Delineating Sub-Watersheds UsingTerrain Analysis in ArcInfo
Chris KlaubeLandscape Ecology
704:450
➲Objectives
➲Rundown in ArcInfo Workstation
➲Speedbumps / Caveats
➲Results
➲Discussion
The Task
➲Delineatesubwatershedboundaries usingDEM and Contourlayers
➲HUC-23 to HUC-26
➲HUC- HydrologicalUnit Code
The Watershed
Goals
➲To compare stream layer derived fromcounty with stream layer created fromDEM
➲To create a 2-ft Contour layer for theentire watershed
Data
➲Original DEM and Contour layers fromNJDEP
➲Monmouth County provided original streamlayer
ArcInfo Commands
import
project
fill
flowdirection
flowaccumulation
*streamnet
streamorder
streamlink
streamline
watershed
streamnet
➲Set threshold for the flow accumulation atseveral different values in order to create astream layer with the right intricacy
➲Usagestreamnet = con(flowacc>2000, 1)
➲Set at: 2,000 -- 1,000 – 500
Stream Layers
Creating Contours
➲Original Contour layer used to delineateHUC-polygons was at a 10-ft interval
➲Used ArcInfo to create 2-ft interval contour
➲Usage:
LATTICECONTOUR <in_lattice> <out_cover><interval> {base_contour} {contour_item}{weed_tolerance} {z_factor}
Caveats
➲New layers created by ArcInfo were in UTMprojection
➲Used ArcMap and ArcCatalog to redefine inNJ Stateplane
Arc Toolbox Data Management Tools Projections and Transformations
➲New Contours begin at elevation ‘0’
References
➲ESRI GIS and Mapping: Support Center.2006. <http://support.esri.com/>