Integrated spatio-temporal analysis of coastal shoreline dynamics of Kozhikode district, southwest India, using remote sensing and Digital Shoreline Analysis System (DSAS)

A comprehensive analysis of long-term shoreline alterations is crucial for effective coastal zone management and for strategizing future coastal development. The current investigation examines a prolonged period (1990–2015) of shoreline transformations along the coastline of Kozhikode district, Kerala, India, employing geo-informatics methodologies. The High Water Line (HWL) was identified as the delineation of the shoreline, which was ascertained through remote sensing technologies and subsequently vectorized. The shoreline has been updated to encompass river creeks and their mouths. The Digital Shoreline Analysis System (DSAS), a tool developed by the United States Geological Survey (USGS) as an extension of ArcGIS, was utilized to ascertain the rate of shoreline change. The Linear Regression Rate method was employed to derive the shoreline change rate. The current DSAS shoreline change analysis revealed that approximately 59.24% (45.5 km) experiencederosion, 0.13% (9.98 km) remained stable, and 40.63% (31.20 km) experienced accretion during the period from 1973 to 2020 within the study area. The coastal taluk exhibiting the most significant erosion in Kozhikode district is Vadakara (Zone I). The rate of erosion is notably higher in Vadakara taluk (82%) compared to Quilandy taluk (53%). The lack of seawalls and other protective shoreline structures has contributed to an increased rate of erosion. Accretion is predominantly observed in the vicinity of harbor areas. The geomorphological characteristics and the presence of resilient rock formations, such as charnockite, along the shoreline also affect the dynamics of erosion and accretion. This study has been conducted at the taluk level in Kozhikode district, providing critical data that can assist coastal managers and researchers in fostering sustainable practices in coastal zone research, management, and planning.