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该研究采用新型的小水流流量自动观测系统,在室内小流域模型上进行了不变雨强和变雨强模拟降雨试验,实时观测了模型流域各沟道的产流过程。试验进行了不同降雨强度(25、50、75、120mm/h)和不同降雨历时(5、10、15min)组合的12次降雨试验,同时进行了30-70mm/h和70-30-70mm/h的变雨强降雨试验。在不变雨强的条件下,仪器与人工测量所得稳定流量的最大平均相对误差仅为2.02%。测量得到的流量过程线呈现出起流、稳定和退水3个明显的阶段。其中,起流和退水过程涨落的剧烈程度、稳定阶段的流量大小随雨强增大而增大,稳定阶段的持续时间与降雨历时成正比。空间上,主沟出口的产流过程明显滞后于支沟出口的产流过程,且其两者之间具有一致的流量过程。在变雨强的情况下,流量过程线没有稳定的阶段,流量随雨强变化而变化。该研究对于深入理解流域产流过程具有重要意义,可为相关的模型研究提供可靠的试验支持。
In this study, a new type of small flow automatic observation system was used in this study. Simulated rainfall experiments with constant rainfall intensity and rainfall intensity were carried out on indoor small watershed model. The runoff of each channel in the model watershed was observed in real time. The experiment carried out 12 rainfall tests with different rainfall intensities (25, 50, 75 and 120 mm / h) and different rainfall durations (5, 10 and 15 min), carried out 30-70 mm / h and 70-30-70 mm / h rainy season rainfall test. Under the condition of constant rain intensity, the maximum average relative error of the stable flow rate measured by the instrument and manpower measurement is only 2.02%. The measured flow rate curve shows three distinct phases: rising, stabilizing and returning. Among them, the intensity of the fluctuations of the easterly and the return processes, the magnitude of the steady-state flow increases with the increase of the rainfall intensity, and the duration of the stable stage is proportional to the rainfall duration. Spatially, the runoff at the outlet of the main channel lags far behind the runoff at the outlet of the branch channel, and there is a consistent flow rate between the two. In the case of changing rainfall, the flow process line has no stable stage, and the flow rate changes with the change of rainfall intensity. This study is of great significance for understanding the runoff process in the basin and providing reliable experimental support for related model studies.