Abstract: A method and system for providing hydraulic modelers with the ability to accurately produce a surface representation of flow data that incorporates transitional elements in the underlying gravity hydraulic network is provided. The method includes triangulating surface techniques and smooth surface techniques that employ functions that enforce rules that preserve monotonicity as well as to preserve Q=0 when TW=HW. The value of Q can be calculated as well as the partial derivatives in the TW and HW directions for a point of interest. A smooth surface interpolation of the data, which maintains the above-noted conditions, and allows the quick evaluation of flow for any point in the data set, is provided.

Abstract: An hydraulics software system for a one-dimensional hydrodynamic numerical model for modeling unsteady flows in sewer and storm water urban drainage systems is provided. The inventive software uses as a numerical model, an implicit four-point, finite-difference solution technique to solve the one-dimensional Saint-Venant equations. The software is designed to select that numerical model, or equation that best describes, or best exhibits the behavior of each of the various structures and flows encountered in complex hydrodynamic systems such as a sewer and storm water drainage systems. Local partial initial modification for subcritical and supercritical transcritical flows is provided. Relaxation for pipe/channel networks are included for achieving computational performance and robustness for commercial software for practical use in water resource engineering.