Environmental Engineering Reference
In-Depth Information
Figure 6.11.
The Merowe Dam on the Nile in Dar al-Manasir, Nubia, Northern Sudan.
Hydroelectric power stations submerge large areas of land because of the requirements of
a reservoir. This has major impacts on ecosystems and human communities.
Source:
Lubumbashi at Wikimedia Commons.
In the past, hydropower fostered economic and social development in many countries
by providing both energy and water management services. However, whereas run-of-river
hydro does not significantly alter a river's flow regime, the creation of a reservoir for
storage hydropower entails a major environmental change by transforming a fast-running
fluvial ecosystem into a still-standing lacustrine one. Through the building of dikes and
weirs, hydroelectric structures affect the river's ecology by changing its hydrologic
characteristics, and by disrupting the ecological continuity of sediment transport and fish
migration. Salmon hatch upstream in a freshwater environment and spend their adult lives
at sea. Eel do it the other way around. Dams disrupt the life cycle of both. Nor is such
disruption limited to a few species of fish. The construction of the Aswan Dam caused
the extinction of the populations of the Nile crocodile downstream and today the papyrus
artworks sold to tourists are based on cultivated plantations because the Egyptian wild
papyrus has almost disappeared.
