黄土丘陵区产流输沙量对地貌因子的响应

Response of runoff and sediment yield to geomorphologic factors in loess hilly area

地貌因素与径流泥沙关系分析是建立流域生态水文模型的一项基础工作.本文选取受人类活动影响相对较小的1959～1969年间的黄土丘陵区水文泥沙资料,分析了黄河中游黄土丘陵区的20余条支流的年均径流量、流域年均输沙量及年均径流系数与集水区面积、河道平均坡降、流域高差和流域干流长等地貌参数的关系.结果表明,在研究区内,地貌参数与流域径流量和输沙量之间表现出类似的变化趋势,即年均输沙量和径流量与集水区面积或河道干流长呈较显著的正相关关系,与河道平均坡降呈幂函数减少关系,而与流域高差未表现出某种趋势性变化特征.年均径流系数与地貌参数之间亦没有表现出明显的趋势性变化关系.

The regressive relationships between hydrological parameters and geomorphologic factors for more than twenty tributaries in the middle reaches of the Yellow River are analyzed based on the observation data obtained in the period from 1959 to 1969. The hydrological parameters are annual average runoff, annual average sediment yield and annual average runoff coefficient. The geomorphologic factors are the water collecting area, average slope of river, elevation difference of watershed, length of main stream. The result shows that the average annual runoff and sediment yield are positively related to the water collecting area and length of main stream, but they decrease with the decrease of river average slope following the exponential law. The response to the elevation difference of water shed is insignificant. No obvious relationship exists between annual average runoff coefficient and geological parameters.