Thursday, June 16, 2016
David Flick, Principal and Founder of Terra Technologies, is proud to announce that the Kansas City District of the U.S. Army Corps of Engineers has approved the Upper Osage River Wetland and Stream Umbrella Mitigation Bank along with its first mitigation site. This umbrella mitigation bank will function as a regional mitigation program in Kansas across the Marais Des Cygnes River and Little Osage River watersheds in the very eastern part of the state.
An umbrella mitigation bank operates as an ongoing mitigation program across an entire watershed by providing a policy framework that guides the establishment of an initial on-the-ground mitigation site as well as numerous future mitigation locations. The umbrella mitigation bank document includes an analysis of historical and current water quality issues within the watershed that identifies immediate and long-term habitat and water quality needs and then determines which locations should receive the highest priority for the establishment of future mitigation sites. The umbrella mitigation bank document also sets policy guidelines about the creation and operation of the mitigation sites, including such factors as performance standards, financial assurances, credit calculations methods, and long-term management.
Situated at the confluence of Pottawatomie Creek and Cockers Branch, the 278-acre Pottawatomie Creek mitigation site is the first location developed as part of the Upper Osage River Wetland and Stream Mitigation Bank.
In its pre-mitigation state as an agricultural property, this site consists of large expanses of artificially drained flat farm fields with some hillsides in its northern and southwestern portions. There are more than 18,750 feet of perennial, intermittent, and ephemeral streams on the property but almost all of that linear footage is significantly degraded. For instance, several small oil wells were operating in close proximity to one intermittent stream and two ephemeral channels and presented a risk of chemical contamination. Most notably though, almost all stream channels are highly incised, mostly severing the connections between all streams other than Pottawatomie Creek and their respective floodplains. The stream base incision was also causing bank erosion and endangering many surrounding mature trees by exposing their root systems. In addition to these impairments, two ephemeral streams had been partially channelized and riparian buffers are relatively thin.
These impairments will be addressed through the following activities:
- Restoring or enhancing 101 acres of riparian buffers
- Establishing 67 acres of forested wetlands and almost 10 acres of emergent wetlands
- Restoring or enhancing an additional 4.5 acres of wetlands
- Establishing or preserving almost 94 acres of wetland buffers and adjacent uplands
- Reducing bank erosion along Pottawatomie Creek by constructing longitudinal peaked stone toe protection
- Constructing 21 rock grade control structures and 26 log grade control structures in seven streams to address stream incision
- Restoring normal sinuosity and channel dimensions to the two channelized ephemeral streams
- Ceasing oil extraction on the site
In addition, severe incision within one intermittent stream will be addressed through the use of the relatively new method of regenerative stream restoration where the incised channel is partially filled to re-establish a stable and healthy new channel that will have improved floodplain connectivity. Floodplain connectivity will also be greatly increased along the highly incised Cockers Branch as a result of a floodplain connectivity weir that will divert some of the stormwater flows onto tens of acres of new wetlands while still allowing low flows and some storm flows to pass through the structure.
Mitigation activities are scheduled to begin in the summer of 2016.
For more information about mitigation services, contact your local office of Terra Technologies.
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