leche

Effective way of dealing with a large number of lakes in a DEM?

Discussion created by leche on Oct 18, 2010
Latest reply on Oct 20, 2010 by Lady_Jane
Hi,

I am working on an area in with a large number of lakes and interested in performing hydrologic modeling using ArcHydro. I was wondering what is the best approach for handling lakes when processing a DEM with ArcHydro? I tried different methods and many failed to give a reasonable result; flow direction with value ranging from 1 to 255, small number of watershed, etc.
Here is the best approach I had so far:
1.I Leveled the DEM using the lake polygon (the lake don???t have any level or height data), performed the DEM reconditioning using the vector stream data available, filled all the sinks in the resulting DEM, then run the regular flow direction and flow accumulation , etc.
I also tried the following:
2.I Leveled the DEM using the lake polygon, performed the DEM reconditioning using the vector stream data available, filled the sinks in the resulting DEM using the deranged polygon option and using the lake polygon shapefile, then run the regular flow direction operation. The result was a flow direction raster with values ranging from 1 to 255 instead of an esri type coded flow direction raster. I then run the flow accumulation many time but the operations never finished.
I finally tried filling all the sinks in the DEM except the lake areas and run the flow direction, flow accumulation, and so on, but the result was similar to 2.
I was wondering if someone could describe a better working approach for handling DEM in area with large number of lakes and depressions.

Thanks in advance

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