Brown County, Kansas

2016-2017

WRS surveyed, designed, and provided construction oversight for stabilization of 650 linear feet of eroding streambank along the Lower Craig/Plum Creek in Brown County, Kansas. Initiated by the Kickapoo Tribal Nation and funded via a U.S. Environmental Protection Agency grant, the project was generated to protect a tribal cemetery on top of the high bank.

Based on information from detailed surveys and geomorphic assessment, WRS recommended installing combinations of longitudinal peaked stone toe protection (LPSTP) and rock vanes in order to reduce streambank erosion. Rock vanes reduce streambank erosion by re-directing flows away from the bank toe and thereby reducing water velocities and shear stress in the near bank region. Rock vanes work with the stream’s natural tendencies and help move the stream toward a more naturally stable condition.

In addition to the rock structures, WRS used vegetated geo-grids to protect the high vertical streambank. The vegetated geo-grids are lifts, or layers of compacted soil, wrapped inside a layer of bio-degradable vegetation-reinforcement fabric, which is in turn held inside of a layer of plastic grid. The lifts are offset 2 feet from the underlying layer. This exposed ledge then provides a protected surface to establish vegetation. In this instance, the vegetation consisted of a native grass mixture along with a cover crop of oats and bare-root tree seedlings. One layer of live willow cuttings was planted under the first layer of vegetated geo-grid.

Construction began in February 2017 and was completed in March 2017. Following installation of the rock structures, the vertical streambanks were reshaped to a minimum 2H:1V slope.