Supercomputers in subsurface transport research: HYDROGEOCHEM on the Hypercube computer

Hydrologic, geochemical, and coupled hydrologic-geochemical models serve as tools for testing various hypotheses about the underlying processes at laboratory and field scales and for identifying questions which must be addressed for making fundamental advances. HYDROGEOCHEM has been developed by interfacing FEMA, a finite-element transport model, with MINEQL and CHEMEQUIL, which are chemical equilibrium models. The iterative-solution algorithm in FEMA provides significantly faster execution speeds and decreased storage requirements in comparison with direct solution methods, and CHEMEQUIL offers substantial reduction in CPU time and storage requirements over MINEQL and similar programs. Error-propagation schemes are being incorporated in the chemical module of HYDROGEOCHEM. 5 refs. (ACR)