International Journal of Research and Scientific Innovation (IJRSI) |Volume IX, Issue IX, September 2022|ISSN 2321-2705
Detection of Surface Water Bodies and Cyanobacterial Blooms using Satellite based Remote Sensing
U.A.D.N. Anuradha*, M.A.A. Karunarathne
Department of Electronics, Wayamba University of Sri Lanka, Kulitapitiya, Sri Lanka
Abstract: For many environmental applications, accurate surface water maps are crucial. It is possible to construct surface water maps by merging data from multiple sources. Due to sensor limitations, complex land cover, geography, and atmospheric conditions, accurate surface water estimation using satellite imagery is still a difficult undertaking. In this study, Sentinel 1 images from Google Earth Engine (GEE) was used to derive a high-resolution water mask. To overcome the limitation of visible satellite images which is the presence of clouds, on this research was focused on using Synthetic-Aperture Radar (SAR) sensors, like Sentinel-1, which penetrate clouds and permitting to get a view of the earth surface, even when clouds are presence. To validate the proposed method, it was applied to three study cases which are located in different climate zones in Sri Lanka. In the meanwhile, this research implemented a time series of Sentinel 2 satellite images from GEE to monitor the distribution of cyanobacterial blooms on those lakes. Recent years have seen an increase in the frequency and severity of cyanobacteria in recreational lakes and reservoirs, which has become a serious concern for the public’s health and a serious environmental danger. Monitoring cyanobacterial blooms serves as the foundation for early detection and treatment. Therefore, the results of this study could be used as a benchmark for future environmental monitoring and management of these Sri Lankan lakes and reservoirs.
Keywords: Synthetic-Aperture Radar, Water Mask, Cyanobacterial Blooms, Satellite Images, Google Earth Engine, Vegetation Index
I. INTRODUCTION
A. Surface Water Detection
Surface water refers to water found in wetlands, rivers, lakes, and the ocean that is located close to the surface of the planet. Due to the ocean’s size and salinity, smaller water bodies are typically included in the definition instead of the ocean. Surface waters are important freshwater resources for both humans and ecosystems. Mainly lakes and reservoirs act as climate regulators and Carbon cycling. It provides water for multiple human practices, from drinking water to recreation, and they support a high level of biodiversity as well as agriculture. For many environmental applications, including flood forecasting and warning, agricultural and urban water management, and modelling the transport of contaminants in water bodies, high-resolution extents of surface water form and dynamics are essential limitations [1]. Since water absorbs the majority of radiation above the near infrared