Home Articles Development of GIS based Coastal Information System

Development of GIS based Coastal Information System

Vimal Garg


Vimal Garg
[email protected]

Ritu Seth


Ritu Seth
[email protected]
Water & Power Consultancy Services (India) Ltd.
Gurgaon, Haryana

Abstract
The paper describes on the development of an information system that could be used as a regulating, management and decision making tool vis-à-vis development activities along the coastal stretches of India. The system aids in implementing and regulating development activities along coastal stretches under CRZ notification issued by Ministry of Environment & Forests, Government of India which stipulates regulation of development activities in areas till 500 m from High Tide Line on landward side those have been designated as Coastal Regulation Zone (CRZ) and have been classified into various CRZ categories. The system helps in identifying areas those could be re-categorized under various CRZ categories to open or close certain stretches for undertaking any development activity based on myriad of factors primarily related to sensitivity of the area. It could also help any future developers in identifying an appropriate site for development of ports, tourist resorts, etc.

Based on the existing guidelines issued by regulating agencies, the most essential components those are required to be a part of such Coastal Information System are mainly Low Tide Line (LTL), High Tide Line (HTL), Town/Regional Planning maps aided by census information as well as information related to occupational profile of the population, population density, latest landuse maps, details of infrastructure facilities like road/rail etc, information of bathymetry, navigational details, marine ecological data etc. The above information could be procured from various agencies/maps or could be derived from high-resolution satellite data. All this spatial and non-spatial information thus can be converted into digital format and geo-referenced where it could be overlaid on each other so as to derive various kinds of information to be used for CRZ activities’ regulation. GIS based Coastal Information System could be developed using high resolution IKONOS or IRS 1C/1D LISS III and PAN merged products for specific dates. Other information could be collected from state departments, topographical maps, IN charts, revenue maps, census records etc. Maps need to be prepared on 1:25,000 scale as per the CRZ guidelines.

Introduction
Development activities in the coastal stretches till 500 m from High Tide Line on landward side are regulated as per Coastal Regulation Zone notification issued in 1991 and subsequent amendments by Ministry of Environment & Forests. Under this notification, the Ministry of Environment & Forests has declared the coastal stretches of sea bays, estuaries, creeks, rivers and backwaters, which are influenced by the tidal action (on the landward side) upto 500 m from High Tide Line (HTL) and land between Low Tide Line (LTL) and the HTL as Coastal Regulation Zone. In case of rivers, creeks or backwaters, this distance is not less than 50 m or width of the creeks, rivers or backwaters whichever is less. The distance upto which development along rivers, creeks as backwater is to be regulated is governed by the distance upto which the tidal effect of sea is experienced in rivers, creeks or backwaters as the case may be identified in CRZ.

The coastal stretches have been divided in four zones looking at the fragility of existing ecosystem, the extent of development and area which are relatively disturbed or undisturbed. They are briefly described below:

CRZ I: Areas which are ecologically sensitive and important such as national parks, marine parks, sanctuaries, reserved forests, wildlife habitats, mangroves, canals, coral reefs, areas close to breeding and spawning grounds of fish and other marine life, areas of outstanding natural landscape, historical, heritage area, areas rich in genetic diversity, etc.

CRZ II: Areas, which have already been developed upto or close to the shoreline. For this purpose developed area is referred to as that area that lies within municipal limits or in other legally designated urban area which is already substantially built-up or which has been provided with approach road & other infrastructural facilities such as water supply, sewerage mains etc.

CRZ III: Areas that are relatively undisturbed and those which do not belong to either CRZ I or II category. These include coastal zone in the rural areas (developed and undeveloped) and also area within municipal limits or in other legally designated upto an area, which is not substantially built-up.

CRZ IV: Coastal stretches in Andaman & Nicobar, Lakshwadweep islands and small islands except those designated as CRZ I, II or III.

A decision making requires enormous amount of information which could be stored, analyzed, overlaid, manipulated and updated to extract appropriate data as and when required. GIS based Coastal Information System is an excellent example of demonstrating the way to integrate information from various sources/agencies for user specific needs.

This GIS based Coastal Information System is an excellent example of demonstrating the way to integrate information from various sources/agencies for user specific needs. The paper demonstrates the use of GIS and Remote Sensing techniques in development of Coastal Information System.

