三峡库区龙河流域降雨和人类活动对水沙关系变化贡献率分析

以三峡库区中心区域的龙河流域为研究对象,利用1963—2010年流域水沙资料,采用Pettitt突变点检验、累积距平法及双累积曲线法分析了该流域输沙量和降雨量的变化趋势,判别出降雨量在1982年、输沙量在1982年和1990年发生了突变。并采用累积量斜率变化率比较法分析了1963—1981年,1982—1990年,1991—2010年3个时段降雨量和人类活动在龙河流域输沙量变化中的相对贡献率。研究表明:以1963—1981年为基准期,1982—1990年间降雨量和人类活动贡献率分别为29.49%和60.51%,1991—2010年间分别为3.38%和96.62%;以1982—1990年为基准期时,1991—2010年人类活动对输沙减小的贡献率为100%。该研究揭示了1963—2010年输沙量的变化趋势及降雨和人类活动对其贡献率,研究不仅对该区水土流失治理、水土保持效益评价具有重要意义,同时为研究三峡水库区间水沙锐减的原因提供一定的理论支持。

Contributions of Precipitation and Human Activities to the Runoff and Sediment Variation in Longhe River Watershed of Three Gorges Reservoir Area

The variation trend of sediment and precipitation in Longhe River Watershed which is the centre of the Three Gorges Reservoir area was analyzed according to the measured data in 1963-2010.Pettitt test,accumulative anomaly analysis and double mass curve analysis were employed for the research.The year 1982 was found to be the inflection point of precipitation,and 1982 and 1990 the inflection points of sediment load.The contributions of precipitation and human activity to sediment change during three periods (1963-1981,1982-1990,1991-2010) were compared and analyzed.Results reveal that with 1963-1981 as baseline period,precipitation and human activ-ity contribute 29.49% and 60.51% respectively to the sediment change in 1982-1990,and 3.38% and 96.62%respectively in 1991-2010;whereas when 1982-1990 is taken as the baseline period,human activity alone contrib-utes 100% to the sediment decrease in 1991-2010.This research reveals the trend of sediment load change in Longhe River watershed during 1963-2010,and also the contributions of precipitation and human activity.It is of great importance to the soil and water conservation and assessment,and also provides theoretical support to the sharp decline of runoff and sediment discharge in Three Gorges Reservoir Area.