John C. Hammond 20200623 comma-delimited text https://doi.org/10.5066/P92UYECV This dataset contains annual metrics quantifying low streamflows, climate, topography, land cover and geology for 325 USGS GAGES-2 watersheds within the Delaware River Basin boundary or with watershed centroids within a 25-mile buffer of the Delaware River Basin boundary. These data were compiled to support an analysis of spatial and temporal patterns and drivers of low streamflows using USGS GAGES-2 watersheds in the Delaware River Basin. This dataset provides several annual low flow metrics as well as climate, topography, land cover, and geology metrics that may be used to infer relationships between elements of the low flow regime and its drivers. 19500401 20190331 publication date Complete None planned -76.7285 -73.5205 42.3261 37.7881 World USGS Thesaurus surface water (non-marine) USGS Metadata Identifier USGS:5ee39e5082ce3bd58d7e1c2a None Delaware River Basin None. Please see 'Distribution Info' for details. None. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. John C Hammond U.S. Geological Survey, NORTHEAST REGION Hydrologist mailing address

5522 Research Park Drive

Catonsville MD 21228 US 443-498-5568 443-498-5510 jhammond@usgs.gov Only approved USGS streamflow values were used in the compilation of this dataset. Climate extractions at daily and annual scale were randomly checked by comparisons to PRISM data extracts as well as gridMET timeseries pulls from https://app.climateengine.org/climateEngine using the GAGES-2 watershed boundaries. All values of calculated and aggregated streamflow, climate, land cover, topography and geology metrics used in this dataset fall within expected ranged and the entries have been checked for duplication and omission. The 325 watersheds used in this study represent the full sample of USGS GAGES-2 watersheds measuring long-term flow in and near the Delaware River Basin with matching data on land cover, topography, soils, geology in a centralized database. John T. Abatzoglou 20111221 raster digital data International Journal of Climatology vol. 33, issue 1 n/a Wiley ppg. 121-131 https://doi.org/10.1002/joc.3413 Digital and/or Hardcopy 19790101 20200609 publication date gridMET Obtained from http://www.climatologylab.org/gridmet.html Chris Daly 20130101 raster digital data https://prism.oregonstate.edu/ Digital and/or Hardcopy 18900101 20200609 publication date PRISM Obtained from prism.oregonstate.edu James Falcone 20110101 tabular digital data n/a US Geological Survey https://doi.org/10.3133/70046617 Digital and/or Hardcopy 20110101 publication date GAGES-2 Obtained from https://pubs.er.usgs.gov/publication/70046617 James A Falcone 20170101 dataset https://www.sciencebase.gov U.S. Geological Survey https://doi.org/10.5066/f7hq3xs4 Digital and/or Hardcopy 20170101 publication date GAGES-2 time series Obtained from https://www.sciencebase.gov/catalog/item/59692a64e4b0d1f9f05fbd39 Tomislav Hengl Jorge Mendes de Jesus Gerard B. M. Heuvelink Maria Ruiperez Gonzalez Milan Kilibarda Aleksandar Blagotić Wei Shangguan Marvin N. Wright Xiaoyuan Geng Bernhard Bauer-Marschallinger Mario Antonio Guevara Rodrigo Vargas Robert A. MacMillan Niels H. Batjes Johan G. B. Leenaars Eloi Ribeiro Ichsani Wheeler Stephan Mantel Bas Kempen 20170216 publication PLOS ONE vol. 12, issue 2 n/a Public Library of Science (PLoS) ppg. e0169748 https://doi.org/10.1371/journal.pone.0169748 Digital and/or Hardcopy Soil Grids Obtained from https://soilgrids.org/ Tom Gleeson Nils Moosdorf Jens Hartmann L. P. H. van Beek 20140609 publication Geophysical Research Letters vol. 41, issue 11 n/a American Geophysical Union (AGU) ppg. 3891-3898 https://doi.org/10.1002/2014GL059856 Digital and/or Hardcopy Global Hydrology Maps Obtained from https://dataverse.scholarsportal.info/dataset.xhtml?persistentId=doi:10.5683/SP2/DLGXYO Streamflow metrics: Using the USGS dataRetrieval R package (De Cicco et al., 2018), daily mean streamflow was downloaded for all 325 sites for the period 1950-01-01 to 2019-08-30. Only approved values were kept for subsequent steps. Daily data was then aggregated to the climate year timestep (April 1 to March 31) corresponding with previous studies focusing on low flow occurrence. Only climate years for each site with less that 10% missing data were kept for subsequent steps. Prior to streamflow metric calculation, daily streamflow values were area normalized to units of mm/d. First, we calculated the annual minimum 7-day flow and associated climate year day of year on which the minimum 7-day flow occurred, which reflect the magnitude and timing of annual low flows. We then calculated the annual low flow deficit by first determining the 2% mean annual daily flow threshold for each watershed, and then calculating the total departure below this threshold for each year. The 2% mean annual daily flow threshold was chosen because 2% corresponds to the period of time typically represented by the annual minimum 7-day flow (7 days/365 days). In wet years when flows do not go below the mean daily 2% threshold, the low flow deficit will equal zero, whereas in drier than normal years, the low flow deficit will exceed the minimum 7-day flow value. Using the 2% mean annual daily flow threshold we also calculated the total number of days below this threshold per year, the maximum continuous number of days below this threshold, and the number of discrete periods below this threshold. These metrics reflect the duration, severity, and frequency of low flow occurrence. Finally, we calculated the 30-day slope in antecedent flow leading to the