Approach
Based on the requirements of a coastal information system, the input data required for query and analysis needs to be ascertained first. Information about the availability of satellite data during spring and neap tides could be derived using the tide charts of the ports for which the Coastal Information System is to be developed. The available latest high-resolution data for spring and neap tides could be used to mark high water line, low water line, CRZ boundaries etc.

The following data layers are useful for such information system:

  • High resolution satellite data for spring & neap tide
  • Port limits
  • Regional development plans /Town planning maps
  • Ecological sensitivity/Marine park
  • Census information
  • Information regarding infrastructure details
  • Navigational Charts
  • Survey of India toposheets
  • Revenue Maps
  • Other details like information on ground water, geology etc

All the above information could be gathered from various sources and converted into digital format to overlay on each other and attaching non-spatial information for data and query analysis. Various conventions to be followed while marking HTL/LTL also need to be taken care of during the procedure, as specified in the guidelines on CRZ notification. Spatial and non-spatial data from several sources could thus be linked together for preparation of the CIS. This GIS based coastal Information System could provide all the required latest information attached to help regulatory authorities and developers in decision making. Miscellaneous latest relevant information can be added to the maps to keep them updated.

Development of an Information System
Development of Coastal Information System requires miscellaneous data in the form of several layers those could be overlaid on each other for analysis thus aiding decision making. Most important ones have been described in subsequent paragraphs:

High resolution satellite data: Latest high resolution satellite data is required to derive information related to high water line, low water line, road and rail networks and landuse pattern of the area. For this, either IKONOS or merged data of Indian Remote Sensing (IRS) Satellite LISS and Panchromatic sensors could be used. Data needs to be acquired for the dates of spring or neap tides so that HTL/LTL could be marked precisely. For data acquisition, dates need to be matched with the help of tide tables and date and time of pass of satellite. Once the water lines have been marked, coastal regulation zone boundaries at 200 m and 500 m from high water line could be marked.

Regional Development/Town Planning Maps: This is other most vital information that is required to be incorporated in a coastal information system. These could be collected from concerned state departments. The maps so gathered need to be digitized and geo-referenced to overlay them on the respective landuse maps and high/low water and CRZ lines. These digitized maps if verified by concerned department of state government would make it authentic.

Information on census and other infrastructural details: For this, revenue maps of the area could be picked up to make it a layer. Subsequently different kind of census information could be attached to it. As per the definition of urban area, 75 percent of the male working resident population should be engaged in non-agricultural practices. The following information need to be attached:

  • Total population
  • Population density
  • Occupational profile (male/female)
  • Main workers in activities related to non-agricultural practices(male/female)
  • Non-workers/ marginal workers (male/female)
  • Existing infrastructural facilities available in the area such as road/rail networks, water supply & sewerage, drainage etc.

Ecological Data: Marine ecological data is important to judge the ecological productivity and sensitivity of an area. A proper systematic and planned marine sampling from surface and bottom is required for information system to determine CRZ category of the area. Existing data could also be made use of. Mangroves could be mapped using satellite data while ascertaining landuse pattern of the area.

IN charts: To make the Coastal Information System a comprehensive one, other navigational data, information of bathymetry, light houses etc could also be picked up from existing sources such as IN charts etc. Such updated information is required for planning maintenance and dredging in port area or navigational routes and helps in better navigational maneuverability etc.

Other miscellaneous information: Other several kind of information like groundwater, geology, salt farming, fishing details, etc could be attached to the Information System to enhance it’s versatility.

Remarks
All the above information could be stored in different layers and could be overlaid on each other analyze the data for user specific needs. Accurately developed Coastal Information System could help re-categorization of existing categories of coastal regulation zones. For this the latest updated information required such as ecological sensitivity, existing development status, census information, occupational profile, regional development plans, information on infrastructural facilities could be picked up from the system. Re-categorization of coastal regulation zones could help to undo over-exploitation or under-exploitation of an area thus making development sustainable. Management and regulation in coastal stretches could be greatly aided by this CIS. If made available for general use or on Internet, it can immensely help future developers to plan their activities properly and efficiently thus avoiding delays in implementation of projects.