The Skykomish and Snoqualmie River basins in western Washington provide spawning, rearing, and migration habitat for several salmonid species, including Endangered Species Act-listed Chinook salmon, steelhead trout, and bull trout. The production, abundance, distribution, and the health of fish and other aquatic life is strongly influenced by water temperature, which affects their physiology and behavior. The Washington State Department of Ecology establishes water temperature criteria and Total Maximum Daily Load standards for designated aquatic life uses, varying between 12 and 17.5 degrees Celsius, depending on the habitat classification and time of year. However, over the past two decades, water temperatures within the Skykomish, Snoqualmie, and Middle Fork Snoqualmie rivers frequently exceeded water temperature criteria, and the 23 degrees Celsius threshold above which water temperatures can be lethal to salmonids. To inform salmonid restoration efforts within these basins, this study used high-resolution airborne thermal infrared (TIR) imagery to quantify the longitudinal stream temperature profiles (LTPs) of the Skykomish, Snoqualmie, and Middle Fork Snoqualmie rivers. This Data Release presents those results with the following items: - Georeferenced, orthorectified TIR and RGB imagery mosaics (.tiff and .sid, respectively) of the Skykomish, Snoqualmie and Middle Fork Snoqualmie rivers, produced by NV5 Geospatial (formerly Quantum Spatial, Inc.), a company specializing in geospatial surveys. The mosaics were made using TIR and RGB images acquired from helicopter-based surveys conducted by NV5 Geospatial during two distinct surveying efforts—August 16-17, 2020, and August 3-5, 2021. The surveys covered a total river length of approximately 133 km, from Goldmyer Hot Springs on the Middle Fork Snoqualmie River to Chinook Bend Natural Area on the Snoqualmie River and from Gold Bar to Monroe, WA on the Skykomish River. - LTPs (.shp) produced by NV5 Geospatial and the U.S. Geological Survey (USGS) using the TIR and RGB mosaics. In addition to the helicopter-based TIR surveys, longitudinal "Lagrangian" drag-probe surveys (hereafter, "float surveys") were conducted by the USGS and Tulalip Tribes on the Skykomish and Middle Fork Snoqualmie rivers. The surveys covered a total river length of approximately 68 km, from the Taylor River confluence to Three Forks Natural Area on the Middle Fork Snoqualmie River and from Gold Bar to Monroe, WA on the Skykomish River. For these float surveys, near-streambed and near-surface water temperature and GPS position were measured at three-second intervals from a non-motorized watercraft drifting downstream at ambient stream velocity. The Skykomish River float survey was conducted over several days between August 24 and September 11, 2020. The Middle Fork Snoqualmie River float survey was conducted over several days between August 17 and September 11, 2020, with a follow-up survey on a reach of interest on August 3, 2021. The resulting LTPs from these float surveys are provided as shapefiles (.shp). Prior to the TIR and float surveys USGS staff deployed 37 in-stream water temperature data loggers along the study area to record water temperature during the data acquisition time frame. Water temperature records were shared with NV5 Geospatial staff to radiometrically calibrate the TIR imagery and analyze the float survey data. These records also assist in interpreting the results of the float surveys. Data from the in-stream water temperature loggers is available for download through the Washington Department of Ecology's Environmental Information Management System (https://apps.ecology.wa.gov/eim/search/default.aspx; Study ID WQC-2020-00164).

