  Energy flux is an acoustic propagation model that calculates the
locally-averaged intensity without computing explicit eigenvalues or tracing
rays. The energy flux method has so far only been used for two-dimensional
problems that have collapsed the third dimension by rotational or translational
symmetry. This report outlines the derivation and implementation of a
three-dimensional ocean acoustic propagation model using a combination of
normal modes and the energy flux method. This model is specifically derived for
a wedge environment with a radial sound speed front at some distance from the
shoreline. The hybrid energy flux model's output is compared to that of another
propagation model for this environment that is built on normal modes alone.
General agreement in the shape, location, and amplitude of caustic features is
observed with some discrepancies that may be attributable to inherent
differences in the model derivations. This work serves as a stepping-stone
toward developing a more generalized three-dimensional energy flux model.
