Response of Ecological Base Flow to Water and Sediment Dispatching in Irrigation Areas Along Water-Deficient and Sediment-Laden River

摘要

Ecological base flow is a basic requirement of water flow for a healthy river ecosystem. But in WeiheRiver the ecological flow is not guaranteed because of the water shortage, high sediment concentrationand considerable agricultural water use along the river. In this study, Baojixia under-tableland irrigationarea was selected as a representative area to which a mathematical model of one-dimensional steadywater non-uniform sediment regulation was applied, to analyse the impact of channel desilting onguaranteeing the ecological base flow of Weihe River. The results indicated that scouring and silting ofthe channel was significantly correlated with the channel water capacity and sediment content inwater flows. In addition, channel desilting contributed to 55.9×104m3 and 79.2×104m3 water saving inthe irrigation area in January and December which belonged to the dry season. Their contribution ratesto basic flow were 3.5% and 4.9%, respectively.