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Specification for coastal regulation zone chart and its development
Implimentation of CRZ notification and its implication
The CRZ notification has put too many restrictions on the development along the coast. In Maharastra, with its coast line 720 km and 54 river creeks, significant stretches in land are badly hit by the CRZ notification. It is posing several problems before the planners and decision makers on one side and investors and developers in other. The CRZ notification as mentioned earlier has put too many restrictions on the development along the coast. Various important issues of CRZ notification and implication involved in the process of planning and development are as follow:
(a) Demarcation of high tide line
High tide line (HTL) in the coastal regulation zone notification is defined as line up to which highest high tide reaches in spring tides. It is delineated by walking over or remote sensing data or by helicopter survey. During delineation of HTL, the geographic coordinate of all-important landmarks is arrived at both in Everest and WGS 84 datum. The Chief Hydrographer to the Government of India is the authority to demarcate the high tide line and has got the proper expertise to demarcate such high tide line(HTL) during spring tide. This line is marked by bathymetric chart of the coastal area with the datum of chart being the lowest low tide.
(b) Demarcation of low tide line
The low tide line is the limit up to which the lowest low tide recedes during spring tide. This line would be arrived at by making a bathymetric chart of the coastal area with the datum of chart being the lowest low tide. For this simultaneous tidal observation would be carried out while bathymetric data is collected by expert surveyors and sounding reduced to the lowest low tide. The line along which zero meter depth occurs on this bathymetric chart is the low tide line.
(c) Dealing with the creeks
In case of creeks, CRZ notifications and subsequent supreme court judgment have stipulated that if the width of creek is up to 350 meters, the CRZ will be 100 meters from the creek and if the width exceeds 350 meters, it will be 150 meters from the creek. Now from where to measure the distance of 100 meters or 150 meters is a point of debate. Expert in the field of Hydrography say that it is possible to demarcate edge of the creek and in that case this distance can be measured from the edge. Other say that in case of creek, even the area up to the water spread will form coastal regulation zone.
Another point in respect of creeks is up to what distance inside the creek, the CRZ notification will be applied. British experts have opined that distance inside creek, where tidal effect of the wave comes to and end, should be considered as the distance inside creek for determine the coastal zone.
(d) Condition regarding mangrooves
It is stipulated that in case of mangrove with an area of 1000m2 or more, would be classified as CRZ with a buffer zone of at least 50 mt. Mangrove is a tropical tree growing, along the coast and requires saline water for its growth. Expert in this field say that mangrove are very important along the coast for breaking of tides and it is valuable resources having several direct uses. Hence proper the protection of mangrove is very important.
(e) Ecologically sensitive features demarcation
In order to implement CRZ Plan, it would be necessary to demarcate and survey of foreshore and offshore features which are ecologically sensitive such as mangrove, spawning ground of marine life, corals and other features like wetland, marsh, swamp, bays, estuaries, creeks, bunds and back waters that are influenced by Tidal action. Coral reefs are the spawning ground of aquatic life, and sea grass bed is important feeding ground for fishes. Mangrove and coral reefs also act as a buffer zone against wave and tidal force, for stabilizing and safeguarding the coast. Before planning to make the CRZ plan chart, the proper evaluation of the coastal features and their proper measure is highly essential.
Charting plan
The compilation of CZR Plan charts is carried out from latest special Hydrographic Survey showing HTL. The details are picked up from analog or digital information available in Hydrographic Survey using modern cartographic technique. The chart is prepared on 1:25,000 scales with demarcation of 200 Mt. & 500 Mt. Lines from HTL along with limit of ecological sensitive areas, extent of coastal stretches and other necessary information required for CZR implementation. The charts will have identical coverage as Survey of India sheet and will be on polyconic projection on WGS-84/Everest datum. The digital copy of charts will be prepared for chart printing as and when required by users. Indian coastline and Island territories is estimated to be covered in about 265 CZR Plan charts.
