There are many areas that should be avoided when building a dam:
These factors could result in compensation claims for the land lost to dams.
People would need to be rehoused and businesses relocated. It is easier to build these projects in areas of low population density.
Some dams have created large reservoirs, which have flooded traditional Native American sacred burial sites and archaeological sites of importance. Governments want to avoid these areas for political reasons and also to prevent costly lawsuits.
Reservoirs should be built close to the areas where their waters will be used, so as to prevent water loss and to make the projects as economic as possible.
Any hydroelectric power generated should be for local use, if possible, to reduce the costs of transporting it.