## 2 The Geo-Hydrological Framework of the Study Area  
The Shkoder city and municipality are positioned in a karst depression of the southeastern Dinarides and developed along the shores of a large lake that takes its name from this city [9]. According to the current political geography, the lake is located between Albania and Montenegro state boundaries and approximatively two-third of its surface administratively belong to the latter [10]. In the south-west a mountain range, which reaches up to 1600 m a.s.l., physically separates the lake from the Adriatic Sea, just 12 km far (Figure 1). Figure 1: Location map of the study area. (**A**) Albanian Buna–Drin river system (in light blue) with the study area (in red). (**B**) Detailed view of the study area in relation to the Shkoder lake: The solid yellow line represents the border between Albania and Montenegro. (**C**) The geological map of the study area, modified from [11] (the Albanian and Montenegro geological surveys are quite different, therefore formations not affected by thrust, i.e., late Cretaceous Flysch, are shown with different colour/names). In panel (**B**,**C**) the dashed yellow line is the Albanian Ramsar boundary, the solid red line delimits the Shkoder municipality, and the yellow dot is the sublacustrine spring. The lake represents a crypto-depression in the Visoki KrS tectonic unit (mainly composed by Mesozoic carbonates, Figure 1C) with a Dinaric direction, being oriented northwest-southeast: 44 km in the longer axis and 14 km in width. The maximum depth is approximatively 60 m in an underwater Montenegrin doline which hosts a sublacustrine spring, called Radus Oko, through which a carbonate aquifer discharges [9]. Excluding this confined peak of depth, the Shkoder lake is a shallow body of water with a mean depth of around 5 m with a maximum of 8.3 m [12]. The average altitude of the lake surface is 6.5 m a.s.l. and the water level can vary seasonally approximately from 4.7 up to 9.8 m a.s.l. in the late summer and during the spring, respectively [10]. Therefore, the depth of the lake extends below the sea level over an area that covers about 44% of the lake surface. Such fluctuations are due to the strict relation between the bathymetry, the lakebed morphology, and the seasonal cycles of the incoming waters (surface drainage and temporary or permanent karstic springs) which influence significantly the areal variation of the covered areas and their associated wetlands. The areal extension seasonally fluctuates between 370 and 600 km\({}^{2}\)[10; 12] with extensive inundations during the spreading of the higher water levels in the northern and eastern flat shore areas, including most of the plot of lands surrounding Skhoder [12]. The most important tributary of the lake is the Moraca River since it provides about 63% of the lake's water and most of the sediments and nutrients. The remaining percentage of flow contribution derives from a series of minor and short rivers. Because of heavy rain over several months, the lower parts of the inflowing rivers fall below the water level of the lake [12]. The Buna River is the only emissary river with an average outflow of 304 m\({}^{3}\)/s. It starts from the southern coast and after a sharp curve, it passes through a narrow rocky passage about few hundred meters downstream the source. This morphological feature is also the main southern geographic doorway to enter the city of Shkoder, historically developed from here northwards. In fact, the oldest settlement that has been inhabited since the Bronze Age, is located on the top of the right slope in that area [13], strategically controlling the passage from north to south in a safe position from enemies and natural events. After the conjunction with the major channel of the lower Drin River (3500 m from its beginning at about 1300 m from the southern outskirts limits of the city) the waters, increased in quantity, flow directly to the Adriatic Sea.