Sustainable Management for Minimizing Land Subsidence of an Over-Pumped Volcanic Aquifer System: Tools for Policy Design

Groundwater management scenarios for the Toluca Valley, Mexico, are examined with a three dimensional groundwater flow model coupled to a one dimensional compaction module. The objective of this study is to establish a management policy for the sustainable development and management of the Toluca aquifer system for minimizing land subsidence. Several scenarios are tested by varying 4 main parameters: recharge, exports to other basins, local consumption, and relocating pumping centers. It is apparent that continuing at current rates of water consumption will lead to subsidence of more than 1.6 m over a 40 year period (2010–2050). Completely stopping exports to Mexico City is not the most important factor in controlling subsidence because the pumping system is mostly located in regions with low clay content, where subsidence is lower. However, decreasing exports by half and relocating the pumping centres to low-clay-content areas does have a positive effect on the overall water budget and subsidence. Based on simulation results, it appears that much of the land subsidence could have been avoided had water policies been applied to restrict pumping in regions with compressible materials. The approach taken in this study could be applied to other locations with similar problems in order to determine the most viable option for water supply.