Surface runoff evaluation in the northeastern Valle de Guadalupe, B.C., Mexico, using the curve number method and satellite data

Abstract

In order to recognize the soil and geomorphologic characteristics of the northeastern part of Valle de Guadalupe, Baja California, and its implications on the runoff volumes in the region, 59 soil samples were collected from the first 5 cm of the soil layer, taking into account the surface relief, soil classification and vegetation cover of each sampling point. Soil moisture content and textural analyses were carried out in the laboratory for each sample. Three raster images were used to complement field data: an Ikonos image, an Aster Image and the Instituto Nacional de Estadística Geografía e Informática digital geologic map I11D82. The Ikonos image was used to calculate the normalized differential vegetation index, the Aster image to evaluate the field slope, and the digital map to obtain geologic information for the study area. Following the runoff curve number method, a computational algorithm was developed (for Ermapper 6.4 software), by using the three raster images and the field data. The algorithm was employed to study the surface runoff potential in the Serranía Matcuatai and to evaluate its runoff volume contributions to Valle de Guadalupe. The mean annual runoff volume contribution was estimated in 258,000 ± 123,000 m³. It was also found that 88% of the study area surface has a runoff potential and only 12% is favorable to infiltration.