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Why does Backbone Lake have poor water quality?

State officials studied ways to reduce bacteria in early 2000s, but no recent work at Iowa's first state park

Backbone State Park
Backbone State Park
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Lake restoration projects happening across Iowa aren’t being considered for Backbone State Park, despite near-constant summer swim advisories caused by high levels of feces in the water.

Backbone, Iowa’s oldest state park, located near Strawberry Point, had swim advisories for 13 of 15 weeks this past summer because of high levels of bacteria in the water. The northeast Iowa lake had 14 advisories in 2018 and 13 in 2017, according to the Iowa Department of Natural Resources beach monitoring program.

People still come to Backbone — 205,300 in 2018 — but they focus on the park’s other activities, such as rock climbing and trout fishing, or they swim carefully, said Park Ranger Dave Sunne.

“To some extent, people are used to it,” he said.

If swimmers don’t have open wounds, have strong immune systems and shower immediately after exiting the water, they likely won’t get sick, Sunne added. Feces can carry parasites or other pathogens that can sicken swimmers.

Backbone Lake was created in the 1930s by damming the Maquoketa River. One of the reasons the lake has poor water quality is because 86,000 acres of farmland drain into a 50-acre lake, Sunne said.

“An inch of rain and we’re going to get a bad water sample,” he said. “It’s runoff from the farm fields. It takes 12 to 24 hours to clear up. That’s what happened this year.”

In the early 2000s, scientists were interested in finding a way to reduce bacteria flow into the lake.

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Iowa DNR environmental specialist Chad Kehrli collected water samples from Backbone Lake in 2003, cultured them and was attempting to figure out whether feces in the water came from livestock, wildlife or humans. By knowing the source of the bacteria, they could perhaps stem the flow, Kehrli said earlier this week.

First, “what is the issue? And then what can we do about it?” he said.

The DNR still is interested in bacteria tracking, but there does not appear to have been a focus on Backbone Lake in recent years.

Many Iowa lakes have undergone restoration projects in recent years to improve water quality.

Kent Park, a Johnson County park, reopened its beach in May after a nearly $3 million lake renovation that included adding new catch basins to filter runoff and new storm sewer intake structures. This was after crews removed 130,000 cubic yards of sediment from the lake bed.

The state has been dredging sediment from the lake at Geode State Park, near Danville, this past summer to reduce the potential for harmful algae that generate toxins that can sicken swimmers.

The DNR determined in the early 2000s soil retention ponds were needed in the Backbone Lake watershed to reduce runoff, but officials did not know whether ponds would hold water because of the porous topography, Sunne said. There also was skepticism private land owners would pay for conservation measures, such as wetlands, buffer strips or cover crops, he said.

“We tried really hard about 20 years ago and came up with a few solutions,” Sunne said. But now “nothing else is in the works.”

Comments: (319) 339-3157; erin.jordan@thegazette.com

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