The Skykomish, Snoqualmie, and Middle Fork Snoqualmie River Basins have historically provided critical spawning, rearing, and core habitat for several salmonid species. These salmonid species include natural populations of Chinook salmon (O. tshawytscha), steelhead trout (O. mykiss), and bull trout (Salvelinus confluentus)—listed as “Threatened” under the Endangered Species Act—as well as coho salmon (O. kisutch)—listed as a ”Species of concern”—pink salmon (O. gorbuscha), chum salmon (O. keta), and native char (S. malma) (Solomon and Boles, 2002; Stohr and others, 2011; Svrjcek and others, 2013; Snohomish County Surface Water Management and the Sustainable Lands Strategy Executive Committee [SWM], 2017; U.S. Fish and Wildlife Service, 2022). Because of the thermal constraints on salmonids and other aquatic species, the Washington Department of Ecology maintains temperature criteria for waters designated for aquatic life uses. These standards range between 12 degrees Celsius (°C) and 17.5 °C, referring to the highest permissible 7-day average of the daily maximum temperatures (7-DADMax), and vary depending on the habitat classification and time of year (Washington Department of Ecology, 2020). Over the past two decades, however, summer 7-DADMax water temperatures within the Skykomish, Snoqualmie, and Middle Fork Snoqualmie Rivers have frequently exceeded these temperature criteria, as well as the 23 °C threshold above which temperatures can be lethal to salmonids (Stohr and others, 2011; Svrjcek and others, 2013; Kubo and leDoux, 2016). To inform salmonid restoration efforts within the Skykomish, Snoqualmie, and Middle Fork Snoqualmie Rivers, this study used high-resolution thermal infrared (TIR) and co-acquired true-color red, green, blue (RGB) imagery from airborne surveys conducted in August 2020 and 2021. The imagery mosaics from the airborne TIR and RGB surveys were used to measure the longitudinal stream temperature profiles (LTPs) of the Skykomish, Snoqualmie, and Middle Fork Snoqualmie Rivers and identify the location of significant thermal features (STFs) expressed at the water’s surface, including cold-water anomalies that could represent thermal refuges and serve as salmonid habitat. These surveys were done twice to evaluate the interannual persistence of STFs and the temporal variability of water temperature patterns in the LTPs, because the presence of STFs and the patterns in LTPs have been shown to vary over time in other studies (Dugdale and others, 2013). The study area for the TIR and RGB surveys, from upstream to downstream, was (1) the Middle Fork Snoqualmie River from above the Goldmyer Hot Springs trailhead to the North Fork Snoqualmie River confluence (33 river miles), (2) the mainstem Snoqualmie River from the North Fork Snoqualmie River confluence to Chinook Bend Natural Area in Carnation, Washington (23 river miles), and (3) the Skykomish River from Gold Bar, Washington to its confluence with the Snoqualmie River in Monroe, Washington (26 river miles). Those results are presented with the following items: - TIR and RGB imagery mosaics (.tiff and .sid, respectively) of the Skykomish Snoqualmie, and Middle Fork Snoqualmie Rivers. - LTPs (.shp) produced from the thermal infrared imagery mosaics. - STFs (.shp) identified using the thermal infrared and true-color red, green, blue imagery mosaics. In addition, water temperature float surveys were conducted on the Skykomish and Middle Fork Snoqualmie Rivers, August–September 2020, and a follow-up survey on the Middle Fork Snoqualmie River August 2021, to evaluate this less expensive and low-tech method of producing LTPs. Float survey data was collected by measuring near-surface and near-streambed (henceforth, “near-bottom”) water temperature, conductivity, and GPS position at three-second intervals from an inflatable kayak drifting downstream at ambient river velocity, following the method of Vaccaro and Maloy (2006). By moving downstream at ambient

The Skykomish, Snoqualmie, and Middle Fork Snoqualmie River Basins have historically provided critical spawning, rearing, and core habitat for several salmonid species. These salmonid species include natural populations of Chinook salmon (O. tshawytscha), steelhead trout (O. mykiss), and bull trout (Salvelinus confluentus)—listed as “Threatened” under the Endangered Species Act—as well as coho salmon (O. kisutch)—listed as a ”Species of concern”—pink salmon (O. gorbuscha), chum salmon (O. keta), and native char (S. malma) (Solomon and Boles, 2002; Stohr and others, 2011; Svrjcek and others, 2013; Snohomish County Surface Water Management and the Sustainable Lands Strategy Executive Committee [SWM], 2017; U.S. Fish and Wildlife Service, 2022). Because of the thermal constraints on salmonids and other aquatic species, the Washington Department of Ecology maintains temperature criteria for waters designated for aquatic life uses. These standards range between 12 degrees Celsius (°C) and 17.5 °C, referring to the highest permissible 7-day average of the daily maximum temperatures (7-DADMax), and vary depending on the habitat classification and time of year (Washington Department of Ecology, 2020). Over the past two decades, however, summer 7-DADMax water temperatures within the Skykomish, Snoqualmie, and Middle Fork Snoqualmie Rivers have frequently exceeded these temperature criteria, as well as the 23 °C threshold above which temperatures can be lethal to salmonids (Stohr and others, 2011; Svrjcek and others, 2013; Kubo and leDoux, 2016). To inform salmonid restoration efforts within the Skykomish, Snoqualmie, and Middle Fork Snoqualmie Rivers, this study used high-resolution thermal infrared (TIR) and co-acquired true-color red, green, blue (RGB) imagery from airborne surveys conducted in August 2020 and 2021. The imagery mosaics from the airborne TIR and RGB surveys were used to measure the longitudinal stream temperature profiles (LTPs) of the Skykomish, Snoqualmie, and Middle Fork Snoqualmie Rivers and identify the location of significant thermal features (STFs) expressed at the water’s surface, including cold-water anomalies that could represent thermal refuges and serve as salmonid habitat. These surveys were done twice to evaluate the interannual persistence of STFs and the temporal variability of water temperature patterns in the LTPs, because the presence of STFs and the patterns in LTPs have been shown to vary over time in other studies (Dugdale and others, 2013). The study area for the TIR and RGB surveys, from upstream to downstream, was (1) the Middle Fork Snoqualmie River from above the Goldmyer Hot Springs trailhead to the North Fork Snoqualmie River confluence (33 river miles), (2) the mainstem Snoqualmie River from the North Fork Snoqualmie River confluence to Chinook Bend Natural Area in Carnation, Washington (23 river miles), and (3) the Skykomish River from Gold Bar, Washington to its confluence with the Snoqualmie River in Monroe, Washington (26 river miles). Those results are presented with the following items: - TIR and RGB imagery mosaics (.tiff and .sid, respectively) of the Skykomish Snoqualmie, and Middle Fork Snoqualmie Rivers. - LTPs (.shp) produced from the thermal infrared imagery mosaics. - STFs (.shp) identified using the thermal infrared and true-color red, green, blue imagery mosaics. In addition, water temperature float surveys were conducted on the Skykomish and Middle Fork Snoqualmie Rivers, August–September 2020, and a follow-up survey on the Middle Fork Snoqualmie River August 2021, to evaluate this less expensive and low-tech method of producing LTPs. Float survey data was collected by measuring near-surface and near-streambed (henceforth, “near-bottom”) water temperature, conductivity, and GPS position at three-second intervals from an inflatable kayak drifting downstream at ambient river velocity, following the method of Vaccaro and Maloy (2006). By moving downstream at ambient

