Hazard Risk Mapping for Informed Disaster Management and Governance

Overview

Climate change, climate uncertainty and associated risk are prominent in current periods and likely to be more profound in future scenarios. The two most notorious climate change impacts, i.e., flood and heatwave, happen due to extreme rainfall or temperature.

The frequency and intensity of these two climatic events are becoming more common, leading to serious damage through infrastructural damages, economic loss and life loss and posing ultimate nation’s growth and properties. To avoid loss and damage from climate disasters, we need better preparedness and coordination across national, regional, state, and local institutions and administrations.

In disaster risk reduction, the first step is to prepare the risk map; however, in the present Indian context, it is missing in most cases (mainly for central and state governments). Hence, it is necessary to prepare a comprehensive hazard-specific risk map for better management and planning.

The ensuing example highlights two different cases including flood related disaster risk in Uttarakhand flood 2013 and extreme heat related risk in NCT Delhi in 2001 and 2017, the focus is on leveraging Geospatial technologies for strengthening resilience and adaptive capacity to climate related hazards and natural disasters.

Vision:To successfully use Geospatial technology and tools for preparing a comprehensive hazard-specific risk map for improved disaster management and planning.

Objectives

y To delineate maximum flood extents along the stretch of Bhagirathi River to identify flood risk areas y To map comprehensive heat risk and linked with the land use to find optimum land use for heat-resilient city planning y To determine the role of anthropogenic activities in triggering disasters y To critically discuss governance issues of existing policy and its gap to address sustainable development and risk control.

Stakeholders Involved

Civil society interaction in the form of public consultation for field surveys, and interactions with government officials for understanding the governance system at the ground level.

Use of Geospatial Technologies

In the case of flood studies, hydrodynamic modelling, coupled with the hydrological model, is used to identify the flood risk area and high flood level (HFL). The popularly applied Soil and Water Assessment Tool (SWAT) hydrological model is used in the present study to compute the volume of peak discharge from 16th–18th June 2013 in the Bhagirathi basin.

The simulation of flood extent was performed using the Hydrologic Engineering Centre’s River Analysis System (HEC-RAS) hydrodynamic model developed by the U.S. Army Corps of Engineers (USACE). Besides, a detailed review of state and national government order and policies has been analysed to unfold the governance dimension of flood risk.

For heat risk study, multidimensional aspects like social, demographic, economic, bio-physical, and environmental data are combined using GIS techniques. Multiple spatial econometric models are utilized to unpack the interrelationship between land use structure and heat risks. Moreover, the land use policy is also analysed.

Key Outputs

y Detailed quantitative flood inventory and flood inundated areas representing the flood risk in the Bhagirathi basin reflected in the flood model simulation. y Association between rapid tourism development and land use alteration in flood-prone areas established with the help of the detailed governance structure analysis, and the following conclusions derived:

Æ The Government of Uttarakhand (GoU)’s move to increase the number of tourists by providing more accommodation overlooked the formulation of concrete policy for tourism development, resulting in mushrooming of guesthouses and hotels invading the riverfront.

Æ Failure to control land use and development activities that often exceeded the carrying capacity of sensitive zones has increased the flood risk of the areas.

Æ The hydropower policy of the state government (2008) mainly focused on the clause of ownership and tenure of the project, rather than paying attention to environment protection, dam safety strategy and hazard preparedness.

Æ The policy never mandated environmental impact assessment (EIA), even for establishing a large hydroelectric power (HEP).

Æ Throughout the state, numerous HEPs were commissioned, under construction and planned for installation ignoring river ecology, channel fragmentation, minimum environmental flow etc. y For Heat risk, two important aspects - density debate and spatial interconnection - are essential to understand in the context of contemporary urbanization in megacities but remained ignored by urban planners.

Æ The percentage share of the slum population in those over-density localities is much higher.

Æ People of these localities are most affected as they have less adaptive capacities such as low quality of houses (i.e., ‘Juhggi-Jhupri’), poor roof shadings, bad cooling facilities and lack of availability of drinking water