Technical Bulletin No. 0516: Modification to the Groundwater Solute Transport Model, the Random Walk, and User's Manual for NCASI Version, GWSTRW

This bulletin discusses NCASI's modification of the groundwater solute transport model, Random Walk, and describes the NCASI version of the model, GWSTRW. Some advantages of the GWSTRW model over the previous versions are as follows: (a) the GWSTRW model minimizes the modification of the Fortran source code needed for each application, (b) the new data input format is self-illustrating and easy to revise, it is more flexible for non-uniform input variables, (c) the model allows specification of the initial contamination condition, (d) it offers restart capability for hydraulic simulation. Finally new algorithms are built into the model which include (a) steady state hydraulic head calculations when multiple wells are located in an artesian or a water table aquifer and (b) provision for first order decay of the contaminant.