Rill and Gullies Erosion

Rill to concentrated flow to classical gully erosion represents a continuum and any classification of hydraulically related erosion into separate factors is, to some degree, subjective. Rills are usually described as small, intermittent water courses that present no obstacles or impediments to tillage operations using conventional equipment. Gullies have historically been described as oversized or entrenched stream channels. Upland gullies are perhaps the most visible eyesores related to erosion and this visibility inspired early studies in the United States to document the magnitude of the problem. Literature pertinent to valley-floor gullies is relatively abundant. The relatively recent advancements in terrain analysis have opened new horizons in approaching erosion problems. In most analyses, stability varies directly with the ratio of cohesion to mass loading and average or worst-case ratios are used for stability predictions. The coupling of Geographic Information System technology with runoff models has created a powerful tool for management of soil and water resources.