What is the result of a raised base level on stream gradient and velocity?

A raised base level in a river or stream system results in a decreased gradient, which in turn leads to reduced velocity and increased opportunities for sediment deposition. When the base level rises, the energy gradient of the stream is diminished because the slope of the riverbed becomes less steep. This lower gradient means that the water flows more slowly.

As the velocity of the stream decreases, it loses the capacity to carry sediments. When the energy of the water is insufficient to transport its load, sediment begins to settle out and accumulate on the streambed, contributing to deposition. Therefore, the correct interpretation of the effects of a raised base level on stream dynamics is that it leads to a decrease in gradient, reduced flow velocity, and an increase in sediment deposition.