太行山小流域降雨-径流关系及其过程的研究

Runoff-Rainfall Relationship in Small Catchment of Taihang Mountain

观测了水源区的太行山小流域径流及降雨过程 ,分析了径流与降雨的关系。结果表明 ,流域降雨季节性变化很大 ,主要集中于 6～ 9月 ,总量达 3 89.2 mm ,占 86.5 % ,11月到翌年 5月仅 60 .75 mm。在旱季 ,流域径流量逐渐下降 ,11月到翌年 5月底减少 0 .0 0 2 3 m3/ s,此期降雨次数和量较少 ,径流量持续下降 ,11月至翌年 3月由于植物叶片枯落 ,浅层土壤水经长时间蒸发后对深层裂隙水无明显影响 ,径流量较稳定 ,进入生长季后 ,流量近至枯竭。雨季降雨是流域径流的主要来源 ,当降雨量小于 5 0 mm时 ,降雨对径流的影响很小。连续暴雨使径流迅速形成洪峰 ,在平均雨强达到 2 8.91mm / h后 ,4 h径流量达最大值 0 .90 5 m3/ s,此期径流量与累积降雨量呈极显著的线性正相关。但洪峰仅持续 1～ 2 h,后期 5 7.3 m m的降雨量并未再次引起洪峰。

Studies on runoff-rainfall relationship are important to understand the hydrological processes and the water balance in a small catchment. By the pressure sensor, H-type weir and rainfall collector, the investigation of runoff and precipitation in a small catchment of Taihang mountains were carried out. The relationship between runoff and rainfall are analyzed. The results indicated that the rainfall in the catchment mainly occurred from June to September, in which the volume makes up 86.5%, 389.2 mm of the total precipitation, and only 60.75 mm from November to May. If the rainfall per event is lower than 50mm, the runoff will not be produced and the discharge keeps decreasing. From November 1999 to the end of May, water level of runoff decreased around 15mm, discharge 0.002 3 m 3/s. Saturated soil and heavy rain are the important conditions for runoff-generating, too. Rainfall in raining season usually is too heavy to infiltrate into soil. The surplus water will become surface runoff and discharge out of the catchment. It is heavy precipitation on 4 July,2000, and it causes the soil to saturate, the following heavy event on 5 July, which has a heavy rate of rainfall by 28.91 mm/h, causes a peak flow discharge 0.905 m 3/s after 4 hours. In this period, the linear relationship between discharge and precipitation was given as the following:Q=0.0454P-0.3556,r 2=0.858, p<0.01.However, the peak flow discharge had continued only for 1 or 2 hours. There was not any peak flow although it had a following 57.3 mm of precipitation. It is significant to be used for agriculture and forestry in the lower valley.