Mexico is among the countries that are facing the greatest water stress, where factors such as climate change, contamination of surface water, groundwater sources, and inefficient management have limited the availability of water resources. Consequently, new supply sources need to be implemented. Rainwater harvesting systems (RHS) are viable and sustainable alternatives, the implementation of which primarily depends on identifying suitable sites and applying technologies that are appropriate for different users. This research used the Analytical Hierarchy Process (AHP) technique in a GIS environment to select the optimal sites for designing RHS, taking into account hydrological, biophysical, and socioeconomic criteria. After determining the ideal sites, the study presents proposals and costs for the design of an urban and rural RHS based on the characteristics of the region and the needs of the community. The findings show that implementing RHS in the study area can be a practical, economical, and efficient alternative for water resource management, since these projects are aimed at sustainability.

The hydrological system of San Juan-Taxco Rivers in located inside of one of the oldest and major mining district in Mexico. Several communities in the area use the rivers water along its flow for domestic water supply and crop irrigation. Sediment is an essential, integral and dynamic part of river basins, in polluted environments these act as sink of heavy metals and as a source of contaminants on the fluvial system. The management and sustainability of sediment should be assessed and secured to achieve good ecological status of the basins, for this task, approaches as ecological risk identification and geochemical indices are being used.Superficial sediment samples were collected in San Juan-Taxco river system. The results demonstrated that the degree of pollution from thirteen heavy metals and metalloids studied decreases in the following sequence: Cd> Zn > Pb > Cu > As > B > Mn > Ni > Fe > Co > Ba > Al and Cr. Cd made the most dominant contribution. Geochemical indices revealed important external anthropogenic influences in the rivers. The geochemical indices indicated very high enrichment for As, Cu, Pb and Zn, and extremely high for Cd in the three-rivers. The calculation of Pollution Load Index (PLI) showed in Cacalotenago River and in Taxco River are the sites with the highly contaminated sediments. PLI values were very high in all the samples sites due mining tailings erosion, wastewater and agriculture run off. Cd, Zn, Pb, Cu and As were the main potential risk elements that will cause harmful biological effects in the riverine environment.

The Taxco mining district is a well-known international producer of silver, jewelry, and precious metal handicrafts. Inappropriate disposal wastes from anthropogenic activities have been deteriorating the hydric resources and threatening the inhabitants’ health, since they use the springwater for human consumption and domestic activities. A multi-tracer approach combining measurements of hydrochemical data, trace elements, and isotopes δ²H, δ¹⁸O, ³H, and ⁸⁷Sr/⁸⁶Sr ratios was undertaken for 18 springwater samples. δ¹⁸O and δ²H indicate that the springwater comes from the rain and had experienced some degree of isotopic fractionation by atmospheric evaporation in some samples at lower altitudes. ³H values on the springwater showed the existence of old and new water. Three groups of springwater were identified according to age: local flow in rhyolites, intermediate flow through red beds to the outcrop point in sandstone and shales, and deep flow in greenschist. The results of this study show the utility of ⁸⁷Sr/⁸⁶Sr ratios in identifying the water–rock interactions and springwater flow paths, suggesting that more widespread use of the strontium isotopic fingerprint is warranted.