Sediment dredging to begin on federal reservoir near Wolf Creek plant

It has the consistency of thin grease mixed with slimy mud and smells rank.

And the Kansas Water Office is sinking an estimated $20 million into removing about 3 million cubic yards – 250,000 dump truck loads – of the guck, officially known as sediment, from the bottom of John Redmond Reservoir. The process will take through the end of 2016.

Sediment is basically top soil that has washed into the lake during the past 50 years.

It has filled in more than 40 percent of the lake, just north of Burlington, which serves as the primary water source for the Wolf Creek nuclear power plant and as a drinking water supply for several communities, said Tracy Streeter, director of the state’s water office.

“The primary driver for the project is to be able to provide water for the nuclear power plant,” said Streeter, referring to the Wolf Creek Generating Station, about three miles from John Redmond, which provides power for about 800,000 homes, including many in central Kansas.

He also said the lake, and river below the dam, are water supplies for several Kansas communities.

This is the first major dredging project on a federal reservoir in the nation. It’s success, challenges, or failure, could set a precedence for how growing amounts of sediment, more than 20 feet deep at some Kansas reservoirs, is handled in the state and across the nation.

“I think a lot of people across the nation will be watching how this goes, seeing if it brings life back to a reservoir,” said Mike Abate, U.S. Army Corps of Engineers chief of civil works for the Tulsa district. “This is the first time we’ve had dredging of this magnitude at a Corps of Engineers Reservoir, in the nation.”

Lessons learned from the drought

John Redmond Reservoir has more than 14 feet of sediment at the bottom of the lake.

The average water depth in the lake is now barely 6 feet. During the drought, the average depth was around 3 feet.

“The drought of 2011 and ’12 really drove the need home,” Streeter said of creating more storage space in John Redmond. “The lake was less than half full, and that was a two-year drought. We knew there was no way we could survive a five year drought. In Kansas, that’s always a possibility.”

Streeter said the project is being paid for with money borrowed through 15-year bonds. Investors in the bonds will be paid back from fees collected by the water office from Wolf Creek and other water users in Kansas.

While this is the first major sediment dredging of its kind, the problem of sediment filling in lakes is well known.

“Anytime an engineer designs a reservoir, he knows it eventually will fill with sediment,” Abate said. “It’s just the way things go.”

Kansas has 24 federal reservoirs, according to Jerry deNoyelles, Kansas Biological Survey deputy director. They range in size from about 3,000 to 16,000 acres at normal water level. Most were built in the 1950s through the 1970s. All have been accumulating sediment since the gates were closed on their dams.

Of 24 reservoirs, 11 of them are filling at a rate where they will be half filled with sediment by the end of this century, according to deNoyelles.

“John Redmond is one of the worst, and there’s Tuttle Creek and Kanopolis,” deNoyelles said. “All look like they’ll lose half of their volume in less than 50 years.”

At first mention, a large reservoir still having half of its water doesn’t sound so bad. But Streeter warns that’s under normal conditions. The shallower the lake becomes due to sediment, the more quickly it’s affected by natural occurrences, like heavy rains and, much worse, drought. Even if it is full in the spring, John Redmond might lose half of its water by fall, during dry conditions.

It’s often been during a drought, when Wolf Creek’s cooling lake was low and electricity demand high, that the nuclear power plant most needed water from John Redmond.

The plant has a license to operate, with water from John Redmond, through 2045, Streeter said.

“We have obligations at that reservoir we have to meet,” he said.

Brad Loveless, executive director of environmental services for Westar Energy, which owns 47 percent of Wolf Creek, said water from John Redmond is key to keeping the small cooling lake next to the power plant full. Because water is necessary to cool the nuclear reactor, the plant can’t operate without an adequate source of water.

Sediment also affects Kansas multi-million dollar outdoor recreation industry at John Redmond and at most other reservoirs.

At Tuttle Creek and Perry reservoirs in northeast Kansas, campgrounds that were once lakeside are now a quarter-mile or more from the water.

Boat ramps that were favored by boaters when the lakes were built now have 30-foot tall trees growing nearby on yards of sediment where yards of water used to be.

The Kansas Biological Survey has said sediment is about 20 feet deep in places at the upper end of Perry, and that the upper end of the lake holds about 100 million cubic yards –about 1.2 billion dump truck loads – of sediment. Tuttle Creek, Kansas second-largest reservoir, is about 43 percent filled with sediment.

What to do with the muck

Some American reservoirs have simply raised what they consider to be their normal water level, by not releasing as much water as usual. John Redmond was the first federal reservoir in Kansas allowed to raise its level two feet several years ago by the Corps of Engineers. However that reduces the amount of space available to store water during heavy rains to prevent flooding downstream.

Just letting the reservoirs fill with sediment while making newer ones sounds good, but is almost financially not feasible, compared to dredging.

“I’m pretty sure dredging will end up being cheaper than making new reservoirs,” Abate said. The licensing process alone, for a new reservoir, could take a decade or more.

Finding a new home for all the millions of cubic yards of “yuck,” is one of the biggest challenges, logistically and financially.

“There’s no market for it so you can’t go around and sell it,” said deNoyelles. “It’s a very fine material, and it’s lost most of its nutrients. It doesn’t make really good soil. It’s not bad, either, but it’s not good enough someone is going to want to buy it. Mostly you’d have to pay a landowner to let you spread it on his property, or place it in a large pit.”

Finding a pit that would hold 3 million cubic yards is out of the question, so planners are using more than 20,000 feet of pipe, 22 inches in diameter, to send the sediment to earthen containment structures on land below John Redmond’s dam.

Much of the land is federally owned.

“We’ll use the material to elevate some of our lands and improve the environmental values,” said Abate, adding the lands would be planted to natural grasses, which should grow well enough in the new dirt. “Usually there’s a charge but this is mutually beneficial.”

‘Buy us some time’

Earl Lewis, Water Office assistant director, said sediment will continue to flow into John Redmond at the rate of more than 1 million cubic yards per year.

The dredging area is several hundred acres in size of the 9,000-acre lake. Up to about 12 feet of sediment will be removed in some parts of the lake. The Corps of Engineers is only allowing removal down to the original bottom of the lake. It can’t be made deeper. Nor is it a total fix.

“This is doesn’t really solve the problem,” Streeter said of the dredging, “but it does buy us some time.”

An important goal of all the groups involved is to find ways to drastically reduce the amount of sediment that flows into the lake. Part of the $20 million will go for conservation projects in the watershed above the lake, such as preventing bank erosion.

“You go up the Neosho River, you can see problem areas. When farmers farm right up next to the river bank, when we get those flood events it washes some huge amounts of sediment down into John Redmond,” Streeter said.

Soil conservation projects have been completed at 31 sites above the lake, he said. Another 300 are still awaiting attention.

Loveless said Westar is increasing its involvement in soil erosion programs and is working with several state agencies and the Corps of Engineers.

“The neat thing is that with these programs we’re paying farmers, to give them an incentive,” Loveless said. “There are a lot of ways we can keep the soil and nutrients where they belong on the farm fields. We understand we need to be preparing not for a rainy day, but for the dry days.”

This story was originally published November 17, 2015 at 8:01 AM with the headline "Sediment dredging to begin on federal reservoir near Wolf Creek plant."