The problematic that commonly arises when protecting springs that supply water for human consumption requires a methodological method to prioritize springs that are used for this purpose according to the greatest need for protection from contamination and exploitation processes. The present study proposed the application of a method to prioritize springs in order to facilitate the sustainable management of springs that urgently need protection.
The stages included in the method were: a) regionalization of the study area considering physical variables, which included precipitation, hydrogeological functioning, and slope of the terrain; b) selection of the springs used for human supply that have the greatest exploitation flows and c) prioritization of springs to be protected based on a multi-criteria evaluation (MCE), considering criteria such as exploitation flow, land use, population to be supplied, conservation of spring water collection systems, existence of alternative supply sources, and marginalization index of nearby populations. Using MCE (through the AHP), it was possible to analyze the different criteria based on the opinion of experts, thereby considering different points of view when assigning a weight to each criterion. The methodological process was performed with the help of geographic information systems (GIS). The study case was the State de Mexico. The National Water Commission (CONAGUA, 2015), a government agency responsible for managing water resources, has 2,937 water use permits registered for the use and exploitation of springs. Of the total springs, 1,997 (67%) are used for human consumption, with an exploitation volume of 94,869,976 m3/year (34.5% of the total allocated volume). These springs are used particularly by rural and semi-urban communities.
Regionalization enabled identifying regions that were homogeneous in terms of the characteristics of the springs and their physical environment. Six of those regions with the largest territorial areas were selected, where 88% of the springs used for human consumption were located. Within each selected region, the springs that were representative of exploitation flow were identified, and a total of 23 were included. Lastly, MCE was applied to identify six springs (one in each region) that were priorities for protection. The prioritization of the springs to be protected in each of the six regions selected will facilitate the future application of protection methods based on the physical characteristics of the springs and their physical and socioeconomic environments.