As part of a larger study examining stream conditions and the effect of best management practices in the Chesapeake Bay watershed, thirty small streams across the Pennsylvania and Maryland piedmont physiographic province were instrumented and monitored for gage height (water level), water temperature, and air temperature using Onset HOBO sensors from March to September 2023. In addition, discrete discharge measurements were made at baseflow at each site. This data release contains four .csv files with time-series for gage height, water temperature, and air temperature for all thirty monitoring locations and a table of discrete discharge measurements and associated field measurement metadata. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

As part of a larger study examining stream conditions and the effect of Best Management Practices in the Chesapeake Bay watershed, thirty small streams on the Delmarva Peninsula were instrumented and monitored for gage height (water level), water temperature, and air temperature using Onset HOBO sensors from March to September 2022. In addition, two discrete discharge measurements were made at baseflow at each site. This data release contains four .csv files with time-series for gage height, water temperature, and air temperature for all thirty monitoring locations and a table of discrete discharge measurements and associated field measurement metadata: Delmarva_2022_Continuous_Air_Temperature.csv Delmarva_2022_Continuous_Gage_Height.csv Delmarva_2022_Continuous_Water_Temperature.csv Delmarva_2022_Discharge_Measurements.csv

This USGS Data Release includes hydrologic data compiled for selected years during the period 1990-2017 to support the development and calibration of a numerical groundwater model used to simulate groundwater flow paths at and near former and currently active military bases in Montgomery and Bucks Counties in southeastern Pennsylvania (Goode and Senior, 2020). The hydrologic data compiled for the study area include: 1) withdrawal (pumping) rates for production and other wells; 2) quarry pumping rates; 3) rates of flow discharged to streams from the National Pollution Discharge Elimination System (NPDES) sources, and 4) measured water levels in wells. The data were compiled from various sources described in the metadata for each type of data, with complete references for data sources listed in (Goode and Senior, 2020). Withdrawal (pumping) and discharge rates in the data release represent annual average rates computed as needed from data compiled from various sources. The principal time periods for compiled data include 1990's, 2010, 2013, 2016, and 2017. Some values are estimated where data were missing or not available.

This USGS Data Release includes hydrologic data compiled for selected years during the period 1990-2017 to support the development and calibration of a numerical groundwater model used to simulate groundwater flow paths at and near former and currently active military bases in Montgomery and Bucks Counties in southeastern Pennsylvania (Goode and Senior, 2020). The hydrologic data compiled for the study area include: 1) withdrawal (pumping) rates for production and other wells; 2) quarry pumping rates; 3) rates of flow discharged to streams from the National Pollution Discharge Elimination System (NPDES) sources, and 4) measured water levels in wells. The data were compiled from various sources described in the metadata for each type of data, with complete references for data sources listed in (Goode and Senior, 2020). Withdrawal (pumping) and discharge rates in the data release represent annual average rates computed as needed from data compiled from various sources. The principal time periods for compiled data include 1990's, 2010, 2013, 2016, and 2017. Some values are estimated where data were missing or not available.

