SPATIAL-TEMPORAL SURFACE WATER AVAILABILITY IN THE TULANCINGO RIVER BASIN, HIDALGO, MEXICO

The Tulancingo River basin is part of the upper Metztitl & aacute;n River basin and has an aquifer deficiency that covers 87 % of its surface area; however, floods have occurred in the valley region. This disparity encouraged the current work, the goal of which was to estimate the spatio-temporal availability of water in the soil within the basin from the modeling of surface water balance elements. Sensitivity analysis of the model fit parameters was performed with the SWATCUP program and the SUFI2 algorithm. The runoff values were estimated with the SWAT program and were compared with the records of the Venados Hydrometric Station, obtaining values of the statistical indicators R-2 = 0.89 and Nash Sutcliffe (NS) = 0.86 for the calibration period (1982-2002); and R-2 = 0.77 and NS = 0.62 for the validation period (2003-2013). Of the nine sub-basins that make up the Tulancingo basin, the upper sub-basins of the Rio Chico (11), Ventoquipa stream (12), and San Lorenzo River (13) showed values 2.2 times higher than the rainfall depth of the lower sub-basins (5, 6, 7, 8, 9, and 10). Surface runoff and infiltration reported maximum values from July to October and minimum values from April to May. The maximum final water availability in the soil occurred in September. Regarding the analysis by periods, the Generalized Additive Model provided a good fit for most of the variables (0.6 < R-2 < 0.94); during the last period, higher values were observed than in the previous periods ( p < 0.001), identifying a change in the hydrological state of the basin. This was mainly associated with a significant change in rainfall, which was reflected in the trend of surface runoff.