Coastal Stability and Micro Morphology; Disturbances due to Human Interventions along West Coast of India

Coastal areas are known as cradles of civilization from the beginning of human settlements and the coastal belts in tropics experience high density of population all over the world. Indian coastal region is one of the most populated coastal belts of the world. Kerala coastal region of South West Peninsular India hosts 2931 person per sq. km. Stability of coastal zone helps to prevent the intensity of coastal hazards like extreme waves, coastal flooding and coastal erosion, which is quite noticeable in the northern part of Kerala state, when compared to the southern coastal region. The paleo-shoreline of Kozhikode coast in northern Kerala is identified as 2.5 to 5 km landward from the modern shoreline in the Beypur – Kallayi sector, 1 to 2 km in the Kallayi – Korapuzha Sector and 1 to 2.5 km in the Korapuzha – Quilandi Sector. This proves that the area is an accreting one over the recent geological history. The sediment discharge of Chaliyar, Korapuzha, Kadalundi and Kallayi rivers along with micro morphology leads to the evolution and development of this coastal plain for last few centuries. Paleo channels of this area changed its direction in many places during Holocene – Pleistocene period under the tidal influence. Nearshore bottom features of the area got diversified with parallel and transverse bars, reefs, exposed and buried rocks. The major nearshore features are demarcated as Kadalur Cape, Thoovappara, Elathur Cape, Thikkodi reef, Kadalur reef, Anchorage reef, Coote reef, Calicut reef, Rocky It, Gilham rocks, Rocky points, Black rock and Puthiyangadi bay. As a fast growing urbanised coastal city of the state, the Kozhikkode coast line is subjected to intense human interventions and thereby adversely affect sustainability of the coastline. Construction of two major fishing harbours, vis. Puthiyappa and Quilandi and Beypur port in 1990s re-defined the coastal morphology and nearshore bottom features of the sector. Shoreline towards the south of Puthiyappa harbour and Beypur breakwater is accreted and vast beach was developed while the Quilandi harbour doesn’t have much influence on sediment drift. Rocky coast, sand bed, seasonal sand bar and exposed and buried rocks have been properly documented in the paper. Along with those natural features, the artificial landforms and coastal protection measures have been analysed for understanding the disturbances in the coastal stability of the area. One-meter contour of the bathymetry line runs parallel to the coast except in the near shore of the Elathur and Kadalur headlands. Current investigations show that 48 percent of the total coastline can be considered as stable (Quilandi - Korapuzha and Korapuzha – Kallayi sectors), while 36 percent is erosion prone (Kallayi – Beypur Sector) and the rest is accreting.