Response to Comment on “Salt-Pump Mechanism for Contaminant Intrusion into Coastal Aquifers”

We appreciate the opportunity to elaborate on aspects of our analysis (1) that were con-densed largely because of space limitations. In our paper, we showed enhanced transport of organic compounds (OCs) from a salt-water source to a freshwater collector. The transport of organic molecules as a result of the “salt pump mechanism ” is clearly not a purely molecular diffusive process, and, in-deed, density differences between the salt-water and freshwater reservoirs influence the transfer of salt and OC across the sand inter-face. These effects were recognized implicit-ly in our paper. The main points we chose to stress were (i) the existence of a high “car