Integrated assessment of future potential global change scenarios and their hydrological impacts in coastal aquifers – a new tool to analyse management alternatives in the Plana Oropesa-Torreblanca aquifer

Abstract

Abstract. Any change in the components of the water balance in a coastal aquifer, whether natural or anthropogenic, can alter the freshwater–salt water equilibrium. In this sense climate change (CC) and land use and land cover (LULC) change might significantly influence the availability of groundwater resources in the future. These coastal systems demand an integrated analysis of quantity and quality issues to obtain an appropriate assessment of hydrological impacts using density-dependent flow solutions. The aim of this work is to perform an integrated analysis of future potential global change (GC) scenarios and their hydrological impacts in a coastal aquifer, the Plana Oropesa-Torreblanca aquifer. It is a Mediterranean aquifer that extends over 75 km2 in which important historical LULC changes have been produced and are planned for the future. Future CC scenarios will be defined by using an equi-feasible and non-feasible ensemble of projections based on the results of a multi-criteria analysis of the series generated from several regional climatic models with different downscaling approaches. The hydrological impacts of these CC scenarios combined with future LULC scenarios will be assessed with a chain of models defined by a sequential coupling of rainfall-recharge models, crop irrigation requirements and irrigation return models (for the aquifer and its neighbours that feed it), and a density-dependent aquifer approach. This chain of models, calibrated using the available historical data, allow testing of the conceptual approximation of the aquifer behaviour. They are also fed with series representatives of potential global change scenarios in order to perform a sensitivity analysis regarding future scenarios of rainfall recharge, lateral flows coming from the hydraulically connected neighbouring aquifer, agricultural recharge (taking into account expected future LULC changes) and sea level rise (SLR). The proposed analysis is valuable for improving our knowledge about the aquifer, and so comprises a tool to design sustainable adaptation management strategies taking into account the uncertainty in future GC conditions and their impacts. The results show that GC scenarios produce significant increases in the variability of flow budget components and in the salinity.

GIS-SWIAS: Tool to Summarize Seawater Intrusion Status and Vulnerability at Aquifer Scale

“…Due to the heterogeneous distribution of seawater intrusion, distributed information and assessments are required to study its impacts [8,30]. For this reason, the methods for modelling [34,35] SWI impacts and the userfriendly tools developed based on them [36][37][38] also require distributed inputs and calculations.…”

“…e results obtained with these physical process models can be applied to assess sustainable management strategies, i.e., strategies that prevent deterioration of the aquifer resource due to SWI [6]. ey can even be employed to propagate impacts of potential local climate change (CC) [7] or global change (GC) scenarios and to identify adaptation strategies [8].…”

Summarizing the impacts of future potential global change scenarios on seawater intrusion at the aquifer scale

“…O F Many authors have assessed hydrological impacts of CC and/or LULC changes in the SWI phenomenon using sharp interface or density-dependent flow models to simulate hydraulic head and salinity in the aquifer (Pulido-Velazquez et al 2018;Romanazzi et al 2015;Klove et al 2014;Rajan et al 2006). Potential climate scenarios are deined by simulating future emission scenarios within physically based climatic models [general circulation models (GCMs) and regional climatic models (RCMs)].…”

Are climate models that allow better approximations of local meteorology better for the assessment of hydrological impacts? A statistical analysis of droughts

“…As far as we know, there are not studies that analyse if climate models that provide the best approximations of the local historical meteorology provide also better assessments of the hydrological impacts. In these cases, the generated local climatic scenarios have to be propagated by using hydrological models (Senent-Aparicio et al, 2018;Pardo-Igúzquiza et al, 2017).…”