Land use effects on embeddedness in the Emory River watershed

The Emory River watershed (2240 km2) drains the Cumberland Plateau and Cumberland Mountains of north-central Tennessee. While large parts of the Emory River watershed are protected from future development by the Obed Wild and Scenic River and the Catoosa Wildlife Management Area, urban development continues by the expansion of towns such as Crossville. Unregulated development is likely to increase fine sediment supply to streams, leading to degraded aquatic habitat. This project was undertaken in order to measure fine sediment and embeddedness levels, and investigate how they vary with land use within the watershed and previously recorded biotic scores. Embeddedness is the degree to which fine sediment occupies space between larger substrate particles and has been shown to be an important aquatic habitat metric.;Embeddedness and fines data were collected at thirty sites across the watershed using the Burns, Skille, King (BSK) method. These data were correlated with land use information obtained from GIS on three spatial scales: (1) The upstream watershed, where all landuse upstream from the sample site is incorporated; (2) the 100 m buffer, an area consisting of land 100 m both sides of the stream and 1km upstream of sample site; and (3) the 50 m buffer incorporating land 50 m both sides of the stream and 1 km upstream of the sample site. Embeddedness and fines data were also correlated with biotic scores from a previous study. Simple linear regressions were used to analyze significant correlations between predictor and explanatory variables.;Significant negative correlations were found between embeddedness and cultivated land at the watershed scale, between embeddedness and deciduous forest at the 100 m buffer scale, and between fines and deciduous forest at the 100 m buffer. A positive significant correlation was found between embeddedness and fines. No significant correlations were found between embeddedness and biotic scores, nor between fines and biotic scores.;Results indicate that increased deciduous forest cover within the 100 m buffer is indicative of a healthier streambed with lower levels of embeddedness and fines. Strong correlations between embeddedness and fines indicate that for future studies, fines can be used as a reasonable estimate for embeddedness levels, using the regression model determined herein. Biotic scores probably did not result in any significant correlations due to few sites having embeddedness levels over 50%. Future development should aim to preserve as much forest cover within 100 m of streams as possible.