The Nature Conservancy’s (TNC) Dunn Ranch Prairie Preserve is comprised of 2,000 acres of tallgrass prairie and contains the entire headwaters of Little Creek, which has been repatriated with federally endangered Topeka Shiner (Notropis topeka). The mainstem and a tributary of Little Creek drain through two box culverts downstream to TNC’s Little Creek Farm.
Historical grazing practices had resulted in severe channel incision downstream of the culverts, creating fish passage barriers preventing the shiner and other aquatic organisms from reaching the headwaters of Little Creek.
In Spring 2022, a fish passage solution was implemented to provide aquatic connectivity between Dunn Ranch and Little Creek Farm to ensure long-term connection and population resiliency for the fish assemblage and channel stability for Little Creek.
The fish passage solution included 1) raising stream grades compatible with the passage ability of Topeka Shiner using a constructed rock ramp to downstream of the culverts; 2) channel reconstruction to restore floodplain connection and reduce future erosion; 3) boulder clusters and root wads to provide sufficient roughness and flow variability within the channel for various passage routes and flow refugia for the shiner; and (4) extensive revegetation throughout the project area.
Data collection to determine project effectiveness has been ongoing since construction completion, including tagging of Topeka Shiners and other fishes to assess up- and downstream movements. Results show that the project has successfully restored fish passage through each culvert, even during recent abnormally dry conditions.
Lastly, beaver dam analogs were constructed at various locations in Little Creek upstream of the culverts following fish passage project completion and research to determine the effectiveness of those structures on the shiner’s population, habitat use, and passage is ongoing.
Steve Herrington, the Associate Director of Water with The Nature Conservancy