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Many storm-water modeling problems consider watersheds comprised of complex flow networks including surfaces, streets, pipes, and channels. Ideally, hydrologic methods would be used to model the accumulation of runoff on surfaces while hydraulic methods would be used to explicitly model the flow in each street, pipe, and channel. In many practical circumstances, only the largest pipes and channels are explicitly modeled with hydraulic methods. Thus, most subcatchments include numerous streets and small pipes that can affect the accumulation and movement of flow. Digital elevation models (DEMs) are widely used to determine geometric characteristics of these subcatchments, but street gutters and pipes are not resolved in such data. To overcome this problem, known streets and pipes are often “burned” into the surface by reducing the local elevations by a specified amount before calculating flow paths …