The U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Conservation and Natural Resources (PA DCNR), Bureau of Geological Survey, provides estimates of groundwater recharge at 197 streamflow gaging stations where streamflow is relatively unaffected by regulation. Baseflow, runoff, and groundwater Recharge estimates were conducted via the Hydrologic toolbox by use of automated streamflow-hydrograph-analysis methods HySEP-Fixed, HySEP-LocMin, HySEP-Slide, PART, BFI-Standard, BFI-Modified, DF-One Param, DF-Two Param, and RORA.

The U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Conservation and Natural Resources (PA DCNR), Bureau of Geological Survey, provides time series trends results using the Mann Kendall family of analyses on select sites across Pennsylvania for baseflow, runoff, groundwater levels, and streamflow percentiles.

The U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Conservation and Natural Resources (PA DCNR), Bureau of Geological Survey, provides time series trends results using the Mann Kendall family of analyses on select sites across Pennsylvania for baseflow, runoff, groundwater levels, and streamflow percentiles.

The U.S. Geological Survey (USGS), in cooperation with the Federal Emergency Management Agency, Pennsylvania Department of Environmental Protection, Pennsylvania Department of Transportation, and Susquehanna River Basin Commission, prepared hydro-conditioned geographic information systems (GIS) layers for use in the Pennsylvania StreamStats application. These data were used to update the peak flow and low flow regression equations for Pennsylvania. This dataset consists of flow accumulation rasters for each 8-digit Hydrologic Unit Code (HUC) area in Pennsylvania, one of the layer types needed to delineate watersheds within the HUC-8 areas, merged into a single dataset. The 59 HUCs represented by this dataset are 02040101, 02040102, 02040103, 02040104, 02040105, 02040106, 02040201, 02040202, 02040203, 02040205, 02050101, 02050102, 02050103, 02050104, 02050105, 02050106, 02050107, 02050201, 02050202, 02050203, 02050204, 02050205, 02050206, 02050301, 02050302, 02050303, 02050304, 02050305, 02050306, 02060002, 02060003, 02070002, 02070003, 02070004, 02070009, 04110003, 04120101, 04130002, 05010001, 05010002, 05010003, 05010004, 05010005, 05010006, 05010007, 05010008, 05010009, 05020001, 05020002, 05020003, 05020004, 05020005, 05020006, 05030101, 05030102, 05030103, 05030104, 05030105, and 05030106.

The U.S. Geological Survey (USGS), in cooperation with the Federal Emergency Management Agency, Pennsylvania Department of Environmental Protection, Pennsylvania Department of Transportation, and Susquehanna River Basin Commission, prepared hydro-conditioned geographic information systems (GIS) layers for use in the Pennsylvania StreamStats application. These data were used to update the peak flow and low flow regression equations for Pennsylvania. This dataset consists of flow accumulation rasters for each 8-digit Hydrologic Unit Code (HUC) area in Pennsylvania, one of the layer types needed to delineate watersheds within the HUC-8 areas, merged into a single dataset. The 59 HUCs represented by this dataset are 02040101, 02040102, 02040103, 02040104, 02040105, 02040106, 02040201, 02040202, 02040203, 02040205, 02050101, 02050102, 02050103, 02050104, 02050105, 02050106, 02050107, 02050201, 02050202, 02050203, 02050204, 02050205, 02050206, 02050301, 02050302, 02050303, 02050304, 02050305, 02050306, 02060002, 02060003, 02070002, 02070003, 02070004, 02070009, 04110003, 04120101, 04130002, 05010001, 05010002, 05010003, 05010004, 05010005, 05010006, 05010007, 05010008, 05010009, 05020001, 05020002, 05020003, 05020004, 05020005, 05020006, 05030101, 05030102, 05030103, 05030104, 05030105, and 05030106.

This metadata record describes monthly estimates of natural baseflow for 15,866 stream reaches, defined by the National Hydrography Dataset Plus Version 2.0 (NHDPlusV2), in the Delaware River Basin for the period 1950-2015. A statistical machine learning technique - random forest modeling (Liaw and Wiener, 2018; R Core Team, 2020) - was applied to estimate natural flows using about 150 potential predictor variables (Miller and others, 2018). Calibration data used for the random forest model are available from (Foks and others, 2020). Each model was run twice, first using all potential predictor variables, which represents a "full" model run, and a second time using the top 20 predictors from the original run, which represents the "partial" model run. Model performance of the full and partial models were compared and identified to be similar. Therefore, predictions for all NHDPlusV2 stream reaches were made using the partial model. Methods used to calibrate the random forest models, and references to predictor data sources are detailed in (Miller and others, 2018). The R scripts used and directions to run the scripts are included in this data release. References cited: Liaw, A., and Wiener, M., 2018, Package 'randomForest': The Comprehensive R Archive Network, https://cran.r-project.org/web/packages/randomForest/randomForest.pdf. Miller, M.P., Carlisle, D.M., Wolock, D.M., and Wieczorek, M., 2018, A database of natural monthly streamflow estimates from 1950 to 2015 for the conterminous United States: Journal of the American Water Resources Association, v. 54, no. 6, p. 1258-1269, https://doi.org/10.1111/1752-1688.12685. Foks, S.S., Miller, M.P., and Hopple, J.A., 2020, Daily-timestep and monthly-timestep estimates of baseflow at 49 reference stream gages located within 25 miles of the Delaware River basin watershed boundary for the years 1950 through 2015: U.S. Geological Survey data release, https://doi.org/10.5066/P9XY70L4. R Core Team, 2020, R-A language and environment for statistical computing: R Foundation for Statistical Computing, https://www.eea.europa.eu/data-and-maps/indicators/oxygen-consuming-substances-in-rivers/r-development-core-team-2006.

