Masses for six-high-velocity flows have been determined from observations of emission from the two lowest rotational transitions of /sup 12/C/sup 16/O and /sup 13/C/sup 16/O. Our method of mass determination is presented in detail, along with an estimation of the magnitude of the uncertainty in the derived values. Derived masses are expected to be within a factor of 2--3 of the actual values. Values for flow momenta, kinetic energies, and mechanical luminosities are also presented. Two determinations of these flow parameters are made for each source: one in which flow inclination to the line of sight is assumed to produce the variation of T(/sub R/ with velocity in the flow and one in which all material is assumed to be moving along the line of sight, and thus no correction for flow inclination need be applied. The actual values of flow momenta, kinetic energies, and mechanical luminosities are expected to be between these two extremes.