An Uncertainty Analysis Approach for Ecosystem Sustainability Based on Groundwater Footprint

Groundwater Footprint (GWF), introduced by Gleeson et al. in 2012, is a groundwater management tool that emphasizes on groundwater dependent ecosystems sustainability. It expresses the areal extent of an aquifer required to cover human needs for groundwater and at the same time to fulfill groundwater-related environmental flow requirements. The estimated aquifer area could be compared to the actual size of the aquifer, in order to assess groundwater use and sustainability.

Natural and artificial recharge, groundwater abstraction and groundwater contribution to the environmental flow are the key parameters in GWF estimation. Reviewing the related literature, the aforementioned key parameters uncertainty is underlined. Consequently, the quantification of the uncertainty associated with these parameters is essential to ensure the robustness of GWF indicator for water management assessments. Special concern should be paid on environmental flow estimation as although there are about more than 200 reported estimation methods, defining environmental flow still incorporates many uncertainties.

Groundwater Footprint (GF), introduced by Gleeson et al. in 2012, is a groundwater management tool that emphasizes on groundwater dependent ecosystems sustainability and expresses the areal extend of an aquifer required to cover human needs for groundwater and at the same time to fulfill groundwater-related environmental flow requirements. Natural and artificial recharge, groundwater abstraction and groundwater contribution to the environmental flow are the key parameters in GF estimation. Reviewing the related literature, the uncertainty associated with the aforementioned key parameters is underlined. The present study focuses on quantifying uncertainty in GF estimation for an aquifer in Central Greece, in Thessaly Prefecture, which is crossed by a river of great importance for the local economy and the sustainability of the local ecosystems. Each of the GF input parameters has been estimated based on available data deriving from previous reports and measurements, however they still incorporate uncertainties. To quantify GF uncertainty, Monte Carlo simulations have been performed using the GoldSim software. The estimated GF is equal to 1.2±0.4 times the actual size of the studied aquifer, indicating the need for better water management for the sustainability of the local groundwater dependent ecosystems. The results of the uncertainty analysis have pointed out the importance of achieving a reliable estimate of the GF key input parameters and the need for specifying environmental flow requirements based on the local ecological conditions.