Water preservation in Sinaloa, Mexico, through instrumented water quality monitoring. Case study: Presidio River

Abstract

In Mexico and many countries there are water quality monitoring networks. However, such monitoring has not been used for decision making due to the lack of technical criteria. In the present investigation, the spatial and temporal distribution of the water quality of the Presidio River, located in the state of Sinaloa, in Mexico, was studied. This river stands out for the diversity of activities carried out on its banks, from mining activities, intensive agriculture to even aquaculture. The monitoring network has eight sampling sites distributed in the lower, middle and upper basin. Through a Geographic Information System, the proportions of land use were identified, associating it with the values of all water quality parameters at each sampling site. Each value was compared with international guidelines to evaluate the quality of surface water bodies (since such guidelines do not exist in Mexico). Subsequently, the sites were grouped using unsupervised cluster analysis. With the analysis of the results, in a next stage criteria adapted to the CONAGUA monitoring network and new technological tools for real-time monitoring will be proposed that allow preserving the water resource, related to the environmental problems identified, among which the most notable were the eutrophication, the presence of heavy metals throughout the riverbed and the presence of pathogens at the mouth of the Presidio River. Real-time measurements of variables related to the identified problems are also suggested (e.g., pH for metals and nitrogen). The resulting criteria for the Presidio River might be useful for most hydrological basins if the proportions of land use on its banks were to be considered and a technical-economic feasibility analysis were to be carried out.