Wadeable stream habitat monitoring at Chattahoochee River National Recreation Area: 2017 baseline report

McDonald, Jacob; Starkey, Eric; Cooper, Christopher

doi:10.36967/2267301

The Southeast Coast Network (SECN) stream habitat monitoring protocol collects data to give park resource managers insight into the status of and trends in stream and near-channel habitat conditions (McDonald et al. 2018a). Wadeable stream assessments are currently implemented at the five SECN inland parks with wadeable streams. These parks include Horseshoe Bend National Military Park, Kennesaw Mountain National Battlefield, Ocmulgee Mounds National Historical Park, Chattahoochee River National Recreation Area, and Congaree National Park. Streams chosen for assessment were specifically targeted for management interest (e.g., trail erosion issues and upstream urban development) or to provide a context for similar-sized stream(s) within the park or network (McDonald and Starkey 2018a). The objectives of the SECN stream habitat monitoring protocol are to: • Determine status of upstream watershed characteristics (basin morphology) and trends in land cover that may affect stream habitat; • Determine the status of and trends in benthic and near-channel habitat in selected wadeable stream reaches (e.g., bed sediment, geomorphic channel units, and large woody debris; and • Determine the status of and trends in cross-sectional morphology, longitudinal gradient, and sinuosity of selected wadeable stream reaches. From June 8–16, 2017 data were collected at Chattahoochee National Recreation Area (CHAT) to characterize the in-stream and riparian habitat of 14 stream reaches (CHAT001–CHAT014). These data, along with geographic information system (GIS) analyses, are presented in this report to describe and compare the watershed-, reach-, and transect-scale characteristics of the surveyed reaches. The report is subdivided based on the Strahler stream order. This Summary (and Key Findings) section gives a general overview of the basin, habitat, and geomorphic characteristics of the surveyed streams as well as any management concerns. A bulleted list is provided for each reach to describe its distinguishing characteristics and/or management concerns. The watersheds draining to the surveyed stream reaches at Chattahoochee River NRA ranged from small mostly forested first-order watersheds to large mostly developed third-order watersheds. Based on the geomorphic and land cover characteristics of the watersheds, the majority of the watersheds (nine out of fourteen) likely have a flashy flow regime (three first-order, four second-order, and both third-order watersheds). The remaining five watersheds likely have less flashy flow regimes because they had lower slope/relief and/or low amounts of development. Gage data are needed to confirm these interpretations of each watershed’s flow regime. Based on bed sediment and geomorphic channel units (GCU), habitat within 10 of the reaches was classified as high energy (three first-order, five second-order, and two third-order streams). The habitat within the four remaining reaches was classified as low energy (two first-order and two second-order). Generally, when present, large woody debris (LWD) were important for step and pool creation and thereby diversification of stream habitat. Given the high energy and flashy classification of many reaches, LWD serves to dissipate energy and trap fine organic material and sediment that would otherwise be transported downstream. Based on the GCUs, bed sediment, and LWD characteristics of the surveyed streams, instream habitat was classified as “good” for four streams (one first-order and three second-order), “fair” for seven streams (three first- order, two second-order, and two third-order), and “poor” for three streams (one first-order and two second-order). Overall, habitat classification for each reach may improve if: (1) there is an increase in stable (non-mobile) in-channel (non-bridging) LWD, (2) there is a reduction in the amount of fine sediment delivered to the reach, and/or (3) habitat (GCU) diversity increases. Conversely, habitat may...

Wadeable stream habitat monitoring at Chattahoochee River National Recreation Area: 2017 baseline report

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