Evolution and Development of Ephemeral Gully Erosion in Hilly and Gully
Region of the Loess Plateau in China
Abstract
Ephemeral gully erosion is a primary mode of soil erosion that is highly
visible, affecting soil productivity and restricting land use. Watershed
is the basic unit of soil erosion control; existing research has focused
on several typical ephemeral gullies or slopes, which do not fully
display changes in ephemeral gullies at a watershed scale. This study
analyzed the spatial-temporal evolution and development rate of
ephemeral gully erosion at the watershed scale on the Loess Plateau from
2009 to 2021 using remote sensing images (0.5 m resolution), unmanned
aerial vehicles (UAV), and field investigations. The results revealed
that: (1) most ephemeral gullies occurred in southwestern parts of the
watershed, with many hills and large slope gradients; (2) average growth
rates of each ephemeral gully frequency, length, density, dissection
degree, and width were 2.87 km 2 y
–1, 1.66 m y –1, 0.12 km km
–2 y –1, 0.0125% y
–1, and 0.04 m y –1 ,
respectively; (3) ephemeral gully erosion volume ( V) and length
( L) had a good power function relationship: V = 0 . 0842 L 1 .
1932 ( R 2 = 0 . 80 ) . The root mean square error (RMSE) and
coefficient of determination (R 2) between the
measured and predicted ephemeral gully volumes suggest that the
V–L relationship has a good predictive ability for ephemeral
gully volume. Thus, the V–L model was used to evaluate the
development rate of ephemeral gully erosion volume in small watersheds
from 2009 to 2021, revealing an average value of 743.20 m
3 y –1. This study proposed a
feasible model for assessing ephemeral gully volume and volume changes
at a watershed scale using high-resolution remote sensing images,
providing a reference for understanding the development of ephemeral
gully erosion in small watersheds over time.