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Abstract
Deforestation followed by soil erosion and subsequent deposition of alluvium in valleys played a critical role in the formation of an historical terrace (Leigh 2010). This terrace adds significant amount of sediment to the tributaries of the Southern Blue Ridge as streams laterally erode the terrace banks. This study examines the contribution of total sediment yield derived solely from eroded historical terrace banks in small watersheds (<20 km) by using floodplain widths as proxies for long-term lateral erosion rates. The bank-derived sediment yield estimates are modeled from the predicted floodplain widths and erodible terrace bank heights with linear regression. Total stream length is a good predictor of both lateral erosion rates and erodible bank heights. Lateral migration and sediment yield results compare favorably to independent yield measurements from five independent watersheds in the region. Modeled estimates fall within 50 percent or better of the observed values at 17.25 to 26.42 tonnes/km/yr.