The following letter appeared in Science today - my colleague Dr. Elizabeth Anderson and I work on rivers around the world and weighed in with our observations about what is lost (but not widely discussed) when development changes a river system. This is in response to recent discussion in Science about the implications of dam development on internationally shared tropical rivers.
Recent pieces in Science rightly call for greater examination of the environmental, political, and economic trade-offs of tropical dams. In his Feature news story “Power play on the Nile” (26 February, p. 904), E. Stokstad explores political uncertainties of the Grand Ethiopian Renaissance Dam. In their Policy Forum “Balancing hydropower and biodiversity in the Amazon, Congo, and Mekong” (8 January, p. 128), K. O. Winemiller et al. herald the potential detriment to one-third of the world's freshwater fish species by unprecedented hydropower dam construction. In his Letter “Tropical dams: To build or not to build?” (29 January, p.456), P. M. Fearnside asks a fundamental question about current development. Assessments of impacts of dams on riparian human populations typically focus on economic issues related to community displacement, or food security risks from loss of land or fisheries. However, riparian human populations stand to lose much more than land, food, and income.
Free-flowing rivers hold special significance in indigenous cultures. In the Amazon, the Shawi bathe in rivers, gathering strength from water carried down from mountains and ancestors (1, 2). The Peruvian Kukama believe that people who have drowned in rivers and whose bodies aren't found live in underwater cities, communicating with relatives through dreams or shamans (3). The Gumuz people of Ethiopia's Blue Nile Valley—living in the shadow of the Grand Ethiopian Renaissance Dam's construction—have described the river as a second God, providing everything they need for living; most cannot imagine life without the river (4). A legendary water-dwelling creature—Mokele-mbembe, or “one who stops the flow of rivers”—has captivated explorers and locals of the Congo Basin for centuries (5). In the Mekong, many indigenous people believe that ancestral or animal spirits can influence flow and quality of water, and fear of mysterious creatures has prohibited fishing in certain areas (6). Native people of northern Thailand engage in ceremonial practices to show respect and gratefulness to supernatural beings thought to influence water resources (7).
We need better understanding of the implications of tropical dam proliferation for riparian human populations. An assessment of human and water security (8) that includes not only economics, politics, and environment but also culture would more accurately capture the costs and benefits of hydropower development and influence decisions on new tropical dams.