Spatio-temporal analysis of shoreline changes and future forecast using remote sensing, GIS and kalman filter model: A case study of Rio de Janeiro, Brazil

Abstract

Shoreline changes embrace alterations due to the physical features and location of the land-water boundary, which can arise from natural or human causes. Natural processes, like sea level fluctuations, erosion, and sediment deposition, impact coasts. Human activities also significantly influence shoreline changes. The study area's shoreline extends 59.80 km from Reduto de Sao Teodosio to Barra de Guaratiba. The study analyzed shoreline changes along a 60 km stretch of the southern coast of Rio de Janeiro (Reduto de Sao Teodosio to Barra de Guaratiba) from 1986 to 2018. This study examines historical shoreline positions, calculating change rates and predicting 2032 and 2042 positions using satellite imagery spanning 1972–2022. The historical shoreline was reconstructed using earlier satellite data. Digital Shoreline Analysis System (DSAS) tools (EPR, LRR, NSM) in ArcMap were then used to quantify change rates statistically. The EPR model reports a maximum annual accretion rate of 19.33 m and a maximum erosion rate of −4.91 m, while the LRR model indicates a maximum accretion rate of 21.31 m and a maximum erosion rate of −5.04 m. In contrast, the NSM model calculates a notably higher maximum accretion rate of 945.96 m and a much more substantial maximum erosion rate of −240.34 m. These findings informed the mapping of anticipated 2032 and 2042 shorelines, helping identify areas of gain and loss, highlighting the vulnerability of certain regions. It's important to note that human activities, such as alterations in beach topography, can influence these models. Protective measures, like those in Rio de Janeiro, Barra Da Tijuca, and Recreio Dos Bandeirantes, may affect erosion and accretion patterns. Additionally, coastal development activities, including seawall dredging, can disrupt natural processes. Effective management of shoreline changes is essential to safeguard ecosystems and communities, with strategies encompassing beach nourishment, vegetation restoration, and sustainable coastal development. Resilient, adaptive coastal management balances human needs and environmental protection amid ongoing changes.