Watershed Delineation above a POINT

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07-18-2010 01:39 PM
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AlirezaDaeminezhad
New Contributor
I am working with ArcHydro to delineate watersheds above some points which has been selected.
Please help me to find the way
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DaveMacDonald
New Contributor II
Nordicnebula,

I'm not an expert in ArcHydro but have been working on a project that involves batch delineating watersheds for specific points. Anyone please feel free to correct me if they see any problems with the methodology as per below, but it seemed to work well for me.

The version I used when creating this methodology was ArcHydro Version 1.4 ArcGIS 9.3 sp1.

Data requirements:

  • DEM (grid)

  • Watercourse/stream polyline shapefile or feature class

  • Point shapefile or feature class to generate the watersheds for. Must have a minimum of the following fields (see ArcHydro Help under for more details):


    • "Name": Name of the point, user entered

    • "Descript": Description of the point, user-entered

    • "BatchDone": Indicates whether the batch delineation functions should perform delineation on this point (�??0�??: delineate, �??1�??: do not delineate)

    • "SnapOn": Indicates whether the point is to be snapped when performing the batch delineations. Default value is "1", i.e. the batch delineation functions will try to snap the point.

    • "SrcType": Type of point. Default to 0 (Outlet). Used by function Delineate from Multiple Inlets and Outlets (Values: 0-Outlet, 1-Inlet)

Steps to follow in ArcHydro:

1. Burn streams into DEM: Terrain Preprocessing --> DEM Manipulation --> DEM Reconditioning
2. Fill sinks in resulting DEM: Terrain Preprocessing --> DEM Manipulation --> Fill Sinks
3. Create flow direction grid: Terrain Preprocessing --> Flow Direction
4. Create flow accumulation gird: Flow Accumulation
5. Define synthetic streams: Stream Definition
6. Stream Segmentation
7. Catchment Grid Delineation
8. Catchment Polygon Processing
9. Drainage Line Processing
10. Adjoint Catchment Processing
11. Watershed Delineation: Watershed Processing --> Batch Watershed Delineation

There are a number of parameters you will have to choose/set along the way. See ArcHydro Help for more information about these parameters. The process inevitably involves trail and error along the way to get the outputs looking how you think they should.

Note the toolbox that come with ArcHydro comes with a geoprocessing model called "Basic Dendritic Terrain Processing" (under Arc Hydro Tools --> Terrian Preporocessing WorkFlow) that combines several of these steps.

Hopefully this helps.

Good luck!

Dave

Dave MacDonald
GIS Coordinator
Saskatchewan Watershed Authority
DaveMacDonald
New Contributor II
Further to my comment above, I've since found a good tutorial document that details all the steps involved in the preprocessing to get to the watershed delineation step.
 
The document is called: "Arc Hydro Tools - Tutorial, Version 1.3 - January 2009" and is Downloadable from: http://andersonruhoff.googlepages.com/ArcHydro_Tutorial.pdf

It appears that I missed a few steps in my previous list that may be important.  The document states that:

"The steps in the Terrain Preprocessing menu should be performed in sequential order, from top to
bottom. All of the preprocessing steps from Flow Direction down to Adjoint Catchment Processing
must be completed before Watershed Processing functions can be used. DEM reconditioning, Build
Walls and Fill Sinks might not be required, depending on the quality of the initial DEM."

Cheers,

Dave