Traditional knowledge and environmental flows

Posted on September 22, 2010

The construction of dams for hydropower generation commonly degrades aquatic ecosystems by disrupting river flows, sediment transport and ecological connectivity.    Although such effects can be partly offset by releasing environmental flows below a dam, in many parts of the world environmental water releases are rare due to a lack of information on the ecological, social and economic implications of different flow regimes.  For example, while around 50% of the electricity supply inCentral Americais generated through hydropower, and electricity demand is growing by 5-9% per year, scientific budgets are small and data on the ecology of rivers are scarce.  A recent study on the Patuca River in Honduras, at a site below a proposed hydropower dam, shows that traditional ecological knowledge obtained from local and indigenous riverine communities can play an important role when scientific information in lacking.  Fishers and other community members provided reliable information on aspects such as flow dynamics, river morphology, the biology of aquatic species, and the ecological, social and cultural values of the river and floodplain.  They were also able to indicate accurately how the same features were affected by changing flow rates and water levels.  This traditional knowledge was combined with hydrological modeling and inputs from experts and workshops to specify desirable environmental flows (base flows, flow pulses, floods) for different months and seasons.  The results predicted that releasing environmental flows would have a minimal impact on the potential for electricity generation, which was significantly reduced in only one month in the 348- month simulation.

Reference:  Esselman, P.C. &  Opperman , J.J.  2010.  Overcoming information limitations for the prescription of an environmental flow regime for a Central American river.  Ecology and Society 15(1): 6. [online] URL:

Posted in: hydrology, social