Application of hydrogeological modelling methods in forecasting seawater intrusion of Pleistocene aquifer in Thai Binh area

Abstract

This paper presents the application of hydrogeological modelling methods in forecasting seawater intrusion in Thai Binh area. Exploitation by UNICEF well systems have increased both inflow and outflow rate in Pleistocene aquifer by 2.4 times. Model is revised by solving steady state and transient models, all input coefficients have been identified (with Kx = 17.3, Ky =17.3, Kz =1.73, specific storage µ*= 0.0036, specific yield µ= 0.16 and effective porosity n0 = 0.16). By modelling two scenarios, we can show that Thai Binh province can keep on exploiting with the current rate Q = 31500 m3/day, the seawater intrusion in the Pleistocene aquifer is still developing but very slow (remain 99% current freshwater area in 2050). However, Thai Binh groundwater reserves cannot meet 50% of water needs in 2050 (if the exploitation rate is increased to 68000m3/day, only 95% current freshwater area remains in 2050).