Spatial and temporal water table dynamic of a common alder riparian forest

Forested riparian areas are valuable because they are rich in biodiversity and more productive than their adjacent upland areas, but they could be threatened by drought. The groundwater level of the riparian zone is an important parameter to quantify the forest hydrological processes thus for their survival. This study examines the influence of riparian zone groundwater level dynamics on the water balance of an alder forest. 

Our research area is a streamside alder ecosystem at the eastern foothills of the Alps, in Hidegvíz Valley (Hungary) experimental catchment. We analysed the water table dynamics in the period 2017-2022 using seven manually detected groundwater wells data. In the case of a selected well, we measured groundwater levels using an automatic pressure probe with high frequency. The related meteorological parameters were also collected in the immediate vicinity of the area.

Using manually measured groundwater level data we found that in summer dry periods streamside water table fall below the level of the streambed causing the stream status changes from effluent to influent. 

Using high frequency water table data we analysed groundwater temporal dynamic and relationship with other environmental parameters seasonally. According to our calculations alder forest ecosystem groundwater transpiration is great in hot rainless periods. As a conclusion these riparian forest types can be characterised as a vulnerable ecosystem  in the changing climate because long dry periods will become more and more common in the future.

Acknowledgement: This article was made in frame of the project TKP2021-NKTA-43 which has been implemented with the support provided by the Ministry of Innovation and Technology of Hungary (successor: Ministry of Culture and Innovation of Hungary) from the National Research, Development and Innovation Fund, financed under the TKP2021-NKTA funding scheme.