Link to USGS homepage

Statistical Summaries of Streamflow in Montana and Adjacent Areas, Water Years 1900 through 2002

By Peter M. McCarthy

Scientific Investigations Report 2004-5266

Prepared in cooperation with the
Montana Department of Environmental Quality,
Confederated Salish and Kootenai Tribes, and
Bureau of Land Management


In response to the need to have more current information about streamflow characteristics in Montana, the U.S. Geological Survey, in cooperation with the Montana Department of Environmental Quality, Confederated Salish and Kootenai Tribes, and Bureau of Land Management, conducted a study to analyze streamflow data. Updated statistical summaries of streamflow characteristics are presented for 286 streamflow-gaging sites in Montana and adjacent areas having 10 or more years of record for water years 1900 through 2002. Data include the magnitude and probability of annual low and high flow, the magnitude and probability of low flow for three seasons (March-June, July-October, and November-February), flow duration of the daily mean discharge, and the monthly and annual mean discharges. For streamflow-gaging stations where 20 percent or more of the contributing drainage basin is affected by dams or other large-scale human modification, streamflow is considered regulated. Separate streamflow characteristics are presented for the unregulated and regulated periods of record for sites with sufficient data.




Purpose and Scope

Site Selection

Methods of Creating the Statistical Summaries

Annual and Seasonal Low-Flow Frequencies

Annual High-Flow Frequency

Flow Duration

Monthly and Annual Mean Discharges

Statistical Summaries of Streamflow

Selected References


Suggested Citation:

McCarthy, P.M., 2005, Statistical summaries of streamflow in Montana and adjacent areas, water years 1900 through 2002: U.S. Geological Survey Scientific Investigations Report 2004-5266, 317 p.

This report is available online in Portable Document Format (PDF). If you do not have the Adobe Acrobat PDF Reader, it is available for free download from Adobe Systems Incorporated.

Download the Full Report (PDF, 22.2MB). (Figure 1 on page 3 in this document is an 11 x 17 page. Use figure 1 below for printing.)

For faster downloading, the report has been split into the following files:

Front covers (PDF, 181KB)
Title pages, Contents, Conversion factors, datum, symbols, acronymns, and abbreviations (PDF, 54KB)
Abstract, Introduction, Methods of Creating the Statistical Summaries, Statistical Summaries of Streamflow (PDF, 470KB)
Figure 1 is 11 x 17 (PDF, 228KB)
Statistical summaries - sites 1-69 (PDF, 5.2MB)
Statistical summaries - sites 70-137 (PDF, 5.2MB)
Statistical summaries - sites 138-205 (PDF, 5.2MB)
Statistical summaries - sites 206-286 (PDF, 6.0MB)
Selected references (PDF, 45KB)
Back covers (PDF, 62KB)

Document Accessibility: Adobe Systems Incorporated has information about PDFs and the visually impaired. This information provides tools to help make PDF files accessible. These tools convert Adobe PDF documents into HTML or ASCII text, which then can be read by a number of common screen-reading programs that synthesize text as audible speech. In addition, an accessible version of Acrobat Reader 5.0 for Windows (English only), which contains support for screen readers, is available. These tools and the accessible reader may be obtained free from Adobe at Adobe Access.

Send questions or comments about this report to the author, P.M. McCarthy (406) 457-5934.

For more information about USGS activities in Montana, visit the USGS Montana Water Science Center home page.

U.S. Department of the Interior, U.S. Geological Survey
Persistent URL:
Page Contact Information: Contact USGS
Last modified: Thursday, January 10 2013, 06:38:58 PM
FirstGov button  Take Pride in America button