19th International CODATA Conference
Category: Knowledge Discovery

The application of spatial analysis in the implementation of a qualitative infiltration model to evaluate the aquifer’s potential recharge for conservation areas of Mexico City

Dr. Felipe Omar Tapia Silva (otapia@centrogeo.org.mx) and Dr. Franz Mora
Center for research in Geography and Geomatics, “Ing. Jorge L. Tamayo” A.C., México D.F.

Mexico City is undergoing a rapid process of urbanization, occupying remnant rural and conservation areas. The land use conversion of natural areas begins with a conversion to agriculture, which has a “bulldozer” fragmentation effect, eliminating forest zones, and making them susceptible for residential use. A predominantly urban land cover, has an important effect on the hydrological cycle, and then by increasing sealed areas to water infiltration, this process alters significantly the aquifer’s recharge, highly reducing the capacity of the aquifer to offer more than 70% of the water consumption of the city.
Based on the application of spatial analysis methods, a water-infiltration model was implemented in a geographical information system, in order to evaluate the recharge potential of some areas of Mexico City’s aquifer. This is a qualitative and spatial model that includes a watershed delineation, -based on a digital elevation model- along with information on soil, precipitation and land cover spatial data.

Throughout the application of the model, relevant information is generated in order to identify areas of high and low recharge potential. This information can be then used to define a general policy for the sustainable land use management of the City, restricting the inadequate land use changes.

The water-infiltration model has been developed using a strategy from algorithms theory called “divide and conquer”, for which the fundamental factors that determine the aquifer’s recharge process have been abstracted, and, later on, analyzed individually. The strategy begins by defining the spatial and temporal variability of these factors, in order to reduce the problem complexity without losing or ignoring relevant information. Finally, the results derived from the complexity analysis are summarized to obtain a single indicator of potential aquifer’s recharge model.

Of the total surface of the studied area with the model, 22% was characterized as low infiltration, 57% of high infiltration and the remainder 21% of very high infiltration. According to the results obtained, 78% of the analyzed area offers still a very important environmental service based on groundwater recharge. However, the risk of degrading the areas of high infiltration is very high, due to they correspond to forested areas and agricultural zones prone to urbanization, following the observed process of land use change and resulting in low infiltration areas.