This data release contains measured streamflow data from U.S. Geological Survey (USGS) streamgages and reported wastewater data from wastewater treatment plants (WWTP) discharge monitoring reports (DMRs) within the Potomac River watershed between October 1, 2021 and September 30, 2024. Mean monthly streamflow data was obtained from 117 USGS streamgages (Table1_Streamgages.csv). Average monthly reported wastewater discharge volumes to surface water were obtained from National Pollutant Discharge Elimination System (NPDES) permits using the United States Environmental Protection Agency’s (USEPA) Environment and Compliance History Online (ECHO) database to obtain DMRs from the Integrated Compliance Information System National Pollutant Discharge Elimination System (ICIS-NPDES). Quality assurance procedures that were used to avoid inclusion of inaccurate data that can be reported on DMRs (Table2_WWTP_DMRs.csv) are documented within the Process Step fields of the metadata. At each streamgage the average monthly accumulated wastewater percentage (ACCWW) was calculated by dividing the total amount of reported wastewater upstream of the streamgage by the measured amount of streamflow (Table3_Streamgage_ACCWW.csv) following similar methods described in Miller and others (2024) and Barber and others (2025). The ACCWW calculations were computed monthly at each streamgage using reported total wastewater discharge, municipal wastewater discharge, and municipal-plus-industrial per- and polyfluoroalkyl substances (PFAS) wastewater discharge which includes municipal wastewater in addition to wastewater from industrial WWTPs that are potential PFAS handling industry sectors defined by the USEPA (2023). The term ‘municipal’ is used here to represent NPDES-permitted facilities with the Standard Industrial Classification code 4952 (‘sewerage systems’) and 'industrial' refers to permitted facilities with Standard Industrial Classification codes other than 4952. Monthly predicted environmental concentrations and constituent loads (i.e. mass fluxes) of eight PFAS and 14 pesticides were estimated at each streamgage following methodology presented by Barber and others (2025) and Miller and others (2024). Monthly PFAS loads were computed by multiplying the discharge volumes from municipal and industrial WWTPs that are potential PFAS handling industry sectors by the median PFAS concentrations measured and reported in Barber and others (2025). Monthly pesticide loads were computed by multiplying the discharge volumes from municipal WWTPs by the median pesticide concentrations reported in Miller and others (2024). Wastewater effluent concentrations from Miller and others (2024) and Barber and others (2025) are provided in Table4_Parameters.csv. Monthly predicted constituent loads from wastewater were summed from WWTPs that discharged to every National Hydrography Dataset Version 2.1 (NHDPlus V2; USEPA, 2012) stream segment Common Identifier (COMID) upstream of each streamgage, not including the COMID where the streamgage was located, to calculate the predicted monthly load at each streamgage (Table5_Streamgage_Parameter_Predictions.csv). Predicted monthly concentrations from wastewater were calculated by dividing the predicted monthly load by measured monthly streamflow at each streamgage (Table5_Streamgage_Parameter_Predictions.csv).

Streamflow was collected at various streamgages in western Pennsylvania in support of the scientific investigations report "Estimation of Base Flow on Ungaged, Periodically Measured Streams in Small Watersheds in Western Pennsylvania". Data observed at the streamgages for the period of August 1, 2014 through March 31, 2017 are considered. This dataset includes 1) all data used to develop prediction intervals for the titled estimation site based upon the titled index streamgage for the period of May 1, 2015 to March 31, 2017 and 2) evaluation of data observed before May 1, 2015. For prediction interval development, a Move.1 regression was developed between the titled estimation site and titled index streamgage. From this regression model, Pearson's correlation coefficient (r) is reported, and the Nash-Sutcliffe efficiency value is computed. The prediction interval development is included for the 95% prediction interval for both the nonparametric and parametric methods. For the parametric method, any prediction interval can be developed by changing Student's t critical value. Any data that were observed before May 1, 2015 were evaluated to see if they fell within the 95% nonparametric prediction interval. The data chosen for the regression development and evaluation is streamflow that is not influenced by runoff. Streamflow that occurred the day of precipitation and two days after is considered influenced by runoff and not included in the dataset. Not all streamgages have the same period of record; dates where data were observed both at the titled index streamgage and estimation site are described below in the "Time Period of Data" section.

Streamflow was collected at various streamgages in western Pennsylvania in support of the scientific investigations report "Estimation of Base Flow on Ungaged, Periodically Measured Streams in Small Watersheds in Western Pennsylvania". Data observed at the streamgages for the period of August 1, 2014 through March 31, 2017 are considered. This dataset includes 1) all data used to develop prediction intervals for the titled estimation site based upon the titled index streamgage for the period of May 1, 2015 to March 31, 2017 and 2) evaluation of data observed before May 1, 2015. For prediction interval development, a Move.1 regression was developed between the titled estimation site and titled index streamgage. From this regression model, Pearson's correlation coefficient (r) is reported, and the Nash-Sutcliffe efficiency value is computed. The prediction interval development is included for the 95% prediction interval for both the nonparametric and parametric methods. For the parametric method, any prediction interval can be developed by changing Student's t critical value. Any data that were observed before May 1, 2015 were evaluated to see if they fell within the 95% nonparametric prediction interval. The data chosen for the regression development and evaluation is streamflow that is not influenced by runoff. Streamflow that occurred the day of precipitation and two days after is considered influenced by runoff and not included in the dataset. Not all streamgages have the same period of record; dates where data were observed both at the titled index streamgage and estimation site are described below in the "Time Period of Data" section.

