人类活动对无定河流域不同地貌区水沙变化的影响

The influence of human activities on the changes of water and sediment in different landforms

为了研究人类活动对无定河流域不同地貌区水沙变化的影响,选择无定河流域内风沙区海流兔河和黄土丘陵沟壑区大理河代表水文站1956-2010年的水文泥沙实测数据。采用Mann-kendall和Pettitt法分别对水文泥沙数据进行趋势分析与突变检验,确定发生突变的临界年份,再利用双累积曲线法的回归方程定量确定人类活动对两种地貌区水沙变化的影响。结果表明:风沙区代表水文站韩家峁站控制流域的面降水量、年径流量和输沙量发生突变的临界年份分别为1970年、1985年和1986年;黄土丘陵沟壑区代表水文站绥德站控制流域的面降水量突变的临界年份为2000年,而年径流量和输沙量临界年份均为1971年。与基准期相比,风沙区年径流量与输沙量分别减少10.02%和43.90%;黄土丘陵沟壑区年径流量与输沙量分别减少21.03%和40.20%。人类活动对风沙区的减水和减沙效益分别为21.74%和81.43%,对黄土丘陵沟壑区的减水和减沙效益分别为27.12%和58.46%。

To study the influence of human activities on the changes of water and sediment on different landforms in Wuding River Watershed,data of flow and sediment in 1956-2010 was collected at the Hailiutu River watershed,the Loess Hilly and gully region of Dali River.Mann-kendall and Pettitt methods were used to study the trend of hydrological and sediment data,and the critical year of the mutation.The double cumulative curve method of regression equation was used to determine the impact of human activities on water and sediment on the two landforms.Results show that rainfall,annual runoff and sediment mutation of the critical years respectively are in 1970,1985 and 1986 at the Hanjiamao station,which is the represent of sandy area.As the sample of Loess Hilly and gully region at the Suide hydrological station,the surface rainfall mutation of the critical year is in 2000,while the annual runoff and sediment load mutation of the critical year are 1971.Compared with the base period,annual runoff and sediment discharge were reducedby10.02% and 43.90%.In loess hilly-gully region,annual runoff and sediment discharge were reducd by 21.03% and 40.20%.Benefits by human activities on the sandy water and sediment were reduced by 21.74% and 81.43%,respectively.Water and sediment were reduced by 27.12% and 58.46% in the loess hilly-gully region.