Wadeable Stream Habitat Monitoring at Horseshoe Bend National Military Park: 2023 Change Report

McDonald, Jacob

doi:10.36967/2318455

This report summarizes stream habitat monitoring conducted under the Southeast Coast Network (SECN) protocol, which assesses the status and trends of stream and near-channel conditions to support park management. The study focuses on a permanently monumented reach (HOBE001) along “Claybed Creek,” a second-order stream within Horseshoe Bend National Military Park. Surveys were conducted in 2019 (baseline) and 2023 to evaluate geomorphic and habitat changes over time. Baseline findings from 2019 indicated that HOBE001 exhibited moderate watershed slope and relief, high drainage shape, and predominantly forested and pasture land cover. The channel appeared to be in the widening stage of evolution and featured multiple elevated entrenched surfaces, interpreted as erosional and semi-ephemeral rather than stable floodplains. In-stream habitat was classified as “poor-to-fair,” largely due to low geomorphic diversity and limited large woody debris (LWD). The 2023 resurvey identified several notable changes in watershed and reach-scale conditions. Land cover analysis revealed a 10% decrease in forested area with a corresponding increase in shrubland, likely driven by upstream forestry activities. Within the reach, a significant treefall event introduced substantial LWD between transects T3 and T4, while channel incision in the upper reach was linked to the loss of a large wood step and upstream migration of a resulting knickpoint. Sediment eroded from upstream areas contributed to increased in-channel bar formation and a statistically significant fining of bed material. Despite finer sediment conditions, habitat quality improved to “fair-to-good” due to increased LWD and greater heterogeneity in geomorphic channel units. These changes suggest enhanced structural complexity and potential for improved habitat stability. However, future conditions remain uncertain and will depend on the persistence of LWD and balance between sediment supply and transport. Stabilization of the large wood may promote further channel adjustment, including possible bifurcation or lateral migration. No immediate management concerns were identified. Continued monitoring is recommended, particularly near the upstream road crossing, where potential knickpoint migration could pose infrastructure risks. Overall, observed changes highlight the dynamic nature of the system and the importance of repeated monitoring to distinguish between transient adjustments and longer-term trends.

Wadeable Stream Habitat Monitoring at Horseshoe Bend National Military Park: 2023 Change Report

Series