An accuracy of + 10.5 meters is required to be maintained over the ground with survey on scale of 1:25,000. Larger scales charting with better accuracy will be done in very sensitive areas. The horizontal distance line of 500 mt. and 200 mt. from the high Tide line is marked on chart using prominent land or built up features and description of the same noted for future reference.
Chart specification
Some specifications are considered for making the CRZ chart. Such specification covers limit of chart, no. of charts, scale, horizontal datum, projection, vertical datum (lowest Astronomical Tides for bathymetry and MSL for topography), unit of measurement and size of charts. The topographical heights are mentioned in meter as per Navigational charts. The neat line size 92x60 cm is used for preparation of CRZ Plan chart (DE), which will include index below the map. Such special chart will have title information including title of chart in one block suitably located in the land area if possible and cautionary note for National/International boundaries.
Marginal Details such as publication legend, copyright legend and chart numbering are shown as per standard procedure for nautical charting. Publication legend is inserted centrally below the southern border of the chart. Copyright legend is shown completely below the publication legend on all charts.
Chart contents
Coastal Zone Regulation Plan chart includes high tide line, low tide line and depiction of 500 mt. and 200 mt. Line from coastline as main contents. The limit and index of ecologically sensitive area such as National Park near shore, sanctuaries, reserved forest and wild life habitats are shown very accurately. The sensitive features like mangroves coral reefs and area close to breading and spawning ground of fish and other marine life are depicted with standard symbol given in INT 5020. The area which have already been developed up to shore line and partially built up urban area, near coast are shown on large scale CZR Plan charts. The new edition legend, adjoining chart number in magenta, panel box at top of right portion of chart and dimension in millimeter are very informatics content of CRZ Plan charts.
Charting source material
The integration of numerous source materials such as topographic, hydrographic, bathymetric and coastal features data into a balanced and harmonic composition on specified scale and projection is required for preparation of CRZ Plan chart. The various source material used for CRZ Plan chart are named as follow: -
(a) Topography:
A complete set of map on scale 1:25,000 published by Survey of India providing coastal coverage and cadastral map are used for depicting land detail and coastal stretches on CRZ chart. Aerial photographs are considered particularly for high tide and low tide period. Satellite imagery data both analog and digital form is used for demarcation and indexing of ecological sensitive features. The Geodetic data collected by Survey of India is also used for charting purpose.
(b) Hydrography:
Hydrographic survey is regularly carried out in entire coastal water as per requirements of agencies and available in analog and digital format. Presently the hydrographic data including coastal information is also available on large scale. Survey Ship of Naval Hydrographic Department collects the hydrographic data and result of local survey is also received periodically from State Port Authorities, Maritime State Government and Minor Port Survey Organization of Ministry of Transport including the coastal details and low water features. Hydrographic survey specifically for demarcation of HTL, LTL, 200mt. and 500mt. Line is carried out periodically along the coast. The published Nautical Chart by National Hydrographic Office covering the coastal area on large scale is also used as hydrographic source for CRZ plan chart.
(c) Digital database:
The CRZ Plan chart is digitized and composite design file of CRZ Plan chart is stored in database for each map project. The updation of this digital database is carried out regularly as and when new hydrographic or coastal data is received. Remote Sensing and Photogrammetry along with GIS technique play an important role to provide the various thematic data for charting. The data from Remote Sensing Satellite because of its synoptic and repetitive capability, have proved to be extremely useful in creating baseline inventories of coastal wetland, coral reef and mangroves, monitoring of protected area and detection of shore line change
Coastal regulation zone
In general the land between low tide line and high tide line is the coastal Regulation Zone. The rapidly increasing human population and industrial development along coast have resulted degradation of coastal ecosystems and diminishing the living resources. In order to conserve coastal resources by controlling their depletion and manage the development activities, the government regulations prohibit certain activities and also list the permissible activities within the CRZ.
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