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Creating Watersheds

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#1
burwelbo

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I am ttrying to delineate the watersheds for a mapping project in Namibia using ArcMap 9.2. I know I have done this before but can't seem to get what I want. I have filled the sinks, calculated the Flow Direction and Flow Accumulation grids and am now trying to create the watersheds. It looks like I need a Pour point file or grid. Is this not the Flow accumulation grid? Can I calculate this file using Flow Accumulation?

Any help with the methodology would be appreciated.

Bruce

#2
burwelbo

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I figured it out. You need to run Basin, not Watershed. The problem I was having was caused by not filling the sinks. If you don't, you get an out of memory error.

#3
MapMedia

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Good - another thing you want to be aware of is the type of DEM you are using. USGS's new hydro dems reflect true routing of hydrology. Otherwise it is prudent to 'burn' the surface hydrology into the dem so it reflects the true routing of surface wates/canals/etc.




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