Real-time US river/stream conditions from a USGS monitoring site. Pass site = the USGS site number (e.g. 01646500 = Potomac River near Washington DC). Returns the latest readings — streamflow (cubic feet/sec), gage height (ft), and water/air temperature where available — with the site name + coordinates and observation time. Useful for flood monitoring, recreation, and hydrology. Source: USGS National Water Information System (keyless, public domain).