The influence of temporal hydrological randomness on seawater intrusion in coastal aquifers

We investigate general effects of temporal hydrological randomness on seawater intrusion in coastal aquifers, using a 2D conceptualization and model parameterization of three coastal aquifer zones on the Mediterranean Sea. These three aquifer cases represent quite different examples of hydrogeological conditions and temporal hydrological and groundwater management variability and statistics. A general result for all aquifer cases is that the effects of temporal randomness on expected salinity in pumped groundwater are greater for spatially homogeneous than for spatially heterogeneous aquifer representations. We quantify also prediction uncertainty around expected groundwater salinity, in terms of the salinity standard deviation and coefficient of variation (CV) in the different aquifer cases. In general, the salinity CV appears to depend much more on the aquifer depth than on the input temporal fluctuation statistics of each aquifer case. Aquifer depth may thus be a main indicator for resulting prediction uncertainty in salinity of pumped groundwater due to temporal hydrological randomness.