Natural ResourcesCivil EngineeringHydrologyHydrologic ModelingUrban HydrologyWatershed HydrologyHydrograph AnalysisRainfall-runoff AnalysisRainfall-runoff ModelingRainfall-runoff ProcessesRainfall-runoff RelationshipsUrban Watershed HydrologyHydrograph FormationInfiltrationInfiltration LossesLinear Reservoir TheoryRunoff EstimationUrban Runoff HydrologyUrban Runoff ModelingUrban Runoff Routing
The Santa Barbara Urban Hydrograph (SBUH) method is a simple means of developing runoff hydrographs from urban watersheds using local data. To use the method, the watershed is divided into pervious and hydraulically connected impervious portions. Rain falling on the impervious portion is considered to be 100% runoff. Rain falling on or flowing across pervious portions is subjected to infiltration losses, the magnitude of which depend on antecedent rainfall. The resulting rainfall excess for each time period is converted to a rate of flow. The instantaneous hydrograph thus obtained is routed through an imaginary linear reservoir with a routing constant equivalent to the watershed time of concentration to obtain the final hydrograph.