Sediment's a growing problem in Kansas lake and reservoirs
03/13/2012 10:29 AM
03/13/2012 10:29 AM
John Redmond Reservoir averages just 6 feet deep.
The lake, which supplies water to several Kansas towns and the Wolf Creek nuclear plant, now sits with only about 58 percent of its original capacity.
The rest is goo.
From the smallest farm pond to the largest reservoirs, all Kansas lakes are slowly filling with dirt. Sediment, the simple mixture of water and dirt, is considered one of Kansas’ largest environmental concerns by some experts.
Currently about 60 percent of Kansans get their water from lakes and that number is expected to grow.
Kansas experts say no simple solutions are in sight.
Dredging a large reservoir could cost $1 billion in tax dollars. Building a new one — even if the state could meet all of the environmental regulations — could cost much more and probably take at least 20 years from initial planning to completion.
Problems are already at hand. Consider:
-- At Toronto Reservoir kayaks are now available at Cross Timbers State Park because much of the lake’s upper end is too shallow for motor boats.
-- Tuttle Creek Reservoir, more than 43æpercent filled in, holds enough sediment to totally fill Cheney Reservoir.
-- Sediment is up to 20 feet deep at Perry Reservoir. Once-popular boat ramps now lead to forests of 35-foot-tall trees where sediment has long replaced water. Perry’s upper end holds about 100 million cubic yards of sediment.
-- Sedimentation is feeding the growth of toxic blue-green algae that caused more than a dozen lakes to be closed to swimming, boating and water skiing this summer. The algae killed some pets and forced water departments to spend more money to purify the water.
-- Most of Kansas’ major reservoirs were built with 100-year lifespans. Many are now 50 to 60 years old.
The Kansas Water Office, charged with long-term planning for future drinking water supplies, ranks the problem on par with the depletion of the Ogallala Aquifer because it so threatens the long-term quality and quantity of our water.
“People can debate climate change back and forth but there’s no question our reservoirs will fill with silt,” said Jerry de Noyelles, the deputy director of the Kansas Biological Survey. “It will be during this century and some will be in the middle of this century.”
Yet the U.S. Army Corps of Engineers, which built some of the large reservoirs in Kansas, says everything is going as planned and problems can be easily fixed on their lakes.
Land of 150,000 lakes
De Noyelles said nearly all of Kansas’ 150,000 impoundments are man-made, from tiny ponds for watering livestock to 24 federal reservoirs of up to 16,000 acres.
About 100 lakes supply water for Kansas towns.
All are doomed.
“They’re going to fill up with their natural surroundings, soil and clay,” said de Noyelles. “It’s nobody’s fault; nothing was done wrong. We have always known the lakes inherently weren’t going to last very long.”
Though all will eventually fill, the sedimentation rates vary greatly across Kansas.
Runoff from places like forests and tallgrass prairie causes few problems. Runoff from farm fields and other places where the soil is frequently disturbed produces the largest amounts of sediment.
Rainfall amounts also contribute heavily.
That means the eastern half of Kansas, with its intensive agriculture and higher rainfall, has a larger sediment problem than western Kansas.
Eastern Kansas is also where most of the state’s population lives and where towns are most dependent on surface water.
Many of Kansas’ lakes were built in the 1930s as the federal Civilian Conservation Corps used the projects to create jobs during the Great Depression.
A need for flood control was a major catalyst for the federal reservoirs after the floods of 1951 scoured river valleys, killed many people and seriously damaged Topeka, Lawrence and Kansas City. Many reservoirs were built from the mid-1950s through mid-1970s.
Though several hold large amounts of muck, there’s one reservoir always mentioned in most serious talks of Kansas’ sedimentation problem.
The problem’s poster child
“John Redmond is our poster child,” said Earl Lewis, Kansas Water Office assistant director. “It now has such a low average depth and has lost more than 40æpercent of its storage area to sediment. If there’s one place in Kansas where we could (soon) have a problem with our water supply, it’s probably it. You wonder what would happen if we’d get a (long-term) drought like in the ’50s.”
It’s not uncommon for Kansas lakes to lose 6 feet of water in one dry year.
Conversely, Lewis said John Redmond is fed by “prolific watershed,” which means a little rain in the right places can quickly raise the lake’s level.
Several Kansas towns downstream from the Coffey County lake get their drinking water from what John Redmond releases into the Neosho River.
Wolf Creek draws water for its cooling lake from a structure just yards below John Redmond’s dam.
Officials at the nuclear facility say a cooling lake at the facility usually holds a lot of excess water in case it’s needed.
Should the cooling lake’s level drop to about 7 feet below normal, the plant would be shut down, said Wolf Creek spokesperson Jenny Hageman.
“There would be no concerns about (endangering) public safety,” said Hageman.
Gina Penzig, Westar Energy corporate communications director, said power to customers probably wouldn’t be interrupted because the utility could obtain power from other energy centers, but electric rates could increase.
Contributor to deadly algae
De Noyelles of the Kansas Biological Survey said there is “very significant connection” between blue-green algae and the increased sediment rates in many Kansas lakes.
De Noyelles said blue-green algae benefits from the fertilizer in the dirt that washes off farm fields and lawns into Kansas lakes.
Blue-green algae blooms have become nearly annual events the past eight summers in Kansas.
Toxins from the algae contaminate the water, causing treatment plants to spend more to produce clean drinking water.
Wichita normally draws about 60 percent of its water from Cheney Reservoir.
In 2006, the Wichita Water Utilities invested $7.6 million in a system that injects ozone into the water supply to handle odor and taste issues.
