Assessment of Flow Paths in Upland Areas and Vegetated Buffers August 2, 2004 I.J. Kim, S.L. Hutchinson, and J.M.S. Hutchinson* The department of Biological and Agricultural Engineering *The department of Geography Kansas State University, Manhattan, KS ASAE Annual Meeting 2004
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Assessment of Flow Paths in Upland Areas and Vegetated Buffers
Assessment of Flow Paths in Upland Areas and Vegetated Buffers. ASAE Annual Meeting 2004. August 2, 2004 I.J. Kim, S.L. Hutchinson, and J.M.S. Hutchinson* The department of Biological and Agricultural Engineering *The department of Geography Kansas State University, Manhattan, KS. - PowerPoint PPT Presentation
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Assessment of Flow Paths in Upland Areas and Vegetated Buffers
August 2, 2004
I.J. Kim, S.L. Hutchinson, and J.M.S. Hutchinson*
The department of Biological and Agricultural Engineering*The department of Geography
Kansas State University, Manhattan, KS
ASAE Annual Meeting 2004
Research Background (1)
Model assumption:– Uniform overland flow– Ex) WEPP, REMM, VFSMOD
Reality:– Concentrated surface runoff in fields– Dillaha, 1986 / Fabis et al, 1993 / Dosskey, 2002
Research Background (2)
Digital elevation model (DEM)– Calculation of hydrological attributes
• Slope, contour line, hill shade, aspect, etc• Flow path and length • LS factor
– Delineating contributing area (e.g. watershed)– Risk assessment for landscape susceptibility
30 m DEM widely used for GIS-Hydrologic model– Accessible data source (i.e., USGS 30m DEM)– Less costly
Typical grid resolution in DEM
SourcesSatellite imagery
Digitizing contour line
GPSLaser
system
Resolution 100(~1) 30~1 10~1 <100
Unit m m m cm or mm
High Cost and data storage
Purposes of Study
Delineating flow path networks and drainage boundaries for hillside areas and vegetated buffers
Determining a suitable grid size for parameterizing model inputs at field scale site
The study area: Fort Riley NE
Kansas River
NIR Image
Study Site
Hillside: grass
Buffer: brushes / trees
GPS Receiver Settings
Model PDOP* Operating mode
Trimble XR and XRS
<4.0Uncorrected GPS &
Post-processing(Differential Correction, DC)
•Date: March 24Date: March 24thth, 25, 25thth and April 14 and April 14thth 2004 2004
•Base station for DC: Range Control Office Station, Ft. RileyBase station for DC: Range Control Office Station, Ft. Riley
•PDOPPDOP**: position dilution of precision: position dilution of precision
•Accuracy: ± 50 cmAccuracy: ± 50 cm
•Vertical accuracy errorVertical accuracy error—a vertical control point (KF0640)a vertical control point (KF0640) —root mean square error (RMSE)root mean square error (RMSE)
Elevation Data Collection
Method for Creating DEM
Interpolation TOPOGRID in ArcInfo
Grid size (m) USGS 30 30 10 3
Accumulating Area (# of cell)
900 m2
( 1 )900 m2
( 1 )900 m2
( 9 )900 m2 ( 100 )
Delineating method(Arc Workstation)
D8
TOPOGRID is essentially based on a discretised thin plate spline technique and an iterative finite difference interpolation.
Limitations and Assumption
Accuracy of grid DEM is dependent on GPS accuracy Becoming overland flow to channel flow is dependent on the
contributing area (the number of cells)
Drainage network delineation:Eight direction (D8) model
E, 20
S, 22
W, 24
N, 26
•FILL / FLOWDIRECTION / FLOWACCUMULATION•Define flow paths from the specific accumulation area (# cell)•BASIN / FLOWLENGTH