Streamflow was collected at various streamgages in western Pennsylvania in support of the scientific investigations report "Estimation of Base Flow on Ungaged, Periodically Measured Streams in Small Watersheds in Western Pennsylvania". Data observed at the streamgages for the period of August 1, 2014 through March 31, 2017 are considered. This dataset includes 1) all data used to develop prediction intervals for the titled estimation site based upon the titled index streamgage for the period of May 1, 2015 to March 31, 2017 and 2) evaluation of data observed before May 1, 2015. For prediction interval development, a Move.1 regression was developed between the titled estimation site and titled index streamgage. From this regression model, Pearson's correlation coefficient (r) is reported, and the Nash-Sutcliffe efficiency value is computed. The prediction interval development is included for the 95% prediction interval for both the nonparametric and parametric methods. For the parametric method, any prediction interval can be developed by changing Student's t critical value. Any data that were observed before May 1, 2015 were evaluated to see if they fell within the 95% nonparametric prediction interval. The data chosen for the regression development and evaluation is streamflow that is not influenced by runoff. Streamflow that occurred the day of precipitation and two days after is considered influenced by runoff and not included in the dataset. Not all streamgages have the same period of record; dates where data were observed both at the titled index streamgage and estimation site are described below in the "Time Period of Data" section.

Streamflow was collected at various streamgages in western Pennsylvania in support of the scientific investigations report "Estimation of Base Flow on Ungaged, Periodically Measured Streams in Small Watersheds in Western Pennsylvania". Data observed at the streamgages for the period of August 1, 2014 through March 31, 2017 are considered. This dataset includes 1) all data used to develop prediction intervals for the titled estimation site based upon the titled index streamgage for the period of May 1, 2015 to March 31, 2017 and 2) evaluation of data observed before May 1, 2015. For prediction interval development, a Move.1 regression was developed between the titled estimation site and titled index streamgage. From this regression model, Pearson's correlation coefficient (r) is reported, and the Nash-Sutcliffe efficiency value is computed. The prediction interval development is included for the 95% prediction interval for both the nonparametric and parametric methods. For the parametric method, any prediction interval can be developed by changing Student's t critical value. Any data that were observed before May 1, 2015 were evaluated to see if they fell within the 95% nonparametric prediction interval. The data chosen for the regression development and evaluation is streamflow that is not influenced by runoff. Streamflow that occurred the day of precipitation and two days after is considered influenced by runoff and not included in the dataset. Not all streamgages have the same period of record; dates where data were observed both at the titled index streamgage and estimation site are described below in the "Time Period of Data" section.

Streamflow was collected at various streamgages in western Pennsylvania in support of the scientific investigations report "Estimation of Base Flow on Ungaged, Periodically Measured Streams in Small Watersheds in Western Pennsylvania". Data observed at the streamgages for the period of August 1, 2014 through March 31, 2017 are considered. This dataset includes 1) all data used to develop prediction intervals for the titled estimation site based upon the titled index streamgage for the period of May 1, 2015 to March 31, 2017 and 2) evaluation of data observed before May 1, 2015. For prediction interval development, a Move.1 regression was developed between the titled estimation site and titled index streamgage. From this regression model, Pearson's correlation coefficient (r) is reported, and the Nash-Sutcliffe efficiency value is computed. The prediction interval development is included for the 95% prediction interval for both the nonparametric and parametric methods. For the parametric method, any prediction interval can be developed by changing Student's t critical value. Any data that were observed before May 1, 2015 were evaluated to see if they fell within the 95% nonparametric prediction interval. The data chosen for the regression development and evaluation is streamflow that is not influenced by runoff. Streamflow that occurred the day of precipitation and two days after is considered influenced by runoff and not included in the dataset. Not all streamgages have the same period of record; dates where data were observed both at the titled index streamgage and estimation site are described below in the "Time Period of Data" section.