Características físicas e hidráulicas de bacias de retenção implantadas pelo programa “Vida Nova Rio Formiga”.

As one of the soil conservation techniques, retention basins have the purpose of accumulating water with the runoff dampening, reducing the flow peak, storing it temporarily in addition to sedimenting suspended solids. In some cases, the water stored by the retention basins generates the recharge of the groundwater, contributing in the long term to reducing pollutants and increasing water quality. The use of water and sediment retention basins in watershed protection programs, such as the ”Produtor de Água” program of the National Water Agency (ANA), has mostly focused on their technical and cost planning, however, little attention has been given to them to the fact that the technique demands constant maintenance. In this context, this study aims to evaluate the physical and hydraulic characteristics of retention basins implemented in the pilot project “Programa Vida Nova Rio Formiga” in order to provide the establishment of measures regarding its management, proposing for the Program to monitor the road retention basins with the methodology used in this work. To determine the maximum water level and sediment intake in the retention basins, a monitoring system of water infiltration in terraces and retention basins was used. To determine the saturated soil hydraulic conductivity, the Guelph Permeameter was used; to measure soil penetration resistance, a Stolf Impact Penetrometer was used; and in order to evaluate the soil moisture of these structures, undisturbed soil samples were collected. The methodology used was sensitive in diagnosing changes in water level and the amount of sediment in the retention basins. The retention basins in the road area received greater water and sediment intake when compared to the basins in pasture area and the use of water and sediment level monitoring equipment has the potential to be extrapolated to their use in all basins of the Program's road area.