Development of gullies and sediment production in the black soil region of northeastern China

摘要

Gully erosion is an important environmental hazard in the black soil region of northeastern China. It is a primary sediment source in the region which needs appropriate soil conservation practices. Gully incision in rolling hills typical of this region was monitored using real-time kinematic GPS to assess the rates of gully development and the resultant sediment production. From 2002 to 2005, gully heads in the study area retreated between 15.4 and 33.5 m, giving an average retreat rate of 8.4 m yr~(-1). Field measurements showed that total sediment production due to gully erosion during the three years ranged between 257 and 1854 m~3 yr~(-1), which is equivalent to 326 to 2355 t yr~(-1), with gully-head retreat accounting for 0 to 21.7% (4.4% in average). The sediment delivery ratio was especially high during the summer rainy season (56% in average). Sediment production by ephemeral gullies and permanent gullies was 1.5 times greater than that from surface erosion. Gully heads retreated faster in the spring freeze-thaw period than in the summer. The stage of gully development could be identified based on short-term changes in the gully erosion rate.