Fluorescence and absorbance spectra were measured in discrete surface water samples collected during three sampling campaigns (Nov 2022, Mar/Apr 2023, Jul 2023) on the Illinois Waterway (IWW) and Chicago Area Waterway System (CAWS), which are the primary drainage of the Illinois River Basin (IRB). Water sampling was conducted concurrently with a boat-based water quality mapping effort using the Fast Limnology Automated Measurement (FLAMe) system (Crawford et al., 2015). Each campaign began in the Chicago metropolitan area, and after having sampled Lake Michigan, entered into the upper extent of the IWW, sampling through the CAWS into the lower reaches of the Des Plaines River and finally the Illinois River. After 8-10 days of traveling downriver through the IWW, sampling ended in the Mississippi River upstream of St Louis, Missouri. Discrete water quality samples were collected from various sites that include main channel, tributaries, and off-channel areas (e.g., backwaters) from a depth of 1 meter (m), typically in the center of the channel or aquatic feature. Between 25 and 40 sites were sampled per campaign dependent upon river conditions and boat accessibility. Data reported here are compiled into three tables: 1) full fluorescence spectra in vectorized format, 2) full absorbance spectra, and 3) summary optical measurements commonly used in statistical analyses.

Here we report optical data collected as part of a collaborative study between USGS Pennsylvania Water Science Center, Pennsylvania Department of Environmental Protection and Water Mission Area Proxies Project. The optical measurements reported here were collected to aide in the characterization of water sources and mixtures and establish proxies (surrogates) for per- and poly-fluorinated alkyl substances within the Neshaminy Creek basin. Data are compiled into three tables: 1) full fluorescence spectra in vectorized format, 2) full absorbance spectra, and 3) summary file of commonly extracted optical indicators and field-based sensor arrays.

Here we report optical data collected as part of a collaborative study between USGS Pennsylvania Water Science Center, Pennsylvania Department of Environmental Protection and Water Mission Area Proxies Project. The optical measurements reported here were collected to aide in the characterization of water sources and mixtures and establish proxies (surrogates) for per- and poly-fluorinated alkyl substances within the Neshaminy Creek basin. Data are compiled into three tables: 1) full fluorescence spectra in vectorized format, 2) full absorbance spectra, and 3) summary file of commonly extracted optical indicators and field-based sensor arrays.

Optical spectra reported here are collected from 17 surface water sampling sites within the Fraser River, a headwaters drainage of the Upper Colorado River Basin in the central western United States. The sample collection was conducted as part of the partnership between the United States Geological Survey’s (USGS) Next Generation Water Observation System (NGWOS) and Proxies Project, in coordination with the USGS Colorado Water Science Center and California Water Science Center, and the East Grand Water Quality Board.

Optical spectra reported here are collected from 17 surface water sampling sites within the Fraser River, a headwaters drainage of the Upper Colorado River Basin in the central western United States. The sample collection was conducted as part of the partnership between the United States Geological Survey’s (USGS) Next Generation Water Observation System (NGWOS) and Proxies Project, in coordination with the USGS Colorado Water Science Center and California Water Science Center, and the East Grand Water Quality Board.

Data are from water samples collected from tributaries of the Great Lakes at three different drainage basin scales, including 1). watershed scale: 8 tributaries of the Great Lakes, 2). subwatershed scale: 5 locations from the greater Milwaukee, Wisconsin area, and 3). small scale: 213 storm sewers and open channel locations in three subwatersheds within the Great Lakes Basin including the Middle Branch of the Clinton River in Macomb County, Michigan (65 sample locations), Red Creek in Monroe County, New York (88 sample locations), and the Kinnickinnic River in Milwaukee County, Wisconsin (60 sample locations). At the watershed- and subwatershed-scale locations, water samples were collected over a 24-hour duration for low-flow periods, and throughout the duration of increased streamflow for runoff-event periods. An individual sample included multiple subsamples that were composited using automatic samplers. At the small-scale locations, discrete grab samples were collected by direct bottle submersion or by peristaltic pump. Water samples were analyzed for absorbance spectra and fluorescence excitation-emission matrices (EEMs), which are presented in this data release. Samples were also analyzed for human-specific viruses, at the watershed- and subwatershed-scale locations only, human- and fecal- indicator bacteria, and dissolved organic carbon (DOC), which are archived in the U.S. Geological Survey National Water Information System (NWIS). These data were used to develop regression models for describing variability of human-associated and fecal indicator bacteria, and an archive of these models is provided. Sample collection, laboratory analyses methods, and a detailed description of the modeling process are described in the associated journal publication: Corsi, S.R., De Cicco, L.A., Hansen, A.M., Lenaker, P.L., Bergamaschi, B.A., Pellerin, B.A., Dila, D.K., Bootsma, M.J., Spencer, S.K., Borchardt, M.A., and McLellan, S.L., 2021, Optical properties of water for prediction of wastewater contamination, human-associated bacteria, and fecal indicator bacteria in surface water at three watershed scales: Environmental Science and Technology, 55, 20, 13770–13782, https://doi.org/10.1021/acs.est.1c02644.

