Typical Reservoires Sedimentation And Their’s Influence On Runoff And Sediment Transport In Weihe River Basin

It is extremely uneven for spatial and temporal distribution of water resources inChina. The reservoirs are the main water conservancy measures, which can be used toadjust the river’s runoff and sediment discharge, as well as storage water resources. By thereservoir group, we can relief our country’s engineering water shortage. At the same time,the reservoirs have great influence on the river’s runoff and sediment yield. In this study,we make use of the following methods, such as the coefficient of variation, coefficient ofskewers, Pearson correlation analysis, cumulative curve method, the deposition rate ofempirical mode method, and so on. At first, we described the reservoir constructionsituation in Weihe river basin. Subsequently, we elaborated the influencing mechanism ofreservoirs to river’s runoff and sediment discharge process. In the end, we estimated thereservoir sediment deposition in Weihe river basin. On the basis of calculated reservoirsediment deposition, we described the effect of reservoir water storage and sedimentintercept to river runoff and sediment discharge. The above incidence can providetheoretical basis for water and sediment regulation. The results are as follows:(1) The serious soil erosion caused reservoir sedimentation. The annual sedimentationof Bajiazui, Fengjiashan, Yangmaowan and Shitouhe reservoir is0.0988×108t,0.0491×108t,68.3574×104t,3.12×104t, respectively. Based on the reservoir sedimentation rate empiricalmode method, we find that the middle-sized reservoirs’ total sediment deposition is0.23636×108t from2001to2011of Weihe River basin. The earliestreservoir in WeiheRiver basin is Wangjiawan Reservoir, which was built in1956. The largest reservoir inWeihe River basin is Bajiazui Reservoir, which was built in1960.(2) The input runoff and sediment distribution of Bajiazui Reservoir is uneven duringthe year. Runoff and sediment discharge concentration distributed from July to September. The runoff during flood season accounted for52.4%of the annual runoff. The sedimentdischarge during flood season accounted for82.2%of the annual sediment discharge.Afterthe application of reservoir impoundment, the runoff and sediment discharge trends to beuniform of the downstream hydrologic station during the year. The drop rate ofaveragedsediment discharge of the downstream hydrology stations decreases with increasingdistance from the reservoir dam.The reduction of Maojiahe station, Yangjiaping station andZhangjiashan station is87.1%,47.8%and33.4%respectively.(3) By the runoff-sediment double mass curve of Zhangjiashan station, Zhuangtoustation and Huaxian station, we know the sediment discharge of the3stations changed,which indicating that besides the runoff impaction to sediment load, human activity is themain reason for the sediment discharge variation trend changed of Weihe River.Meanwhile, the turning point of the runoff-sediment double mass curve corresponded tothe time of the reservoirs’ impoundment. The accumulation amount of sediment reductionis4.52×108t from2001to2008without the rainfall influence, estimated byrunoff-sediment double mass curve of Zhangjiashan station. The accumulation amount ofsediment reduction is5.78×108t from2003to2008without the rainfall influence,estimated by runoff-sediment double mass curve of Zhuangtou station. The accumulationamount of sediment reduction is11.24×108t from2001to2008without the rainfallinfluence, estimated by runoff-sediment double mass curve of Huaxian station.