Area bodies of water filling in with dirt

Water. It's essential to all of us. But pollution and limited resources threaten our water supplies, and a confusing web of entities controls who gets water and how much. The Herald's exclusive, six-part series examines important water issues facing Franklin County.

East central Kansas, like most of eastern Kansas, is dependent on surface water -- lakes, rivers and creeks -- for its main source of drinking water.

And those lakes are filling in -- from the three large U.S. Army Corps of Engineers lakes such as the ones at Pomona, Melvern and Hillsdale in the Marais des Cygnes River basin; to the smaller municipal lakes.

"The Corps projects were designed for a useful, productive life of 100 years," Tom Sloan, Lawrence legislator and member of the Kansas Water Authority, said. "But Kansans are going to be living in Kansas longer than that 100 years."

But that's if the Corps lakes last the full 100 years, he said.

Development and agricultural practices in the fast-growing northeast and eastern Kansas region have increased sedimentation that are filling up the lakes with dirt and goo even faster than experts expected.

"Our lakes are filling in," Mark Jakubauskas, Kansas University research associate professor  and team leader for the Applied Science and Technology for Reservoir Assessment Initiative, said. "The north end of Perry Lake, for instance, has lost about a thousand acres over the past 30 years.

"That's lakefront property that's been lost. It's trees, grass and wetlands now."

The shallow water not only lowers the reservoir's water storage capacity but also promotes the growth of blue-green algae, which diminishes the quality of the drinking water, he said.

"Many reservoirs in Kansas have experienced some level of taste and odor problem," Jakubauskas said.

Jakubauskas's team has been using a  special high-tech sonar system to measure the depth, or "bathymetry," of lakes in Kansas.  

Jakubauskas said the system shows many Kansas lakes are silting more rapidly than expected.

Jakubauskas said before this research, state and local governments and agencies had little information on the state lakes, such as how much drinking water they hold or how long that water will last.

His team also uses a boat-mounted coring machine with a hollow tube to remove a core of sediment from the reservoir to measure the sediment depth and to learn what kind of sediment it holds and whether it's rocky, silty or sandy. The type of sediment determines to how expensive the dredging process might be and how much needs to be dredged to rehabilitate the lakes, he said.

Working out deals with the Corps of Engineers to protect and preserve the lakes will be one of the top issues facing Kansans in the future, Sloan said.

"Long-term, we need to look at addressing the big reservoirs," Sloan said.

Dredging will be expensive, he said.

KU's Jakubauskas estimates that to remove 91.5 million cubic yards of bottom crud from Perry Lake could cost up to $457.5 million.

However, several community groups, farmers and individuals teamed up to cut the amount of runoff and chemicals leaching into Hillsdale Reservoir, after it became apparent that lake was prematurely aging years before its life expectancy.

The Hillsdale Water Quality Project has won national recognition for its work and is being copied by groups around other lakes.

The Marais des Cygnes River Basin Advisory Committee has embarked on a WRAPS -- Watershed Restoration and Protection Strategy -- program to cut the amount of soil erosion, agricultural chemicals and urban contaminants in an effort to cut pollution, Sloan said.

However, the problem is even worse for small municipal lakes, Sloan said.

"They're older, they're smaller," he said. "The cities that are drawing from them are maxing them out."

"These people don't have the deep pockets to go out and do surveys," Jakubauskas said. "They're going to be among the first affected because their lakes are small, they affect a small population and they don't have a lot of money to rehabilitate these lakes."

Mission Lake in Brown County has lost 50 percent of its volume since its construction in 1924.  

KU research has shown that Gardner Lake in Johnson County has become so shallow in its upper end that it is now only a few feet deep.

The state recently set up a grant program that begins next year that will pay half the costs of to dredge municipal lakes, Sloan said.

Although they have to come up with half the costs, the program has attracted 20 cities seeking grants for the work, he said.

Normally, first-time grant programs, especially those that require cities to come up with half the cost of something as expensive as dredging, don't get many takers at first, he said.

"The fact that we've got 20 cities applying suggests that there's a serious need," Sloan said.