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Results of peak-flow frequency analysis and regionalization for selected streamgages in or near Maine, based on data through water year 2019 (ver. 3.0, August 2021)

Metadata Updated: October 28, 2023

The U.S. Geological Survey (USGS) recently completed a report documenting methods for peak-flow frequency analysis following implementation of the Bulletin 17C guidelines ( The methods provide estimates of peak-flow quantiles for 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (AEPs) for selected streamgages operated by the USGS and Environment Canada. In association with the report, this data release presents peak-flow frequency analyses for 148 streamgages (127 stations in Maine, 16 in New Hampshire, and 5 in New Brunswick, Canada). Included are 148 individual ".PRT" text files that contain results of the flood-frequency analyses of annual peak flows from all of the selected streamgages. The files were generated using version 7.3 of USGS software PeakFQ (; Veilleux and others, 2014) to conduct flood-frequency analyses using the expected moments algorithm (England and others, 2018). The peak-flow files used as input to PeakFQ were obtained from the USGS National Water Information System (NWIS) database ( and contained annual peak flows ending in water year 2019. Results of the flood-frequency analyses at streamgages that did not have storage or regulation in the watershed (124 of the total 148) were used to develop peak-flow regression equations for estimating the selected AEPs at ungaged sites in Maine. Results from the unregulated streamgages that had periods of record of at least 20 years (51 of the 124) were used for a Maine skew analysis also outlined in the report.
This data release also includes eight Excel tables summarizing the results of the peak-flow frequency analyses and peak-flow regionalization. Tables include basin characteristics used in the regionalization, information needed for flood-frequency analyses including periods of record used in analyses and skew values, maximum instantaneous floods , flood frequency estimates , information needed for advanced accuracy analyses for the streamgages and information needed for calculation of the 90-percent confidence intervals of the peak-flow equations for the AEPs.

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Metadata Created Date June 1, 2023
Metadata Updated Date October 28, 2023

Metadata Source

Harvested from DOI EDI

Additional Metadata

Resource Type Dataset
Metadata Created Date June 1, 2023
Metadata Updated Date October 28, 2023
Publisher U.S. Geological Survey
Identifier USGS:5d2781bce4b0941bde650e8c
Data Last Modified 20210802
Category geospatial
Public Access Level public
Bureau Code 010:12
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Harvest Object Id 40b987bd-85d3-408f-811b-e823ba5eeff9
Harvest Source Id 52bfcc16-6e15-478f-809a-b1bc76f1aeda
Harvest Source Title DOI EDI
Metadata Type geospatial
Old Spatial -71.9604,42.4475,-66.4673,47.6577
Publisher Hierarchy White House > U.S. Department of the Interior > U.S. Geological Survey
Source Datajson Identifier True
Source Hash af7a6142a04b352706210f6a886996375b103549e0c0e53c0d2dd69e3b610a98
Source Schema Version 1.1
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