Daily mean discharge is needed for water resource management of selected streams in the Fortymile River Basin. The U.S. Geological Survey, in cooperation with the U.S. Bureau of Land Management, developed a technique for estimating seasonal discharge at two short-record streamgage sites in the basin and evaluated the accuracy of the estimated records. Daily mean discharge values were estimated for May 15–September 30 for 1976–82 and 2006–18 for the U.S. Geological Survey streamgage sites 15330000, North Fork Fortymile River above Middle Fork near Franklin, Alaska and 15331000, Middle Fork Fortymile River near mouth near Chicken, Alaska. Relations between discharge for each study streamgage and an index streamgage, 15348000, Fortymile River near Steele Creek, Alaska, for concurrent seasonal periods in 2019 and 2020 were developed using the maintenance of variance extension type 3 (MOVE.3) record extension technique. The MOVE.3 regressions were used to estimate daily mean discharges at the study streamgage sites for the selected season for the longer period of record of the index streamgage. In addition, estimated records were generated from the regressions for the concurrent seasonal periods to evaluate the accuracy of the record extension techniques.

This dataset contains selected information about U.S. Geological Survey (USGS) streamgages in Alaska that had at least 5 years of daily streamflow record through September 30, 2017. The goals for developing this dataset were to identify USGS streamgages that had at least 5 years of daily streamflow that responded mostly to seasonal meteorological inputs, that had a definable drainage basin above a minimum size from which basin characteristics could be determined, and that provided streamflow data not similar to another streamgage record in the dataset. Streamgages meeting these criteria for at least part of their records constituted the dataset for a study investigating seasonal flow regimes and streamflow drivers for Alaska. For 253 streamgages meeting selection criteria, data include period of record characteristics, basin characteristics, and flow regime cluster analysis results. The basin characteristics are provided in their original U.S. customary units and as values transformed to metric units. For an additional 78 streamgages, data include the special conditions affecting streamflow that disqualified the streamgage from the study, including recurring outburst floods, regulation, urbanization, hydrologic redundancy with another streamgage, drainage basin below minimum size, or an indeterminate drainage basin.

This data set contains selected information about U.S. Geological Survey (USGS) streamgages in Alaska that had at least 5 years of daily streamflow record through September 30, 2017. The goals for developing this dataset were to identify USGS streamgages that had at least 5 years of daily streamflow that responded mostly to seasonal meteorological inputs, that had a definable drainage basin above a minimum size from which basin characteristics could be determined, and that provided streamflow data not similar to another streamgage record in the dataset. Streamgages meeting these criteria for at least part of their records constituted the dataset for a study investigating seasonal flow regimes and streamflow drivers for Alaska. For 253 streamgages meeting selection criteria, data include period of record characteristics, basin characteristics, and flow regime cluster analysis results. The basin characteristics are provided in their original U.S. customary units and as values transformed to metric units. For an additional 78 streamgages, data include the special conditions affecting streamflow that disqualified the streamgage from the study, including recurring outburst floods, regulation, urbanization, hydrologic redundancy with another streamgage, drainage basin below minimum size, or an indeterminate drainage basin.

This dataset contains drainage basin boundaries for 253 U.S. Geological Survey (USGS) streamgages in Alaska that had at least 5 years of daily streamflow through September 30, 2017, three of which were delineated for alternate basin conditions. This compilation includes selected boundaries produced in 2014 (https://doi.org/10.5066/P143KNEJ). Additional basin boundaries were delineated from the streamgage location to the nearest USGS Watershed Boundary Dataset (WBD) HUC boundary and along HUC boundaries from that intersection to the basin headwaters. Streamgages selected for drainage basin delineation included streamgages in Alaska that met selection criteria for a statewide study of seasonal flow regimes (Curran and Biles, 2021). Sites for that study included USGS streamgages that had at least 5 years of daily streamflow that responded mostly to seasonal meteorological inputs, that had a definable drainage basin above a minimum size from which basin characteristics could be determined, and that provided streamflow data not similar to another streamgage record in the dataset. For three streamgages, the drainage basin boundary was delineated for the drainage area associated with regulated (diverted) or unregulated streamflow conditions contemporaneous with a period of streamflow record other than the present. Selected basins were previously published in the WBD as "NWISDrainageArea" features.

This dataset contains drainage basin boundaries for 253 U.S. Geological Survey (USGS) streamgages in Alaska that had at least 5 years of daily streamflow through September 30, 2017, three of which were delineated for alternate basin conditions. This compilation includes selected boundaries produced in 2014 (https://doi.org/10.5066/P143KNEJ). Additional basin boundaries were delineated from the streamgage location to the nearest USGS Watershed Boundary Dataset (WBD) HUC boundary and along HUC boundaries from that intersection to the basin headwaters. Streamgages selected for drainage basin delineation included streamgages in Alaska that met selection criteria for a statewide study of seasonal flow regimes (Curran and Biles, 2021). Sites for that study included USGS streamgages that had at least 5 years of daily streamflow that responded mostly to seasonal meteorological inputs, that had a definable drainage basin above a minimum size from which basin characteristics could be determined, and that provided streamflow data not similar to another streamgage record in the dataset. For three streamgages, the drainage basin boundary was delineated for the drainage area associated with regulated (diverted) or unregulated streamflow conditions contemporaneous with a period of streamflow record other than the present. Selected basins were previously published in the WBD as "NWISDrainageArea" features.

