This program performs a multipurpose routing of flows in a reservoir system for up to twelve periods of uniform or varying length per year based on varying flow requirements at reservoirs, diversions and downstream control points. Power peaking and energy requirements at reservoirs can be accommodated. The program can accept any nonlooping configuration of reservoirs, diversions, power plants and requirements, but does not provide for channel routings (i.e., attenuation of flows in river channels) or percolation losses. It can assign economic values to all outputs and summarize and allocate these in various ways. It can automatically iterate to optimize yield at a specified location. The flexibility of input and output requirements and of computation techniques enable the program to solve relatively simple problems with minimum effort or elaborate complex problems with a relatively high degree of accuracy. The program is intended for use on a variety of computer systems, and for this reason, coding is in FORTRAN IV and adheres as much as possible to operations that are common to FORTRAN software available to practically all large computers.