Transformation and Resilience on Urban Coasts

CASE STUDY SITE

 

KOLKATA

Transformation and Resilience Analysis on Urban Coast of Kolkata

  • This case study deals with the megacity of Kolkata located in India

    Scientific Team

    Key Contact Point Physical Sciences Team Social Sciences/ Economics Team Local Partners
    Ramesh Ramachandran Purvaja Ramachandran Ramachandra Bhatta Institute of Environmental Studies and Wetland Management, Government of West Bengal.
    rramesh_au@yahoo.com Ajay Ray Ahana Lakshmi Calcutta University.
      Robin, R.S. Naren, P  
      Dipnarayan Ganguly Priya Narayanan  
      Debasish Tudu    

BIOPHYSICAL/ HUMAN SYSTEMS MODELLING

Objectives

  • 1)To model the interaction of human decisions and the biophysical environment in the megacity.
  • 2)To employ a biophysical model for urban surface-atmosphere energy and water exchange.
  • 3)To predict heat stress, boundary layer height and flooding across the urban city.

Methodology

The SUEWS (Surface Urban Energy and Water Balance Scheme) urban land surface model will be used as biophysical modelling of Kolkata city. The SUEWS output will be directly link to the World Risk Index (WRI). This will involve close linkages with risk indexing and scenario developments to ensure that the appropriate variables are modelled and assessed. The biophysical model will be run for the past 20 years and the model performance will be assessed by modelling the known events in the last 20 years; most importantly the heat stress and flooding events, that would have produced exposure to high WRI values. Moreover, the flooding scenarios in the river system will be simulated with the coupled SWAN-ADCIRC model.

Analysis

Threat of coastal vulnerability due to flooding is very high in the low-lying areas of Kolkata city. The meteorological, tidal conditions and coastal defence systems are process drivers for proper assessment of coastal flood risk of the city. Hoogly River experiences ‘tidal bore’. The tidal characteristic is semi-diurnal in nature with the neap and spring variations ranging from 2.0–5.0m. The water level variation is very high (about 2.5 m) during flood tide and low (about -2.2 m) during ebb tide in the Hooghly River. The combined effect of tide, wind and wave action are in the symmetric phase increase the risk of flooding on the low lying area of the city. Therefore, evaluation of coastal flood risk is a key requirement in hazard management and planning.

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Activities

  • 1)Land use/land cover mapping of Kolkata city.
  • 2)Data collection on vulnerability due to river flooding, storm surge, cyclones etc.
  • 3)Collection and analysis of city development plans (CDPs) for the drainage pattern, and infrastructure like dykes, roads, railways, etc.
  • 4)Fine resolution Digital Elevation Model (DEM).

Work Plan

Timeline (2014) Activity progress
July 15-30 Topographic datasets using SRTM Completed
August 01-30 Meteorological data collection and analysis Ongoing
August 15-30 Land use/ land cover mapping of Kolkata city (1990 to 2013) Planned
July 20 - Sep 30 Collection and analysis of city development plans Ongoing
Sept 01-30 Digital Elevation Model (DEM)- Topographic data collection through RTK GPS/Total Station/Digital Level Planned
Sept 15-30 Hydrodynamic data sets Planned
Oct 1-30 Simulation of river flood model Planned

Documents

Research Work Program 1

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Research Work Program 2

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RISK MODELLING/ DECISION MAKING SCENARIOS

Objectives

  • 1)To develop a profile of Kolkata city based on the ward-wise specific climate change vulnerability and coping capacity
  • 2)To assess the socio-economic and infrastructure development of the city-wards vulnerable to the impacts of climate change
  • 3)To provide forums for stakeholder dialogue on vulnerability reduction and adaptation planning
  • 3)To provide a vehicle for inter-city communication and learning

Methodology

The city of Kolkata consists of 141 wards. Ward-level data on socio-economic parameters including total population (male, female, 0-6, SC and ST), literates and illiterates, main and marginal workers (cultivators, household labourers and other workers) and non-workers have been procured from National Census database. For the purposes of data collection and analysis, the wards have been grouped based on certain socio-economic indicators, namely levels of literacy and worker participation rate, considered suitable indicators of region’s state of development.

In order to assess exposure of Kolkata city to floods, high temperature and sea level rise, the biophysical data are being procured from IMD, CWET and PMSL at the required frequencies such as hourly, weekly and monthly to study diurnal, seasonal and annual variability.

Analysis

Preliminary Analysis (July 2014)

The megacity of Kolkata is located on the east bank of river Hooghly, at the tail end of river Ganga, approximately 180 km away from Bay of Bengal, with an average elevation of 9 meters above mean sea level. Kolkata city has a very high density of population (approximately 24,000/sq.km).

As a first step towards understanding existing climate change, the mean monthly rainfall for Kolkata was obtained from the IMD. The sixty-year long term data (1949-2009) was grouped into two subsets (1949-1969 and 1969 -2009). Figure 1 presented below shows the increasing long term average rainfall on the one hand and increasing variability on the other based on the assessment of two long term periods. The preliminary analysis indicates the increasing vulnerability in terms of extreme weather events and also exposure to risk factors.

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Activities

The project envisages 3 stakeholder meetings for each case study site:

  • 1) A kick-off meeting to introduce TRUC to stakeholders, results from SUEWS and WRI before integration as well as the TRUC conceptual framework will be available
  • 2) Case study scenario workshops with input from WP3, to provide information and also a key dialogue space for stakeholders.
  • 3) An 'exit' workshop to feedback TRUC findings and explore implications for future policy and research collaboration

Work Plan

Duration Particulars Status as on 15th July 2014
July 01-10 Formal linkage with the Centre for Urban Economic Studies - Department of Economics, Calcutta University Completed
July 01-20 Identification and collection of macro data sets on socioeconomics, census, land use and land cover, climate, meteorological and regional planning (temporal and spatial) Ongoing
July 10-20 Planning of secondary/primary data collection from key informants Ongoing
July 20-30 Data collection (historical, zonation and urban planning, ward-wise distribution of population and characteristics, flood-prone areas, elevation data, meteorological data) To be Completed
August 01-15 Stakeholder consultation meetings with guidelines and manual from Dr. Matthias To be Completed
August 15-25 Development of draft case study reports To be Completed
August 30-Sept 5 Final case study report with data sets To be Completed

Documents

Research Work Program 1

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Research Work Program 2

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