Modeling Seawater Intrusion to Coastal Aquifers in South Coast of Laizhou Bay, China

Yawen Chang,Bill X Hu,Xue Li,A Szymkiewicz,B Jaworska-Szulc,A Sadurski

doi:10.1051/e3sconf/20185400004

Abstract

In this study, a two-dimensional SEAWAT 2000 model is developed to simulate the seawater intrusion to coastal aquifers and brine water/fresh water interaction in the south of Laizhou Bay, Shandong Province, China and forecast the seawater intrusion and brine water/freshwater interface development in the coming years. The model profile is perpendicular to the coastal line, about 40 km long and 110 m in depth, and consists of two interfaces, freshwater-saline water interface and brine water-saline water-seawater interface. The parameters of aquifers in the SEAWAT-2000 model are calibrated by trial-error method repeatedly to fit the head and salinity measurements. Based on the historical groundwater and brine water exploration and natural precipitation condition, the prediction results indicate that equivalent freshwater head in shallow freshwater-saline water area will decrease year by year and decline 2.0 m in the forecasting period, caused by groundwater over-pumping for irrigating farmlands. The groundwater head in the brine-saline water area will also decrease about 1.8 m in forecasting period. A larger depression cone appears in the brine area, with smaller funnels in other areas. The salinity in the brine area finally drops below 105g/l. In the meanwhile, the salinity increases in other areas, damage fresh groundwater resources.

Highlights

Climate change, sea-level rise, variation of land use haveleaded to serious seawater intrusion to coastal aquifers (Werner et al 2013).To meet water needs in the agriculture, lives and industry, groundwater resources have been seriously over exploited in the last several decades (Datta et al 2009)
The salinity of the shallow freshwater area increases, the main reason is that the exploitation amount of fresh water is higher than recharge, which decreases hydraulic head and increases salt water inflow into the shallow layers
SUMMARY AND CONCLUSIONS The groundwater head at the freshwater-saline water area is decreasing year by year under drought condition, and the annual variation is about 0.3 m, and the hydraulic head decrease in the forecasting period is about 2 m

Summary

Introduction

Climate change, sea-level rise, variation of land use haveleaded to serious seawater intrusion to coastal aquifers (Werner et al 2013).To meet water needs in the agriculture, lives and industry, groundwater resources have been seriously over exploited in the last several decades (Datta et al 2009).Physically, the seawater intrusion is a density-dependent issue (Guo et al.2002). Some other studies were on freshwater-saline or brine water areas. A large scale of a twodimensional cross-section, perpendicular to the coastal line in the Laizhou bay, China is chosen to study the variations of both fresh water-saline water interface and brine-saline water interface with time.

Results

Conclusion