GMS includes an interface to the UTCHEM model in the 3D grid module. UTCHEM is a multi-phase flow and transport model developed by the Center for Petroleum and Geosystems Engineering at the University of Texas at Austin. UTCHEM is ideally suited for pump and treat simulations, particularly the simulation of surfactant-enhanced aquifer remediation (SEAR). Future iterations of the GMS/UTCHEM interface will include the simulation of biodegradation.