Evaluation of drainage hydro credit implementation in the Vargem Grande stream basin in Montes Claros, Minas Gerais, Brazil

The urbanization process generally increases impermeable surfaces, reduces rain infiltration, increases the volume of surface runoff and the frequency of urban flooding. The Vargem Grande stream basin, object of this study, has a waterproofing of 64.94% of its area of about 18 km². The channel on Vicente Guimarães avenue where the basin's outflow is located has a drainage system that quickly directs the runoff to the bottom of the valley, where some flooding has already been observed. This article will assess the need to implement the Drainage Hydro credit, with the objective of reducing the growth of the waterproofing rate in the studied basin, from the damping of hydrographic peaks or the increase of permeable areas on the ground. Hydrographs were simulated with additions to every 10% of the current impermeable area until it equals to the area of the hydrographic basin. Hydrographs were also simulated with reductions to every 10% of the current impermeable area until they return to their natural flow conditions. From the obtained results, it could be verified that the implementation of this measure is a valuable strategy for the amortization of the hydrograph peaks, reducing the drained volumes.