Final answer:
A significant drawback of damming an area for hydroelectricity is the displacement of humans and disruption of communities, in addition to various environmental impacts like habitat loss, blockage of fish migrations, and alteration of river ecosystems.
Step-by-step explanation:
The drawbacks of damming an area for the purpose of generating hydroelectricity for a community include a range of environmental and social impacts. One significant drawback is the displacement of humans from their homes that would be flooded as a result of dam construction.
This leads to loss of community, culture, and traditional livelihoods. Environmental consequences are also critical drawbacks, encompassing the loss of natural wildlife habitats, increased acidity in water causing erosion to hydroelectric turbines, the blockage of fish migration routes, especially for species such as salmon, and ecological impacts due to the alteration of water flow, chemistry, and sediment loads in river ecosystems. Furthermore, reservoirs can also collect silt over time, which may displace water storage capacity and eventually render the dams useless or even hazardous.