A multiple natural hazard analysis, SECMOL College region, near Leh, Ladakh, North India, with applications for community-based DRR
Authors: Petterson Michael , Wangchuk Sonam , Konchok Norgay 
Published: March 2020

Purpose

This paper places a college at the centreof a multi-hazard assessment (earthquake, flood and landslide). The college is within a less studied, rural area of Ladakh, North India. Research focusses on a case study (Students Educational and Cultural Movement of Ladakh (SECMOL) College), close to Leh, Ladakh, and extends to incorporate/apply thinking from/to the wider Ladakh region. The approach adopted, centring on the hazard assessment of a single entity/local area, allows a rapid uptake of hazard recommendations within a college environment planning to continue its existence for decades ahead. A sister paper (Pettersonet al., 2019) documents the active involvement of college staff and students in the principles of geohazard assessment and the development of student-centric hazard assessments of the college and their home village. SECMOL is a self-sufficient, alternative, college, organised along strong environmentally sustainable principles. The paper aims to discuss these issues.

Design/methodology/approach

This work has adopted different strategies for different hazards. Fieldwork involved the collection of quantitative and qualitative data (e.g. shape and size of valleys/river channels/valley sides, estimation of vegetation density, measurement of sediment clasts, angle of slopes, assessment of sediment character, stratigraphy of floodplains and identification of vulnerable elements). These data were combined with satellite image analysis to: define river catchment character and flood vulnerability (e.g. using the methodology of Collier and Fox, 2003), examine catchment connectivity, and examine landslip scars and generic terrain analysis. Literature studies and seismic database interrogation allowed the calculation of potential catchment floodwater volumes, and the collation of epicentre, magnitude, depth and date of seismic events, together with recent thinking on the return period of large Himalayan earthquakes. These data were used to develop geological-seismic and river catchment maps, the identification of vulnerable elements, and disaster scenario analyses.

Findings

This research concludes that SECMOL, and much of the Ladakh region, is exposed to significant seismic, flood and landslide hazard risk. High magnitude earthquakes have return periods of 100s to c. 1,000 years in the Himalayas and can produce intense levels of damage. It is prudent to maximise earthquake engineering wherever possible. The 2010 Leh floods demonstrated high levels of devastation: these floods could severely damage the SECMOL campus if storms were centred close by. This study reveals the connectivity of catchments at varying altitudes and the potential interactions of adjacent catchments. Evacuation plans need to be developed for the college. Northern ridges at SECMOL could bury parts of the campus if mobilised by earthquakes/rainfall. Slope angles can be lowered and large boulders moved to reduce risk. This work reinforces recommendations that relate to building quality and urban/rural planning, e.g. using spatial planning to keep people away from high-risk zones.

Practical implications

The frequency of hazards is low, but potential impacts high to very high. Hazard mitigation actions include engineering options for hazardous slopes, buildings to be earthquake-proofed, and evacuation management for large floods.

Originality/value

Methodologies undertaken in this research are well-tested. Linkages between disciplines are ambitious and somewhat original. The application of this work to a specific college centre site with the capacity to rapidly take up recommendations is novel. The identification of catchment inter-connectivity in this part of Ladakh is novel. This work complements a sister paper (Pettersonet al., 2019) for community aspects of this study, adding to the novelty value.