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.
Did they say you could do this at the same cell size?
Yes, same cell size as the 1 metre.
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.
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
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