Landslide forecasting in NE

Landslides triggered by heavy and incessant downpours disrupting vital road connectivity in the Northeast region for days together recur every year, causing economic and environmental problems apart from claiming lives and causing injuries. The region’s having an effective system of issuing early warnings on likely landslide events is critical to mitigating the risks. India has 4.3 lakh square kilometres of area prone to landslides, of which 1.8 lakh square kilometres are in the region. The Geological Survey of India (GSI) has been preparing a landslide inventory and landslide susceptibility map under a programme called National Landslide Susceptibility Mapping. The landslide susceptibility map categorises the landmass into three zones: “high,”, “moderate,”, and “low” based on the degree of likelihood of future landslide occurrence in an area under natural conditions. According to information furnished by the Central Government in Parliament in February, the GSI has completed the preparation of the baseline landslide susceptibility map for these three categories. The Central Government requested that the landslide-prone states make use of the map for land use zoning regulations. Using this map in respect of infrastructure projects such as highways, large office building construction, and hydro projects in the region is easier said than done, as alignments of highways or site selection for some of the critical infrastructure projects in the region had been done long ago. Yet, zoning regulations in respect of new construction activities in the areas included in the GSI inventory can be beneficial in minimising damage and preventing loss of assets and lives. The National Disaster Management Authority (NDMA) has approved the Landslide Risk Mitigation Scheme (LRMS) with a financial outlay of Rs. 43.92 crore under Improving Disaster Risk Governance of State Disaster Management Authorities (SDMAs) and District Disaster Management Authorities (DDMAs) in July 2019 to provide financial and technical support to landslide-prone states for site-specific landslide mitigation. It is a pilot scheme to demonstrate the benefits of landslide mitigation measures along with landslide monitoring, awareness generation, capacity building, training, etc. The NDMA has signed a Memorandum of Understanding (MoU) with the SDMAs of Sikkim, Mizoram, Nagaland, and Uttarakhand for the implementation of the scheme, and Rs. 29.60 crore has been released to these states. The 15th Finance Commission recommended an allocation of Rs. 750 crore from the National Disaster Mitigation Fund (NDMF) for seismic and landslide risk reduction in the Himalayan region and for all the states in the Northeast during the next five years. States in the region can reduce landslide risks by undertaking mitigation measures under the scheme and with funds made available by the central government. One of the key lessons learned during the five-year pilot project from 2017 to 2022 on the Landslide Early Warning System for Darjeeling and Nilgiris initiated by the GSI in collaboration with the NDMA and respective SDMAs is that daily landslide bulletins can be an important tool for communicating complex landslide forecasts to decision makers. States in the region requesting GSI undertake a similar early warning project on landslides can be useful in developing a comprehensive system for landslide forecasting. While such early warning or landslide forecast bulletins can help the state government, district, and local authorities identify critical zones, accurate assessment of load bearing capacity before clearance of infrastructure projects involving heavy construction or for the construction of buildings for housing government and private offices, educational institutions, hospitals, and private houses in the hilly region is of paramount importance. Ignoring the risks, overlooking potential landslide hazards, and passing the environmental impact assessment as a mere technical formality can prove costly in landslide-prone zones. Heavy landslides at 53 locations of the Haflong-Silchar railway line last year are grim reminders of how ignoring caution by geologists about landslide risks and recommendations for alternative alignment resulted in the blocking of the railway line for months together. The expert committee headed by Mahesh Chandra Sarma, which predicted way back in 1976 about the Josmath land subsidence that occurred last, cautioned that “the geology of many locations in the Himalayan region is unstable and dynamic, and environment clearance is mandatory before any major construction project is taken up.” How seriously such warnings are taken into consideration by the authorities concerned while clearing projects is the question that needs to be asked again and again. The catastrophic landslide at Tupul railway construction camp in Noney district in Manipur last year, which claimed 61 lives and left 18 injured, gave rise to the question of how comprehensive the environmental impact assessments are or how seriously the recommendations given by experts in such assessment reports are considered during project execution for risk mitigation. Landslide risk mitigation measures must not be allowed to be ignored and left to be tackled as a post-disaster response. Prioritising landslide risk assessments during project planning and clearance will go a long way in mitigating potential hazards in the ecologically fragile northeast region and ensuring the sustainability of infrastructure.