Utilization of Multi-Temporal Sentinel-1 Satellite Imagery for Detecting Aquatic Vegetation Change in Lake Rawapening, Central Java, Indonesia

Abstract

Lake Rawapening has high ecological, historical, and economic value​​, such as in terms of agricultural irrigation, fisheries, hydropower generation, and tourism. However, a major problem faced by the lake is the uncontrolled growth of aquatic vegetation. Monitoring of the dynamics of the condition of the vegetation cover on the waters needs to be conducted periodically as one of the lake management efforts. We propose an Automatic Aquatic Vegetation Extraction method to monitor the dynamics of the condition of the lake's vegetation using multitemporal C-band radar satellite imagery. The method utilizes data from the SAR satellite imagery to ascertain the maximum water boundary, which can be used to distinguish between aquatic and terrestrial vegetation. The Otsu algorithm approach was used to determine the boundary between land and water areas. The method was applied on several dates, employing VV and VH polarizations. The results show that the proposed method could rapidly monitor lakes and their aquatic vegetation from year to year. The overall accuracy of the study varied from 79.48 to 88.46 percent, with an average of 84.4 percent.

Keywords:

• Sentinel-1
• Otsu threshold
• Lake surface water detection
• Aquatic vegetation detection

Additional information

Funding

This paper is part of the research activities entitled ‘The utilization of remote sensing data to monitor watersheds and lakes in Indonesia.’ The research was funded by the National Research Priority activity at the Remote Sensing Application Center, Indonesian National Institute of Aeronautics and Space (LAPAN) in 2020. Thanks go to Dr. Orbita Roswintiarti, the Deputy of Remote Sensing LAPAN, Dr. Rokhis Khomarudin, the Director of the Remote Sensing Application Center LAPAN, and colleagues at LAPAN for their discussions and suggestions. The authors thank the anonymous reviewers for their efforts and constructive comments, which allowed us to improve the manuscript.