topic Re: Generate Streams from DEM in Water Resources Questions

Generate Streams from DEM

ClarkLangridge — Thu, 22 Sep 2016 16:48:18 GMT

Here is the some background. I am trying to create streams from DEM. The DEM data is LiDAR product, in 1 meter resolution. I exported a small area of the province. The number of raster cells = 1200million. I did the hydroconditioning of the DEM, Fill and Flow Direction. All finished successfully within decent time. But the Flow Accumulation took 40 hours to finish.

I was watching an online video on ArcHydro. The presenter said that the tools can be run on any size of data from a watershed to a whole state or even a country. I want to know how you would run the Flow Accumulation Tool for a state , in my case, a province.

Re: Generate Streams from DEM

DanPatterson_Retired — Thu, 22 Sep 2016 18:57:12 GMT

Did they say you could do this at the same cell size?

Re: Generate Streams from DEM

ClarkLangridge — Thu, 06 Oct 2016 10:58:16 GMT

Yes, same cell size as the 1 metre.

Re: Generate Streams from DEM

DanPatterson_Retired — Thu, 06 Oct 2016 11:58:26 GMT

You had better reduce the extent to what you actually need, or reduce the cell size. A doubling of the cell size will reduce the raster to 1/4 of its original size. Do you really need 1 m resolution for a flow accumulation? Is the input data that accurate? I would suggest that you would see better results if you to a reasonable cell size. Report the number of rows and columns that you have so further advice can be provided.

Re: Generate Streams from DEM

ArthurCrawford — Mon, 10 Oct 2016 18:02:25 GMT

Another option would be the tools from the Center for Research in Water Resources. I have used their Optimized Pit Removal to quickly process data to then get streams for large areas. I used this tool to extract streams for the continent of Africa from SRTM data and was recommended to me by one of our hydrology experts.

Link: tools.crwr

Optimized Pit Removal

Contains ArcGIS (version 10.1) geoprocessing script tools for removing pits (or sinks) from Digital Elevation Models using a combination of cut and fill. This alternative to the standard Fill tool provides more realistic flow paths with less required manual adjustment. Ideal for high-resolution datasets such as LiDAR.

Arthur Crawford - Esri