## 2 Methodology and Database  
### Study Area  
The watershed chosen as the study area has a surface area of 1183.23 km\({}^{2}\) and is located in the North-West Region of Romania, mostly in Cluj County (Figure 1). The upper Somes Mic watershed is located in the south-western part of Cluj County. From an administrative perspective, the study area comprises a series of 11 administrative territorial units (Belis, Budureasa, Capusu Mare, Floresti, Gilau, Maguri-Racatau, Manastireni, Margau, Marisel, Risca, and Savadisla). The study area has a range of altitudes, with the lowest point being 360 m and the highest point being 1700 m. Within this range, there are different categories of hills and mountains. The area of low and medium hills, with altitudes between 360 and 500 m, covers 109.82 km\({}^{2}\); the category of high hills, with altitudes between 501 and 750 m, covers 245.55 km\({}^{2}\); the category of very high hills, with altitudes between 751 and 1000 m, covers 185.27 km\({}^{2}\); and the category of low-altitude mountains, with altitudes between 1001 and 1500 m, covers 592.51 km\({}^{2}\). The remaining 50.06 km\({}^{2}\) falls within the category of medium-altitude mountains, with altitudes between 1501 and 1700 m.  
The study area is characterized by steep slopes, with slope values between 11.25\({}^{\circ}\) and 22.5\({}^{\circ}\), representing 35% of the entire area. The remainder of the study area is covered by moderately sloping slopes with values between 4.5\({}^{\circ}\) and 11.25\({}^{\circ}\), representing 25%. Very steep slopes and horizontal slopes each account for 18% of the area. With the smallest percentages of 1% and 3%, respectively, are very gently sloping slopes, gently sloping slopes, and steep slopes. As to mean annual temperatures, in the study area they vary between 1.6 \({}^{\circ}\)C and 9 \({}^{\circ}\)C. Temperatures below 6 \({}^{\circ}\)C are considered moderate, while temperatures above 6 \({}^{\circ}\)C are considered high and are suitable for agricultural practices in Romania. The multiannual mean precipitation within the study area ranges from 688 mm/yr to 1300 mm/yr. This value, which is considered average, is due to differences in elevation ranging from low and medium hills (360-500 m) to medium-elevation mountains (1501-2000 m). For the largest extent of the study area, the mean annual precipitation ranges from 1000.1 mm/yrto 1200 mm/yr, an area represented by low-altitude mountains. Therefore, the study area has a good water supply over most of the territory. The study area is covered by a total of 18 soil types, categorized into 8 soil classes, each of which has different properties. From a pedological point of view, the analyzed territory presents soils of the Cambisols class on the largest area (722 km\({}^{2}\), representing a percentage of 61% of the analyzed area) and soils of the Spodosols class on an area of 204 km\({}^{2}\), representing 17%, and Clay-visols cover 114 km\({}^{2}\) of the studied area (10%). The Antrisioils class represents 5%, occupying 59 km\({}^{2}\). The Cernisols class occupies 4% (43 km\({}^{2}\)), and the additional class (Waters) 3% covers 38 km\({}^{2}\), with the remaining area containing soils belonging to the Vertisols and Hidrisoils classes. In the study area, forest vegetation occupies the largest portion, covering 62.64% of the total land. This forest is primarily a mix ofiferous and deciduous species, including _Abies alba, Pinus sylvestris, Carpinus betlulus, Populus alba_, and _Salix_. Permanent grasslands account for 19.77% of the area, consisting of alpine and subalpine calcareous grasslands, rupicolous Pannonian grasslands, and basophilic grasslands from the Alysso-Sedion albi group. Unproductive lands, mainly covered by swamp vegetation, make up 6.89% of the total area. Arable lands, used for agriculture, occupy 5.17%. Built-up areas, classified under courtyards and constructions, account for 2.94% of the study region.