Objetivo
Water systems are facing ageing infrastructure and increasing competing demands for water and energy. Yet, systems operation is still often based on rigid, outdated rules without clear indication of objectives. Given future water availability uncertainty under climate change, the only way forward capable of meeting current and future society demands for water, energy and food is to find adaptation solutions to restore and protect ecosystem services.
The definition of adaptation strategies capable of reconciling water and energy demands with environmental demands and ecosystem services is thus a global change issue both in Brazil and abroad. While such adaptation strategies span across a broad scope of areas and disciplines, system operation is a particularly important one given it will allow better use of infrastructure already in place.
While identifying improved operational solutions for reservoirs and water systems is not a new problem, converting important and complex ecosystem services into relevant operating objectives, as well as identifying plausible institutional settings that will allow deployment of these solutions in the real world under present and future changing conditions is a completely different, and challenging task. The current project goes beyond water system modeling and proposes an innovative framework to identify adaptation pathways to restoration of ecosystem services. The scientific contribution of this proposal lies in three main elements:
The first is the identification of the ecosystem (floodplain) services related to the flood regime, detailing which are the main components leading to these services and how they are related with the control promoted by several dams upstream. The impacts of water infrastructure in the natural systems are relatively well-known, including impoundment of free-flowing river habitat, blockage of fish migration, reduced water quality in reservoirs and downstream river reaches (Acreman and Dunbar, 2004), interruption of flooding regimes and geomorphological processes that maintain aquatic habitat diversity downstream, which are required to sustain healthy riverine ecosystems (Jager and Smith, 2007). However, less known are the ecosystem services affected by those impacts, which are often associated with slack-water habitats and riparian vegetation trap silt and nutrients, provision of fertile soils, and protection of the upland areas from flooding and erosion. While there are methods for quantifying the components of the flow important to ecosystem functioning (Poffet al, 1997), the current project will contribute to quantifying the processes and feedback mechanisms between flow, structure and ecology (Vileset al,. 200820, Hannah et al,. 2007 and Petts et al,. 2006), and to finding the linkages between those and the ecosystem goods and services relevant to the local population.
Second, the presence of several competing objectives for water, energy and food in a watershed poses a challenge to the development of basin-wide, multiobjective, operational strategies (Tilmant and Goor, 2009). The incorporation of ecosystem services as another key objective further complicates the decision-making process by increasing the number of alternative operational policies. Finally, reservoir operators also face various uncertainties including future hydrologic conditions (Barossoet al., 2002; Tilmantet al., 2007), future energy prices (Wallace and Fleten, 2003), climate change (Augustin et al. 2008) and reduced future storage relative to water and energy demands. The current project will contribute to the identification of operational system solutions that not only incorporate the water demands for ecosystem services, but that is also efficient in terms of water allocation for energy production and water supply in a large-scale, multi-reservoir system under hydrologic uncertainty.
Finally, while technical operating solutions may appear promising in the paper, the perception of the users on how fair it will allocate the water and the presence of mechanisms and institutional settings to ensure fairness (e.g. economic compensation, payment for environmental services and water charges) are critical to its acceptance and implementation. The current project will contribute by calculating the resulting tradeoffs from meeting ecosystem demands, developing different mechanisms to share this tradeoff among water users and proposing water management instruments capable ofdelivering the solutions to the field.
