GEOMORPHOLOGICAL MAPPING AND ENVIRONMENTAL ZONING APPROACH TO COASTAL MANAGEMENT IN HAVELOCK ISLAND, SOUTH ANDAMAN, INDIA

摘要

Havelock Island of South Andaman District is located as the part of Archipelago group of Andaman Formations with the distinct geomorphological units, mostly covered by forests and fringed by wide shore platforms and coral banks in Andaman Sea. Geomorphologically. the island units may be categorized as coastal hill ranges of limestone, calcareous sandstones, claystones and mudstones; intermontane valleys and valley flats; coastal wetlands; reef terraces; promontories, headlands, cliffs, embayments and shore platforms; occasional sea beaches and shore fringed coral banks. The carbonate sediments are widely distributed in the shore platforms and associated reef terraces of the island. Thicker alluviums are only available along the intermontane valleys and valley flats, and in the wetlands around the fringe of a few drainage channels fed by hill streams and salt water inflows of tides. Forests of the island surface units are classified as mangrove and marshes, littoral vegetations, moist deciduous, semi-evergreen and evergreen vegetations. From the sections of exposed ill cliffs it is visible that rocks of Neogene formations are jointed, tilted, fractured and faulted with products of weathered debris and soils under Tropical Marine Environment. The hill slopes without forest cover areas are vulnerable to soil erosion under heavy rain in the prevailing North-east and South-west monsoon of the humid tropics. Settlement habitation started in valley flats and shore fringes in the decade of 1970's to reclaim the lands for further habitation, vegetable gardening and plantation, but expanded tourism activities with infrastructure development after tsunami year(2004) the present island become exposed to visitors pressures for attractive destination sites( scenic hills, forests, seashores and coral banks). The present paper discuss about the significance of geomorphological mapping, forest mapping and environmental zoning approach to the coastal management particularly for the vulnerable parts of the island for its sensitivity to tropical rainy and marine environments. Detail mapping of geomorphological units, forest types and zonation. temporal land use - land cover changes and environmental zoning classifications using geospatial techniques will be useful output for the coastal managers to develop the island units in a sustainable manners against the expanding tourism pressures at present.