鹰潭小流域季节性降雨径流特征研究

Seasonal Rainfall-Runoff Characteristics at Small Catchment of Yingtan Area

降雨是影响低丘红壤坡地土壤侵蚀和养分随径流迁移的一个关键因子。利用三角量水堰自动测量径流量和自动雨量计观测数据,分析了鹰潭小流域的季节性降雨径流特征。小流域降雨主要发生在4～6月,总量达512.4mm,占观测时段总雨量的70.1%,而旱季7～9月仅为218.9mm。上游、下游围堰累积径流量随旱季、雨季的变化表明:小流域降雨-径流-土壤水界面水分转化可分为土壤水补给阶段(4月14日～6月14日)、土壤水饱和阶段(6月15日～7月28日)和土壤水消耗阶段(7月28日以后)。雨季径流量对降雨的响应波动超过旱季。日累积降雨量与日累积径流量有极显著的正相关关系。径流小区水样分析结果说明观测期下坡径流小区总氮(TN)、总磷(TP)浓度高于上坡。

Rainfall is a key factor affecting soil erosion and nutrient cycle by runoff in low hilly red soil area. The seasonal rainfallrunoff characteristics at small catchment of Yingtan area was analyzed, based on the weir logged data and precipitation data. The results indicated that the rainfall at the catchment mainly occurred from April to June, in which the volume makes up 70.1%, 512.4 mm of the total precipitation and only 218.9 mm from July to September for dry season. Three stages of water transformation among the interface of precipitation runoffsoil water could be determined, in terms of the cumulative discharge variation with season at upper stream and lower stream, which is the stage of subsurface water recharge from April 14th to June 14th, the stage of subsurface water saturation from June 15th to July 28th and the stage of exhausting after July 28th. The discharge in rainy season corresponds more frequently than in dry season. The linear relationship between daily discharge and precipitation was significant. In addition, the total nitrogen concentration and phosphorus concentration in runoff after each single storm at lower slope is higher than upper slope after measuring the water samples from erosion plots.