ANALYSIS OF DEGRADATION PROCESSES IN RESERVOIRS ON THE BASIS OF REMOTE SENSING DATA

Abstract

Aim of the study: The primary objective was to assess spatio-temporal changes of the vegetation occurring in 12 reservoirs located in the Odra River basin. The analysis was made for reservoirs of different constructions, i.e. single stage, two-stage and lateral. The second purpose was to analyze possibility using remote sensing data to monitor the dynamics of the vegetation processes. Material and methods: Monitoring and mapping of spatio-temporal changes of the vegetation occurring in the reservoirs was analyzed on the basis on Sentinel-2 data. The analysis was based on the NDVI and the WAVI indices. To specify spatial changes of vegetation, the reservoirs were split into zones equals to 250 m.The statistical analysis was aimed at comparing the NDVI and the WAVI values between designated zones. In turn, Cluster analysis (CA) was used to group reservoirs into clusters on the basis of similarities between the NDVI and the WAVI values. Results and conclusions: Cluster analysis (CA) showed that each reservoir is separate water body where decisive impact on degradation process could have different factor. There was observed that two-stage construction focuses degradation processes in pre-reservoir and protect water resources in the main part. Additionally, relatively new solution – lateral reservoirs seems to be alternative preventing degradation processes. Taking into account possibility of using satellite imagery, there was observed that resolutions of Sentinel-2 satellite imagery allow to monitor vegetation processes in terms of time and space. The major limitation of using remote sensing data is high cloud density, which significantly reduces the number of observations during most of the year.

Keywords

• reservoirs
• water transparency
• satellite imagery
• sentinel-2
• overgrowth process