Factors affecting bluff development around a mountain reservoir: a case study in the Polish Carpathians

ABSTRACT Evolution of the bluffs within the shore zone of a reservoir is dependent on many environmental factors. In this study, a characterization of bluffs was presented with reference to the entire shore zone of a mountain reservoir. The research was conducted on the Czorsztyn reservoir – one of the largest functioning reservoirs within the Polish Carpathians (created in 1997). The analysis was based on a study conducted in 2015 and 2016 with the use of a Terrestrial Scanning Laser (TLS) and Airborne Laser Scanning (ALS), (data from 2013). The objectives are to identify the bluffs’ height on the mountain reservoir shoreline and assess the impact of various environmental factors (geological basement, slope exposure and gradient, bluff position in a different part of the reservoir, water level, wave height and the presence of landslides) on bluff development. Environmental factors were assessed using statistical methods, Beta factor and Principal Component Analysis. After 18 years of operation, bluffs on the reservoir covered 89% of the shoreline. The maximum height reaches about 10.00 m, and most often does not exceed 2.00 m. The most developed bluffs (height) are found in the south-western and western exposures of the shoreline. Amongst the analyzed factors affecting the bluff development on the Czorsztyn reservoir, the wave height, water level, the position of bluffs within the shoreline, slope gradient and exposure were identified as the dominant factors based on statistical analysis. Due to the fact that multiple factors are acting together, the distinction of the dominant factor affecting bluff development is difficult.