Monitoring hydrostatic level variability on the banks of several canals in the Danube delta

The Danube Delta is a dynamic wetland system where surface and groundwater are closely interconnected, primarily influenced by the water levels of the Danube River. Given the shallow depth of the water table, the fluctuations in river discharge can impact groundwater levels in the delta. This study shows hydrostatic levels along the banks of several canals in the Danube Delta through field measurements conducted during high-water (spring) and low-water (autumn) periods. Shallow boreholes were drilled using a hand auger manual set to determine groundwater levels and analyze sediment composition. During fieldwork, it was observed that when groundwater was encountered in the boreholes, the water often began to rise until reaching a stable level. The extent of this rise was influenced by the sediment type affecting the distance the water travelled before stabilizing. This highlights the role of sediment composition in controlling groundwater movement, particularly in relation to capillarity and permeability. The collected data were used to generate spatial representations of hydrostatic variations. Furthermore, correlations were established between sediment granulometry, groundwater fluctuations and hydrological extremes, revealing some relationships between sediment characteristics, surface hydrology and subsurface water dynamics in this complex deltaic environment. The results contribute to highlighting the groundwater behaviour in response to seasonal water level changes, with potential implications for wetland management.