基于SCS水文模型的泥石流预报模型在四川宝兴冷木沟的应用

The Application of Debris Flow Forecast Model Based on SCS Hydrological Model in Lengmu Gully

2013年4月20日四川芦山7.0级地震后,四川省宝兴县冷木沟沟道内新增大量崩塌、滑坡物源,在强降雨的诱发下,极易发生泥石流灾害,且沟口直面县城,直接威胁着整个县城的生命、财产安全。利用SCS水文模型,根据冷木沟流域的地貌特征将其划分成17个子流域,在子流域不同的土地利用数据及水文土壤条件下进行产流、汇流计算,最后通过叠加得到冷木沟流域出口断面的汇流过程;对2012年8月18日发生的泥石流汇流过程进行探讨预测,结果显示,本次泥石流的洪峰流量为278 m3/s,泥石流总量为20.2×104m3,计算得到的泥石流总量与实际调查结果的相对误差为7.8%;用同一方法预测2013年5月23日冷木沟支沟黑沟的泥石流汇流过程,计算的洪峰流量为38.2 m3/s,与实际监测值的相对误差为4.2%。说明此模型对于冷木沟流域具有适用性,且效果较好,可用于宝兴县冷木沟泥石流的流量预测及泥石流灾害规模预测,将对宝兴县的泥石流防灾减灾工作提供科学指导。

Great amount of fresh landslide deposit was accumulated in the channels of Lengmu gully in Baoxing County after the Lushan earthquake on April 20 th,2013. It is a great threaten for the county due to the potential debris flow and its close direction to the resident sites. To simulate the debris flow in this gully on August 18 th,2012,17 sub-watersheds were divided according to the landform,and the runoff was calculated in each sub-watersheds according to different land use data and hydrological soil conditions. The result shows that the peak flow discharge is 278 m^3/ s,and the total amount of the debris flow is 20. 2 × 10^4m^3,with 7. 8% relative error by comparing with the actual survey result. The same method is used to the debris flow in the Hei gully on May 23 th,2013.The result shows that the peak flow discharge is 38. 2 m^3/ s,with 4. 2% relative error by comparing with the actual monitoring value. It indicates that this model can be used for the prediction of debris flow in this gully and will provide scientific guidance for debris flow disaster prevention and reduction.