Converting a NEXRAD Rainfall Map into a Flood Inundation Map by ...

main conceptual components for the integration system is described in thischapter as well as the case study used for the pilot implementation and proof ofconcept.3.1.1 Identifying Modeling ElementsThe modeling features in a hydrologic or hydraulic simulation model mustbe uniquely identified so that input and output time series associated with themcan be labeled appropriately. For the purpose of this integration this uniqueidentifier is called the "ModelCode".In HEC-HMS the identification of modeling elements is done by using theHMSCode, which is a text string used within HEC-HMS to identify each modelfeature (called a Hydrologic Element in HEC-HMS); in HEC-RAS there is nosingle identifier used within the RAS model, rather each cross-section is identifiedby its stationing distance from the upstream end of a river, a river is broken intoreaches, which generally flow from confluence to confluence in a river network.An effective RASCode is thus constructed by joining the river, reach, andstationing labels in a comma separated text string.3.1.2 Geographic RepresentationsThere must be an exact one-to-one match between the geographicrepresentation of modeling elements in the hydrologic and hydraulic model and inthe GIS. ModelCode attributes must be attached to the corresponding Arc Hydrofeatures.For HEC-HMS, the geographic match is accomplished by using the ArcHydro schematic network, and by associating HEC-HMS Hydrologic Elements,26