State water officials in Kansas are preparing to launch a $20 million project to dredge sediment out of the John Redmond Reservoir near Burlington, about 80 miles southwest of Lawrence.
But John Redmond is not the only reservoir in Kansas that is filling up with sediment. By the end of this century, researchers say, the state's 24 federal reservoirs will have lost more than half their original capacity, and dredging them all will not be a viable option.
"Restoring the original volume of the 24 at the end of the century, at today's prices, would cost $13.6 billion," said Jerry deNoyelles, deputy director and senior scientist at the Kansas Biological Survey, located at Kansas University. "And where would we put all this sediment if we chose to dredge it out and put it somewhere?"
The dredging project at John Redmond is being financed over 15 years with state bonds. The first year's payment on those bonds, $1.6 million, is included in the budget bill that Gov. Sam Brownback signed Friday. Most of that money will come from the state's Water Plan Fund, which receives revenue from a fee that's added to water utility bills.
Over the life of the bonds, state water officials are recommending that 75 percent come from the water plan fund and 25 percent come from fees charged to water customers who buy water from the reservoir — a proposal that some say could result in steep hikes in water bills for customers downstream.
Water issues east and west
Soliciting ideas and concerns from the public about how to address the state's long-term water needs was the focus of a public meeting on the KU campus last month, sponsored by the Kansas Department of Agriculture and the Kansas Water Office. The meeting was part of Brownback's directive to develop a 50-year "vision" for sustaining the state's water resources.
Much of the work on that project so far has focused on water supply issues in western Kansas, which relies heavily on groundwater resources in the Ogallala Aquifer, which is being rapidly depleted due to irrigation farming.
But deNoyelles warned that eastern Kansas will soon face its own set of critical water issues because here, people rely on surface water that is impounded in artificial lakes.
"The governor is asking for a 50-year plan," deNoyelles said. "Over the next 50 years, seven of our reservoirs will become 50-percent infilled with sediment."
Most of the reservoirs in eastern Kansas were built after World War II and were primarily intended to provide flood protection, deNoyelles said. But they also serve as sources of water supply for municipalities, including Lawrence, which draws part of its public water supply from Clinton Lake.
In 2009, the most recent year measurements were taken, Clinton Lake was estimated to be less than 10 percent filled in with sediment, according to data from the Kansas Water Office.
The problem with man-made lakes
"Reservoirs are not natural lakes," deNoyelles said. "Natural lakes are thousands of years old. Reservoirs never will be. Reservoirs are constructed around the world, and in Kansas, where there are few natural lakes. Think about that a little bit. That might be a red flag."
Natural lakes, he said, exist mainly in rocky areas where the soils are shallow and there are few nutrients to feed plant and animal life. Most man-made lakes, by contrast, are built where soils are deep, and easily eroded by flowing water, and rich in nutrients that promote algae growth.
"Long ago, in Kansas and elsewhere, we discovered the bounty from deep, rich soils," deNoyelles said. "And particularly in Kansas at the same time, we recognized that we need to hold onto water. There's a lot there at times, but then it goes rushing by and it's gone."
Currently, he said, there are more than 200,000 water impoundments in Kansas, ranging in size from small farm ponds to large federal reservoirs. But the 24 federal reservoirs hold three times the volume of all the other impoundments put together.
Many of those smaller impoundments are located uphill, or upstream, from the reservoirs, and they have helped hold back some of the sediment that otherwise would have gone into the lakes. But as those smaller impoundments fill up with sediment too, he said, they will eventually start releasing even more sediment into the reservoirs.
Search for long-term solutions
Short of dredging, deNoyelles said, there are other options that communities in eastern Kansas may consider, such as constructing floodwater bypasses around the dams so that some of the sediment in high-erosion events doesn't get trapped in the lake. But since most of the dams were built for flood protection in the first place, he said, that won't be a viable solution in most cases.
Building new reservoirs may also be a possibility, he said. "But will there be places in Kansas, and on whose land will those reservoirs be built?"
In the end, he said, people in eastern Kansas will have to confront the same challenge as their western Kansas neighbors in figuring out how to get by with less.
"There are still communities in Kansas where 50 percent of their reservoir water use during the summer is for watering lawns," deNoyelles said. "And we are going to have to get way more serious about conserving water, both for groundwater systems and surface water systems."