A STUDY ON LAND AREA DRAINAGE IN COASTAL AREA

Abstract

The drainage systems in the coastal region is predominantly different as compared to urban drainage systems. The coastal region is vulnerable to natural disasters such as storm surges, sea level rise, tidal variations, tsunami and cyclones. The characteristics of the coastal region which includes climate, rainfall, soil, vegetation and terrain/topography varies from place to place. The major factor considered while designing coastal drainage system for any industrial or urban area is topography, availability of natural slope, constraints in land use and land cover and mean sea level. If the elevation of terrain/topography of coastal region is above compare to mean sea level, the industrial or urban area has to be protected with efficient drainage system which can flow with gravity to dispose the run-off generated within the short duration to avoid flooding in that region. Meanwhile, it has to be checked for constraints in pipeline systems and rectify for efficient dispose the runoff generated.The elevation of terrain/topography is below/ equal/ slightly above as compare to mean sealevel, the coastal area will be more vulnerable to external flooding caused by tidal variation, cyclones, rise in sea level, storm surges, tsunami etc., these natural disasters may finally result in inundating the low lying areas, loss of valuable properties, loss of lives and waterlogging and it may also lead to accumulation of silts in agricultural land. To protect the area from external flooding, the measures that can be considered are flood plain zoning, planned urbanization, increasing the elevation of roads, providing adequate drainage system, adjustment in life style, cropping pattern and flood warning / preparedness system. In the present study, the above problems were considered with the help of two case studies at two different coastal regions located at Pudimadaka village, Visakhapatnam, Andra Pradesh and Mithakhari, Port Blair, Andaman and Nicobar Island coastal. For the analysis, modern techniques such as Arc-GIS model, Auto-CAD model and SWMM model were applied and the results showed that, the effect of the flood can be minimized efficiently by making use of these modern techniques. It was observed that, the coastal area is more vulnerable to external flooding caused due to natural disaster. This study helps the planner to monitor the coastal environment due to natural hazards and it may also provide platform for the planning of drainage system.