ASSESS OF THE EFFECTS OF LAND MANAGEMENT AND CATCHMENT HYDROLOGY ON WELL WATER QUALITY OF NITRATE IN LEON, GUANAJUATO, MEXICO

The Metropolitan Area of ​​León is located as the sixth most populous in Mexico, with 1,436,733 inhabitants. It sits one of the most important industrial areas in the country. It covers an approximate area of 687 km² and is limited by areas of higher altitude topography on their flanks. The population is supplied mainly from groundwater from deep wells that extract water from Leon Valley aquifer system, located within the urban zone and beyond. Analysis was performed on the concentration of N-NO₃-and Cl-from 2.568 deep wells measured data collected from historical records of 8 years. From this database, 1.114 correspond the recording of wells within the city, of which 462 have higher concentrations than those specified in Norm for drinking water in Mexico. As part of the analysis we obtained the rate of change in the concentration of N-NO₃-, against time, for some wells, the results are between 1 and 5mg/l/año. This rate of change is attributed to the recharge of water from urban use. It makes a relationship balance of chloride in selected wells, through these results is estimated that the proportion of poor quality component can reach unsustainable levels in short time.