3. Volcano, Floods

Volcano, Floods

2020-11-09 18:24:25

  • Occurs in continental weak zones, only Barren Island

Floods

  • 40mil hectare flood prone
  • Flash floods - very fast rise and recession, small volume and high discharge, occurs in hilly sloping lands, depression/ cyclonic storms causes, sudden release of water, warning using Doppler radars

Natural Causes

  • Heavy rainfall,
  • sediment deposition - river beds shallow,
  • Cyclone - sea waves spreads water in coastal areas,
  • Change in course, Tsunami, Lack of lakes

Anthropogenic Causes

  • Deforestation, interference in drainage system,
  • international dimension, population pressure,
  • poor water and sewerage mgt

Vulnerability

  • 85% rainfall in 3-4 months
  • Brahmaputra basin : monsoon, fragile hills susceptible to erosion, frequent earthquakes, cloud bursts
  • Ganga : mostly done by northern tributaries, RAJ MP experience of heavy floods, encroachment of flood plains
  • NW River Region : inadequate surface drainage causes inundation and water logging, indiscriminate use of water for irrigation - drainage problem water logging, rivers change their course frequently
  • Central and Deccan IN : inundation, destroy valuable crops, infra, millions rendered homeless,

NDMA Guidelines

  • Construct reservoirs, dams, other water storages
  • Build embankments/flood Levees/ Flood Walls
  • Restoring original Drainage system
  • Channel improvement/ desilting/ dredging of rivers
  • Diversion of flood water into naturally/ artificially constructed channel
  • Catchment area treatment

Non Structural Measures

  • Flood plain zoning : regulate land use,
  • flood proofing : providing raised platform for shelter
  • flood management plans,
  • Integrated water resources management
  • Apada Mitra #scheme- train community volunteers in prone districts

Urban Floods

Caused

  • heavy rainfall in short period,
  • urbanisation,
  • low drainage capacity

Impact and Mitigation

  • localised,
  • disruption of water supply, communication etc

Mitigation

  • Pre Monsoon phase : estimation of emergency needs, familiarisation of stakeholders, ID teams to maintain drains and roads
  • During : timely warning, response focuses primarily on emergency relief, mental health support
  • Post : Rehab

NDMA Guidelines

  • Inventory of water supply,
  • catchment as basis of design,
  • Contour data determine boundaries
  • Design flow ot estimate peak flow rates,
  • Removal of Solid waste,
  • Drain inlet connectivity,
  • Rain Gardens
  • ID areas at risk classification of structure, Response, Sanitation, Capacity Dev,
  • Urban flooding cells to coordinate all activities

Existing Challenges

  • Less imp to comprehensive risk assessment,
  • ignorance of mapping different factors,
  • unsatisfactory coordination among diff institutions,
  • lack info sharing
  • disintegrated investment decision
  • lack of consultation w/ stakeholder