The integrated impacts of human activities and rising sea level on the saltwater intrusion in the east coast of the Yucatan Peninsula, Mexico

Saltwater intrusion is a major hazard to coastal communities as it causes degradation of fresh water resources. The impact of rising sea level on the saltwater intrusion into coastal aquifers has been studied for decades, but how human activities affect the extent of saltwater intrusion is poorly understood. Human activities are known to influence groundwater availability indirectly by affecting precipitation patterns and directly by extracting groundwater and reducing recharge. In this paper the authors investigated the integrated impacts of human activities and rising sea level on aquifer recharge in Quintana Roo, Mexico, by incorporating anthropogenic impacts on groundwater recharge into an analytical saltwater intrusion model. The impact of human activities on groundwater extraction was firstly calculated; then, the resulting groundwater recharge was used in a Ghyben–Herzberg analytical model to determine the inland distance of saltwater intrusion. The analytical model tested six scenarios stemming from different combinations of human development patterns, hydrological settings, hydraulic conditions and rising sea level to obtain the range of possible inland movement of saltwater intrusion. Our results indicate that the groundwater recharge will decrease to 32.6 mm year−1 if human activities increase by 50 % more. With 1-m sea level rise, inland saltwater intrusion distance is estimated to be up to 150 and 1 km under head-controlled and flux-controlled scenarios, respectively. A sensitivity analysis of the model reveals that the large hydraulic conductivity of the Quintana Roo aquifer (0.26–68.8 m s−1) is the most important factor in determining saltwater intrusion distance. Therefore, in this aquifer, the response to human activities is greatly exceeded by natural hydrogeological conditions.