GEOLOGY

Detailed explanation-1: -A flood occurs when a stream’s discharge becomes so great that it exceeds the capacity of the channel, therefore causing the stream to overflow its banks. Geologists view floods as normal and expected events. 100 year flood occurs on average about every 100 years.

Detailed explanation-2: -Flood-occurs when the discharge of a stream becomes so great that it exceeds the capacity of its channel and overflows its banks. Flood Control-includes artificial levees, flood control dams, and placing limits on floodplain development.

Detailed explanation-3: -When the discharge of a river increases, the channel may become completely full. Any discharge above this level will result in the river overflowing its banks and causing a flood. The stage at which the river will overflow its banks is called bankfull stage or flood stage.

Detailed explanation-4: -In a natural situation, an increase in discharge (cubic feet/second) will result in an increase in all three parameters-the river becomes wider, deeper and flows at a higher velocity. When a stream channel can no longer accommodate increased discharge it overflows its banks and a flood occurs.

Detailed explanation-5: -Discharge increases at the same time when gradient decreases when we observe the distance from a stream’s headwaters to its mouth. If we want to determine the reason why discharge increases we could observe it and see that the principle channel is richer in tributaries as it goes downstream.