with a mean of 21.5 years. These data were digitized from published UNESCO archives by Charles Vцrцsmarty, Balaze Fekete, and B.A. Tucker of the Complex Systems Research Center (CSRC) at the University of New Hampshire (Vцrцsmarty, 1998). River discharge is typically measured using a rating curve that relates local water level height to discharge. This rating curve is used to estimate discharge from the observed water level. The rating curves are periodically rechecked and recalibrated through on- site measurement of discharge and river stage. USGS: The U.S. Geological Survey's (USGS) supports the acquisition, processing, and long-term storage of water data.
Water Data for the Nation serves as the publicly available portal to a geographically seamless set of much of the water data maintained within NWIS. Nationally, USGS surface-water data includes more than 850,000 station years of time-series data that describe stream levels, streamflow (discharge), reservoir and lake levels, surface-water quality, and rainfall. The data are collected by automatic recorders and manual field measurements at installations across the Nation. Data are collected by field personnel or relayed through telephones or satellites to offices where it is stored and processed.
The data are processed automatically in near real time, and in many cases, current data are available online within minutes. Streamflow data can be download in the National Water Information System (NWIS) web interface at the following link: http://waterdata.usgs.gov/nwis . All available data for each station and from all available sources have been merged to constitute observed in-situ discharge (Figure 1). Figure 1: Available discharge data for all stations from different sources D.3 River Discharge ATBD. Reference: RD_CCI-0006-ATBD - Issue 2.0 – 31/07/2025 Open/Public © 2019 CLS. All rights reserved. Proprietary and Confidential. 9/31