Impacts of Water and Sediments Decreasing on Downstream Region and Lower Reaches of Wei River and the Yellow River

The flow regime of the Wei River and the Yellow River has been changed in recent years.The water and sediment amounts,the precipitation and water use of the Wei River and its main tributaries were analyzed,and the cause and impacts of water and sediment amounts decreasing on flow regime of the Wei and the Yellow River were expounded.It was pointed out that water and sediment decreasing were mainly caused by precipitation decrease and water use increase.The main factor,casing the river regime changeoftheWeiRiver,wasthedecreaseofwaterandsediment.