Adolfo Villanueva

The Taim wetland conflict: a compromise between environment conservation and irrigation.

Abstract The Taim federal environmental protection area was created in 1978 to promote conservation of this subtropical wetland, one of the last existing ecosystems of this kind in southern Brazil. However, the protected area does not include lake Mangueira, the Taims main water source, which is surrounded by intensive rice farming. Rice irrigation demands a large proportion of water during the dry season (40,000 m3/year out of 50,000 m3/year inflow to the lake). A severe drought (1989-1991) almost dried the Taim wetland, resulting in legal actions to enforce the conservation status. As a consequence, several studies were undertaken to elucidate the Taims hydrological behavior, and to determine adequate water resources management policies. Results show that the ecosystem cannot withstand the present rate of water extraction. The two problems are: (i) defining a suitable plan to manage water extraction, and (ii) ensuring that the farmers respect it. A plan has been proposed, which includes forecasting the available volume and the complementary use of water from the nearby lake Mirim. The final form of the regulations, and their enforcement procedures, are under discussion with federal law enforcement officers, federal and state environmental and water resources agencies, and farmers.

Flood control measures in União da Vitoria and Porto União: structural vs. non-structural measures

Abstract In recent years Uniao da Vitoria and Porto Uniao have suffered severe floods, after a long period of normal to low floods. The important economic losses and psychological impact generated a great deal of discussion and studies about their causes. The population blamed the backwater effect of the Foz do Areia dam for the impact of the floods. This fact caused a major conflict, that lasted more than ten years, between the population and the state power company, owner and operator of the dam. This paper presents the main flood causes, the dam impact and the structural and non-structural measures studied in order to cope with the problem.