The 3DHP data model will require a hydro-enhanced elevation surface that reflects the flow characteristics of the hydrography network. The elevation data source will be enhanced with the z-values assigned to the vertices of the hydrography network so that the hydro-enhanced surface contains flowpaths reflected in the hydrography. We will discuss use cases for hydro-enforcement, the hydro-enhancement process in 3DHP, and the derivatives planned to support the 3DHP data model.