Federal reservoirs are losing water storage capacity. Economic analysis on Tuttle Creek Reservoir suggests that streambank stabilization combined with riparian forest buffers can save $42 million in annual dredging costs to prolong storage capacity.
Groups Cooperate to Slow Reservoir Sedimentation
Even an avid University of Kansas fan can see the benefits of collaborating with K-State.
Retired teacher Dave Royer of Arrington proudly wears KU attire and has a four-foot lighted KU sign in his yard; however, when he noticed the Delaware River eroding the bank along his cropland he turned to K-State Research and Extension and its many local, state, and federal partners to solve the problem.
Landowners across the state are concerned about erosion and sediment entering nearby reservoirs. In addition to being valuable recreation resources, federal reservoirs in Kansas supply municipal and industrial water for two-thirds of the state’s population.
In 2009, the Kansas Forest Service received a federal grant to use GIS (geographic information system) to assist the Delaware River Watershed Restoration and Protection Strategy group to identify areas where stabilizing streambanks could slow flood water and deposit sediment in riparian buffers — areas planted with vegetation — instead of reservoirs. The grant focuses on the main stem of the Delaware River, Banner Creek Lake and Atchison County Lake subwatersheds, and several other watersheds that carry high sediment loads.
Marlene Bosworth of Sabetha coordinates the Delaware River WRAPS project and talked with Royer about applying for funding to repair the streambanks on his property.
“The eroded bank was vertical,” said Bosworth pointing to the reshaped streambank on Royer’s property. She explained that the bank was now sloped to allow vegetation to grow. Carefully placed boulders redirect the river’s current toward the center instead of eroding the bank.
Three projects on Royer’s property and four other sites have been completed. Eight more are designed and waiting for Kansas Department of Health and Environment (KDHE) funding.
WRAPS started in response to the need to address nonpoint source pollutants such as sediment. K-State agronomists, K-State Research and Extension watershed specialists, the Kansas Center for Agricultural Resources and the Environment (KCARE), and the Kansas Forest Service working closely with KDHE and the Kansas Water Office provide expertise on best management practices to improve water quality and reduce erosion. Forty WRAPS projects are under way in Kansas.
The projects are too expensive for individual landowners to undertake alone, but the costs are small compared to the expense of dredging Kansas reservoirs. The estimated cost for dredging sedimentation from Perry Lake, which the Delaware feeds into, would be $5.6 million per year.
“Perry Lake has already lost 25 percent of its storage capacity, and Perry isn’t the most serious case,” said Bob Atchison of the Kansas Forest Service. “A 2007 study found the major cause is stream- and river-carried sediment.”
Dave Bruton, a regional forester, works with landowners to develop buffer zones of grass and trees between fields and streambanks. Trees hold their ground and actually gain land mass during flooding, said Bruton. And trees filter out pollutants in rainfall runoff before it can reach a natural water source.