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Environmental flows to support sustainable development in East Africa

Congress: 2008
Author(s): Musonda Mumba**, Elizabeth Anderson*, Julius Sarmett***, and Joseph Muthike****
*USAID Global Water for Sustainability Program and Department of Environmental Studies, Florida International University, Miami, Florida USA **WWF Eastern Africa Regional Programme Office, Nairobi, Kenya ***Ministry of Water, Wami-Ruvu Basin Water O

Keyword(s): environmental flows, iwrm, sustainable development, kenya, tanzania
AbstractFreshwater ecosystems provide important services that support sustainable development, including clean water supply and food production (provisioning services), waste assimilation (regulating services), and flood control (supporting services). However, the ability of freshwater ecosystems to provide these services depends on sufficient flows of unpolluted water to maintain ecosystem function. Over-extraction, over- regulation, and unchecked contamination lead to ecosystem degradation and the loss of essential services to human communities. Freshwater ecosystems are disproportionately affected by human activities when compared with terrestrial ecosystems and the statistics are alarming: the flow of nearly 60% of large rivers worldwide has been altered by dams; more than 50% of wetland area in North America and Europe has been lost; and the percentage of freshwater fauna considered imperiled is significantly larger than that of terrestrial fauna. As human demands for water intensify, especially in previously undeveloped areas, creative, adaptive approaches are needed for balancing the water needs of humans with those of freshwater ecosystems. Environmental flow assessment (EFA) is a tool for identifying the line between the quantity and quality of water needed to maintain ecosystem health and the amount of water available to humans. The EFA concept has evolved over several decades and presently more than 200 methods exist for estimating environmental flows. These methods have helped to increase awareness among water managers for the need to maintain a certain amount of flow to safeguard aquatic ecosystems. But, identifying which methods are most appropriate in different environmental, economic, social, and political scenarios remains a challenge. In addition, the transition from recommendations to implementation phases of an EFA has also proven difficult. Here we synthesize the lessons learned from two ongoing EFA initiatives in East Africa. In the transboundary Mara River Basin (Kenya/Tanzania), an EFA team of scientists and water resource managers has applied the widely-used Building Block Methodology to identify the flows and quality of water necessary to sustain a desirable level of aquatic ecosystem function. In addition to meeting basic human needs along the river system, this assessment has also focused on flows necessary to maintain the vast herds of migrating animals in Masai-Mara National Reserve (Kenya) and Serengeti National Park (Tanzania). These two jewels of nature are the single most important sources of wildlife-based tourism income to both countries. In the Wami River Basin (Tanzania), a multidisciplinary team of scientists, led by the basin water office, is using an exploratory approach to EFA which draws upon at least three established EFA methods. The Wami flows through Saadani National Park, the closest national park to the City of Dar es Salaam. The Wami and its neighboring river the Ruvu is also an important water source to Dar es Salaam. Together these case studies reveal important lessons about different approaches that can be taken to identify and protect environmental flows that contribute directly to sustainable development.
2011 IWRA - International Water Resources Association - - Admin