Impact assessment of combined climate and management scenarios on groundwater resources and associated wetland (Majorca, Spain)

Climate change impact on a groundwater dependent wetland and natural recharge has been investigated in the Inca-Sa Pobla coastal aquifer for the year 2025. Temperature and precipitation based on the downscaled output from a general circulation model (GCM) was coupled to a groundwater model to estimate the impacts of climate change and management practices on groundwater. Management practices were based on changes in the volume of water extracted for agricultural and domestic purposes. Climate change impacts on the hydrogeological system were based on downscaled HadCM3 outputs for future medium-high (A2) and medium-low (B2) greenhouse gas scenarios developed by the IPCC [IPCC, 2001. Climate change 2001: the scientific basis. In: Houghton, J.T., Ding, Y., Griggs, D.J., Noguer, M., Van Der Linden, P.J., Dai, X., Maskell, K., Johnson, C.A. (Eds.), Contribution of Working Group I to the Third Assessment Reports of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 881 pp]. Assessment of the impacts on the water level of the wetland were carried out by estimating the flow rate of springs discharging from the aquifer obtained by changes of agricultural land use and water supply allocation and variation of recharge according climate scenarios. The greatest reduction in recharge was observed in scenario A2 (-21%), while recharge in scenario B2 remained relatively unchanged (-4%). However, as uncertainties arising from GCM outputs maybe greater than the differences simulated here results are only indicative of the system response. In order to preserve the spring discharge at its current level (17Mm³/yr), which successfully prevents the wetland from drying up, a decrease in groundwater extraction is needed. In addition, the reallocation of agricultural wells is recommended under both scenarios. Spring discharge was affected the most by agricultural wells located near the wetland, as indicated by the sensitivity analysis.