CSDMS TauDEM Clinic “Hands On” Exercise¶
Introduction¶
Goal¶
Be able to use TauDEM tools to derive hydrologically useful information from Digital Elevation Models (DEMs)
Purpose¶
The purpose of this exercise is to introduce Hydrologic Terrain Analysis using TauDEM and to guide you through the steps of running some of the more important functions required to delineate a stream network. Comprehensive documentation on the use of each TauDEM function is given in the online help that is part of the program. TauDEM (Terrain Analysis Using Digital Elevation Models) is a set of Digital Elevation Model (DEM) tools for the extraction and analysis of hydrologic information from topography as represented by a DEM. This is software developed at Utah State University (USU) for hydrologic digital elevation model analysis and watershed delineation and may be obtained from http://hydrology.usu.edu/taudem/taudem5.0/. In this exercise, you will perform the following tasks:
- Basic Grid Analysis using TauDEM functions, including.
- Pit Remove
- D8 Flow Directions
- D8 Contributing Area
- Grid Network
- D-Infinity flow direction
- D-infinity Contributing Area
- Stream Network Analysis using TauDEM functions, including
- Stream Definition by threshold
- Move Outlets to Streams
- Stream Reach and Watershed
- Peuker Douglas
- Peuker Douglas Stream Definition
- Specialized Grid Analysis using TauDEM functions, including
- Wetness index derived from slope to area ratio
- D-Infinity Distance Down
Data¶
For this tutorial the Logan River watershed is used as an example; you can get it from demo data link . Once you extract the archive, you will get:
- logan.tif - GeoTiff Digital Elevation Model (From USGS)
- LoganOutlet.shp - ESRI Shapefile vector data
All data are in EPSG:26912 - NAD83 / UTM zone 12N.
Software¶
- QGis - You can get it from the download section of QGis site
- Sextante Plugin with the TauDEM extension for Sextante
- TauDEM
You can get more information about the installation in the main page
Basic Grid Analysis using TauDEM functions¶
Pit Remove¶
Pits are grid cells surrounded by higher terrain that do not drain. Pit Remove creates a hydrologically correct DEM by raising the elevation of pits to the point where they overflow their confining pour point and can drain to the edge of the domain. For more info check Pit Remove in TauDEM help.
Pit Remove Window
Just use logan.tif as input and loganpitrem.tif as output. To double-check the resoult you can use Raster Calculator (Raster menù) to create a map made of the differences between the output and the input.
Area changed by Pit Remove tool
D8 Flow Direction¶
This function takes as input the hydrologically correct elevation grid and outputs D8 flow direction and slope for each grid cell. For more info check D8 Flow Direction in TauDEM help.
D8 Flow Window
The resulting D8 flow direction grid is illustrated in the next figure. This is an encoding of the direction of steepest descent from each grid cell using the numbers 1 to 8 with this encoding: 1 - East, 2 - Northeast, 3 - North, 4 - Northwest , 5 - West, 6 - Southwest, 7 - South, 8 - Southeast. . This is the simplest model of the direction water would flow over the terrain.
D8 Flow Output