I was wondering if it is possible to use rainfall data (raster) as an input to Arc Hydro for determining stream lines?
I am learning Arc Hydo and have gone through a couple of tutorials. As far as I can see, the tutorials mostly talk about DEM editing (selecting/filling sinks, AgreeDEM etc.). But I can't find a place where rainfall data can be used to determine the amount of water entering leaving cells. It seems as if the stream definition were only based on topography and the number of upstream cells.
My questions are:
Is there a way (and documentation/tutorial) to use rainfall and/or landcover (e.g. soil vs concrete) data as an input to Arc Hydro for determining streams and watersheds?
If yes, how do modelers use such input? (e.g. by defining some weight values for each cell.)
If not, are there other ArcGIS or open source package similar to ArcHydro but can take into account precipitation?
P.S. I searched on GIS SE, and there is related question about Calculating watershed runoff with landuse and rainfall data? how to compute rainfall. My question concerns how to use rainfall data.
Best Answer
You are correct that Arc Hydro only uses elevation information to delinieate streams, catchment, etc. There is not a tool built in to do exactly what you're asking. Arc Hydro does provide other tools such as calculating drainage area centroid, and longest flow path. These tools may be helpful to you in finding catchment properties in a more traditional watershed analysis.
If your goal is to obtain flow volumes from rainfall information, I recommend looking into HEC-HMS. If you aren't familiar with it, this is a hydrology program that integrates nicely with Arc GIS through the HEC GEO-HMS extension. Both the stand alone program and the GIS extension are free. You can find some very nicely prepared tutorials available here.