『Abstract
　This paper analyzes the results of a theoretical simulation of sea water intrusion and its dynamics. The assignment of hydrochemical facies identifies whether the aquifer is in the phase of sea water intrusion or freshening, indicating the status of the aquifer in terms of the advance or regression of the saline front. A new multi-rectangular diagram is proposed that aids interpretation of these important processes through the representation and evolution of hydrochemical facies (hydrochemical facies evolution diagram, HFE-D). As an example, the HFE-D is applied to an alluvial aquifer in the Vinaroz-Peniscola（nの頭に〜、iの頭は´） Plain (Spain), where Ca-Cl facies characterize the sea water intrusion phase, while Na-MixHCO3/MixSO4 facies characterize a freshening stage.』

Introduction
Cation exchange reactions and dynamics of sea water intrusion
Hydrochemical facies in the sea water intrusion and freshening stages
Diagram to identify hydrochemical facies evolution (HFE) in the intrusion and freshening stages
Conclusions
Acknowledgments
References