Effects of gully head height and soil texture on gully headcut erosion in the Loess Plateau of China

Abstract Gully head erosion is one of the most important types of erosion on the Loess Plateau, but little is known about its relationship with microtopography. The purpose of this study was to evaluate microtopographic effects on the process of gully erosion, the rate of gully retreat and gully morphology using different gully head heights. A series of scour tests (flow discharges were 2, 4 and 6 l min−1) were conducted indoors, and the amount of soil lost increased with both the rate of gully retreat and the initial gully head height. Compared to silty soils (S), sandy soils (N) showed higher soil losses, but also higher sediment reduction benefits. In addition, a principal component analysis was used to examine the relationships among topographic factors and to classify the degree of erosion into three categories. The four topographic factors (amplitude, roughness, surface incision and slope) were closely correlated, and all were negatively correlated (P