You already have a large amount of water flowing in that direction, so when an excess or a surge comes at one time, it will flood along with the water that was already present (i.e., flash flood).
Flooding
Flooding can cause erosion of stream banks, change the stream channel morphology, alter water quality by carrying pollutants, and disrupt aquatic habitats by displacing or killing organisms.
Fluvial flooding is - Produced by the action of a river or stream. Coastal flooding is - An overflowing of water onto land that is normally dry.
fish
flooding
The water from the melting snow can add on to a river or stream and it can over flow, that will cause the flooding.
A bank beside a stream might be called a levee. Some levees are natural and some are man made to prevent flooding in low lying areas.
The floodplain.
It keeps rising water inside stream channels.
Lowlands??Lowland doesn't mean along the stream, but the lowlands are the areas that get flooded more often.
It keeps rising water inside stream channels.
people in Bangladesh make floods worse by building less structured homes and putting rubbish in gutters .