This metadata record describes monthly estimates of natural baseflow for 15,866 stream reaches, defined by the National Hydrography Dataset Plus Version 2.0 (NHDPlusV2), in the Delaware River Basin for the period 1950-2015. A statistical machine learning technique - random forest modeling (Liaw and Wiener, 2018; R Core Team, 2020) - was applied to estimate natural flows using about 150 potential predictor variables (Miller and others, 2018). Calibration data used for the random forest model are available from (Foks and others, 2020). Each model was run twice, first using all potential predictor variables, which represents a "full" model run, and a second time using the top 20 predictors from the original run, which represents the "partial" model run. Model performance of the full and partial models were compared and identified to be similar. Therefore, predictions for all NHDPlusV2 stream reaches were made using the partial model. Methods used to calibrate the random forest models, and references to predictor data sources are detailed in (Miller and others, 2018). The R scripts used and directions to run the scripts are included in this data release. References cited: Liaw, A., and Wiener, M., 2018, Package 'randomForest': The Comprehensive R Archive Network, https://cran.r-project.org/web/packages/randomForest/randomForest.pdf. Miller, M.P., Carlisle, D.M., Wolock, D.M., and Wieczorek, M., 2018, A database of natural monthly streamflow estimates from 1950 to 2015 for the conterminous United States: Journal of the American Water Resources Association, v. 54, no. 6, p. 1258-1269, https://doi.org/10.1111/1752-1688.12685. Foks, S.S., Miller, M.P., and Hopple, J.A., 2020, Daily-timestep and monthly-timestep estimates of baseflow at 49 reference stream gages located within 25 miles of the Delaware River basin watershed boundary for the years 1950 through 2015: U.S. Geological Survey data release, https://doi.org/10.5066/P9XY70L4. R Core Team, 2020, R-A language and environment for statistical computing: R Foundation for Statistical Computing, https://www.eea.europa.eu/data-and-maps/indicators/oxygen-consuming-substances-in-rivers/r-development-core-team-2006.

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) observed streamflow and qualifier indicating the presence of precipitation or runoff at various streamgages, 2) all data used to develop prediction intervals for the titled estimation site based upon the titled index streamgage for use in runoff influenced streamflow analysis, 3) all data used to develop prediction intervals for the titled estimation site based upon the titled index streamgage for streamflow measurement schedule analysis, and 4) 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 along with evaluation of data observed before May 1, 2015.

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) observed streamflow and qualifier indicating the presence of precipitation or runoff at various streamgages, 2) all data used to develop prediction intervals for the titled estimation site based upon the titled index streamgage for use in runoff influenced streamflow analysis, 3) all data used to develop prediction intervals for the titled estimation site based upon the titled index streamgage for streamflow measurement schedule analysis, and 4) 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 along with evaluation of data observed before May 1, 2015.

The U.S. Geological Survey (USGS), in cooperation with the Federal Emergency Management Agency, Pennsylvania Department of Environmental Protection, Pennsylvania Department of Transportation, and Susquehanna River Basin Commission, prepared hydro-conditioned geographic information systems (GIS) layers for use in the Pennsylvania StreamStats application. These data were used to update the peak flow and low flow regression equations for Pennsylvania. This dataset consists of flow direction rasters for each 8-digit Hydrologic Unit Code (HUC) area in Pennsylvania, one of the layer types needed to delineate watersheds within the HUC-8 areas, merged into a single dataset. The 59 HUCs represented by this dataset are 02040101, 02040102, 02040103, 02040104, 02040105, 02040106, 02040201, 02040202, 02040203, 02040205, 02050101, 02050102, 02050103, 02050104, 02050105, 02050106, 02050107, 02050201, 02050202, 02050203, 02050204, 02050205, 02050206, 02050301, 02050302, 02050303, 02050304, 02050305, 02050306, 02060002, 02060003, 02070002, 02070003, 02070004, 02070009, 04110003, 04120101, 04130002, 05010001, 05010002, 05010003, 05010004, 05010005, 05010006, 05010007, 05010008, 05010009, 05020001, 05020002, 05020003, 05020004, 05020005, 05020006, 05030101, 05030102, 05030103, 05030104, 05030105, and 05030106.