake, near Creston, held nearly 30 fishing tournaments yearly. By 2004, that number dropped to a mere two. Common carp wreaked havoc, stirring up sediment and turning Twelve Mile’s formerly clear water into a murky brown. Fewer people came to the lake. Drinking water drawn from the lake required more chemicals for treatment.
“It got to the point where Creston started drawing water from Three Mile Lake because it was less expensive to treat. It was obvious the lake had a problem,” said Paul Goldsmith, who coordinated watershed efforts as District Conservationist for USDA-NRCS in Union County.
Work to repair the lake began in 2005, partially draining the water and deepening more than 1,000 feet of shoreline to roughly 30 inches deep. Rocks (rip rap) placed almost entirely around the perimeter of the lake stabilized the shoreline. Terraces, buffers and structures placed in the watershed years before would help protect the restoration work. The DNR removed common carp and then restocked fish.
The lake bounced back, sustaining its improvements over the last decade. Fishing tournaments returned quickly and are back to about 30 a year. The last water clarity reading showed you could see down in the water 5 feet. Creston uses Twelve Mile as a drinking water source again, in addition to Three Mile.
“The lake has developed into a great fishery since renovation,” says Andy Jansen, DNR fisheries biologist, noting sampling at Twelve Mile has found bluegills larger than 10 inches and crappies exceeding 12 inches, plus 14- to 18-inch walleyes and 12-inch perch.
Wildlife has taken notice, too. “With good water quality comes good vegetation. With bad water quality you get no vegetation. All one has to do is pay attention to waterfowl in the spring and fall to understand that they use areas like Twelve Mile Lake with clean water and healthy vegetation,” says Chad Paup, DNR wildlife management biologist at the Grand River Wildlife Unit, which includes Twelve Mile. “Iowans are without a doubt looking at water quality and understand the benefits that go with it. They can see it with their own eyes and if it doesn’t look healthy, then they will avoid it. At Twelve Mile Lake they apparently like what they see.”
Part of Twelve Mile’s continued success comes from an ongoing commitment. The DNR added more fishing habitat in 2015, and both NRCS and WIRB funded additional conservation practices in the watershed to keep sediment in check.
WIRB provided funding to the Creston City Water Works to buy 98 acres of land upstream and to install a sediment detention dike, which has reduced the amount of sediment. WIRB also worked with the Union Soil and Water Conservation District to install grade stabilization structures, terraces, water and sediment control basins and grass waterways in the watershed, which have reduced sediment reaching the lake by more than 2,400 tons.
