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Effects of Silt on Ecosystems Behind Hydroelectric Dams

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How does deposited silt in a reservoir affect the ecosystem?

A

Silt contains nutrients that become trapped behind a reservoir. The silt absorbs sunlight, warming the water and decreasing dissolved oxygen. Ecosystems downstream are starved of nutrients while the reservoir supports large algal blooms.

B

Silt creates habitats behind the reservoir for breeding fish. This can deplete oxygen supplies.

C

Deposited silt behind a reservoir can clog pipes and reduce visibility for divers.

D

A lack of deposited silt is actually one of the major problems with dams. Reservoirs behind dams have little substrate for fish and aquatic insects.

E

Silt can create small islands behind the reservoir. These can encourage a more biodiverse ecosystem upstream from dams.