Impact of climate change on permanent lakes in a semiarid region: Southwestern Mediterranean basin (S Spain)

Abstract

In recent decades, many wetlands in the Mediterranean watershed have dried up. We forecast the impact of climate change on the hydrology of three permanent lakes in a semiarid areo of the southwestern Mediterranean region. To achieve this, we applied daily water balance models to calculate variations in water levels and validated our approach using actual lake level measurements spanning over 20 years. To delve into groundwater/lake interactions, we calculated several hydrological indices and compared evaporation with the water level drop during extremely dry periods. After validating the three hydrological models, we applied the RCP 4.5 and RCP 8.5 climate change scenarios. We found Zóñar Lake highly resilient to climate changes because of groundwater contributions, resulting in minimal lake level oscillations even during periods of low rainfall. However, spring management and/or groundwater extractions may affect the lake hydroperiod. The Amarga and Grande lakes have weaker lake/groundwater interactions and show significant water lake level fluctuations, making them more sensitive to climate change. Indeed, our model predict that these lakes will transition into semipermanent or seasonal playa-lakes by mid-21th century. We found that deep and spring and/or groundwater-fed lakes are less vulnerable to climate changes. These results highlight the importance of developing robust hydrogeological models in such water bodies, focusing on the climate changes vulnerability of wetlands in semiarid regions, in order to formulate an integrated strategy for water resources management.