近50年挠力河流域上游径流深变化过程及其驱动机制研究

Runoff Depth Variation Process of Upper Reaches of Naoli River Basin and Its Driving Mechanism in Recent 50 Years

近50年挠力河上游径流深总体上呈递减趋势,并且径流深的递减与面上降水量的递减总体上一致,但不同的时段,径流深突变较为明显,并且与面上降水量的多少出现反常现象。通过运用双累积曲线法,得出自1963年以来,研究区域面上降水量与径流深的关系发生了明显的变化,主要表征为径流系数呈减少趋势。采用径流系数差异的秩和T检验法（α=0.05,n1=7,n2=43,T=255,T1α=108.52,T2α=248.47,T〉T2α〉T1α）,同样得出1956~1962年径流系数系列与1963~2005年径流系数系列之间不具有一致性。运用降水—径流深频率曲线分析得出,同样的降水频率下,得出1963~2005年期间比1956~1962年期间径流系数也有显著的减少。研究结果表明：①降水是径流深变化的关键驱动力;②集水区域人为活动导致土地利用/覆被的变化,是径流系数突变的重要原因之一;③自2001年起,径流深的变化主要受龙头桥水库的调节以及水稻灌溉用水量的控制。建议应当增大龙头桥水库生态环境的调水功能,严格限制宝清水文站以上水稻田的发展面积;开展坡耕地退耕还林,增加森林的保育力度。本研究方法及结论,对未来科学配置挠力河流域水资源,尤其是寻求合理的湿地水资源恢复方案,以及分析三江平原旱化过程及其原因的具有参考意义。

In recent 50 years,the runoff depth of the upper reaches of the Naoli River Basin has shown an obvious decreasing trend,besides,the decreasing trends of both the runoff depth and area precipitation are basically consistent,however,the runoff depth shows a remarkable mutation and even an abnormal phenomena with area precipitation amount in different period of time.Through the double mass curves analysis,it is concluded that the relationship between the area precipitation and the runoff depth within study area has a great change since 1963,especially,the runoff coefficient appears in a decreasing trend.By adopting the runoff coefficient difference Rank and T test（α=0.05,n1=7,n2=43,T=255,T1α=108.52,T2α=248.47,TT2αT1α）,it is also concluded that there is no consistency between the runoff coefficient series from 1956 to 1962 and the ones from 1963 to 2005.By analyzing the precipitation-runoff depth frequency curves,it is indicated that,under the same precipitation frequency,the runoff coefficient in 1963-2005 is much smaller than that in 1956-1962.The research results show that（1） the precipitation is a key driving force for runoff variation;（2） the land use/cover changes posed by human activities is one of important causes contributing to runoff coefficient mutation in the cathchment area;（3） the runoff depth variation is mainly controlled by the Longtouqiao Reservoir and the water consumption by rice field irrigation since 2001.It is proposed to extend the water allocation function of Longtouqiao Reservoir on the ecological and environmental aspects;strictly limit the cultivation area of rice field over Baoqing Hydrometry Station;implement the conversion from slope farmland to forest land and enhance the forest conservation.This research method and conclusion are of reference significance for allocating water resources in Naoli River Basin in future,especially for seeking for a wise scheme for restoring wetland water resources,and even for analyzing the aridity process of Sanjiang Plain and its cause.