Implementing environmental flows in integrated water resources management and the ecosystem approach

Abstract

In many of the world's river basins, the water resources are over-allocated and/or highly modified, access to good quality water is limited or competitive and aquatic ecosystems are degraded. The decline in aquatic ecosystems can impact on human well-being by reducing the ecosystem services provided by healthy rivers, wetlands and floodplains. Basin water resources management requires the determination of water allocation among competing stakeholders including the environment, social needs and economic development. Traditionally, this determination occurred on a volumetric basis to meet basin productivity goals. However, it is difficult to address environmental goals in such a framework, because environmental condition is rarely considered in productivity goals, and short-term variations in river flow may be the most important driver of aquatic ecosystem health. Manipulation of flows to achieve desired outcomes for public supply, food and energy has been implemented for many years. More recently, manipulating flows to achieve ecological outcomes has been proposed. However, the complexity of determining the required flow regimes and the interdependencies between stakeholder outcomes has restricted the implementation of environmental flows as a core component of Integrated Water Resources Management (IWRM). We demonstrate through case studies of the Rhône and Thames river basins in Europe, the Colorado River basin in North America and the Murray-Darling basin in Australia the limitations of traditional environmental flow strategies in integrated water resources management. An alternative ecosystem approach can provide a framework for implementation of environmental flows in basin water resources management, as demonstrated by management of the Pangani River basin in Africa. An ecosystem approach in IWRM leads to management for agreed triple-bottom-line outcomes, rather than productivity or ecological outcomes alone. We recommend that environmental flow management should take on the principles of an ecosystem approach and form an integral part of IWRM.Key words IWRM; ecosystem approach; environmental flows; implementation Approche écosystémique et mise en oeuvre de débits environnementaux dans la gestion intégrée des ressources en eau Résumé Dans de nombreux bassins du monde les ressources en eau sont surexploitées et / ou profondément modifiées, l'accès à une eau de bonne qualité est limité ou concurrentiel, et les écosystèmes aquatiques sont dégradés. Le déclin des écosystèmes aquatiques peut avoir un impact sur le bien-être humain en réduisant les services fournis par des rivières, des zones humides et des plaines d'inondation saines . La gestion des ressources en eau d'un bassin nécessite de répartir l'eau entre des acteurs concurrents, dont notamment l'environnement, des besoins sociaux et le développement économique. Traditionnellement, cette répartition a été pratiquée sur une base volumétrique pour atteindre des objectifs de productivité sur le bassin. Il est cependant difficile de répondre à des o...

Advancing Environmental Flow Science: Developing Frameworks for Altered Landscapes and Integrating Efforts Across Disciplines

“…In addition, strategies to increase freshwater inflow rates to coastal ecosystems must accommodate human needs to gain political support (Montagna et al 2002). Researchers have proposed flexible broad-scale environmental flow plans that can be implemented in a manner that will meet ecological objectives while avoiding economic loss and land-use conflicts (e.g., Overton et al 2014;Pang et al 2014;Yang and Yang 2014), including plans catered to coastal habitats. For example, Sun et al (2015) proposed an environmental flow framework that examines spatial and temporal patterns of inland streamflow on estuarine habitats while considering human land-use requirements.…”

The changing role of ecohydrological science in guiding environmental flows

“…the Yangtze River, China, and the River Thames, UK). These managed systems are essential to the contemporary economies, and a return to a natural flow regime is not economically feasible (Overton et al 2014). Under the WFD, such river reaches are declared heavily modified water bodies and have an objective of reaching GEP.…”

“…Transboundary issues may also occur between states within a federation. For example, in Australia, the Murray-Darling Basin Ministerial Council (MDBMC), which oversees the Basin Authority, includes ministers from each of the basin states (Queensland, New South Wales, Victoria and South Australia) and the Australian Capital Territory (Overton et al 2014). Engagement and partnerships between the Basin Authority and state jurisdictions is seen as essential for managing the basin (Banks and Docker 2014).…”

“…Conceptual frameworks are important for high-level management of ideas and scientific findings. Environmental flows can sit within many possible frameworks, such as IWRM, environmental impact assessment (EIA), ecological benefits of flood (Ecoflood) or the ecosystem approach (Overton et al 2014). More work is required to develop links with appropriate frameworks and to assess their utility for managing, communicating and delivering environmental flow science.…”

“…Irrespective of the complexity of scientifically-based environmental flow methods, they must be integrated into basin water management plans (Overton et al 2014) and encompass legal issues and governance aspects. Banks and Docker (2014) reported that institutional arrangements for flow releases from dams in the Murray-Darling Basin, Australia, are organized for irrigation and it is difficult to respond to environmental flow needs.…”