It is presented results from observations of gross rainfall and throughfall regimes for three successional phases in a stand located at Caçambe sub-basin, Pedra Branca massif, Rio de Janeiro. From 04/11/10 to 04/11/11 were carried 27 samplings after the rain events. Gross rainfall and throughfall were measured with 12 rain gauges in an area of advanced secondary forest, 6 in an early secondary succession and 6 in the edge. Total gross rainfall was 2357,07 mm. Average throughfall, 89±13% in the edge, 94±14% in initial secondary bush and 75±07% in advanced secondary forest, are in range of literature values for the Atlantic Rain Forest. Interception increased simultaneously to the advance of the secondary succession. This improved interception suggests the importance of forest preservation to mitigate flooding in vulnerable cities such as Rio de Janeiro. Chemical analysis for Na+, K+, Mg+2 e Ca+2 were evaluated in 12 out of 27 rain events. The results resembled literature, with the exception of high total quantity and concentration to Ca+2. The urban-industrial expansion in the zone west of the city is spoiling the forest patch and probably is causing the excess of metal emissions at Caçambe. In addition, Rio Centro record confirms a growing gross rainfall tendency in the end of this decade. From December to April is the mass movement and flooding period in Rio de Janeiro and its increasing intensity of gross rainfall completes the environmental fragility scenario.