Delineating Sub-Watersheds Using Terrain Analysis in ArcInfo

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Delineating Sub-Watersheds Using Terrain Analysis
in ArcInfo

• Chris KlaubeLandscape Ecology
• 704450

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• Objectives
• Rundown in ArcInfo Workstation
• Speedbumps / Caveats
• Results
• Discussion

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The Task

• Delineate subwatershed boundaries using DEM and
  Contour layers
• HUC-23 to HUC-26
• HUC- Hydrological Unit Code

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The Watershed
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Goals

• To compare stream layer derived from county with
  stream layer created from DEM
• To create a 2-ft Contour layer for the entire
  watershed

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Data

• Original DEM and Contour layers from NJDEP
• Monmouth County provided original stream layer

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ArcInfo Commands

• import
• project
• fill
• flowdirection
• flowaccumulation
• streamnet

streamorder streamlink streamline watershed
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streamnet

• Set threshold for the flow accumulation at
  several different values in order to create a
  stream layer with the right intricacy
• Usagestreamnet con(flowaccgt2000, 1)
• Set at 2,000 -- 1,000 500

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Stream Layers
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Creating Contours

• Original Contour layer used to delineate
  HUC-polygons was at a 10-ft interval
• Used ArcInfo to create 2-ft interval contour
• Usage
• LATTICECONTOUR ltin_latticegt ltout_covergt
  ltintervalgt base_contour contour_item
  weed_tolerance z_factor

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Caveats

• New layers created by ArcInfo were in UTM
  projection
• Used ArcMap and ArcCatalog to redefine in NJ
  Stateplane
• ? Arc Toolbox ? Data Management Tools ?
  Projections and Transformations
• New Contours begin at elevation 0

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References

• ESRI GIS and Mapping Support Center. 2006.
  lthttp//support.esri.com/gt