APPLICATION OF THE HYDROLOGY MODEL SWRRB TO THE WATERSHED EL TEJOCOTE, ATLACOMULCO, STATE OF MEXICO

This research examined the calibration mode of the SWRRB (Simulator for Water Resources in Rural Basins) model whose importance resides in knowing runoff and sediment yield without having gauging stations. The site was a watershed called El Tejocote (17 556 ha), located in Atlacomulco, State of México. The objective was to compare the simulated and observed values of water yield, sediments yield, peak runoff and biomass in a period of five years (1980 to 1984). The basin was divided into ten portions, based on land use. The results showed that 75 % of sediment yield came from steep cultivated hillsides and 80 % of the sediment yield was produced in july and august. For corn (Zea mays L.) yield in rainfed agricultural lands, the model predicted an average of 113 kg ha-1 more than was observed. On the other hand, the predicted maximum and mean peak runoff, exceeded the observed values by 17 and 28 % respectively; however, they showed similar standard deviation. Regression analysis between observed and simulated water yield had R2 of 0.799, 0.875 and 0.605 on annual, monthly and daily bases; while the R2 of sediment yield was 0.789, 0.736 and 0.411 on annual, monthly and daily bases, respectively.