topic Re: How do you choose a threshold value for flow accumulation using the Con tool with a 1 meter DEM? in Renewable Energy Questions

How do you choose a threshold value for flow accumulation using the Con tool with a 1 meter DEM?

AngelaStemen — Sat, 18 Jan 2020 01:35:25 GMT

I am trying to identify stream networks of a certain area and also differentiate between ones with flowing water year round, intermittently and dry creek beds. What kind of threshold value would I use for the Con tool Expression. Online examples give 100 but that is way too small and has too large of an output of stream networks. I don't want to go too high but also not too low. My max upper value for the Flow Accum tool is 357399264. If anyone has any advise I greatly appreciate it. Thank you.

Re: How do you choose a threshold value for flow accumulation using the Con tool with a 1 meter DEM?

RyanWalter — Fri, 17 Jan 2025 21:31:08 GMT

Hey @AngelaStemen, I know your post has been around a while with no answers, but I can do my best. Whether a stream exists year round (annual) or at only intermittently (perennial) is going to depend entirely on the area you're working in. There are many factors that contribute to a stream's existence. You can use flow accumulation to get a good idea of the annual stream set, but there are always going to be other factors you'll need to consider. I'm guessing this problem is long solved, but for the future, the ESRI team has made flow accumulation a *lot* easier to understand. I'd check out this resource to learn more.