What would be a result of building a dam in the transition zone of a river? 

A)  increased amount of sediment reaching the floodplain zone 
B)  decreased amount of water in the watershed 
C)  decreased water flow downstream 
D)  increased amount of water in the source zone

Transition Zone

An area or region where there is a shift from one geographical feature, climate type, or ecological condition to another.

Watershed

A geographical area where all water running off the land drains into a shared body of water, such as a river, lake, or ocean.

Floodplain Zone

An area of land adjacent to a stream or river which stretches from the banks of its channel to the base of the enclosing valley walls and experiences flooding during periods of high discharge.