This dataset presents high-resolution thermal infrared (TIR) and true-color RGB (red, green, blue) imagery mosaics, longitudinal stream temperature profiles, thermal points of interest, and river centerlines from airborne surveys of the Quillayute, Dickey, Sol Duc, Calawah, South Fork Calawah, Sitkum, and Bogachiel Rivers (203 river kilometers; 126 river miles total). All datasets were produced and initially processed by NV5 Geospatial (NV5). The U.S. Geological Survey (USGS) performed additional processing of the longitudinal stream temperature profiles and thermal points of interest, as described below. TIR and RGB images were acquired by NV5 on August 29-31, 2022, using a FLIR SC6000 LWIR sensor and a Sony Alpha 7R III camera mounted in a fiberglass enclosure to a Bell 206 Long Range helicopter. Images were acquired during afternoon hours to maximize the thermal contrast between the river water and the banks. At a flying altitude of 350-450 m (1,148-1,476 ft) above ground level, the FLIR SC6000 and Sony Alpha 7R III achieved ground sampling distances of less than 50 cm (20 in.) and 10 cm (4 in.), respectively. TIR imagery mosaics (.tif) for individual surveys and a single RGB imagery mosaic (.sid) for the entire study area were developed by NV5, and river centerlines (.shp) were manually digitized by NV5 using the imagery mosaics as guides. Points were then generated by NV5 every 50 m (164 ft) along the centerlines to quantify the longitudinal stream temperature profiles (LTPs; .shp). Summary statistics, in degrees Celsius, were computed by NV5 for each point in the profile by sampling pixel values of water temperature along the centerline in the corresponding TIR mosaic within a 2-m (6.56 ft) radius buffer around each point. The statistical information was used by USGS to identify sampling points that fall on non-water features such as boulders or bridges, and then filter these points from the final dataset. LTPs assist in identifying the water temperature gradient in the river and changes in the gradient due to the potential influence of thermal exchange processes, such as water inflows (tributaries, lateral groundwater flow, hyporheic flow, etc.) or increased heating from a low percentage of effective riparian shading. These profiles are also an important component of models that estimate water temperature based on climate and land use scenarios. Thermal points of interest (POIs; .shp) were manually identified by NV5 and USGS across the channel, riparian zone, and floodplain. Such features include cold-water anomalies that may represent thermal refuges and serve as salmonid habitat. POIs were classified by USGS as one of four types: (1) tributary; (2) lateral groundwater / side channel / small tributary; (3) hyporheic / diffuse groundwater; or (4) point source effluent. Summary statistics were computed by USGS for each POI using a sample of water temperature values from pixels in the corresponding TIR mosaic within a 0.6-m (1.97 ft) radius buffer around each point. The automated sampling of the POIs included pixels that are not purely water, but instead mixed with other in-stream and riparian features, such as boulders, woody debris, and tree canopy. Therefore, the water temperatures reported for POIs where the 0.6-m radius sampling area contains mixed pixels are often skewed. The POI temperatures should thus serve as indicators where thermal heterogeneity requires additional investigation and potentially more precise quantification. All data is projected in UTM 10N and the horizontal datum is NAD83(2011).

