StreamStats — The Complete Guide: Watershed Delineation and Flow Estimates in One Click

StreamStats is an online GIS service from the USGS. Click a point on a stream and it delineates the drainage basin upstream, computes the basin characteristics and estimates flows from regional regression equations. There is nothing to install and no registration — just a browser and an internet connection. One thing to know up front: coverage is limited to basins in the United States.

StreamStats

U.S. Geological Survey (USGS)

Browser-based GIS application for delineating watersheds and estimating streamflow statistics in the United States.

Get it from the vendor

What you get

Automatic delineation — the drainage boundary above the outlet point you pick.
Basin characteristics — area, slope, precipitation and further parameters depending on the state.
Flow statistics — peak flows for return periods and low flows from the regional equations.
Batch processing — many points submitted in a single request.
Time of travel — estimating how fast a spill or a wave moves downstream.

Who it suits and its limits

Drainage, highway and bridge engineers on US projects who need a design flow for an ungauged stream. Outside the United States the tool is of no practical use. Even within the US, available data and equations vary from state to state, and results are statistical estimates that should be checked against gauged records.

Related tools

For flood-frequency analysis of gauge data — PeakFQ. For a full rainfall-runoff model of the basin — HEC-HMS. For delineating catchments yourself from any elevation model, anywhere in the world — WhiteboxTools.