论文部分内容阅读
为研究三峡库区大宁河流域土壤侵蚀的状况和特点,应用SWAT模型对大宁河流域进行了产流产沙模拟,并基于SWATCUP工具中的SUFI-2方法对模型进行了参数敏感性分析、校正、验证和不确定性分析(2008—2010年为校正期,2011—2013年为验证期),进而分析了流域内土壤侵蚀状况和不同土地利用、土壤类型和坡度对土壤侵蚀的影响,并提出了土壤流失超标区域防治措施。结果表明:(1)校正后的SWAT模型在大宁河流域产流模拟中,校正期和验证期的p-factor值分别为0.89和0.75,r-factor值分别为0.75和0.69,R~2分别为0.92和0.91,NS分别为0.87和0.91;在产沙模拟中,校正期和验证期的p-factor值分别为0.90和0.95,r-factor值分别为1.04和1.05,R~2分别为0.77和0.75,NS分别为0.74和0.72。构建的SWAT模型适合大宁河流域产流产沙模拟和土壤侵蚀状况研究,且不确定性满足要求。(2)整个大宁河流域2008—2013年的平均侵蚀模数为468.88t/(km~2·a),总体土壤侵蚀强度属于微度,但在局部子流域(1,2,3,4,22)的土壤侵蚀强度属于轻度,超过了流域土壤流失容许量500t/(km~2·a),其面积占整个流域的37.44%。(3)导致轻度土壤侵蚀区域土壤流失超标的因子包括土地利用类型中的耕地和草地、土壤类型中的深色淋溶土和饱和黏磐土以及坡度>25°的耕地和草地,其中饱和黏磐土所占面积过多可能是导致轻度侵蚀区域土壤流失超标的最主要原因。建议在轻度土壤侵蚀区域,对饱和黏磐土、坡度>25°的耕地和草地进行一定比例的退耕还林和退草还林。
In order to study the status and characteristics of soil erosion in the Daninghe River Basin of the Three Gorges Reservoir Area, SWAT model was used to simulate the runoff and sediment production in the Daning River basin. The sensitivity of the model was analyzed based on the SUFI-2 method in the SWATCUP tool. Correction, validation and uncertainty analysis (2008-2010 correction period and 2011-2013 validation period), and then analyzed the impact of soil erosion and different land use, soil types and slope on soil erosion in the basin and Proposed soil erosion exceeded the regional control measures. The results show that: (1) In the runoff simulation of Daning River Basin, the calibrated SWAT model has p-factor values of 0.89 and 0.75 for the calibration and validation periods, respectively, with r-factor values of 0.75 and 0.69, respectively, Respectively, 0.92 and 0.91, respectively. The NS values were 0.87 and 0.91, respectively. In the sand production simulation, the p-factor values during the calibration and validation periods were 0.90 and 0.95, respectively, and the r-factor values were 1.04 and 1.05 respectively 0.77 and 0.75, NS respectively 0.74 and 0.72. The constructed SWAT model is suitable for runoff and sediment production simulation and soil erosion in the Daning River Basin, and the uncertainty meets the requirements. (2) The average erosion modulus of the entire Daninghe River basin from 2008 to 2013 was 468.88t / (km ~ 2 · a). The overall soil erosion intensity belongs to the micro-degree. However, in the sub-basin , 22) is mild, exceeding the permissible amount of soil erosion in the basin by 500t / (km ~ 2 · a), accounting for 37.44% of the total basin. (3) Factors that cause excessive soil erosion in light soil erosion area include cultivated land and grassland in land use type, dark leaching soil and saturated clay soil in soil type and cultivated land and grassland with slope> 25 °, in which saturated The excessive area of sticky soil may be the most important reason for soil erosion in areas with slight erosion. Proposed in the mild soil erosion area, the saturated sticky soil, slope> 25 ° of arable land and grassland for a certain proportion of returning farmland to forest and forest.