This dataset presents high-resolution thermal infrared (TIR) and true-color RGB (red, green, blue) imagery mosaics, longitudinal stream temperature profiles, thermal points of interest, and river centerlines from airborne surveys of the Quillayute, Dickey, Sol Duc, Calawah, South Fork Calawah, Sitkum, and Bogachiel Rivers (203 river kilometers; 126 river miles total). All datasets were produced and initially processed by NV5 Geospatial (NV5). The U.S. Geological Survey (USGS) performed additional processing of the longitudinal stream temperature profiles and thermal points of interest, as described below. TIR and RGB images were acquired by NV5 on August 29-31, 2022, using a FLIR SC6000 LWIR sensor and a Sony Alpha 7R III camera mounted in a fiberglass enclosure to a Bell 206 Long Range helicopter. Images were acquired during afternoon hours to maximize the thermal contrast between the river water and the banks. At a flying altitude of 350-450 m (1,148-1,476 ft) above ground level, the FLIR SC6000 and Sony Alpha 7R III achieved ground sampling distances of less than 50 cm (20 in.) and 10 cm (4 in.), respectively. TIR imagery mosaics (.tif) for individual surveys and a single RGB imagery mosaic (.sid) for the entire study area were developed by NV5, and river centerlines (.shp) were manually digitized by NV5 using the imagery mosaics as guides. Points were then generated by NV5 every 50 m (164 ft) along the centerlines to quantify the longitudinal stream temperature profiles (LTPs; .shp). Summary statistics, in degrees Celsius, were computed by NV5 for each point in the profile by sampling pixel values of water temperature along the centerline in the corresponding TIR mosaic within a 2-m (6.56 ft) radius buffer around each point. The statistical information was used by USGS to identify sampling points that fall on non-water features such as boulders or bridges, and then filter these points from the final dataset. LTPs assist in identifying the water temperature gradient in the river and changes in the gradient due to the potential influence of thermal exchange processes, such as water inflows (tributaries, lateral groundwater flow, hyporheic flow, etc.) or increased heating from a low percentage of effective riparian shading. These profiles are also an important component of models that estimate water temperature based on climate and land use scenarios. Thermal points of interest (POIs; .shp) were manually identified by NV5 and USGS across the channel, riparian zone, and floodplain. Such features include cold-water anomalies that may represent thermal refuges and serve as salmonid habitat. POIs were classified by USGS as one of four types: (1) tributary; (2) lateral groundwater / side channel / small tributary; (3) hyporheic / diffuse groundwater; or (4) point source effluent. Summary statistics were computed by USGS for each POI using a sample of water temperature values from pixels in the corresponding TIR mosaic within a 0.6-m (1.97 ft) radius buffer around each point. The automated sampling of the POIs included pixels that are not purely water, but instead mixed with other in-stream and riparian features, such as boulders, woody debris, and tree canopy. Therefore, the water temperatures reported for POIs where the 0.6-m radius sampling area contains mixed pixels are often skewed. The POI temperatures should thus serve as indicators where thermal heterogeneity requires additional investigation and potentially more precise quantification. All data is projected in UTM 10N and the horizontal datum is NAD83(2011).

This data release contains geospatial datasets that identify thermal zones across multiple reaches of four tributaries to Lake Ontario: St. Regis River, Salmon River, South Sandy Creek, and Sandy Creek. High-resolution uncrewed aircraft system (UAS)-based optical and thermal infrared imagery and ground level field observations are included. Shapefiles for each tributary reach identify thermal zones that are three, five, ten, and fifteen percent different than a reference temperature calculated as a mean along the approximate centerline of each reach. These data are accessible as an online webmap: https://ny.water.usgs.gov/maps/thermalrefugia

This U.S. Geological Survey (USGS) data release describes two 30-meter (m) raster datasets of topographic wetness indexes (TWI) for the Upper and Lower Colorado River basins. The data reside in GeoTIFF (Geographic Tagged Imaged File Format) multiplied by 10 and saved as an integer file to reduce space (colorado14_twX100i.tif and colorado15_twiX100.tif). The TWI units are dimensionless. The dataset resides in the Albers96 NAD83 projection. The source data used were 30-meter digital elevation (DEM) models from the NHDplus Version 2 data suite (U.S. Environmental Protection Agency, 2012).

