密云水库流域近三十年径流变化及归因分析

发布时间：2019-03-02 13:46

【摘要】：密云水库作为北京市最重要的地表水水源地，对首都水安全和可持续发展具有重要的战略意义。近30年来，其水文情势演变受人类活动和气候变化的影响日益增强，呈现出和以往历史时期不同的特点。以密云水库上游流域的下堡、三道营、张家坟、戴营和下会5个水文站控制的子流域为研究对象，探讨各子流域不同分级径流在年代际的演变特点，综合统计方法和模型方法揭示近30年密云水库流域径流演变的归因规律，并尝试采用流量历时曲线和基流退水方程建立对不同分级径流、特别是基流部分演变的驱动因子进行量化分析的途径。主要结果如下：（1）在近50年径流总体减少的大趋势下，1980~2008年期间流域年径流量先小幅增加后显著减少，其中各子流域的汛期径流量在2000年代均显著减少，下堡子流域10月份径流超过汛期径流量。洪水流量与总径流变化趋势一致，枯水流量在不同子流域有不同的演变趋势，三道营和戴营子流域2000年代流量历时曲线的低流量部分上移。除年降雨总量外，降雨年内分布尤其是大降雨对径流变化亦有重要影响。（2）基于改进Budyko曲线的统计法和SWAT水文模型法的结果表明，1980年代到1990年代，气候变化使径流增加，作用强于土地利用变化的减水作用；1990年代到2000年代，气候变化对径流减少起主导作用，沟道上塘坝建设造成的蒸发增加亦对径流减少有不可忽略的影响。（3）利用改进的Burr XII分布的四参数统计模型较好地模拟了各子流域的流量历时曲线，，定性揭示了模型参数对气候和土地利用变化的响应规律，可进一步应用于归因分析不同分级径流演变的驱动因子。基于Brutseart and Nieber（1977）方法对流域基流退水的分析表明，表征流域蓄水特性的参数n取定值1.28时，另一参数K的变化可定性反映蒸发和和人类活动对退水的季节性影响。两种方法的研究都为定量评价气候变化和人类活动对不同量级径流变化的影响提供了新的途径。
[Abstract]:As the most important source of surface water in Beijing, Miyun Reservoir is of great strategic significance for water security and sustainable development in the capital. In the past 30 years, its hydrological situation has been increasingly affected by human activities and climate change, showing different characteristics from previous historical periods. Taking the sub-watersheds controlled by five hydrological stations in the upper reaches of Miyun Reservoir, including Lower Fort, Sandaoying, Zhang Jiafen, Dai Ying and Xiahui, as the object of study, this paper discusses the inter-decadal evolution characteristics of different grades of runoff in each sub-basin. Comprehensive statistical method and model method are used to reveal the attribution law of runoff evolution in Miyun reservoir basin in recent 30 years, and try to establish different grade runoff by using discharge duration curve and basic flow regression equation. In particular, the driving factors of the partial evolution of the basic flow are quantitatively analyzed. The main results are as follows: (1) under the general trend of decreasing runoff in the last 50 years, the annual runoff increased slightly and then decreased significantly during 1980 / 2008, in which the runoff in flood season in all sub-basins decreased significantly in the 2000s. The runoff of Xiapao sub-basin in October exceeded the runoff in flood season. The variation trend of flood discharge and total runoff is consistent with that of total runoff. The low flow rate of Sandaoying and Dai Ying sub-basins moves up in the 2000s in different sub-basins, and the low-flow part of the discharge duration curve in the two sub-watersheds moves up in different sub-basins. In addition to annual rainfall, rainfall distribution during the year, especially heavy rainfall, also has an important impact on runoff variation. (2) the results of the statistical method based on the improved Budyko curve and the SWAT hydrological model method show that from 1980s to 1990s, the effect of climate change on runoff is stronger than that of land-use change on water reduction; From 1990's to 2000's, climate change played a leading role in runoff reduction, and the increase of evaporation caused by the construction of the upper channel pond dam also had an innegligible effect on runoff reduction. (3) using the improved four-parameter statistical model of Burr XII distribution, the discharge duration curves of each sub-basin are simulated well, and the response law of the model parameters to climate and land use change is revealed qualitatively. It can be further applied to attribution analysis of driving factors of runoff evolution in different grades. Based on the Brutseart and Nieber (1977) method, the results show that the variation of the other parameter K can qualitatively reflect the seasonal effects of evaporation and human activities on the backwater when the parameter n is 1.28, which is used to characterize the characteristics of the catchment water storage in the basin, and the variation of the other parameter K can reflect the seasonal effect of evaporation and human activities. The study of both methods provides a new way to quantitatively evaluate the impacts of climate change and human activities on runoff of different magnitude.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P333

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