Usos múltiplos da água e a sustentabilidade nas sedes municipais da bacia hidrográfica do rio Marapanim-PA.

Abstract

The colonization of northeaster Pará is considered one of the oldest at Amazon area, where a disorderly occupation over time caused several impacts on the environment and water resources, mainly related to the territory of the hydrographic basin of the Marapanim River. In this context, the research aimed to integrate concepts of water demand and availability, adding hydrological and socio-environmental factors to the analysis of the hydrographic basin as a natural unit of area for the management and application of public policies in the municipal cities of Castanhal, Igarapé-Açu, Marapanim, São Francisco do Pará and Terra Alta, which belong to the hydrographic basin of the Marapanim River. The goal of the research was to evaluate the management process of those localities, through sustainability index with Pressure - State - Response (PER) indicators, combined with the characterization of multiple uses of water. The main demand for water in those localities is public water supply, with an estimated volume of 2,228.18 m³ / day. However, within the limits of the locality, agriculture was the activity that were responsible for the higher demand, 28,022.46 m³ / ha, followed by livestock production, 899, 82 m³ / day. The region's water availability was estimated by rainfall monitoring, in which September-October-November were months with fewer rainy days, with the highest percentage of rainfall in the month concentrated in a few days. The sustainability index of the municipal cities of Castanhal, Igarapé-Açu, Marapanim and Terra Alta were 0.40; 0.50; 0.44; 0.54 and 0.5 respectively, which represents an average value. The city of São Francisco obtained an index value of 0.54, considered as a good index value. The characterization of multiple uses of water is essential to understand the relationships of availability and demand for water that occur at hydrographic basin of the Marapanim River, as well as the application of the sustainability index based on the pressure - State - response model, allowing both integrated and individual assessment of hydrological, environmental, political and social indicators, which allows a more targeted view of the needs of each territory, thus helping to guide public policies managers during decision making process.