Flash flood control works around the Maracanã stadium district in Rio de Janeiro, Brazil

Summer rainstorms frequently cause flash flooding in northern areas of Rio de Janeiro in Brazil. After decades of problems the city's water authority has finally planned a coordinated series of works to mitigate the hazard once and for all. One of the most critical areas is in the Mangue district, home to the Maracanã stadium, which is drained by five rivers. This paper describes the planning, design and management of a variety of flood control works currently under construction. Valued at around £300 million, these include five new deep detention reservoirs, enlargement of existing 1·8 km long culverts and construction of a 2·4 km long river diversion tunnel. All river flows are also now monitored by the city's new operation and control centre.