Ephemeral gullies caused by snowmelt: A ten-year study in northeastern China

Abstract

Ephemeral gully erosion of cultivated land may be serious in early spring because of snowmelt runoff and lack of vegetation cover during this period. The snow in winter is redistributed by winds and accumulates in low-lying gullies, furrows, forest shelterbelts and forest lands, which become the main source of snowmelt runoff in spring. This study selected three different hillslopes according to snow redistribution in the black soil region of northeastern China and investigated the ephemeral gully erosion caused by snowmelt runoff from 2009 through 2018. The results showed that drainage area was the main controlling factor of ephemeral gully development. Due to the influence of snow redistribution, volumetric soil loss of ephemeral gully erosion in cultivated hillslopes affected by forestland and forest shelterbelt were more than 2 times greater than that of cultivated hillslopes without other sources of snowmelt runoff. A snow redistribution factor, SR, calculated through surveyed snow depth, accounted for the influence of snow redistribution on ephemeral gully erosion. Ridge tillage increased the threshold value of runoff needed for initial formation of ephemeral gullies, and decreased the number of gullies formed, but it also accelerated the development of single ephemeral gullies once they formed because furrows accumulated more runoff feeding to the drainage areas. A tillage practice factor, T, was used to reflect the influence of ridge tillage on ephemeral gully erosion. A statistical model for estimating ephemeral gully volume was developed that included as independent variables snowfall (SN), snow redistribution factor (SR), drainage area (A) and tillage practice factor (T). Using these parameters, along with bulk density of soil (BD), soil loss (Mg) by ephemeral gullies was estimated to be 0.102*SN1.104*SR*A0.90 *T3.0 *BD (R2 = 0.76).