BUGS Scratchpad 1.1 is a flexible contaminant fate and transport numerical model that includes chemical and biokinetic reactions. It simulates two dimensional fate and transport of multiple reactive solute and sorbed species. Reactions include single and multiple ordered, monod, double monod and competitive inhibition reactions; and kinetic or equilibrium paritioning.

BUGS Scratchpad 1.1 provides the following:

• One and Two Dimensional grid mesh with unlimited number of nodes.
• Saturated Steady-State flow.
• Unlimited number of reactive solutes.
• Unlimited number of reactive sorbed species.
• Equilibrium, Single Order Decay, Multiple Order Decay, Monod, Double Monod, Competitive Inhibition, Linear Partitioning, Langmuir Partitioning, and Freundlich Partitioning Reactions.
• Dual detailed form views and spreadsheet-like table views of most input variables.
• Integration with the Windowsclipboard, eliminating the entering of large datasets by hand.
• User-configurable spreadsheet-like output grids for viewing numerical output.
• User-configurable time series and profile graphs of any of the output variables.
• Printer support for output graphs.

To solve the governing equations, BUGS Scratchpad 1.1 implements the Integrated Operator Splitting method using an Explicit Finite difference solution for the transport of solute species and the Linear Integrated Method for the solution of chemical and biological reactions.

BUGS Scratchpad 1.1 is written to run under Microsoft Windows3.1, Windows 95/98 and Windows NT/2000. It has not been tested on Windows XP, Server 2003 or Vista.