The present work concerns a physical-conservationist deterioration diagnosis carried out in the sub-watershed of the Ibicuí-Mirim river, located in the state of Rio Grande do Sul, Brazil. The study area is 8.882,50 ha in size, and was divided into 49 micro-watersheds. The methodology consisted in determining the Ruggedness coefficient (RN) from the physical properties of the micro-watershed, and classifying the coefficient into land-use classes. The diagnosis of the area showed that the level of environmental deterioration in the Ibicuí-Mirim sub-watershed is 30.16%. Land-use classification concluded that 28.8% of the area of the sub-watershed is indicated for forestry, 32.5% for agriculture or urbanization, 28.6% for pasture or urbanization, and 10.1% for pasture or urbanization.
Ruggedness index; environmental deterioration; watershed