Method to predict cropland ephemeral gully erosion

Erosion of farmland due to concentrated flow is very severe on many unprotected fields across the United States. Small channels can turn into large gullies if not controlled. These small channels are routinely obliterated by tillage of the field and other routine farm operations only to be reformed again. Opposing slopes adjacent to an ephemeral gully allow runoff to reestablish a channel in approximately the same location. Since the 1960s, the Universal Soil Loss Equation (USLE) has been used to estimate rill and sheet erosion. This paper describes the Ephemeral Gully Erosion Model (EGEM). EGEM is a modification of the Agricultural Research Service Ephemeral Gully Erosion Estimate (EGEE) computer model to meet the Natural Resources Conservation Service (NRCS) needs. Limited field data obtained by NRCS were used to validate the single event component of EGEM. This paper presents a summary of these studies. There were no data available at the time of the model development to validate the average annual concept of the model. ARS conducted validation studies for the EGEE model.