## 3 Method Validation
### River KRA  
The KRA River is located on the central Adriatic coast of Croatia (Figure 5) [28]. It is known for its attractive karst lakes, waterfalls, and long estuaries. The river system is comprised of several tributaries, cascading lakes, waterfalls, and long karstic estuaries. \begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline \multirow{2}{*}{\(\mathbf{Q}_{\textit{historic }}\)**(m\({}^{3}\)/s)**} & **Precipitation** & \(\mathbf{Q^{x}}\)_average,future_ & \(\mathbf{Q^{x}}\)_future_ & \(\mathbf{D^{x}}\)_future_ & \multirow{2}{*}{**FOS**} & \(\mathbf{D^{x}}\)_design_ & \(\mathbf{Q^{x}}\)_average,design_ \\  & **Change (\%)** & **(m\({}^{3}\)/s)** & & & **(m\({}^{3}\)/s)** & & **(m\({}^{3}\)/s)** & **(m\({}^{3}\)/s)** \\ \hline \multicolumn{8}{c}{Maximal change scenario for the year 2100} \\ \(Q_{average}^{average}\) (9.81) & Annual (\(-7\)) & 9.12 & 0.43 & 3.86 & 0.8 & 3.09 & 7.30 \\ \(Q_{average}^{max}\) (51.81) & Wet period (\(+7\)) & 55.44 & 0.77 & 42.63 & 1.2 & 51.15 & 66.53 \\ \(Q_{average}^{min}\) (4.29) & Dry period (\(-25\)) & 3.22 & 0.22 & 0.72 & 0.8 & 0.58 & 2.57 \\ \hline \multicolumn{8}{c}{Minimal change scenario for the year 2100} \\ \(Q_{average}^{average}\) (9.81) & Annual (\(-2\)) & 9.61 & 0.43 & 4.07 & 0.8 & 3.25 & 7.69 \\ \(Q_{average}^{max}\) (51.81) & Wet period (\(+2\)) & 52.85 & 0.75 & 39.62 & 1.2 & 47.54 & 63.42 \\ \(Q_{average}^{min}\) (4.29) & Dry period (\(-5\)) & 4.08 & 0.26 & 1.05 & 0.8 & 0.84 & 3.26 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Jadro Spring estimated variables for the year 2100, the first iteration. The catchment area of the Krka River is 2500 km\({}^{2}\) and is located in the coastal and mountain karst dinaride areas. According to the Koppen climate classification, the wider area of the Krka River is classified as Cfb/Cfa, where Cfa = moderately warm humid climate with hot summers and Cfb = moderately warm humid climate with warm summers. The total annual precipitation is approximately 900 mm, and the maximum precipitation (two-thirds of the total precipitation) is most likely to occur from September to March. The main Krka River spring near Knin is Krcic, at an elevation of 224 m a.s.l. There are several smaller springs that create temporary tributaries and karst lakes, of which Lake Visovac is the largest, with a series of waterfalls between them. Its long and attractive estuary begins downstream from the last waterfall, the Skradinski Buk, and continues through Sibenik Bay to Sv. Ante the channel to the sea (Figure 5). The river is 72.5 km long, and the estuary area is 23.5 km. The river has a large fall on the riverbed (average slope of approximately 0.3%) and seven waterfalls that have distinct landscape values (more than one million visitors in 2019). The river's large gross head and winter flows make it productive for hydropower generation; hence, five hydropower plants were built with small relative reservoirs. The landscape value of the river and its biodiversity are the main barriers to a more complete utilization of its hydropower potential. The river is the main source of drinking water for the two regional water supply systems, and there is a constant problem with the capacity of the water supply system during the peak tourist season because of the environmental streamflow restrictions at waterfalls. With the development of tourism, this problem will become increasingly complex and demanding. It is a karst hydrological system with a large catchment area and relatively open boundary in contact with the sea. It does not have a large retention capacity, and the transformation from input to output is fast. The river has a huge drop in its bed, which increases the flow energy of the streamflow, allowing the water to move fast through the river network. Specific hydrogeological settings are responsible for the dynamic recharge system manifested in river flow, which is highly responsive to rainfall (Figure 6). Figure 5: Overview of the coastal zone of the Sibenik-Krin County and Krka River catchment boundaries.