The impact of climate change on the dynamics of the water level of Lake Skadar

Lake Skadar is the largest freshwater body on the Balkan Peninsula. It is recognized as a wetland of international importance under the Ramsar Convention and holds the status of a national park in Montenegro. The results presented in this study indicate a significant downward trend in monthly water levels during the period 1948-2021, ranging from -14.9 cm in September to -24.0 cm per decade in May. Water levels show significant variation both seasonally and annually (cm per decade): from -16.8 (autumn) to -21.7 (spring), i.e., -19.3 (year). Standardized deviations suggest that the most pronounced decline began in 1981, a pattern further confirmed by the Rescaled Adjusted Partial Sums. Total precipitation in Lake Skadar's drainage basin has shown little to no change. However, there has been a significant increase in air temperature, and thus increased evaporation. According to ERA5-Land data, the annual total evaporation trend in the lake basin reaches up to 10.0 mm per decade. The substantial increase in evaporation has probably resulted in a significant reduction in runoff (Y) derived from precipitation contributing to stream flow. The trend of the mean annual runoff (Y) from 1 m2 is -45 mm per decade, and the flow of the Morača River, the main tributary of the lake, -2.5% per decade. Notably, over the past 14 years, Lake Skadar recorded both its highest water level (2010) and its lowest (2017). We appreciate that the long-term trend of falling water levels is influenced by significant warming of the atmosphere, which has led to increased water evaporation. Short-term fluctuations in lake water levels are primarily driven by variations in precipitation within the catchment area, which are likely linked to atmospheric oscillation patterns. In addition, human impact is evident near the confluence of the Morača River and Lake Skadar, particularly due to the intensive extraction of gravel and sand. To preserve the ecology and economy of Lake Skadar, its natural and cultural heritage, urgent measures are necessary by the countries (Montenegro and Albania) within whose territories this natural gem is located.