Mapping, Inventory and Change Detection of Wetlands of Thavanur Grama Panchayath using Multispectral Satellite Imagery

Abstract

Wetlands are the submerged or waters saturated lands, both natural and man-made, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water, the depth of which at low tide does not exceed 6 meters. Effective wetlands management and protection are critical. Accurate and comprehensive wetland classification maps as well as spatiotemporal change information are essential for ecological protection and local government decisions. Wetland mapping and classification help to preserve and improve wetland quality. A study was conducted on wetland mapping, inventory and change detection wetlands of Thavanur Grama Panchayath in Malappuram district of Kerala using multispectral satellite imageries of high resolution (2.4x2.4m) during the year 2020-2021. The image processing was carried out by Visual Interpretation Technique. The accuracy of mapping was assessed by kappa coefficient. The various wetland classes found in Thavanur Grama Panchayath were Aquaculture, Marshy land, River and other ponds and small waterbodies. The major wetlands identified in the Panchayath were Ayankalam kayal, Maravanchery kaayal, Varo kaayal, Thavanur kaayal (marshy type wetlands), Bharathapuzha River, Ayankalam aquaculture, Mathur aquaculture and several other ponds. The change detection analysis showed that the percentage change in wetland during the decade was found maximum for pond and well (-33.18%). The major land use changes during the period 2008 and 2018 were that coconut plantation increased by 70.79 ha, paddy land decreased by 61.62 ha and marshy land decreased by 7.04 ha. The kappa coefficient of mapping was obtained as 0.93 which indicted good accuracy.