As an alternative to the RiverWare Exchange utility, (see “Exchange Description” for details), some RiverWare users employ a data object-based approach to track water exchanged between accounts. In this approach, the user tracks the exchange with rules that reference specifically named slots on data objects. This section describes a utility, called the Data Object Exchange Builder, that helps to create this type of exchange by adding slots to the data object and creating supplies on the workspace. The rules must be defined by the user; no further discussion is provided as to what the rules do or how they are written.