7. The Gap Between Best Practice and Actual Practice in the Allocation of Environmental Flows in Integrated Water Resources Management

A major component of environmental sustainability in water resource development is the explicit allocation of water to meet ecosystem needs. This environmental water allocation is commonly referred to as an environmental flow, which is the main subject of this chapter. A shift towards more consideration of water needs of ecosystems/environment in Central and South America has been more irregular, with some countries increasingly articulating and prioritizing these needs (e.g., Costa Rica and Colombia) and others not. The situation is similar in Africa, where ambitious new water policies with substantial attention to environmental protection have appeared in Eastern and Southern Africa (McClain et al., Int J Water Resour Dev 29(4):650–665, 2013) and Asia, where China stands out as a globally important country undergoing rapid change in its outlook towards environmental flows (Wang et al., Ecol Appl 21:163–174, 2009). In this chapter, we explore the status of environmental flow science and practice around the world, focusing on the gap that exists between environmental flow levels suggested by aquatic scientists and those actually protected in water regulations. With a wealth of science and different technologies to make use of, some of the most difficult challenges in applying best environmental flow practices lie in the governance processes and equitable allocation among water users and the environment. This brings us back to the promise of IWRM itself as a process to facilitate integration of these factors in a highly participatory fashion. In this chapter, we have endeavored to summarize the promise and highlight the current challenges of environmental flow assessment and implementation to enable the protection of ecosystems in the process of IWRM.