This dataset summarizes selected basin and streamflow special conditions for USGS streamgages in Alaska that are commonly used for site and period of record selection for regional analyses, through water year 2022. The data consist of a table providing information about the type of streamflow available for the site, site special conditions related to the timing of data collection, basin special conditions related to drainage area and urbanization, and a summary of water years for daily mean streamflow and annual peak streamflow affected by regulation or outburst flooding. The data were compiled using peak-streamflow codes assigned in the USGS National Water Information System (NWIS; https://doi.org/10.5066/F7P55KJN), USGS publications, USGS streamgaging notes, and other sources.

This dataset summarizes selected basin and streamflow special conditions for USGS streamgages in Alaska that are commonly used for site and period of record selection for regional analyses, through water year 2022. The data consist of a table providing information about the type of streamflow available for the site, site special conditions related to the timing of data collection, basin special conditions related to drainage area and urbanization, and a summary of water years for daily mean streamflow and annual peak streamflow affected by regulation or outburst flooding. The data were compiled using peak-streamflow codes assigned in the USGS National Water Information System (NWIS; https://doi.org/10.5066/F7P55KJN), USGS publications, USGS streamgaging notes, and other sources.

This dataset contains 474 drainage basin boundaries for U.S. Geological Survey (USGS) streamgages in Alaska, including supplemental drainage basin boundaries for alternate conditions for 3 of the 471 streamgages. The basin boundaries were delineated from the streamgage location to the nearest USGS Watershed Boundary Dataset (WBD) HUC boundary and along HUC boundaries from that intersection to the basin headwaters. The dataset also includes the streamgage locations used for delineation, which consist of points snapped from the streamgage coordinates in the USGS National Water Information System to the USGS National Hydrography Dataset flowline representing the respective streams. Streamgages selected for drainage basin delineation included: (1) streamgages having at least 10 years of peak-streamflow data through water year 2012, used for a statewide flood frequency study (Curran and others, 2016), and (2) streamgages in Cook Inlet Basin, regardless of record length, used for development of Cook Inlet Basin Streamstats in 2016 (https://streamstats.usgs.gov/ss/). For three streamgages, a supplemental drainage basin boundary was delineated for the drainage area associated with regulated (diverted) streamflow conditions contemporaneous with a period of streamflow record other than the present. Selected basins were previously published in the WBD as "NWISDrainageArea" features.

This dataset contains 474 drainage basin boundaries for U.S. Geological Survey (USGS) streamgages in Alaska, including supplemental drainage basin boundaries for alternate conditions for 3 of the 471 streamgages. The basin boundaries were delineated from the streamgage location to the nearest USGS Watershed Boundary Dataset (WBD) HUC boundary and along HUC boundaries from that intersection to the basin headwaters. The dataset also includes the streamgage locations used for delineation, which consist of points snapped from the streamgage coordinates in the USGS National Water Information System to the USGS National Hydrography Dataset flowline representing the respective streams. Streamgages selected for drainage basin delineation included: (1) streamgages having at least 10 years of peak-streamflow data through water year 2012, used for a statewide flood frequency study (Curran and others, 2016), and (2) streamgages in Cook Inlet Basin, regardless of record length, used for development of Cook Inlet Basin Streamstats in 2016 (https://streamstats.usgs.gov/ss/). For three streamgages, a supplemental drainage basin boundary was delineated for the drainage area associated with regulated (diverted) streamflow conditions contemporaneous with a period of streamflow record other than the present. Selected basins were previously published in the WBD as "NWISDrainageArea" features.

This data release documents the data used for the associated publication "Evaluating hydrologic region assignment techniques for ungaged watersheds in Alaska, USA" (Barnhart and others, 2022) The data sets within this release are stored in 14 files: (1) Streamflow observations and sites used. (2) Statistically estimated streamflow values computed for each site. (3) Streamflow statistics computed from observed and estimated streamflow values at each site, basin characteristics for each site, and hydrologic regions (clusters) for each site. (4) A dataset describing the optimal number of hydrologic regions into which the considered sites were grouped. (5) P-values from a multiple comparisons analysis testing for statistical differences between clusters for each basin characteristic and streamflow statistic. (6) A matrix of zeros and ones describing the performance of each hydrologic region assignment technique considered in the publication associated with this release. (7) A dataset of variable importance generated by random forest modeling-based hydrologic region assignment techniques evaluated. (8-14) Daily datasets of simulated SnowModel (Liston and Elder, 2006) runoff (snowmelt + rainfall), precipitation, glacial melt, snow water equivalent, snow covered area, liquid precipitation, and air temperature for Alaska, USA at a 1 km grid cell size.