Diagnóstico da qualidade ambiental em bacia hidrográfica urbana - Estudo de caso - a sub-bacia do Arroio Cadena - Santa Maria - RS

Abstract

Through this study, we aimed at reflecting upon the environmental diagnosis of an urban hydrographic basin. The theoretical approach has been based on the technique of pressure-state-impact-response (PEIR) in order to obtain quality rates through physical, environmental and socioeconomic characteristics of the Arroio Cadena sub-basin located in Santa Maria, central region of Rio Grande do Sul. This structure has as its general philosophy to analyze environmental problems. The art state was researched based on 17 environmental indicators of varied themes through geoprocessing linked to processes of acquisition of descriptive features from the studied region. The indicators qualification and quantification were based on the condition that the human activities produce pressure upon the environment that can affect its state, which, in turn, brings impact to society and to ecosystem, making the government, organizations and population in general do something towards the system, searching for the stability of it. From these indicators on, scores for each hydrographic basin unit were generated and they were specified through a previous, technical and specialized knowledge in order to write up the weight of each study feature. On the following, the implications of each index on the environmental quality were checked, making out a letter of environmental quality , which presents a compilation of study features through the algebra of maps, besides the treatment of the final result by inferior kriking that led to examine the uncertainties included in the proposed method. The final study is composed by a special database that can be extended and over questioned in several areas of the scientific knowledge. The results can help the decision makers understand the consequences of their decisions upon the environment, as well as they can help organize the processes of decision making in a more correct and democratic way.