A BIOGEOMORPHOLOGICAL INDEX OF STREAM HEALTH FOR MOUNTAIN STREAMS IN NORTHEASTERN GEORGIA

The field of natural stream design brings together three distinct disciplines: engineering, ecology, and fluvial geomorphology. Balancing these three sciences for applications in stream restoration can be difficult, requiring research and field work dealing with, for example, a site’s substrates or benthic ecosystems. Only with an understanding of the current situation and knowledge of historical ecological and geomorphic scenarios for the site can a restoration be successful. This study attempts to streamline the process of understanding current stream health, using a large geomorphic and biologic dataset from 17 small mountainous forest streams in Northeastern Georgia to quantify physical and biological impairment of a stream and to create an integrated inventory of the health of a particular stream. Statistical analyses are used to identify which geomorphic variables, including parameters such as pool and riffle geometries, bankfull depths, and pebble count data, best describe the level of stream degradation. Benthic macroinvertebrate samples in concert with the North Carolina Benthic Index are used to assess the biologic health of the streams. The biologic findings are correlated with the geomorphic results in a biogeomorphological index of stream health, which can aid stream restoration designers in planning remediation techniques for a given site.