Shoreline dynamics using cloud platform and remote sensing: a case of Maharashtra Coast, India

The coastal regions of Maharashtra, India are experiencing significant shoreline changes due to both natural and anthropogenic factors. This study investigates these changes using Google Earth Engine, Digital Shoreline Analysis System (DSAS) and ArcMap, focusing on seven coastal districts of Maharashtra state namely Palghar, Thane, Mumbai Suburban, Mumbai, Raigarh, Ratnagiri, and Sindhudurg. Multi-temporal Landsat satellite images were used for extraction of historical shoreline (1993 to 2023) in cloud platform Google earth engine and further were analyzed in DSAS and ArcMap10.7. Statistical techniques like Shoreline Change Envelope (SCE) and Net Shoreline Movement (NSM) were used to measure the spatial extent of shoreline shift. The rate of change was calculated using the End Point EPR) and Linear Regression Rate (LRR) to quantify the rate of coastal erosion and accretion. Around 8416 transects were placed at 100m intervals along the coast, with approximately 32% of the transects indicating erosion, 44% accretion and remaining are in stable condition. The research revealed that Palghar experiences the most dramatic shoreline alterations among the seven coastal districts, with highest rate of erosion (EPR) -20.5 m/yr. Aside from that, Mumbai has the highest accretion rates up to a maximum (EPR) 50 m/yr. Thane, Mumbai, Ratnagiri and Sindhudurg has eroded less in comparison to Raigarh and Mumbai Suburban coast. LRR yields the average erosion at -1.13 m/yr and average accretion at 2.31 m/yr from 1993 to 2023 for 1486km long shoreline of Maharashtra. The Net areal change was estimated to be 20.43 sq.km was calculated by subtracting total area lost from total area gained over the three decades. Finally, recognizing the erosion and accretion hotspots using cloud computing, remote sensing and Geographic Information System along the larger region like Maharashtra coast can assist academicians, policymakers and stakeholders. This research also enables remote sensing and coastal researchers to understand regional shoreline dynamics.