Lok Sabha Question No. 1567 (UNSTARRED), answered on 2024-07-31
Subject: Research on Landslides and Soil Erosions
Ministry: EARTH SCIENCES
Asked by: Shri Kamakhya Prasad Tasa

## GOVERNMENT OF INDIA

## MINISTRY OF EARTH SCIENCES LOK SABHA UNSTARRED QUESTION NO. 1567

## TO BE ANSWERED ON WEDNESDAY, 31 ST  JULY, 2024

## RESEARCH ON LANDSLIDES AND SOIL EROSIONS

## 1567. Shri Kamakhya Prasad Tasa:

Will the Minister of EARTH SCIENCES be pleased to state:

- (a) whether it is a fact that every year landslides and soil erosions are increasing in the northeastern region;
- (b) if so, the details thereof and the action taken by the Government in this regard;
- (c) whether  the  Government  has  conducted  any  study  to  identify  natural  and  traditional methods for reducing landslides and soil erosion in hilly areas particularly in the northeastern region;
- (d) if so, the details thereof and if not, the reasons therefor; and
- (e) the details of the funds allocated for research and development on addressing landslides and soil erosion?

## ANSWER MINISTER OF STATE (INDEPENDENT CHARGE) FOR MINISTRY OF SCIENCE AND TECHNOLOGY AND EARTH SCIENCES (DR. JITENDRA SINGH)

- (a) The  Geological  Survey  of  India  (GSI)  is  mandated  to  conduct  landslide  studies  in  the landslide  prone  areas across  19  States/Union  territories  of  the  country.  However, wherever soil erosion is found to be the cause of the landslide suitable measures as per site requirements are also suggested.

GSI has collected data of 592 nos. of landslides that occurred since April 2017 to July 2024 in different States of North-eastern region (NER), which have impacted lives and/ or  infrastructure.  Analysis  of  these  data  show  a  mixed  trend  with  periodic  ups  and downs in  number  of  occurrences  of  landslides.  To  infer  conclusively  about  the  exact nature  of  trend  of  landslide  incidents,  long-range  (at  least  of  20-years)  landslide occurrence data with exact date of occurrence is required.

The year-wise distribution of such 592 new landslides are given in the table below, which shows  that  in  2019-20,  there  is  less  reported  landslides.  This  clearly  indicates  that occurrence of landslides in the NER is having a mixed trend as per the following data:

| Year    |   Post disaster landslide studies completed |
|---------|---------------------------------------------|
| 2017-18 |                                          28 |
| 2018-19 |                                          49 |
| 2019-20 |                                          45 |
| 2020-21 |                                          65 |
| 2021-22 |                                          78 |
| 2022-23 |                                         102 |
| 2023-24 |                                          29 |
| 2024-25 |                                         196 |
| Total   |                                         592 |

- (b) The steps taken by GSI in the field of landslide management includes data on landslide susceptibility at different scales for regional to site-specific land planning and spreading awareness among communities through Landslide Awareness/Contact programmes and is briefly outlined below:
- i. In  landslide  studies,  major  activities  of  GSI  are  Pre-disaster  studies  (multi-scale landslide  susceptibility  mapping  &  conducting  landslide  awareness  programme); Post-disaster studies (landslide inventory mapping  and  site specific detailed geological mapping, slope stability analysis and landslide monitoring), and Regional landslide forecasting
- ii. GSI launched the National Landslide Susceptibility Mapping (NLSM) Programme since 2014-15 for generating the baseline data on 1: 50,000 scale and completed the landslide susceptibility mapping of 4.3 lakh sq.km of the landslide prone areas in India. The landslide Susceptibility Map classified landslide prone hilly terrains of the country into High, Moderate and Low zones based on proneness to land sliding. Under  this  programme,  GSI  also  mapped  1.85  lakh  sq  km  area  in  Sikkim, Meghalaya,  Assam,  Manipur,  Nagaland,  Mizoram  and  Tripura  with  historical 41,063 nos. of landslides polygons using both remote sensing (RS) and field-based source  data.  The  landslide  susceptibility  maps  and  the  landslide  information  are uploaded  in  OCBIS  portal  (http://bhukosh.gsi.gov.in/Bhukosh/Public)  for  public viewing and downloading.
- iii. For local landslide management, mesoscale (1: 10,000) scale susceptibility mapping of prioritised sectors has been initiated as per the SOP developed by GSI. Work in 39 sectors have already been completed by 2022.
- iv. GSI  as  part  of  the  LANDSLIP  project  (www.landslip.org)  has  developed  an experimental regional Landslide Early Warning System (LEWS) based on rainfall thresholds for two pilot study areas viz. Darjeeling district of West Bengal and the Nilgiris  district  of  Tamil  Nadu.  GSI  has  also  initiated  R  &  D  activities  for developing  regional  landslide  Forecasting  systems  (LEWS)  in  landslide-prone states of NER viz. Sikkim, Assam, Meghalaya, Mizoram, Nagaland where work is under progress.
- (c)  &  (d)  Yes.  GSI  provides  suitable  recommendations for landslide risk  reduction which also includes  both  natural  and  traditional  methods  as  per  the  site  conditions.  However, wherever soil erosion is found to be the cause of the landslide, suitable measures as per  site  requirements  are  also  suggested.  GSI  provides  recommendations  on  both structural/non-structural  and  natural  methods  for  reducing  landslide  hazard  in  the northeast.  The  recommendations  are  based  on  the  knowledge  of  site  condition  as landslides are very site-specific disasters.
- (e) The details of fund allocation and expenditure on various Specialized Investigations including landslide studies in GSI for last 3 years and current year is given below;

| Budget (in lakhs)   |   2021-22 |   2022-23 |   2023-24 |   2024-25 (upto June 2024) |
|---------------------|-----------|-----------|-----------|----------------------------|
| Budget Grant        |    300    |    300    |    330    |                     320    |
| Expenditure         |    292.33 |    291.15 |    315.76 |                     107.72 |

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