Catchments and Watersheds
Catchments and watersheds to define drainage areas of the land surface that contribute flow to particular edges on the HydroNetwork. A catchment is the local drainage area associated with a particular HydroEdge. A watershed is a collection of catchments capturing the entire land surface area draining through a connected set of HydroEdges. Hydro response units define the hydrologic properties of the land surface.
This chapter includes:
· Catchment and Watershed definitions in the ArcGIS Hydro Data Model
· Raster based techniques for drainage delineation
· Sample raster based drainage delineations
· Drainage delineation using the hydro network
· Hydro response unit basics
Click here to view the PDF version of Chapter 4
Chapter 4 Data
The Washita.mdb Geodatabase contains the FlowEdges, Edge Catchments, and Hydro Points of the Upper Washita Watershed in Oklahoma. These three datasets represent each of the three data types available for use in the ArcGIS Hydro Data Model, namely points, lines, and polygons. The other feature classes (Watershed, Waterbody, and HydroEdges) were created when the model was instantiated, and they do not contain any data. WashitaNet_Junctions is a point feature class that was created upon building the WashitaNet geometric network. These junctions are located at the intersections of the FlowEdges, and are used in performing network traces.
The geodatabase (in zipped format) can be found in the folder ArcGIS\Chapter4\Chapter4data, along with the DLL file needed in order to run the ArcGIS Hydro Data Model in ArcCatalog or ArcMap. For instructions on how to use the DLL file and deploy the data model, go to the Instructions page.
This geodatabase was derived from data obtained from the Nation Elevation Dataset - Hydrologic Derivatives web site. It may be downloaded from http://edcnts12.cr.usgs.gov/ned-h/washita.html as of 6/15/00.
Chapter 4 Display
The data from Chapter 4 can be viewed as a map document in ArcMap.
