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以位于东北典型黑土区的黑龙江省乌裕尔河流域中上游为研究区,利用依安站31年的日水沙观测资料,对流域水沙的季节性动态特征进行了分析,对影响水沙关系的自然及人为因素进行了探讨。观测数据表明,7-9月的径流量占全年的64.7%,对本区的产流起主导作用;径流平均含沙量在4月融雪期和6月底到7月中旬明显高于其他时段,含沙量的季节变化与径流的变化明显不同。为描述各影响因素对含沙量变化的贡献,本文通过将含沙量的季节变化与其影响因素的变化进行关联,提出了一种从多因素联合影响中分离出单因素影响的思路,分析表明:冻融作用对裸地的径流含沙量影响剧烈,明显增加土壤侵蚀;在地表有无植被及耕作措施情况下,降雨侵蚀力的增加都将增加径流含沙量;植被的出现可以削弱降雨侵蚀力增大时的增沙效应,但7月降雨侵蚀力的增沙作用超过了作物覆盖的减沙作用。所提方法可方便地用于缺少对比观测实验地区的土地利用和管理措施水保效用评价。
Taking the middle and upper reaches of Wuyuel basin in Heilongjiang Province as a typical black soil area in northeastern China as a study area, the seasonal dynamic characteristics of runoff and sediment in the basin were analyzed based on the 31-year daily observation data of the Yashan station. The relationship between natural and human factors were discussed. The observed data show that the runoff in July-September accounted for 64.7% of the whole year, which played a leading role in the current runoff in this area. The mean runoff sediment concentration in April was significantly higher than that in other periods during the melting period from April to the middle of June to mid- Sediment seasonal changes and runoff changes significantly different. In order to describe the contribution of each influencing factor to the change of sediment concentration, this paper proposes a way to separate the influence of single factor from the combined effect of multiple factors by analyzing the seasonal variation of sediment concentration and the change of its influencing factors. : Frozen-thaw effect on the runoff sediment concentration in the bare land significantly increased soil erosion; in the absence of vegetation and tillage on the surface of the case, the increase of rainfall erosion will increase runoff sediment concentration; vegetation can weaken the rainfall Sediment-enhancing effect at increased erosivity, but the effect of increasing rainfall erosive force in July over the sediment-reducing effect of crop cover. The proposed method can be easily applied to evaluate the effectiveness of land-use and management practices for soil conservation in areas lacking comparative observation.