Rashtriya Barh Ayog

Geography glossary

Also called: National Flood Commission · Topic: Natural Hazards and Disaster Management in India · NCERT: Class 11, Ch 6 "Natural Hazards and Disasters: Causes, Consequences and Management"

Meaning

Rashtriya Barh Ayog (RBA, National Flood Commission) was set up in 1976. It was the first national body to study India's flood problem for the whole country. Its 1980 report estimated 40 million hectares (mha) of India as liable to floods [3].

It matters because its 40 mha figure is the standard measure of India's flood-prone area. NCERT uses it, and it is still the starting point for flood planning and exam questions.

Explanation

Why a national commission was needed

  • Floods in India are regional, not local.
  • They hit large river basins, such as the Ganga and the Brahmaputra, not single points the way an earthquake does.

  • One river can cross many states, so no single state can see the whole problem.

  • Floods are seasonal and their causes are well known.

  • Most floods build up over days during the monsoon (June-September).
  • Because the causes are understood, they can be studied and planned for at the national level. The RBA was set up to do this.

What the RBA found

  • Flood-prone area: 40 mha (1980 report) [3].
  • A flood-prone area is land that is likely to go under water when runoff (rainwater flowing over the ground into streams) is more than a river channel can carry.

  • The extra water spills onto the floodplain (the low, flat land beside a river).

  • Main causes it looks at:

  • Natural causes: long, heavy rain; Himalayan snowmelt; cyclone storm surge (seawater pushed onto the coast by cyclone winds); low infiltration (little water soaking into the ground); silt settling on riverbeds.
  • Human causes: deforestation; unscientific farming; roads, railway embankments and canals blocking the natural flow of water; homes and farms built on floodplains and riverbeds.

How silt makes the flood-prone area grow

  • Hill slopes are cleared:
  • Soil erodes and is washed into rivers.
  • The silt settles on the riverbed downstream, so the bed rises.

  • The river holds less water and spills over sooner, even after normal rain.

  • The result shows in the numbers:

  • RBA, 1980: 40 mha flood-prone [3].
  • The Working Group on Flood Management and Region Specific Issues (2011) put the largest area ever affected by floods at 49.815 mha [3].

Flood control tools linked to its work

  • Structural measures (physical works): embankments (raised earth walls along a river) and dams (they store floodwater and release it slowly).
  • Catchment measures (in the upper area that feeds the river): afforestation (planting trees) and limits on building.
  • Floodplain measures: removing encroachments (illegal buildings), moving people to safer ground, and floodplain zoning (dividing the floodplain into zones by how often each zone floods, and fixing what may be built in each zone).
  • Non-structural measures: flood forecasting, flood insurance and the "room for the river" approach.

Where it occurs

  • Scope: all of India. It was a national commission set up by the Government of India in 1976, and it reported in 1980 [3].
  • Most flood-prone zone: Assam, West Bengal, Bihar and eastern Uttar Pradesh.
  • Floods here are riverine and long-lasting. The Brahmaputra and the Ganga's northern tributaries carry huge flows and heavy silt across flat plains.

  • Examples: the Brahmaputra in Assam (yearly floods and bank erosion, which is the river eating away its banks) and the Kosi, the "sorrow of Bihar".

  • Occasional floods: the northern rivers of Punjab and Uttar Pradesh, in years of heavy monsoon rain.

  • Flash floods, now more common: Rajasthan, Gujarat, Haryana, Punjab. Dry ground cannot absorb sudden heavy rain, and drainage channels are blocked.
  • Winter floods: Tamil Nadu (Coromandel coast), from November-January, caused by the retreating (northeast) monsoon.
  • States named as especially vulnerable (NCERT Class 7): Uttar Pradesh, Bihar, Kerala, Andhra Pradesh and Assam.
  • World pattern: floods are worst in South, Southeast and East Asia, especially China, India and Bangladesh.

Don't confuse with

  • Working Group on Flood Management and Region Specific Issues (2011): the RBA (1980) gave the flood-prone area (40 mha). The 2011 Working Group gave the maximum area ever affected (49.815 mha) [3].
  • Model Floodplain Zoning Bill (1975): the Union Government sent it to all states in 1975, before the RBA was even set up (1976) [4]. It is a draft law, not a commission.
  • Central Water Commission (CWC): a permanent agency. It is the nodal organisation (lead agency) for flood forecasting and runs 332 stations [2]. The RBA was a commission set up to study the flood problem.
  • NDMA flood guidelines: Management of Floods (2008) and Urban Flooding (2010) come from the National Disaster Management Authority, not from the RBA.

Prelims Hooks

  • Rashtriya Barh Ayog = National Flood Commission. It was set up in 1976 and reported in 1980.
  • RBA (1980) flood-prone area = 40 mha. Working Group (2011) maximum area ever flooded = 49.815 mha [3].
  • Order: Model Floodplain Zoning Bill (1975) → RBA set up (1976) → RBA report (1980) → Working Group (2011).
  • Floodplain zoning law has been passed only by Manipur, Rajasthan, Uttarakhand and the former J&K [4]. Trap: Assam and Bihar, the most flood-prone states, have not passed it.
  • The nodal agency for flood forecasting is the CWC, not the IMD and not the RBA. It runs 332 stations (199 river-level + 133 dam/barrage inflow) [2].
  • Most flood-prone states (NCERT Figure 6.6): Assam, West Bengal, Bihar. Tamil Nadu floods in winter (November-January).

Mains Points

  • Flood risk is growing, mostly because of people (GS-III, Disaster Management):
  • The flood-prone area was 40 mha (RBA, 1980), and the maximum area ever flooded reached 49.815 mha (2011) [3].

  • Deforestation, silted riverbeds, homes built on floodplains and blocked drainage turn normal monsoon peaks into disasters.

  • Too much reliance on embankments, too little floodplain management:

  • Embankments trap silt, so the riverbed rises above the land around it. When the wall breaks, the damage is worse (Kosi, Kusaha breach, 2008, in Nepal).
  • Since 1975, only four states have passed a floodplain zoning law [4].

  • India needs non-structural tools: zoning, CWC's 5-day advance flood advisories [2], flood insurance and "room for the river".

  • Planning by river basin: the RBA looked at floods across the whole country, not state by state. Basin-wide forecasting by CWC across 20 major river basins [2] and inter-state coordination of dam releases continue that approach.

Related concepts

Read more

Sources

  1. 1Class 11, Ch 6 "Natural Hazards and Disasters: Causes, Consequences and Management" (primary)
  2. 2CWC, Flood Forecasting / Hydrological Observationcwc.gov.in · tier 1
  3. 3PIB, "Flood Affected Area"pib.gov.in · tier 1
  4. 4PIB, "National Floodplains Zoning Policy"pib.gov.in · tier 1