Pipe fits Devil's Lake problem: Tool should prevent overtopping
By Tim Damos, Capital Newspapers
Water levels at Devil’s Lake got so high during the June 2008 flood that the lake overtopped, causing massive damage and dangerous conditions.
Crews installed a pump that sent excess water into a nearby creek. But it took about seven months for that maintenance-heavy system to lower the lake by 5 feet.
"We know it’s going to happen again," Park Superintendent Steve Schmelzer said of the flooding event.
But next time, officials will have a tool that will help prevent the damage that caused the state’s most visited park to remain closed for weeks.
This week construction crews are converting a 20-inch diameter pipe — used since 2002 to siphon phosphorus from the lake’s deepest point — into a gravity feed system so it can more easily be used to manage lake levels.
The project entails digging up a portion of the mile-long pipe, lowering its highest point by about 4.6 feet and inserting another flow valve.
That will place the pipe’s highest point below the surface when water levels exceed the "Ordinary High Water Mark," a legal reference point that defines the outermost edges of the lake.
"I don’t believe we’ll ever have another overtopping of this lake," said Dick Lathrop, a lake scientist with the state Department of Natural Resources who is managing the project. "Now we have a pipe that can be easily turned on whenever we hit that high-water mark."
Lathrop also oversaw the original installation of the pipe in 2002, and said it has since removed about 6,000 pounds of phosphorus from the lake.
The sediment is left over from the four resorts and 60 cottages that once surrounded the lake, and from a sewer pipe that broke sometime in the 1970s and leaked until it was repaired in the early 1980s.
Phosphorus causes algae blooms. And some types of algae provide a food source for certain snail species that host the swimmer’s itch parasite, Lathrop said.
One pound of phosphorus is estimated to produce 500 pounds of algae, Lathrop said. So he estimates the 6,000 pounds of phosphorus removed from the lake has prevented more than 3 million pounds of algae from growing.
The phosphorus is siphoned into the normally-dry Babbling Brook Creek on the north end of the lake. Lathrop said this is environmentally safe because the amount of dissolved phosphorus dumped is less than .1 percent of the phosphorus load in the Baraboo River.
Schmelzer said converting the pipe to a gravity feed system is a $48,000 project that will be primarily funded by a $36,000 state lake protection grant secured by the Friends of Devil’s Lake State Park. A federal Environmental Protection Agency grant might provide an additional $10,000, he said.
Underwater conditions at the lake seem to have changed dramatically since the siphoning system was installed, said Joel Bornitzke, who owns the 3 Little Devils dive shop in Baraboo and has been diving at Devil’s Lake since 1980.
"We used to have a real slimy green algae that grew along the rocks," Bornitzke said. "We don’t even see it anymore."
He also said the number of snails has gone down, which has led to a decrease in the number of swimmer’s itch cases.
"As divers, we just wanted to see better visibility," Bornitzke said. "And we were getting that until the floods last year. Hopefully (the new gravity feed system) is going to straighten out that problem for us, too."