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Abstract

Wetlands are crucial for water regulation, habitat creation and carbon storage within river valleys. On the other hand, they are particularly sensitive to groundwater variability, especially in terms of the biodiversity and carbon emission. We propose a methodology of estimation of the uncertainty of the groundwater level in wetlands based on groundwater numerical modelling, Monte Carlo simulations, and spatial (GIS-supported) calculations. Random but realistic scenarios of recharge of the wetlands’ groundwater constitute the input to the groundwater model which is looped in Monte Carlo simulations producing series of random output groundwater heads. A large number of simulations enables statistical analysis of the whole spectrum of the groundwater variability, both in vertical as in horizontal dimensions. When compared to the threshold conditions, the statistics stemming from the simulations may be than used to calculations of the risks of biodiversity loss, carbon emission and overall health of the wetlands.As the case study we selected semi-natural wetlands in the valley of the River Rospuda (North-East Poland). A scenario reflecting the current recharge applied to the first-level aquifer in the wetlands revealed relatively limited variability of the groundwater head which in turn translates into stable conditions of the habitats. However, a scenario of slight deficit of water result in drastic drop of mean groundwater level which may be dangerous for the wetlands’ welfare.