Environmental evaluation of Andean piedmont urbanization process in Santiago de Chile

Watersheds are complex environmental systems, where geomorphologic, hydrologic, climatic and ecological processes take place, and which are severely impacted by urbanisation. In this paper, six Santiago Andean piedmont watersheds have been researched according with the degree of urbanisation that they reach, which varies between Macul-San Ramon, where about 40% of their land covers has been already urbanised, until Pirque, where agricultural and rural features are still dominants. Using geographical information systems, the impact of urbanization on several ecological indicators, such as vegetative productivity, biomass, soil moisture and surface temperature are analysed. Total Imperviousness Areas Runoff Coefficients and Environmentally Sensitive Areas allow the estimation of the state of the watersheds ant their contribution to the environmental health of Santiago city.