WaterNet: A GIS Application for the Analysis of Hydrologic Networks Using Vector Spatial Data

Traditionally, stream and sub-watershed characterization in GIS has been accomplished using a DEM-based terrain analysis approach; however, there is a large amount of existing vector hydrographic data difficult to accurately reproduce using DEMs. WaterNet is a GIS/hydrologic application for the integration and analysis of stream and sub-watershed networks in vector format. Even with vector data, hydrologic inconsistencies between streams and sub-watersheds do exist, and are revealed in the form of streams crossing drainage divides and sub-watersheds with more than one outlet. WaterNet rectifies these inconsistencies and couples the two datasets. Most algorithms involving traces of dendritic networks employ a form of tree traversal which requires topologic information to be organized into specialized data structures. On the contrary, WaterNet develops topologic relationships from GIS attribute tables, which, in combination with sorting and querying algorithms, make the calculation process efficient and easy to implement. With the topologic relationships of the streams and sub-watersheds, WaterNet can perform traces to calculate cumulative network parameters, such as flow lengths and drainage areas. WaterNet was applied to the catchment of the Texas Gulf coast for a total of 100 cataloging units (411,603 km 2 ) and 60,145 stream lines (183,228 km). Address for correspondence: Francisco Olivera, Department of Civil Engineering, Texas A&M University, 3136 TAMU, College Station, Texas 77843-3136, USA. E-mail: [email protected] 356 F Olivera, S Koka and J Nelson © 2006 The Authors. Journal compilation © 2006 Blackwell Publishing Ltd Transactions in GIS , 2006, 10(3)