APPLICATION OF GIS NETWORK ROUTINES FOR WATER-FLOW AND TRANSPORT

Network routines are implemented within several geographic information systems (GISs). These routines are primarily used in traffic routing and allocation analyses, and very little work has been done on their application in water resources. This paper describes Dijkstra's algorithm, which is used for most network implementations in a GIS and how its routing and allocation techniques can be implemented for water flow and transport. Dijkstra's algorithm is limited by the fact that it requires the resistance to flow be known before the magnitude of the flow is determined, but these two variables are usually interdependent. The consequences of this limitation with regard to water-resources applications is discussed. The types of problems suitable for GIS water-network analysis are identified. Three applications-drainage-network verification and sizing using rational method, watershed isochrone determination, and steady-state flow computations-are discussed in detail, and their network application within the Arc/Info GIS is presented. These applications are embedded directly within a GIS, thus simplifying the modeling environment.