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A Simple Drainage Enforcement Procedure for Estimating Catchment Area Using DEM Data

A Simple Drainage Enforcement Procedure for Estimating Catchment Area Using DEM Data. David Nagel, John M. Buffington , and Charles Luce U.S. Forest Service, Rocky Mountain Research Station Boise Aquatic Sciences Lab Boise, ID October 20, 2011. Study Area. Middle Fork Salmon River.

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A Simple Drainage Enforcement Procedure for Estimating Catchment Area Using DEM Data

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  1. A Simple Drainage Enforcement Procedure for Estimating Catchment Area Using DEM Data David Nagel, John M. Buffington, and Charles Luce U.S. Forest Service, Rocky Mountain Research Station Boise Aquatic Sciences Lab Boise, ID October 20, 2011

  2. Study Area Middle Fork Salmon River 10,000 km of rivers and streams ~ 1,000 km used by salmon

  3. Our Purpose Estimate catchment area Discharge Grain size Salmon spawning habitat

  4. Data 10 m NED DEM dataset http://ned.usgs.gov/ NHD stream lines http://nhd.usgs.gov/

  5. Problem NHD stream DEM flow line Flow accumulation lines from DEMs do not match vector stream lines

  6. Drainage Enforcement Objective Non-enforced Enforced Recondition the DEM so all cells drain toward the stream and downstream

  7. Foundation of Watershed Analysis • Fill • Flow direction • Flow accumulation Fill Direction Accumulation

  8. Flow Accumulation 1,000 12,000 Counting up the number of cells that contribute to a location on the stream = catchment area

  9. Raster Accumulation to Vector Raster accumulation 12,000 cells Attribute corresponding vector

  10. Mismatch Between Raster and Vector Without Enforcement Non-enforced Enforced Can’t attribute vector if data are mismatched

  11. Why the DEMs and Stream Lines Do Not Match in Flat Valleys

  12. DEM Production Process 1) Aircraft 2) Aerial photo 3) Stereo plotter 6) LT4X 4) Map production 5) Scan and tag LT4X, Infotec Development, Inc.

  13. Original Contours and 10 m DEM Model 500 m LT4X Original 40’ contours 2 m contours derived from 10 m DEM Blue box = 100 m x 100 m

  14. Original Contours and 10 m DEM Model With Streams LT4X 2 m contours derived from 10 m DEM Original 40’ contours

  15. LT4X made the DEMs from the original contours There were no contours in flat valleys, so there wasn’t information for generating the DEM data Cartographers drew stream lines where they saw them, independent of the LT4X model

  16. Why Not Use LiDAR? Site scale vs. landscape scale

  17. Drainage Enforcement Algorithms • ANUDEM - ArcGIS • AGREE – Arc Hydro Tools • IDDEA – Forest Service

  18. ANUDEM Implemented by ArcGIS (Topo to Raster) Not designed for reconditioning DEMs directly - requires contour lines or point input Contour file sets may become too large Avoids “trenching” Hutchinson, M.F., 1989. A New Procedure for Gridding Elevation and Stream Line Data with Automatic Removal of Spurious Pits. Journal of Hydrology, 106:211-232.

  19. AGREE Algorithm Implemented by Arc Hydro Tools Dewald, T., NHDPlus User Guide, U.S. EPA and USGS, April 29, 2008 Hellweger,F., 1997. AGREE — DEM surface reconditioning system. Center for Research in Water Resources

  20. Drainage Enforcement with AGREE Original Reconditioned Arcs must point downstream Sharp drop may modify watershed boundaries Uses “trenching”

  21. IDDEA Method Inverse Distance Drainage Enforcement Algorithm Grid stream lines Generate Euclidean distance from all stream lines Drop stream by constant value (e.g. 200 m) and Invert distance, multiply by constant: (1/d) * 1000 Subtract result from original DEM Where cij, 200, else eij – ((1 / dij) * 1000) cij is a stream channel cell at raster location ij eij is the elevation at ij dij is the Euclidean distance at ij

  22. 1) Grid Stream Lines Vector to raster conversion

  23. 2) Euclidean Distance from Streams

  24. 3) Inverse Euclidean Distance (1/d) * 1000 100 10 200 0.1 50 Value decreases (unitless) 200 0.02 Force constant drop (200 m) at stream channel Enforcement decreases away from the channel

  25. DEM Minus Inverse Distance minus =

  26. Profile Results Preserves relative topography and watershed boundaries

  27. Run Flow Accumulation Non-enforced Enforced

  28. Attributing Vectors Non-enforced Enforced Higher probability of accurately attributing vectors with the correct contributing area

  29. Results Comparison

  30. Disadvantages of the IDDEA Method “Trenches” the DEM Meander bends smaller than cell size get cut off and reroute flow “Trenching” Cut-offs

  31. Advantages of the IDDEA Method Works relatively quickly at landscape scales Preprocessing of raster or vector data is not required Preserves relative topography and watershed boundaries

  32. Thank you

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