## 2 Materials and Methods  
### Study Area  
Cluj County, with an area of 6674 km\({}^{2}\), is located in the NW part of Romania, between the parallels of 46\({}^{\circ}\)24\({}^{\prime}\)47\({}^{\prime\prime}\) and 47\({}^{\circ}\)28\({}^{\prime}\)44\({}^{\prime\prime}\) north latitude and the meridians of 23\({}^{\circ}\)39\({}^{\prime}\)22\({}^{\prime\prime}\) and 24\({}^{\circ}\)13\({}^{\prime}\)46\({}^{\prime\prime}\) east longitude, and includes 81 Territorial Administrative Units (TAUs). Cluj County is located in the center of Transylvania at the intersection of three large physical-geographical units, namely: Transylvania Plain, Somesan Plateau (Cluj and Dej Hills) and the Apuseni mountain area (Figure 1). The geomorphological, lithological, bioclimatic and pedological differentiation creates a great variability of vegetation factors in this area. Of the total area of the county, 63.8% is occupied by agricultural land, 25.1% by forest land, 2.9% by constructions, 1.8% by roads, and 5% by degraded and unproductive land. The hilly area of Cluj County is geographically part of the greater Transylvanian Depression. This represents the largest inter Carpathian negative morphological area, formed during the alpine cuts, with a general appearance of hills and plateaus, tectonically compartmentalized into sequences of geomorphological zones, arranged almost concentrically, in increasingly lower steps, from the outside to the inside, with great variations in structure and relief from one area to another [36; 37]. The Transylvanian plain includes the southeastern part of Cluj County, and is characterized by altitudes between 250 and 500 m, with gentle hills separated by narrow valleys, often with excess humidity, with ridges on southern exposures and with gentle slopes and  
Figure 1: The geographical location of the study areas; (**a**) Batin river basin, (**b**) Risca river basin, (**c**) Chinteni river basin. slope processes on northern exposures. The average annual temperature is 8-9\({}^{\circ}\)C and the annual total precipitation is 500-600 mm. Starting from a partially woody vegetation, but with a dominating grassy hay vegetation, clay parent materials rich in calcium carbonate, in interaction with the other solidification factors, favored the strong dominance of bioaccumulation, forming black soils in this area: chernozem, cambic chernoziom, faeoziom, rendzina, pseudorendzine, etc. [36]. The Somesan Plateau includes the central and northwestern part of Cluj County. In the Somesan Plateau, the relief is much more energetic and active, with intense slope processes triggered over time. The southern slopes are short and steeply segmented, with ravines and torrents. The northern slopes are longer, colder, and undulating, with the general elevation between 450 and 800 m. The average annual temperature is 7-8 \({}^{\circ}\)C and the average annual precipitation is 600-700 mm. The specific conditions of areas in the forest area with a rainfall surplus of +50 to +100 mm annually and parent materials poorer in basic elements led to the predominance of weakly to moderately acidic bioaccumulation and leaching, with the formation of soils from the class of luvisols: preluvosol, luvosol, etc. Pseudoglyic soils or pseudoglyic subtypes, to varying degrees, are also common. The premontane area of the Apuseni mountains is located in the northwestern marginal part of Cluj County; although in some places it presents a gentler relief, it differs climatically and ecologically, and this continues with the montane area, where between 800 and 1200 m altitude only, some areas are still worked as arable on plateaus and southern exposures. The three river basins (Figure 2) chosen for the IntErO model implementation belong to the three large physical-geographical units previously mentioned. The Batin river basin and village of Batin are located in the northern part of the Transylvanian Plain, the southeastern part of Cluj County, equidistant from the cities of Beckean, Dej and Gherla.