India has a vast coastline of about 7,500 km, including the coasts of Andaman & Nicobar and Lakshadweep islands. While these coasts provide the country with abundant natural resources, they also pose a threat to the security of the country. The entire coastal area of the country harbours some of the most ecologically sensitive areas and also experiences natural hazards like storm surges and cyclones.
The country’s coastline is inhabited by approximately 25% of the total population of the country. A majority of this population lives within 50 km from the shoreline. This includes 10 million fisherfolk who depend directly on the sea for their livelihood. These communities and the infrastructure of national importance are prone to several vulnerabilities, both natural and human induced. In the last few years, the frequency of these natural hazards has increased largely due to climate change.
Expert committee
Understanding the need to protect the fragile coastal ecosystem from the pressures of developmental activities and to examine the coastal management approach in the country in a holistic manner, the Ministry of Environment and Forests (MoEF) of the Government of India had constituted an expert committee under the chairmanship of Prof. M. S. Swaminathan in June 2004. Based on this, a draft Coastal Management Zone (CMZ) Notification, 2008 was issued which received large number of representations. To review these comments, the Ministry constituted another committee under the chairmanship of Prof. Swaminathan in June 2009. This committee, after examining the comments suggested that the Coastal Regulation Zone (CRZ) Notification, 1991 be continued and improvements be incorporated in it. One of the suggestions made was to conduct hazard mapping exercise for the purpose of protecting the life and property of local communities.
An initiative
A step towards incorporating this suggestion has been taken by the MoEF that has signed a Memorandum of Understanding with Survey of India for the mapping and delineation of hazard lines along India’s coasts. The Rs 125 crore project, called Coastal Hazard Line Mapping Project, is part of the World Bank assisted Integrated Coastal Zone Management project. The entire project is pegged at about Rs. 1000 crore.
The ministry has proposed to demarcate the hazard line in entire coastal areas of the mainland, about 5,500 km. According to MoEF sources, the project aims to conserve the fragile ecosystem and protect the livelihood of communities staying in those areas. A clearly demarcated hazard line would also see the government getting a more assertive position in matters pertaining to development activities in these regions.
Mapping the coasts
Survey of India (SoI), the nodal mapping agency of the country responsible for the project, maintains data on major parameters such as the tidal data and elevation data. SoI maintains these records on a day-to-day basis and has these records of the last 50 years. The methodology for demarcating the hazard line has been worked out in consultation with reputed national institutions like Survey of India (SoI), Space Application Centre (SAC), Ahmedabad, Department of Ocean Development, Chennai and Centre for Earth Science Studies (CESS), Thiruvananthapuram.
Further, to obtain international experience, Prof. John Pethick, advisor to UK Government on coastal issues was also brought in to firm up the methodology. Within two years from the date of signing of MoU, SoI would complete the aerial photography and thereafter would start generating maps with the hazard line. The total time period for the entire project is four and a half years. Both MoEF and SoI would be the repositories of the data generated. Under this project, the hazard line for the mainland coast of India will be mapped and delineated. This will include the collection and presentation of data on identifying flood lines over the last 50 years (which includes sea level rise impacts), and a prediction of the erosions to take place over the next 100 years. This process will involve:
- Surveys and preparation of digital terrain models for the entire mainland coast;
- Collection of historical tide gauge data and its analysis to determine flood levels over the next 100 years;
- Analysis of maps and satellite imagery since 1967 to predict the erosion line over the next 100 years;
- Preparation of composite maps, showing the hazard line on the digital terrain model;
- Transfer of the hazard line to topographic maps for public dissemination. Once the hazard line is delineated, ground markers will be constructed. This is important as the revenue maps used for local planning purposes are not comparable to topographic maps.
A contour map with 0.5 m elevation upto 7 km from the high tide line on the landward side would be demarcated and on this contour map, the hazard line taking into account the extent of flooding due to sea level rise, increase in tides, waves and the shoreline change will be demarcated. Maps on 1:10,000 scale will be generated for the entire coastline. Data will be computed at each tide guage. The technologies involved in the process include digital aerial photography and digital photogrammetry, tidal data extrapolation using regression analysis, ground control using GPS and GIS analysis for delineation of the final hazard line.
Public private partnership
Public private partnership (PPP) will be an important aspect of the project, with about 70 percent of the cost component being outsourced. According to SoI sources, while working on the modalities, it was observed that there is a need to outsource some of the functions including aerial photography and photogrammetry with digitisation. Through the PPP model, the project aims to promote geospatial industry. include aerial photography and photogrammetry with digitisation.
Draft notification
In addition to this project, the draft CRZ Notification, 2010 has been published for consultation. Thereafter, the draft CRZ Notification, 2010 would be issued under the Environment (Protection) Act, 1986. In this draft CRZ Notification, 2010, the hazard line mapping has been incorporated in the coastal zone management planning. The newly proposed infrastructure would be located at a safer location keeping in view the hazard line. Precautions would be taken such as hard engineering, soft engineering for protecting the dwelling units of local communities living within the hazard line. However, new dwelling units would be located on the landward side of the hazard line.
Optimistic outlook
According to MoEF and SoI, this is one of the world’s biggest geospatial projects especially for natural hazard mapping at such a micro level, and both the organisations are excited about the project and optimistic of its success.
Deepali Roy, Assistant Editor, [email protected]
