Question

These has been an increase in number of flash floods and also the duration of floods because of_____ *

2 points​

Answer 1

Densely populated areas are at a high risk for flash floods. The construction of buildings, highways, driveways, and parking lots increases runoff by reducing the amount of rain absorbed by the ground. This runoff increases the flash flood potential.

Answer 2

The reasons for the increase in the number of flash floods and also the duration of floods are:

• Flash floods are short-duration, extremely localized phenomena with a very high peak, with fewer than six hours from the onset of the rainfall and the peak flood.
• Poor drainage system: When drainage systems are clogged or encroachments block the natural flow of water, the flood scenario intensifies.
• Urban areas: Because of their hard surfaces, urban areas are more likely to encounter "surface water" flooding.
• Construction of Dams: Dams are constructed to keep water that has been raised in order to create electricity (hydroelectric power) and to lessen the risk of flooding. On the contrary, because of faulty construction, can sometimes lead to collapse and causes flooding.
• Urbanization, land subsidence (ground sinking), and climate change have raised the likelihood of catastrophic flooding.