Methods for peak-flow frequency analysis and reporting for streamgages in or near Montana based on data through water year 2015
Links
- Document: Report (2.26 MB pdf)
- Data Releases:
- USGS data release - Peak-flow frequency analyses for 99 selected streamgages in or near Montana, based on data through water year 2015
- USGS data release - Peak-flow frequency analyses for 14 selected streamgages in the Beaverhead River and Clark Fork Basins Montana, based on data through water year 2016
- USGS data release - Peak-flow frequency analyses for 14 selected streamgages in the Ruby, Jefferson, and Madison River Basins, Montana, based on data through water year 2016
- USGS data release - Peak-flow frequency analyses for selected streamgages in the Upper Yellowstone River Basin, based on data through water year 2022
- USGS data release - Peak-flow frequency analyses for selected streamgages in Dawson and Richland Counties, and the Powder River Basin, Montana, based on data through water year 2022
- USGS data release - Peak-flow frequency analyses for selected streamgages on tributaries of the Bighorn, Tongue, and Lower Yellowstone Rivers, based on data through water year 2021
- USGS data release - Peak-flow frequency analyses for selected streamgages on the Bighorn, Tongue, and Lower Yellowstone Rivers and tributaries and Home Creek, Montana, based on data through water year 2021
- USGS data release - Peak-flow frequency analyses for selected streamgages in and near the Milk River Basin, Montana, based on data through water year 2018, part 2
- USGS data release - Peak-flow frequency analyses for selected streamgages in and near Teton County, Montana, based on data through water year 2019
- USGS data release - Peak-flow frequency analyses for selected streamgages in Carbon County, Montana, based on data through water year 2018
- USGS data release - Peak-flow frequency analyses for selected streamgages in and near the Milk River Basin, Montana, based on data through water year 2018, Part 1
- USGS data release - Peak-Flow Frequency Analyses for Selected Streamgages in Missoula and Granite Counties, Montana, Based on Data through Water Year 2018
- USGS data release - Peak-flow frequency analyses for Elk Creek at Augusta, Montana, based on data through water year 2018
- USGS data release - Peak-flow frequency analyses for 11 selected streamgages in Jefferson County, Montana, based on data through water year 2017 (ver. 1.1, September 2019)
- Download citation as: RIS | Dublin Core
Abstract
This report documents the methods for peak-flow frequency (hereinafter “frequency”) analysis and reporting for streamgages in and near Montana following implementation of the Bulletin 17C guidelines. The methods are used to provide estimates of peak-flow quantiles for 50-, 42.9-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities for selected streamgages operated by the U.S. Geological Survey Wyoming-Montana Water Science Center (WY–MT WSC). These annual exceedance probabilities correspond to 2-, 2.33-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals, respectively.
Standard procedures specific to the WY–MT WSC for implementing the Bulletin 17C guidelines include (1) the use of the Expected Moments Algorithm analysis for fitting the log-Pearson Type III distribution, incorporating historical information where applicable; (2) the use of weighted skew coefficients (based on weighting at-site station skew coefficients with generalized skew coefficients from the Bulletin 17B national skew map); and (3) the use of the Multiple Grubbs-Beck Test for identifying potentially influential low flows. For some streamgages, the peak-flow records are not well represented by the standard procedures and require user-specified adjustments informed by hydrologic judgement. The specific characteristics of peak-flow records addressed by the informed-user adjustments include (1) regulated peak-flow records, (2) atypical upper-tail peak-flow records, and (3) atypical lower-tail peak-flow records. In all cases, the informed-user adjustments use the Expected Moments Algorithm fit of the log-Pearson Type III distribution using the at-site station skew coefficient, a manual potentially influential low flow threshold, or both.
Appropriate methods can be applied to at-site frequency estimates to provide improved representation of long-term hydroclimatic conditions. The methods for improving at-site frequency estimates by weighting with regional regression equations and by Maintenance of Variance Extension Type III record extension are described.
Frequency analyses were conducted for 99 example streamgages to indicate various aspects of the frequency-
analysis methods described in this report. The frequency analyses and results for the example streamgages are presented in a separate data release associated with this report consisting of tables and graphical plots that are structured to include information concerning the interpretive decisions involved in the frequency analyses. Further, the separate data release includes the input files to the PeakFQ program, version 7.1, including the peak-flow data file and the analysis specification file that were used in the peak-flow frequency analyses. Peak-flow frequencies are also reported in separate data releases for selected streamgages in the Beaverhead River and Clark Fork Basins and also for selected streamgages in the Ruby, Jefferson, and Madison River Basins.
Suggested Citation
Sando, S.K., and McCarthy, P.M., 2018, Methods for peak-flow frequency analysis and reporting for streamgages in or near Montana based on data through water year 2015: U.S. Geological Survey Scientific Investigations Report 2018–5046, 39 p., https://doi.org/10.3133/sir20185046.
ISSN: 2328-0328 (online)
Study Area
Table of Contents
- Acknowledgments
- Abstract
- Introduction
- Overview of Bulletin 17B and Bulletin 17C Guidelines for Peak-Flow Frequency Analysis
- The Expected Moments Algorithm Procedures in Relation to Montana Peak-Flow Datasets
- Selected Considerations for Peak-Flow Frequency Analysis
- Methods for Peak-Flow Frequency Analysis
- Methods for Peak-Flow Frequency Reporting
- Summary
- References Cited
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Methods for peak-flow frequency analysis and reporting for streamgages in or near Montana based on data through water year 2015 |
| Series title | Scientific Investigations Report |
| Series number | 2018-5046 |
| DOI | 10.3133/sir20185046 |
| Year Published | 2018 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Publisher location | Reston, VA |
| Contributing office(s) | WY-MT Water Science Center |
| Description | Report: vi, 39 p.; Data Releases |
| Country | United States |
| State | Montana |
| Online Only (Y/N) | Y |
| Additional Online Files (Y/N) | Y |
| Google Analytic Metrics | Metrics page |