Get The Absorbent City: Urban Form And Flood Risk Management

The adverse effects of flooding include: Loss of human life. Property and infrastructure damage. Road closures, erosion, and landslide risks.

Flood hazard means a potential danger to life, property or natural resources due to storm water runoff or inundation, including deposition of slit and debris, erosion, or the presence of standing water.

Impacts of urban flooding It disrupts the normal working of the city by damaging water supply, sewerage, power transmission lines, communication, transportation, and infrastructure. The environment is further damaged as the vegetation gets washed away during the extreme flow of water.

The most common is when rivers or streams overflow their banks. These floods are called riverine floods. Heavy rain, a broken dam or levee, rapid icemelt in the mountains, or even a beaver dam in a vulnerable spot can overwhelm a river and send it spreading over nearby land.

Some of the most significant events of urban flooding include Mumbai Floods of 2005, Kolkata in 2007, Delhi in 2009, Bangalore in 2015 and the Hyderabad floods of 2020.

Flood: An overflow of water onto normally dry land. The inundation of a normally dry area caused by rising water in an existing waterway, such as a river, stream, or drainage ditch.

Urban flooding is significantly different from rural flooding as urbanization leads to developed catchments, which increases the flood peaks from 1.8 to 8 times and flood volumes by up to 6 times. Consequently, flooding occurs very quickly due to faster flow times (in a matter of minutes).

Causes of flash flooding include heavy rain, ice or debris jams, and levee or dam failure. These floods exhibit a rapid rise of water over low-lying areas. In some cases, flooding may even occur well away from where heavy rain initially fell.