VALIDATION OF A PHOSPHORUS INDEX APPLIED TO A WATERSHED BY GEOPROCESSING TECHNIQUES

Abstract

Currently the crisis of the water has been aggravated due to series of factors that from climatic questions and geographic to politics. As Tundisi (2000) the quality of the water is grown worse quickly, threatening the suppliment sources. There are many causes for thiscrisis, but among them the most frequently cited are the increase of the urbanization tax, that increases the necessity of multiple usages of the water, the population increase, that consumes more resources and needs bigger agricultural area for its maintenance, and the biggest demand for energy and industrialized processes. Although the neo-maltusian vision has been criticized for many authors is undeniable that population increase generates greater necessity of use of agricultural ground. Until the second half of century XIX the crises were related to the bad quality of the water due the lack of basic sanitation. In the second half of century XX, the main problems were related to the contamination of the water with toxic elements, many of them caused by agricultural activity (Tundisi, 2000, Bertuol, 2001).