东北漫川漫岗黑土区浅沟和切沟发生的地貌临界模型探讨

Geomorphic Threshold Model for Ephemeral Gully Incision in Rolling Hills with Black Soil in Northeast China

对东北漫川漫岗黑土区进行实地测量及地形图量算,推求出临界模型,校验了Moore的沟蚀发生公式。研究发现,该区浅沟发生的临界阈值和指数参数分别为0.063 1和-0.464 3,切沟发生的两参数分别为0.116 1和-0.445 7。同时发现Moore的沟蚀预测公式在该研究区并不适用。通过与野外实测浅沟和切沟发生位置对比,临界模型预测的沟蚀位置较好地反映了野外实际状况。

The theory of geomorphic threshold has been widely applied in study of predicting the area of ephemeral gully incision. Based on the measurement in field and relief map, this paper got the coefficient （α） and （b） in threshold model S = αA^-b（ where S is local slope, A is upslope drainage area） , and verified whether the gully incision formula used by Moore is suitable in study area. The analysis showed that the threshold value （α） and exponent coefficient （b） are 0.1161 and -0.4457 respectively for gully, 0.0631 and -0.4643 respectively for ephemeral gully; and that gully incision formula used by Moore is not suitable in study area. Compared with the distribution of ephemeral gully in field, it is found that the prone area predicted by threshold model is fairly well consistent with the actual ephemeral gully distribution. Meanwhile, it was found that the bigger the b value in threshold model, the more unsusceptible the prone area to the change of threshold value, vice versa, which is approved by the prone area of gully incision. These provide primary design guidance for local soil and water conservation.