nishnabotna / Platte edu umbrella mitigation Bank site 1 -
Buchanan County, Missouri
Situated at the confluence of the Platte River and Castile Creek, the 291-acre Castile Creek mitigation site is the first location developed as part of the Nishnabotna / Platte EDU Wetland and Stream Umbrella Mitigation Bank. This umbrella mitigation bank, the first in northwest Missouri, will replace impacted wetlands and streams as a regional mitigation program within all areas that drain to the Missouri River from the Iowa state line to the Kansas City area.
Not only is this Swallowtail’s largest mitigation project to date, this site also has the most potential for floodplain management and environmental gain. In addition to restoring this vast property from agricultural fields to native wetland, riparian, and prairie habitats, the onsite levees were breached which reestablished floodplain connectivity to 170 acres of land along the very floodprone Platte River. In all, this mitigation site legally protects one or both sides of 1.9 miles of perennial rivers as well as 0.6 mile of intermittent and ephemeral streams. This legal protection and the associated widening of the currently narrow riparian corridors to widths of 600 feet will be especially valuable in this location because Castile Creek is granted the highest level of priority by the responsible regulatory agencies because it is a designated fish spawning habitat; the property had previously been a high-level priority for purchase by the Missouri Department of Conservation.
In its pre-restoration state as an agricultural property, this site consisted of large expanses of artificially drained flat farm fields, most of which were protected by levees which reduced the connectivity between the Platte River and Castile Creek and their floodplain and therefore exacerbated flooding elsewhere. Additionally, several ephemeral streams were eradicated or highly modified by agricultural earthwork.
These impairments were addressed through the following activities:
Restoring floodplain connectivity through multiple levee breaches along the Platte River and Castile Creek
Restoring or enhancing 119 acres of riparian buffers
Restoring 84 acres of herbaceous wetlands and 53 acres of forested wetlands
Establishing or preserving almost 19 acres of wetland buffers and adjacent uplands
Restoring normal sinuosity and channel dimensions to a previously eradicated ephemeral stream
Mitigation activities began in early 2018 and the site has flooded numerous times since then through the levee breaches.