湘西北低山丘陵小流域降雨侵蚀力计算及其特征研究

    Calculation and Characterization of Rainfall Erosivity in Small Watersheds of Hilly Region in Northwest Hunan

    • 摘要: 依据湖南省西北部武陵山区女儿寨小流域1999年建站以来9 a(2000—2008年)降雨过程资料进行降雨侵蚀力计算及分析,以EI30计算结果为基准,并采用EI10EI60、CREAMS模型中次降雨估算模型、半月步长的日雨量雨强模型及武汉市日雨量模型进行计算,探讨各种模型在本流域的适宜性。结果表明:流域年均降雨侵蚀力为5 423.06 MJ·mm·hm-2·h-1,且主要集中在4—8月,次降雨量与次降雨侵蚀力、月降雨量与月降雨侵蚀力、年降雨量与年降雨侵蚀力均为乘幂关系。各模型中以EI30最为适宜,半月步长的日雨量雨强模型经改写为半月步长的日雨量模型,并确定模型参数后有较好的适宜性,非线性多参数模型也很适合本流域降雨侵蚀力的评价,但今后还需选择更精确的适用于本流域的模型参数。

       

      Abstract: Based on the data accumulated during the 9 years from 2000 to 2008 on rainfall processes in the Nüerzhai small watershed in Wuling Mountains of Northwest Hunan, rainfall erosivity was calculated and analyzed. With the calculation of Model EI30 as baseline, Model EI10,EI60 and CREAMS was used for assessing single rainfall, daily rainfall and rain intensity of a half-month time step and daily rainfall in Wuhan to explore applicability of various models in this watershed. Results show that the mean rainfall erosivity was 5 423.06 MJ·mm·hm-2·h-1, and occurred mainly in the period from April to August.Power-law relations were observed between single rainfall and single rainfall erosivity, monthly rainfall and monthly rainfall erosivity, and yearly rainfall and yearly rainfall erosivity.Among the models, EI30 was the most suitable one. The half-month time step daily rainfall and rain intensity model was modified into a half-month time step daily rainfall model, and made more applicable with its parameters specified.Non-linear multi-parameter models were also very applicable to assessment of rainfall erosivity of the watershed. However, further study is to be done to select more accurate parameters suitable to the watershed.

       

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