Current state of water resources in Vyzhnytskyi National Natural Park

Abstract

Abstract: The study presents a comprehensive assessment of the current state of water resources in Vyzhnytskyi National Natural Park, located in the Bukovinian Carpathians of western Ukraine. The research applies an integrated hydrological, geomorphological, and hydroecological approach to investigate the functioning of small mountain river systems and to evaluate their response to climatic variability and localized anthropogenic pressures. The park occupies an area of 11,238 ha, of which 8,246.2 ha are provided for permanent use by the park administration, while the remaining territory is utilized by other land users according to functional zoning. The park lies within the basins of the Cheremosh River (a tributary of the Prut) and the Siret River (a tributary of the Danube) and is characterized by a dense network of small mountain streams, including the Vyzhenka River with its tributaries Mala Vyzhenka and Liskivets, as well as the Stebnyk, Sukhy, and Lekechi rivers. River feeding is dominated by precipitation, supplemented by snowmelt and groundwater inflow.

The methodological framework combines field hydromorphological surveys, measurements of flow velocity and channel geometry, meteorological observations, and analysis of long-term hydrological data. Remote sensing and GIS techniques were employed to examine channel patterns, floodplain structures, erosion and sedimentation processes, and land-use dynamics within river catchments. Satellite-based datasets, including CHIRPS (Climate Hazards Group InfraRed Precipitation with Station data) for precipitation (2000–2025) and GLDAS (Global Land Data Assimilation System) for soil moisture, were processed using the Google Earth Engine platform to quantify seasonal and interannual hydroclimatic variability.

The results reveal pronounced seasonal contrasts in precipitation and soil moisture, with maximum rainfall occurring in summer, frequently in the form of high-intensity convective storms, and minimum values recorded in winter, mainly as snowfall. Significant interannual variability was identified, with annual precipitation ranging from 201.5 mm in 2009 to 1,220.3 mm in 2024. Soil moisture dynamics display a clear seasonal pattern, peaking in spring and summer, closely correlated with precipitation trends, thereby confirming the dominant influence of climatic factors on the hydrological regime of the park’s river systems. Observed shifts in flood timing and magnitude, increased discharge during extreme rainfall events, and instability of winter ice cover indicate a high sensitivity of mountain rivers to ongoing climate change.

Hydroecological assessment shows that most watercourses preserve a natural or slightly modified character. Morphological features such as rocky riverbeds, rapids, waterfalls, and V-shaped valleys promote self-purification processes and sustain high levels of aquatic biodiversity. Localized anthropogenic impacts are primarily concentrated near settlements and recreational zones and include riparian vegetation degradation, partial channel regulation, bank reinforcement, siltation, and solid waste accumulation. The Vyzhenka River basin and the lower reaches of the Stebnyk, Sukhy, and Lekechi rivers exhibit the highest degree of human influence, whereas the upper reaches of the Stebnyk and Sukhy rivers remain dominated by natural erosional processes driven by flow energy and localized land-use changes.

Overall, the ecological condition of the park’s water bodies corresponds to a “good” hydromorphological status in accordance with the EU Water Framework Directive (2000/60/EC). The study emphasizes the necessity of long-term hydrological monitoring and adaptive water management strategies to maintain ecological stability under conditions of climate variability and increasing anthropogenic pressure. The findings provide a scientific basis for improving hydrological observation networks, designing conservation measures, and implementing sustainable water resource management within protected mountain areas. Furthermore, the integrated application of field investigations, remote sensing, and GIS analysis demonstrates an effective methodological approach for hydroecological assessment and supports evidence-based decision-making for biodiversity conservation and ecosystem management.