RESUMO
Droughts are causing severe damages to tropical countries worldwide. Although water abundant, their resilience to water shortages during dry periods is often low. As there is little knowledge about tropical drought characteristics, reliable methodologies to evaluate drought risk in data scarce tropical regions are needed. We combined drought hazard and vulnerability related data to assess drought risk in four rural tropical study regions, the Muriaé basin, Southeast Brazil, the Tempisque-Bebedero basin in Costa Rica, the upper part of the Magdalena basin, Colombia and the Srepok, shared by Cambodia and Vietnam. Drought hazard was analyzed using the variables daily river discharge, precipitation and vegetation condition. Drought vulnerability was assessed based on regionally available socioeconomic data. Besides illustrating the relative severity of each indicator value, we developed drought risk maps combining hazard and vulnerability for each grid-cell. While for the Muriaé, our results identified the downstream area as being exposed to severe drought risk, the Tempisque showed highest risk along the major streams and related irrigation systems. Risk hotspots in the Upper Magdalena were found in the central valley and the dryer Southeast and in the Srepok in the agricultural areas of Vietnam and downstream Cambodia. Local scientists and stakeholders have validated our results and we believe that our drought risk assessment methodology for data scarce and rural tropical regions offers a holistic, science based and innovative framework to generate relevant drought related information. Being applied to other tropical catchments, the approaches described in this article will enable the selection of data sets, indices and their classification - depending on basin size, spatial resolution and seasonality. At its current stage, the outcomes of this study provide relevant information for regional planners and water managers dealing with the control of future drought disasters in tropical regions.
Assuntos
Acesso à Informação , Secas , Agricultura , Rios , ÁguaRESUMO
RESUMO A Bacia Hidrográfica Lagos São João (BHLSJ), no Estado do Rio de Janeiro, é reconhecidamente de grande importância para a conservação de recursos naturais e hídricos. No entanto, apesar dos constantes esforços de conservação e recuperação dos ecossistemas aquáticos, as ameaças e os desafios de gestão são diversos. A gestão dos recursos hídricos em bacias hidrográficas requer processos de tomada de decisão assertivos, para garantir a conservação das águas (em quantidade e qualidade) e os seus múltiplos usos. Para maior efetividade, esses processos demandam análise integrada de um grande número de variáveis que, em conjunto, podem gerar diferentes alternativas de gestão e cenários, facilitando, assim, a tomada de decisão. Nesse sentido, ferramentas de análise que possam identificar, quantificar e espacializar as ameaças efetivas à integridade ecológica dos ecossistemas aquáticos em bacias hidrográficas tornam-se relevantes. O presente artigo teve por objetivo apresentar o desenvolvimento e os resultados do diagnóstico da BHLSJ, gerado por meio de um protocolo baseado no risco à integridade ecológica. Como resultado da aplicação dessa metodologia, pode-se concluir que a BHLSJ se encontra em situação de moderado a alto risco ecológico - sendo ameaçada, principalmente, por fatores como a retificação dos rios e as pastagens degradadas - e necessita de ações urgentes de recuperação, com foco nas unidades hidrológicas mais ameaçadas.
ABSTRACT Lagos São João River Basin, located in Rio de Janeiro state, Brazil, is known of great importance for the conservation of natural and water resources. However, despite constant efforts to conserve and restore the aquatic ecosystems, many are the threats and management challenges. The water resources management in river basins requires assertive decision-making processes to ensure the conservation of water quantity and quality and its multiple uses. Aiming to be more effective, these processes require an integrated analysis of a large number of variables, which together can lead to different management alternatives and scenarios, thereby facilitating decision-making. In this sense, analytical tools that can identify, quantify and spacialize the current threats to the ecological integrity of aquatic ecosystems become relevant. This article aimed to present the development and results of the diagnosis of Lagos São João River Basin, generated through a risk-based protocol to ecological integrity. As a result of the application of this methodology, it can be concluded that Lagos São João River Basin is in a situation of moderate to high ecological risk, being threaten by river engineering and degraded grassland, demanding urgent restoration actions, focusing on the most endangered hydrologic units.
RESUMO
Este artigo visou registrar o processo de implementação da cobrança pelo uso da água no território fluminense, iniciada em 2003 pela experiência pioneira de arrecadação pelo uso em rios federais da Bacia do Rio Paraíba do Sul. No ano seguinte, a cobrança foi ampliada para todas as águas estaduais (superficiais e subterrâneas), configurando-se em experiência singular no país por iniciá-la sistematicamente em todo o seu território. A despeito das polêmicas e tensões suscitadas inicialmente, o Estado avançou sobremaneira na estruturação do modelo de gestão baseado no tripé comitê-agência-cobrança. Os maiores desafios hoje se concentram em assegurar dois aspectos essenciais para a gestão dos recursos hídricos: (i) conferir agilidade/flexibilidade na aplicação dos recursos arrecadados e (ii) induzir maior racionalidade ao uso da água por parte dos serviços de abastecimento público em regiões caracterizadas por escassez crônica.
This article aimed to record the process of implementation of the charging system for water use in the territory of Rio de Janeiro State, since the pioneering experience of charging use in federal rivers (ANA-CEIVAP). In the following year, charging in Rio de Janeiro state waters configured a singular experience in the country, especially because it started simultaneously throughout the state. In spite of the claims initially directed to the implantation of the pricing process, in the last years the State has greatly improved in structuring a management model based on the committee-agency-collection tripod. The major challenges today are focused on two key aspects for the management of water resources: (i) to give agility/flexibility in the application of collected funds and (ii) to induce more rational water by public water services use in regions characterized by chronic shortages.
