Hernández-Guzmán Rafael, Ruiz-Luna Arturo, Berlanga-Robles César Alejandro
Centro de Investigación en Alimentación y Desarrollo A.C., Lab. Manejo Ambiental, Mazatlán, Sin., México.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2008 Oct;43(12):1471-82. doi: 10.1080/10934520802253465.
Results on runoff estimates as a response to land-use and land-cover changes are presented. We used remote sensing and GIS techniques with rainfall time-series data, spatial ancillary information, and the curve-number method (NRCS-CN) to assess the runoff response in the San Pedro subbasin. Thematic maps with eight land-cover classes derived from satellite imagery classification (1973, 1990, and 2000) and hydrologic soil-group maps were used as the input for the runoff calculation. About 20% to 25% of the subbasin landscape has changed since 1973, mainly as consequence of the growth of agriculture. Forest is the main cover, although further analyses indicate that forest is degrading from good to poor conditions when evaluated as a function of the spectral response. Soils with low infiltration rates, classified as the hydrological soil-group "C", were dominant in the area (52%). The overlaying of all the hydrological soil groups with the land-use map produced a total of 43 hydro-group and land-use categories for which runoff was calculated using the curve-number method. Estimates of total runoff volumes (26 x 10(6) m3) were similar for the three dates analyzed in spite of landscape changes, but there were temporal variations among the hydro-group and land-use categories as a consequence. Changes are causing the rise of covers with high runoff potential and the increase of runoff depth is expected, but it can be reversed by different management of subbasin hydro-groups and land-use units.
本文给出了作为对土地利用和土地覆盖变化响应的径流估算结果。我们运用遥感和地理信息系统技术，结合降雨时间序列数据、空间辅助信息以及曲线数法（NRCS-CN），来评估圣佩德罗子流域的径流响应。利用从卫星图像分类（1973年、1990年和2000年）得出的八种植被类型专题地图以及水文土壤组地图作为径流计算的输入数据。自1973年以来，该子流域约20%至25%的景观发生了变化，主要是农业发展的结果。森林是主要的覆盖类型，不过进一步分析表明，从光谱响应的角度评估，森林正从良好状态退化至较差状态。渗透速率低的土壤，被归类为水文土壤组“C”，在该区域占主导地位（52%）。将所有水文土壤组与土地利用图叠加，产生了总共43个水文组和土地利用类别，利用曲线数法计算了这些类别的径流。尽管景观发生了变化，但所分析的三个日期的总径流量估算值（26×10⁶立方米）相似，不过各水文组和土地利用类别之间存在时间变化。这些变化导致具有高径流潜力的覆盖类型增加，预计径流深度也会增加，但通过对子流域水文组和土地利用单元的不同管理可以扭转这种情况。