This dataset includes georeferenced, high-resolution, airborne thermal infrared (TIR) and high-resolution true-color imagery, a polyline shapefile of the channel centerline, a polyline shapefile with TIR sample points for longitudinal stream temperature profiles, and a tabular file with longitudinal stream temperature profiles for the Donner und Blitzen River and its tributaries, Oregon. The aerial TIR surveys were conducted with a helicopter by NV5 Geospatial and are published as 17 raster mosaics in GeoTiff format with a resolution of 0.3 meters (m). The TIR mosaics contain corrected surface temperatures in degrees Celsius (C) (multiplied by 10 to create an unsigned integer pixel type). The longitudinal stream temperature profiles have temperatures in degrees C. The TIR dataset encompasses 159 kilometers (km) of the Donner und Blitzen River and its tributaries that extends from near Frenchglen, Oregon into the basin headwaters on Steens Mountain. The TIR surveys were collected during the afternoons (13:00-17:00) of August 13, 14, and 15, 2020. The TIR surveys were calibrated using continuous temperature loggers deployed at 29 in-stream locations distributed longitudinally throughout the survey area. The true-color imagery is published as a single raster mosaic of the entire surveyed upper Donner und Blitzen River basin stream network with a resolution of 0.1 m. Channel centerlines were manually digitized within a geographic information system. Stream temperatures for longitudinal profiles were sampled using both automated and manual methods along the channel centerline from the TIR imagery. The stream temperatures were plotted versus channel distances upstream along the Donner und Blitzen River, starting from the bridge over the river near Page Springs Campground to create longitudinal stream temperature profiles, which may be used to interpret groundwater discharge patterns and to identify potential cold-water refuges.

This dataset includes georeferenced, high-resolution, airborne thermal infrared (TIR) and high-resolution true-color imagery, a polyline shapefile of the channel centerline, a polyline shapefile with TIR sample points for longitudinal stream temperature profiles, and a tabular file with longitudinal stream temperature profiles for the Donner und Blitzen River and its tributaries, Oregon. The aerial TIR surveys were conducted with a helicopter by NV5 Geospatial and are published as 17 raster mosaics in GeoTiff format with a resolution of 0.3 meters (m). The TIR mosaics contain corrected surface temperatures in degrees Celsius (C) (multiplied by 10 to create an unsigned integer pixel type). The longitudinal stream temperature profiles have temperatures in degrees C. The TIR dataset encompasses 159 kilometers of the Donner und Blitzen River and its tributaries that extends from near Frenchglen, Oregon into the basin headwaters on Steens Mountain. The TIR surveys were collected during the afternoons (13:00-17:00) of August 13, 14, and 15, 2020. The TIR surveys were calibrated using continuous temperature loggers deployed at 29 in-stream locations distributed longitudinally throughout the survey area. The true-color imagery is published as a single raster mosaic of the entire surveyed upper Donner und Blitzen River basin stream network with a resolution of 0.1 m. Channel centerlines were manually digitized within a geographic information system. Stream temperatures for longitudinal profiles were sampled using both automated and manual methods along the channel centerline from the TIR imagery. The stream temperatures were plotted versus channel distances upstream along the Donner und Blitzen River, starting from the bridge over the river near Page Springs Campground to create longitudinal stream temperature profiles, which may be used to interpret groundwater discharge patterns and to identify potential cold-water refuges.

An Innerspace 456 single-beam echosounder in conjunction with a Trimble® differential Global Positioning System (DGPS), HYPACK® navigation software, and Ashtech Z-Xtreme and Trimble® R8 Global Navigation Satellite System (GNSS) receivers was used to survey 7 chutes and 3 backwaters on the Missouri River yearly from 2011-13. These chutes and backwaters are located on the Missouri River between Newcastle, Nebraska and Rulo, Nebraska in the States of Nebraska, Iowa, and Missouri. Surveys of chutes consisted of topographic and bathymetric data collected along transects spaced 30.48 m apart from high bank to high bank. Surveys of backwaters consisted of topographic and bathymetric data collected along a transect grid of 76.2 m spacing. The data were collected by the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers (USACE) Omaha District as part of the Missouri River Habitat Assessment and Monitoring Program.