Rethinking Conjunctive Use of Surface and Groundwater in Liuyuankou Irrigation System

摘要

Conjunctive use of surface and groundwater has proved to be effective in many arid and semi arid irrigation areas.In Liuyuankou Irrigation System (LIS),most of surface water diverted from the Yellow River is used for rice irrigation in the upstream area,which causes shallow groundwater tables.Surface water and lateral groundwater flow recharges downstream aquifers,and groundwater is pumped for dry land crops.Soil salinisation resulting from shallow groundwater tables in the upstream and increasing groundwater depth in the downstream area threaten the environmental sustainability and economic feasibility of agricultural production.This paper describes modeling tools to develop and implement water saving and sustainable irrigation options for the LIS.Modeling analysis shows that using pumped groundwater in the upstream area is an effective way to increase groundwater depth and thus reduces phreatic evapotranspiration losses,and shifting saved surface water to the downstream area can prevent deep groundwater tables in this area.By the proposed innovate strategies of conjunctive use,real water savings and sustainable development can be achieved.