Debra Ary, Water Department superintendent of pumping and production, said blue-green algae spikes can raise daily production costs. It can also make the department rely more on water from groundwater.
“We’re really fortunate to have those two sources of water,” Ary said. “Most places (in Kansas) aren’t so fortunate.
At high levels, the algae endangers any animal that comes in contact with water. This summer several dogs died from infected water at Milford Reservoir.
Blue-green algae carries a putrid odor that also discourages lake use.
De Noyelles said lakes with high sedimentation are turbid and shallow, both of which cause water temperatures to rise. The warmer the water, the faster the algae can bloom. Higher water temperatures also make for poor fishing conditions and hurt fish populations.
Tom Langer, Kansas Department of Health and Environment director of environmental health, agreed that “the No. 1 factor is the nutrient load” when it comes to blue-green algae.
He also said other conditions — including lots of sun, extreme heat, little wind and little flow-through —contributed to this summer’s record blue-green algae outbreak in Kansas.
All is going as planned
The Corps of Engineers isn’t surprised or alarmed at any issues related to sedimentation on its lakes.
Stephen Spaulding, Corps of Engineers hydrologist, said sedimentation rates were factored into the planning of all of their reservoirs.
Much of the current sediment has accumulated where it has little effect on the lake’s main uses.
“When sediment comes in, it settles out and forms a delta at the upper end of the lake,” Spaulding said. “Things are still in line for what the reservoirs were designed for.”
He said there is still plenty of space for flood control.
Spaulding said that Perry Reservoir currently has about 15 feet of sediment in the lake’s main body, but there’s still about 50 feet of water in some places.
Even when the portion of the lake set aside for sediment is filled Spaulding said the lakes will still be viable and useful.
He sees no reason for alarm even though some lakes are on the downhill side of their proposed 100-year lifespans.
“We’re not going to worry about it. Who knows what regional needs will be in 20 to 30 years from now?” Spaulding said. “When that time comes, we’ll work with people to see if we can modify plans accordingly.”
Spaulding said one easy option is to simply raise what’s considered a lake’s normal level a few feet. Most of the federal projects include huge areas of land around the lakes so the lake levels can be raised if needed.
For instance, if El Dorado Reservoir’s current normal level is 1,274 feet above sea level, it could be increased to 1,276 feet to compensate for space lost to sedimentation.
“For all practical purposes it really doesn’t effect the actual operation at the lake,” Spaulding said. “As the pool gets higher, the space is increased dramatically, too.”
Just a few feet, he said, could prolong a reservoir’s life 20 years.
No easy solutions
Most Kansas experts say there are problems within the corps’ simple solution.
Lewis and de Noyelles pointed out that most Kansas water supply lakes don’t have a lot of extra space like the federal lakes do.
Many city and community lakes are surrounded by houses and docks.
“Raise the water level a few feet in some places, like Gardner City Lake, and it will be in somebody’s living room,” de Noyelles said.
There are also concerns how much water a lake can hold to prevent flooding, especially in times of massive flooding like in 1993 when many Kansas lakes were full.
Another option — dredging the lakes of sediment — is not easy or inexpensive.
De Noyelles said it could cost $1 billion or more to dredge a lake the size of Cheney Reservoir in the future.
The 123-acre Mission Lake, the water supply for Horton in northeast Kansas since being built in the 1920s, was dredged a few years ago.
According to Mark Jakubauskas, Biological Survey assistant research professor, there was “æ.æ.æ.æmore sediment in that lake than water.”
Removing that sediment cost more than $6.5æmillion.
“They took out 1 million cubic feet of sediment and Perry (Reservoir) has more than 100 million feet of sediment,” Jakubauskas said. “It has 100 times the problem. The cost would be amazing.”
One of the problems, he said, is what to do with the sediment once it’s removed. “The problem is that it’s really not good for anything,” he said. “Maybe you could make pots out of it.”
The Mission Lake project entailed piping sediment to settle into a new dam. If the sediment had to be hauled to another location, the price of the project would grow exponentially.
Another option would be to let existing lakes eventually fill with sediment and start getting water from new lakes.
“One big problem is finding the right sites,” Lewis said, “when they’ve already picked the best reservoir sites. There are others, probably, but not nearly as good.”
Nor is building new reservoirs fast or cheap.
Lewis estimated simply getting the proper licensing to build a new lake could take 10 to 15 years.
Environmental regulations put in place since original lakes were built would make new construction almost impossible.
Rep. Tom Sloan, R-Lawrence, and Sen. Carolyn McGinn, R-Sedgwick, have been trying to push for solutions in Topeka for several years.
Both are frustrated the state has done little to plan for problems that are certainly coming.
They agree the state needs to expand programs that decrease sedimentation by stabilizing soil along rivers and streams that drain into lakes.
“We need riparian areas and wetlands if we’re going to decrease rapid sedimentation,” McGinn said. “Instead of farming right up to the tributary, we need to put in (native grass) buffer strips.”
Sloan and McGinn said the state is headed in the wrong direction for such programs.
“The state water office has been very underfunded for the last four years,” McGinn said. “Some of the programs that really decrease sediment are some of the ones that are being cut.”
They’re also frustrated more Kansas residents aren’t calling for the state to get more involved in its sedimentation problem.
Sloan hoped Atlanta’s Lake Lanier going nearly dry from a drought in 2008 and leaving about 3 million people worrying about having drinking water would be a wake-up call.
Sloan hears few Kansans with such worries or intentions.
“A lot of people seem to think that can never happen here,” Sloan said. “It can happen here.”