The Growth Characteristics of Gully Erosion over Rolling Hilly Black Soil Area of Northeast China
In this study, short-term gully retreat was monitored from the active gullies selected in representative black soil area, using differential GPS. With the support of GIS, multitemporal digital elevation models (DEM) were constructed in light of the data collected by GPS and used for further analysis. Based on the analysis of multi-temporal DEM, we discussed the erosion-deposition characteristics of a gully and a developing model for black soil gully area of Northeast China was proposed. The results are: (1) The analysis of the monitored gully data in 2004 indicated that the retreat of gully head reached more than 10 m, gully area extended 170-400 m2, gully net eroded volume 220-320 m3 and gully erosion modulus 2200-4800 t·km-2·a-1. (2) Compared with the mature gully the initial gully grows rapidly, and its erosion parameters are relatively large. The erosion parameters have not only to do with flow energy, but also with growth phase. (3) There are significant seasonal differences in gully erosion parameters. The extension of gully area and width dominates in winter and spring without marked net erosion while changes mainly occur in gully head expansion and net erosion in rainy seasons. (4) It is remarkable for freeze-thaw erosion in the black soil area of NE China. The gully wall of SG2 extended 0.45 m under freeze-thaw effect in 2004, and the distance of gully head retreated maximally 6.4 m. (5) Due to freeze-thaw action and snowmelt, gully is primarily in the interior adjustment process in winter and early spring. There are much more depositions compared with that in autumn, which can almost happen throughout the gully, while erosion mostly occurs near head, esp. for gullies having a relatively long history of development.
rolling hilly black soil areas of Northeast ChinagullyDEMGPS
NETL
NSTL
万方数据
维普
