Methodological proposal for the evaluation of sustainability in aquifers: Case study, Mexico

Abstract

A methodology of sustainability indicators in aquifers is proposed, which describes quantitative and qualitative changes in the system. There is no other methodology proposed in the consulted bibliography to evaluate the sustainability of aquifers with all the indicators proposed here and with this weighting by scenarios, the main contribution of this work, which shows the sustainability evaluation for any aquifer in the country. The proposed indicators are 1) groundwater contribution to the base flow of surface streams; 2) water supply; 3) discharge/recharge; 4) groundwater contamination risk; 5) groundwater dependence; 6) groundwater quality; 7) cities growth; 8) aquifer vulnerability; 9) saline intrusion and salinization, and 10) investment in water infrastructure. It is feasible to evaluate aquifer sustainability with an empirical, systematical, and simple indicator methodology in which values are assigned to the variables involved. Weights were assigned by authors to the indicator, according to its relevance to aquifer sustainability. Scenarios with numerical value are proposed for each indicator, which show the condition of the aquifer. A final score of the sustainability index relates all the indicators. This index was classified into four categories: sustainable, moderately sustainable, lowly sustainability, and unsustainable. The evaluation was carried out at the national level (653 aquifers); the results show seven sustainable aquifers, 623 moderately sustainable, 23 of lowly sustainability and non unsustainable. Greater emphasis should be placed on sites with an unsustainable index, analyzing the indicators that confer this category to improve their condition.