土石山区山坡降雨入渗产流模型

A hillslope infiltration-runoff model in earth-rock mountain regions

在分析土石山区下垫面特性的基础上,引入碎石体积比例系数量化土壤中碎石对入渗的影响,并考虑山坡基岩凹凸面及封闭裂隙储留,构建了一种包括植被截留、洼地储留、土壤入渗、壤中流、基岩凹凸面及封闭裂隙储留等计算模块的土石山区山坡降雨入渗产流模型;采用径流小区天然降雨产汇流试验对模型进行验证,并与现有山坡降雨入渗产流模型的模拟结果进行了对比分析。结果表明:与现有模型相比,构建的入渗产流模型可以较好地模拟地表径流强度和土壤入渗率,实测值与模型模拟值较为吻合;暴雨期土壤入渗率的模拟值远小于实测值,可能原因在于该模型忽略了碎石与土壤的直接接触面间可能形成的水流快速通道,未考虑土石山区山坡土壤层和基岩层中可能存在的优先流,模型尚需进一步完善和改进。

A hillslope infiltration-runoff model in earth-rock mountain regions was established, including vegetation interception,depression storage,infiltration,subsurface flow,and concave and fissures storage of the bed rock. Based on the analysis of the underlying surface characteristics in earth-rock mountain regions,the volume fraction of rock fragments in soils was introduced to qualify their impacts on infiltration. The concave and fissures storage of the bed rock was also considered in the present model. Field experiments on runoff yield and confluence of natural precipitation were carried out for model verification,and the simulation results of the present model were compared and analyzed with that of existing hillslope infiltration-runoff models. The results show that compared with existing models,the model proposed in this paper can well simulate the runoff and infiltration rate,and the measured values are in good agreement with the simulated ones.However,during storm periods,the simulated infiltration rates are far less than the measured ones. A possible reason is that rock fragments in soils may cause the formation of fast flow paths in the earth-rock interface,which is neglected in the present model. This model needs to be further refined and improved to consider the priority flow paths inside the soil layers and bedrock layers in earth-rock mountain regions.