Landslide and Flood Early Warning System

In News 

• Recently, the Council of Scientific And Industrial Research National Geophysical Research Institute (CSIRNGRI) has launched an ‘Environmental Seismology’ group to develop a ‘Landslide and Flood Early Warning System’ for the Himalayan region.

Relevancy

• Its need was necessitated following the flash floods at Chamoli district in February when a steep glacier on the Nandadevi peak in Garhwal Himalaya got detached.
• It caused a major avalanche and inducing flash floods in the Rishi Ganga and Alaknanda rivers in Chamoli (Uttarakhand). It killed several persons downstream and caused damage to two power plants. 

About ‘Landslide and Flood Early Warning System’

• It is based on real-time monitoring with dense seismological networks, coupled with satellite data, numerical modelling and geomorphic analysis.
• This would enable a crucial warning several hours prior, which will save human lives and property.

What are Landslides?

• Landslides are more widespread than any other geological event and can occur anywhere in the world. 
• They occur when large masses of soil, rocks or debris move down a slope due to a natural phenomenon or human activity. 
• Mudslides or debris flows are also a common type of fast-moving landslide.
• Landslides can accompany heavy rains or follow droughts, earthquakes or volcanic eruptions. 

• Areas most vulnerable to landslides include:
  • steep terrain, including areas at the bottom of canyons;
  • land previously burned by wildfires;
  • land that has been modified due to human activity, such as deforestation or construction;
  • channels along a stream or river;
  • any area where surface runoff is directed or land is heavily saturated.

• Which part of India is landslide-prone?
  • The entire Himalayan tract, hills/ mountains in sub-Himalayan terrains of North-east India, Western Ghats, the Nilgiris in Tamil Nadu Konkan areas are landslide-prone.
•  Impact: 
  • Landslides can cause high mortality and injuries from rapidly flowing water and debris. The most common cause of death in a landslide is trauma or suffocation by entrapment.
  • Broken power, water, gas or sewage pipes can also result in injury or illness in the population affected, such as water-borne diseases, electrocution or lacerations from falling debris.
  • People affected by landslides can also have short- and long-term mental health effects due to loss of family, property, livestock or crops.
  • Landslides can also greatly impact the health system and essential services, such as water, electricity or communication lines.
• Steps: 
  • The Geological Survey of India (GSI) has taken initiatives in the field of landslide risk reduction and management through landslide susceptibility mapping in various scales in different parts of the country including the North-Eastern Region (NER) and Sikkim.
  • GSI in its landslide studies included Pre-disaster studies (multi-scale landslide susceptibility/hazard/risk mapping & conducting landslide awareness programme); and Post-disaster studies (landslide inventory mapping and site-specific detailed geological mapping, slope stability analysis and landslide monitoring).

Flood and its Types 

• It is a temporary inundation of large regions as a result of an increase in the reservoir, or of rivers flooding their banks because of heavy rains, high winds, cyclones, storm surge along the coast, tsunami, melting snow or dam bursts.
  • Flash Floods: It is defined as floods that occur within six hours of the beginning of heavy rainfall. In the case of flash floods, warnings for timely evacuation may not always be possible.
  • River Floods: They are caused by precipitation over large catchment’s areas. These floods normally build up slowly or seasonally and may continue for days or weeks as compared to flash floods.
  • Coastal Floods: They are associated with cyclonic activities like Hurricanes, tropical cyclones etc. 
• Steps: 
  •  A Flood Management Programme (FMP) was launched during XI Plan for providing assistance to States for works related to flood management and erosion control.
  • Various training programmes are run by the National Water Academy, Pune which serves the objective of the National Flood Management Institute recommended by NDMA. 
  • Central Water Commission (CWC) has initiated actions for expansion and modernisation of its flood forecasting network. 
    • CWC has provided necessary technical guidance to States for the preparation of Emergency Action Plans (EAPs) by concerned dam owners.
    • CWC had prepared a model bill on Flood Plain Zoning way back in 1975. The legislation has been enacted by three States namely, Manipur, Rajasthan and Uttarakhand.
  • Flood data is being collected in a systematic manner through the hydrological and flood forecasting network of the Central Water Commission. 
  • A Water Resources System (WRIS) has been launched where such digitised data is available.

Source: TH