Tide-Rainfall flood quotient

Tide–Rainfall flood quotient

Subject: Science and Technology

Context: The Indian Institute of Technology Bombay team devised a new metric to understand if a coastal city is more prone to floods caused by tidal events or extreme rainfall.

Concept:

• It formulates metrics based on the rainfall data, tidal data, and topography of the region.
• It was based on study of data from flood-prone coastal regions – Mithi riverCatchment in Mumbai, Jagatsinghpur District in Odisha, and Greater Chennai Corporation in Tamil Nadu.
• It helped classify these regions into ‘storm tide dominated’ or ‘pluvial (rainfall) dominated’ regions.

1. Mithi catchment: Storm tide dominated flood
2. Jagatsinghpur: “Pluvial dominate” as High rainfall inundated several areas in the central region and the flatness of the terrain prevented easy drainage of the floodwater into the Bay of Bengal
3. Chennai: “Pluvial dominated” as Rainfall was cause in Northern and central region and storm tide as cause in eastern coastal region

Significance of metric:

• Better flood risk management system in long term planning for disaster preparedness. Ex- 1) Storm-dominated Mithi catchment can see plan for as closure dams, tide breakers, and storm surge barriers at appropriate locations. 2) “Pluvial dominated” region can see structural measures such as rainwater storage structures, lakes, and detention basins should be prioritised in the flood management plans