Basic Research on the Prime Runoff Process of Rainfall in a Hillside Slope

1.裸露坡面降雨径流过程利用坡面渗漏仪对土壤水分运动的蒸发、降雨入渗、地表径流和地下水径流过程进行了初步研究。其次，以蒸发和降雨量作为地表边界条件，对土壤水分运动进行了数值计算。在计算结果的基础上，讨论了土壤水分运动与地表径流、土壤水分再分配与地下水径流的关系。坡面降雨入渗由于干燥、土壤中的微小动物和根部腐烂而产生的大小不同的裂隙和孔洞等大的连续开口(大孔隙)的存在，影响雨水对土壤的入渗。为了阐明降雨入渗与ph.…之间的关系在丘陵地区的斜坡上进行了更多的命名和大孔隙、入渗试验和土壤调查。这些结果表明，降雨开始后，降雨入渗率迅速下降，最终入渗率过大，不符合土壤的主要特性。首先，根据毛细管内粘性流动和土壤非饱和水流相结合的模型，计算了含微孔土壤的降雨入渗量。这些计算表明，细小的大孔隙使导水率提高了5-10倍。其次，基于以下假设计算了含有粗大孔隙的土壤的降雨入渗量：(A)粗大孔隙中填充了具有高渗透系数的粗多孔材料。(2)这些粗大孔隙周围的土壤均匀、均质。计算结果与田间试验测得的入渗曲线吻合较好。较少

1. The Runoff Process of Rainfall in Bare SlopeThe process of evaporation, rainfall infiltration, surface and groundwater runoff have been basically investigated in connection with soil moisture movement using the slope lysimeter equipments.First, the energy budget techniques have been used for determining evaporation from the bare slope of lysimeter. Next, the soil moisture movement were calculated numerically using the evaporation and rainfall as boundary conditions of soil surface. On the basis of the calculated results, the relationships between soil moisture movement and surface runoff, re-distributions of soil moisture and groundwater runoff were discussed.2. Rainfall Infiltration in a Hillside SlopeThe presence of large continuous openings (macropores) such as cracks and holes of differing sizes caused by desiccation, tiny animals in the soil and the rotting of roots, affects the infiltration of rainwater to soil.In order to clarify the relations between rainfall infiltration ph … More enomena and macropores, infiltration tests and a soil survey made on the slope of a hilly region. These results indicate that the infiltration rate of rainfall decreased rapidly after rain began, and that the final infiltration rate too large for the prevailing soil character.Based on the results, a simulation method was established and investigated. First, the amount of rainfall infiltrating soil containing fine macropores was calculated from a model that combined viscous flow within the capillary tubes and unsaturated soil water flow. These calculations showed that fine macropores increase the hydraulic conductivity of the 5-10 fold. Next, the amount of rainfall infiltrating soil containing coarse macropores was calculated based on the following assumptions: (a) The coarse macropores were filled with coarse, porous material of high hydraulic conductivity. (b) The soil around these coarse macropores was uniform and homogenerous. The calculated results agree well with the infiltration curve obtained from field tests. Less