zoning of flood plains – The Core IAS

zoning of flood plains

Context:

  • Most people in villages farm under flood in the highly fertile but sensitive flood plains, and concrete encroachments in these areas have, in many cases, exacerbated the devastation caused by flooding. This is where zoning comes in.

Flood plains:

  • A river expands and contracts naturally over seasons and in different years. A flood plain is an area adjacent to the river which normally gets flooded when the river swells.
  • Well maintained flood plains, free from wanton construction and concrete, are natural defences against flooding farther inland. They are also useful for recharging groundwater levels and maintaining the water table.

Importance:

  • Identifying flood plains is thus crucial. Experts do this based on topographical features around rivers. For instance, flood plains often contain oxbow lakes – basically abandoned meandering channels of the river, where it once flowed prior to changing its course.
  • Zoning involves demarcating areas around rivers likely to be affected by floods of different magnitudes and frequencies, in order to specify the types of permissible developments there. This is done so that whenever floods do actually occur, the damage is minimal.
  • As per guidelines on floodplain zoning by the National Disaster Management Authority, defence installations, industries, and public utilities like hospitals, electricity installations, water supply, telephone exchanges, aerodromes, railway stations, commercial centres, etc. should be located such that they are above the levels corresponding to a 100-year frequency or the maximum observed flood levels.

Lack of zoning affect both people and the floodplains:

  • Encroachment and mismanagement of flood plains leading to non-suitable construction activity and concretization of flood plains.
  • This poses risks to both peple and property, and the health of the flood plains themselves. On one hand, non-suitable constructions play a part in pushing floods further inland, increasing the area harmed and damage caused during floods. Concretisation also leads to it taking far longer for floods to subside as the water simply does not drain.
  • On the other hand, this kind of flooding is not good for flood plains themselves, affecting the fertility and quality of the soil as well.

Countrywide problem:

  • In fact, despite the Centre’s directions, so far only four states – Manipur, the erstwhile Jammu & Kashmir, Rajasthan and Uttarakhand – have adopted the act in papers. However, the implementation of the plans has been underwhelming in these states with no delineation and demarcation of flood plains undertaken even by them.