Flood Control in An Urban Basin. Case of Matanza-Riachuelo, Argentina (PAP014804)

Código

PAP014804

Autores

JUAN CARLOS BERTONI, Juan Pablo Brarda, Enzo Vergini, Silvina Helena Garrido, Mario Schaider

Tema

Flood risk management in mega cities

Resumo

Matanza-Riachuelo River Basin (CMR; 2,238 km2) drains through Buenos Aires City (CABA) and 14 other districts of the metropolitan area. Given its complex socioeconomic and environmental status, Matanza Riachuelo is the most emblematic basin in Argentina and discharges in the Rio de la Plata River. Along this river, 8.3M of people are settled (20.7% of the Argentinian population) and more than 13,000 industries are located there. Since 2006, Autoridad de Cuenca Matanza Riachuelo (ACUMAR) was created to manage the basin, integrated by both the National and Provincial States and CABA. These entities are sentenced by the national justice; therefore, ACUMAR is under strict monitoring of the National Supreme Court of Justice. Main hydric problems arise from organic and inorganic pollutant being repeatedly discharged and, from the frequent floods. There are four basic types of flood origins: a) swollen tributaries, b) Southeast blow (causes a physical barrier at the river mouth due to the water elevation in Rio de la Plata River), c) extreme rains (pluvial flooding) and, d) rising water table levels. A combination of these effects is considered to be the fifth cause of flooding and may cause a critical situation in the vulnerable urban area. In 2009, ACUMAR established the Urban Drainage Master Plan applying an Integrated Water Resources Management (IWRM) approach in order to achieve sustainability in constructions. The plan aimed to control rising superficial runoff and was funded by the International Bank for Reconstruction and Development (Loan BIRF 7706-AR). Having an original budget of U$S850M it became the biggest amount designated to Latin America's environmental sanitation, constructions, territorial management, industrial streamlining and institutional strengthening of a hydrographic basin. The plan involves many projects, being of the main the construction of 11 reservoirs designed to temporally store water to buffer the floodwaters upstream of the basin. Buffering will cause lower maximum flows and retarded waves downstream where population increases. The construction will be executed next to the courses of the reaches on natural depressions in the rural zone; besides, fill slope of roads will be part of the bank retaining of the reservoirs. Engineering studies in the area are currently being performed. The completion of the project is estimated to be in 2015 and it will require U$S75M as part of the Loan. A national law of water occupation right was created concerning the urban and metropolitan water floods management; this law carries advantages on Public Administration in the economic, juridical, environmental and administrative framework during extreme meteorological events.