Phys. Geog. Geom. 2025, 48(1): 18–25

https://doi.org/10.17721/phgg.2025.48.1/129.01

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Geomorphometric and climate analysis of a river basin system using freely-available global geodatasets (the case of the Bystrytsia Pidbuzka)

Ivan S. Kruhlov, Olesia O. Burianyk, Anatoliy D. Smaliychuk
Ivan Franko National University of Lviv, 41, P. Doroshenka St, Lviv, 79000, Ukraine

 

Abstract
A river basin system, which is used to study channel runoff, is hierarchically represented as a network of sub-basins. Geomorphometric (altitude, surface slope) and climatic (air temperature, precipitation) properties of the sub-basins are important factors determining runoff. To predict river runoff, future changes in climatic indicators must also be taken into account. We selected the Bystrytsia Pidbuzka river basin of 500 km² located at the junction of the low Carpathian Mountains and the Forecarpathian Upland to demonstrate possibilities of a geomorphometric and climatic analysis using freely available global geodata.
The radar digital elevation model FABDEM V1-2 has a resolution of 30 m. It afforded delineation, using functions of digital hydrological analysis, a system of 21 sub-basins ranging from 63 to 5038 ha and referring to the stream links of 4–6 Strahler orders. We applied zonal statistics function to calculate mean altitude and slope values of the subbasins, which are in the range of 259–656 m and 0–13°, respectively. FABDEM V1-2 afforded rather accurate delineation of the watersheds and realistic calculation of the slope even within flat terrain. However, it had to be modified by “burning in” of the stream network.
Climatic geodata CHELSA V2.1 with a resolution of ~1 km was used to determine the average annual and average monthly air temperature and precipitation values of the sub-basins for 1981–2010, as well as the probable average annual values of these indicators for 2071–2100 according to the SSP3-7.0 climate change scenario. Again, the zonal statistics function was applied for this purpose. At the beginning of this century, the average annual temperature of the sub-basins was +4 – +8.5°C, and the average annual precipitation was 726–1055 mm. The SSP3-7.0 scenario projects an increase in average annual temperature by 3.6°C in all sub-basins with a slight increase in precipitation. CHELSA geodata does not reliably characterize small dissected basins due to insufficient geometric resolution. Nevertheless, CHELSA geodata is convenient for quick actual and future climate analysis for both regions and local areas over 10 km².

Keywords
Basin system, the Bystrytsia Pidbuzka, geomorphometry, climate change, CHELSA climatic geodata, FABDEM digital elevation model

 

Received: 3 March 2025 / Accepted: 23 March 2025 / Published online: 30 March 2025