STREAM NETWORK DELINEATION USING ARC HYDRO AND TauDEM: A comparison of approaches using The Upper Sevier and the Little Bear River Basins Alphonce C. Guzha

OBJECTIVES (a) To evaluate river network delineation using: Arc Hydro tools Terrain analysis using Digital Elevation Models (TauDEM) The National Hydrography dataset (b) Compare drainage densities obtained from each of these methods

Upper Sevier The Upper Sevier River Watershed covers the headwaters of the Sevier River, Garfield, Iron, Kane, Wayne and Piute Counties in south-central Utah.

Little Bear

Data Sources Data for this project was obtained from : http://www.seamless.usgs.gov NED http://www.nhd.usgs.gov NHD

Arc Hydro The following procedures were performed: Terrain Preprocessing DEM reconditioning Filling sinks Flow direction and accumulation Stream definition and segmentation Catchment grid delineation and polygon processing Drainage line processing and adjoint catchment processing

TauDEM Seven different procedures for stream network delineation available: Use of existing streams DEM curvature based approach Contributing area threshold Grid order threshold Area and slope threshold Area and length threshold http://hydrology.neng.usu.edu/taudem/

For this project I selected only three methods: Existing streams-Stream network raster defined from D8 flow directions function DEM curvature based-Method flags entire grid and examines each quadrant of 4 grid cells and unflags the highest. Remaining flagged cells are deemed "upwards curved" and these define the channel network. Contributing area threshold-  A threshold on the contributing area is computed by the D8 method and this is used to delineate streams.

DEMs UPPER SEVIER LITTLE BEAR

Results Upper Sevier ArchHydro NHD Flowlines

ArcHydro NHD Length of drainage (km) 1840.5 2488.4 Drainage area (km2) 3115.2 3222 Density (km-1) 0.59 0.77

Little Bear NHD flowlines ArcHydro

NHD ArcHydro Length of drainage (km) 559.36 462.2 Drainage area (km2) 743 717 Density (km-1) 0.75 0.64

Upper Sevier TauDEM DEM curvature based

Little Bear TauDEM DEM curvature based

Upper Sevier Parameter DEM curvature Existing streams Contributing area Threshold Drainage Density (km-1) 0.63 0.69 0.72 Drainage Length (km) 2039 1998 2178 Drainage area (km2) 3236.5 2897.0 3025.1

Little Bear Parameter DEM curvature Existing streams Contributing area Threshold Drainage Density (km-1) 0.66 0.61 0.70 Drainage Length (km) 471.9 420.3 506.5 Drainage area (km2) 715 689 723.5

Threshold Levels Upper Sevier ArcHydro- 6 Existing streams –8 DEM curvature – 8 Contributing area- 15 (automatically selected) Little Bear

General conclusion Generally the different methods used give values of drainage density that close match. The various TauDEM tools give results that are close to each other and closely match the NHD networks The value of the stream threshold used is very critical in the delineated networks

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