Colorado River Basin Natural Flow and Salt Data

This documentation supports the Current Natural Flow and Salt Data for the Colorado River found on this web site.

NOTE: Several of these files are extremely large, and are best accessed by downloading before reading. To do so, "right click" on the link and select "Save Target As" to save the file to your hard drive.

Natural Flow and Salt Data Index

Current Natural Flow and Salt Data
      Natural Flow Supporting Data
      Natural Salt Supporting Data

Previous Natural Flow and Salt Data

Provisional Natural Flow Data

Upper Basin

1971-2020 1906-1970
  • The streamflow extension project supersedes data in the report below. Refer to the extension report (Lee and Salas, 2006) in the Documentation section for a list of affected stream gauges.

  • A record of data used to compute natural flow from 1906-1971 in the Upper Basin was extracted from Microfiche. These records are available in an Excel format upon request from the Upper Colorado Regional Office. The official data for natural flow from 1906-1971 does not exactly match the Microfiche for 4 gauges (09124600, 09211200, 09328500, 09355500). These differences are documented in a June 2000 status report presented to the Technical Modeling Subcommittee of the Salinity Control Forum. Reclamation intends to explore and document the resolution of these differences in the near future.

Lower Basin

  • Lower Basin Decree Accounting and reservoir regulation data are stored in Reclamation's Lower Colorado Hydrologic Data Base. These data are available upon request from the Boulder Canyon Operations Office.

Last Updated: 20APR2022