The most important input variable required is the local energy slope. This may be equal to the average energy slope of the river, but can be significantly higher at bends or near structures that disrupt the flow patterns. Issues relating to choice of energy slope value are discussed in the user guidelines. Further input data required includes the proposed angle of the bank after installation of the rip-rap and the maximum depth of the flow at the site, rock characteristics (natural angle of repose and specific gravity) and a design factor of safety. Finally a depth of interest can be specified to ensure thatthe program lists a particular depth that may be of interest to the designer.

Output from the program is of two types - tabular and graphical.

Output data consists of a table of required rock size at a range of depths and bank angles.

Graphical data is simply a graph of required rock size against depth, with separate lines for the different bank angles.

It must be noted that the RIPRAP program performs the rock stability analysis only.

Other important aspects of rip-rap design include calculation of, or choice of energy slope value, toe anchoring of rip-rap, rock gradation, and filter design. These issues are discussed in the Design Guidelines but are not part of the RIPRAP software.