Data are from water samples collected from tributaries of the Great Lakes at three different drainage basin scales, including 1). watershed scale: 8 tributaries of the Great Lakes, 2). subwatershed scale: 5 locations from the greater Milwaukee, Wisconsin area, and 3). small scale: 213 storm sewers and open channel locations in three subwatersheds within the Great Lakes Basin including the Middle Branch of the Clinton River in Macomb County, Michigan (65 sample locations), Red Creek in Monroe County, New York (88 sample locations), and the Kinnickinnic River in Milwaukee County, Wisconsin (60 sample locations). At the watershed- and subwatershed-scale locations, water samples were collected over a 24-hour duration for low-flow periods, and throughout the duration of increased streamflow for runoff-event periods. An individual sample included multiple subsamples that were composited using automatic samplers. At the small-scale locations, discrete grab samples were collected by direct bottle submersion or by peristaltic pump. Water samples were analyzed for absorbance spectra and fluorescence excitation-emission matrices (EEMs), which are presented in this data release. Samples were also analyzed for human-specific viruses, at the watershed- and subwatershed-scale locations only, human- and fecal- indicator bacteria, and dissolved organic carbon (DOC), which are archived in the U.S. Geological Survey National Water Information System (NWIS). These data were used to develop regression models for describing variability of human-associated and fecal indicator bacteria, and an archive of these models is provided. Sample collection, laboratory analyses methods, and a detailed description of the modeling process are described in the associated journal publication: Corsi, S.R., De Cicco, L.A., Hansen, A.M., Lenaker, P.L., Bergamaschi, B.A., Pellerin, B.A., Dila, D.K., Bootsma, M.J., Spencer, S.K., Borchardt, M.A., and McLellan, S.L., 2021, Optical properties of water for prediction of wastewater contamination, human-associated bacteria, and fecal indicator bacteria in surface water at three watershed scales: Environmental Science and Technology, 55, 20, 13770–13782, https://doi.org/10.1021/acs.est.1c02644.

This data release contains the results from a study that characterized the concentration and quality of dissolved organic carbon (DOC) in the McKenzie River, a relatively pristine watershed in western Oregon, and its link to forming disinfection by-products (DBPs) in treated drinking water. The study aimed to identify the primary source(s) of DOC in source water for the Eugene Water and Electric Board’s (EWEB) conventional treatment plant on the McKenzie River near river mile 11, upstream of Hayden Bridge. The two classes of regulated compounds examined—trihalomethanes (THMs) and haloacetic acids (HAAs)—form when organic carbon in raw source water reacts with chlorine and (or) bromine during water treatment. The data release includes six general types of data: 1) the concentration of dissolved organic carbon in filtered water samples; 2) the concentration of disinfection by-products (DBPs) in finished (treated) drinking water; 3) raw absorbance data for filtered water samples; 4) fluorescence excitation-emission matrices in vectorized format; 5) Parallel factor analysis (PARAFAC) component loadings for the fluorescence excitation-emission matrices; and 6) the percentages of different land cover for the watersheds draining to the sampled sites.

This data release contains the results from a study that characterized the concentration and quality of dissolved organic carbon (DOC) in the McKenzie River, a relatively pristine watershed in western Oregon, and its link to forming disinfection by-products (DBPs) in treated drinking water. The study aimed to identify the primary source(s) of DOC in source water for the Eugene Water and Electric Board’s (EWEB) conventional treatment plant on the McKenzie River near river mile 11, upstream of Hayden Bridge. The two classes of regulated compounds examined—trihalomethanes (THMs) and haloacetic acids (HAAs)—form when organic carbon in raw source water reacts with chlorine and (or) bromine during water treatment. The data release includes six general types of data: 1) the concentration of dissolved organic carbon in filtered water samples; 2) the concentration of disinfection by-products (DBPs) in finished (treated) drinking water; 3) raw absorbance data for filtered water samples; 4) fluorescence excitation-emission matrices in vectorized format; 5) Parallel factor analysis (PARAFAC) component loadings for the fluorescence excitation-emission matrices; and 6) the percentages of different land cover for the watersheds draining to the sampled sites.

Clear Lake, located within the Coast Range west of California's Central Valley, is the largest natural freshwater lake contained fully within the state. The lake has three arms: a large open-water region to the northwest (Upper Arm), a smaller and narrower region to the southeast (Lower Arm), and the smallest and narrowest region to the east (Oaks Arm). Water quality in Clear Lake is degraded by both by mercury contamination and harmful algal blooms (HABs). The mercury contamination is largely associated with the Sulfur Bank Mercury Mine (SBMM), a Superfund site managed by the U.S. Environmental Protection Agency (USEPA) since 1992 located on the eastern end of the Oaks Arm. Mercury contamination from SBMM and its biogeochemical mercury cycling within the lake are the focus of research being conducted by the U.S. Geological Survey (USGS) in cooperation with USEPA. Monitoring and modeling efforts are being implemented to improve understanding of the ways that nutrient dynamics affect the cycling, transport, and bioaccumulation of Hg. This data release documents measurements related to organic matter concentrations and characteristics in Clear Lake, California. Data files reported here provide full spectral results for absorbance (Clear_Lake_Full_Spectra_Absorbance_Data.csv) and fluorescence (Clear_Lake_Vectorized_Fluorescence_Data.csv) analyses as well as calculated fluorescence indices and arrays (Clear_Lake_Sample_Summary.csv) used for statistical modeling for proxy development. Commonly reported diagnostic absorbance wavelengths and fluorescence excitation-emission pairs contained in these spectra as well as a set of commonly calculated indices have been released to the USGS National Water Information System (NWIS) database. The optical measurements reported here were collected to establish additional potential surrogates for mercury (Hg) and methylmercury (MeHg) concentrations and to provide more complete spectral information on temporal and spatial patterns of organic matter within the lake. Other water-quality data for the samples included in this data release are published in Marvin-DiPasquale and others (2020) and Agee and others (2024).