For the Annual Water Yield model, does the Watershed vector input have to be delineated from a DEM? Is a DEM needed for the model input? I assumed the watershed data input was a polygon?
I have spent a lot of time clipping, reclassifying and processing my land cover maps to a watershed boundary (polygon) I downloaded from the Environment Agency (UK). I only discovered that I may need a DEM by going through this forum. Unfortunately it did not say anywhere in the AWY model guidance that a DEM was needed (ctrl+F returned no mention of a DEM).
The Annual Water Yield model does not require a DEM as input (see the User Guide Data Needs section for a complete list of required inputs and their formats). Because the AWY model does not use a DEM to route water around the landscape (unlike our other freshwater models), it’s not strictly necessary to use a DEM to delineate the watershed (which we do recommend for the other models). So yes, you can use the one from the UK Environment Agency for the AWY model.