MODFLOW simulations of groundwater recharge from canal leakages in a loess irrigation area

ABSTRACT Groundwater movement in the loess irrigation area affects soil water dynamics, crop growth status, and water ecological stability. Studying its variations under different water supply conditions is significant for the rational utilization of groundwater. In this article, a hydro-geological model was established by analyzing the strata of the Baojixia irrigation area, and the characteristics of groundwater movement in this area under canal leakage were analyzed by using MODFLOW in GMS. Conclusions are: (1) In the upper sub-irrigation area, MODFLOW can be used to simulate the groundwater movement. (2) Variation of groundwater is small under the condition of leakage and recharge from the canal system. Water can infiltrate into the third layer of soil, but with a different hydraulic head in each layer. (3) The vertical velocity of canal leakage recharge is about 0.033 m/d. (4) When evaporation is not considered, after 15 days, seepage water can arrive at the farthest range of the upper sub-irrigation area. The study can provide a reference for groundwater formation mechanism and distribution law research in the loess irrigation area, and help explore the basic Q5 model of using irrigation water to recharge groundwater and improve the guarantee rate of crop water demand.