minimum 7-day flow each year for each watershed as a metric reflecting rate of change. Climate metrics: Using the intersectr R package (Blodgett, 2020), daily values of watershed average precipitation (P), potential evapotranspiration (PET), maximum temperature, minimum temperature, and Palmer Drought Severity Index (PDSI) were obtained from gridMET (Abatzoglou, 2013). Monthly watershed average values of precipitation and mean temperature were also obtained from PRISM (Daly, 2013) back to January 1950. Climate metrics were aggregated to the climate year timestep by summing P, PET , taking the mean of temperatures and PDSI. Land cover, topography, geology metrics: Select variables were obtained from the GAGES-2 database (Falcone, 2011) for the watersheds used in this study: drainage area, snow percent as precipitation, freshwater withdrawal, percent irrigated agriculture, number of power plants, sum of powerplant megawatts, NLCD 2006 forest cover, NLCD 2006 cultivated land cover, NLCD 2006 water cover, NLCD 2006 snow and ice cover, NLCD 2006 developed land cover, NLCD 2006 impervious percent, watershed mean elevation, watershed mean slope, watershed mean available water capacity, watershed mean permeability, watershed average clay content, watershed average silt content, watershed average sand content, and the number of major dams. Additionally, time series of water use, accumulated NID storage and impervious area were obtained from Falcone (2017). In addition, watershed average depth to bedrock was extracted from Hengl et al. (2017), while watershed average porosity was extracted from Gleeson et al. (2014). Storage in meters was calculated by multiplying depth to bedrock and porosity. Abatzoglou, J. T. (2013), Development of gridded surface meteorological data for ecological applications and modelling. Int. J. Climatol., 33: 121–131. Blodgett, D. (2020). intersectr: Spatiotemporal Intersections. R package version 0.0.2. https://github.com/USGS-R/intersectr Daly, C. (2013). Descriptions of PRISM spatial climate datasets for the conterminous United States (PRISM Doc., 14 p.). Corvallis, OR: PRISM Cli- mate Group, Oregon State University. De Cicco, L.A., Hirsch, R.M., Lorenz, D., Watkins, W.D., 2018, dataRetrieval: R packages for discovering and retrieving water data available from Federal hydrologic web services, doi:10.5066/P9X4L3GE Falcone, J. A. (2011). GAGES-II: Geospatial attributes of gages for evaluating streamflow (Digit. Spat. Data set). Reston, VA: U.S. Geological Survey. Falcone, J.A., 2017, U.S. Geological Survey GAGES-II time series data from consistent sources of land use, water use, agriculture, timber activities, dam removals, and other historical anthropogenic influences: U.S. Geological Survey data release, https://doi.org/10.5066/F7HQ3XS4. Gleeson, T., Moosdorf, N., Hartmann, J., & Van Beek, L. P. H. (2014). A glimpse beneath earth's surface: GLobal HYdrogeology MaPS (GLHYMPS) of permeability and porosity. Geophysical Research Letters, 41(11), 3891-3898. Hengl, T., de Jesus, J. M., Heuvelink, G. B., Gonzalez, M. R., Kilibarda, M., Blagotić, A., ... & Guevara, M. A. (2017). SoilGrids250m: Global gridded soil information based on machine learning. PLoS one, 12(2). 20190901 Annual_low_flow_climate_watershed_properties_DRB_06052020.csv Comma Separated Value (CSV) file containing data. Producer Defined staid USGS station ID USGS Defined 1349700 148471320 climyear Climate year using April 1 to March 31 definition USGS Defined 1950 2018 min7dayflow_mmd Minimum 7-day flow USGS Defined 0 3.78 milimeters per day day_of_climate_year_min_7_day_flow day of the climate year with the minimum 7-day flow USGS Defined 1 365 day of climate year days_below_low_flow_threshold Number of days below the 20% mean daily flow threshold USGS Defined 0 237 days deficit_mm Total flow anomaly below the 20% mean daily flow threshold USGS Defined 0.0 23.5073859 milimeters totallowflowperiods Number of discrete low flow periods below the 20% mean daily flow threshold USGS Defined 0 40 unitless meanlowflowlength Mean length of low flow periods USGS Defined 0.0 88.0 days maxlowflowlength Max length of low flow periods USGS Defined 0 141 days slope_30_days_leading_to_7_day_low_flow Slope of streamflow during 30 days prior to 7-day minimum flow USGS Defined NA No Data USGS defined -1.025 0.1285 milimeters per day slope_7_days_leading_to_7_day_low_flow Slope of streamflow during 7 days prior to 7-day minimum flow USGS Defined NA No Data USGS defined -3.73 0.11 milimeters per day prism_p_mm Total annual precipitation from PRISM USGS Defined 632 2328 milimeters prism_tmean_C Annual mean temperature from PRISM USGS Defined 3.45 15.85 degrees C gridmet_p_mm Total annual precipitation from gridMET USGS Defined NA No Data USGS defined 707 2314 milimeters gridmet_pet_mm Total annual potential evapotranspiration from gridMET USGS Defined NA No Data USGS defined 786 1483 milimeters gridmet_tmax_C Annual maximum temperature from gridMET USGS Defined NA No Data USGS defined 8.61 22.11 degrees C gridmet_tmin_C Annual minimum temperature from gridMET USGS Defined NA No Data USGS defined -1.46 9.98 degrees C class GAGES-2 watershed classification USGS Defined Non-ref GAGES-2 non-reference USGS gages USGS defined Ref GAGES-2 reference USGS gages USGS defined drain_sqkm GAGES-2 drainage area USGS Defined 1.6 17579.8 square kilometers snow_pct_precip Watershed average snow percent of precipitation from GAGES-2 USGS Defined 9.0 36.6 percent freshw_withdrawal Watershed total freshwater withdrawal from GAGES-2 USGS Defined 3.0 1947.4 megaliters per square kilometer per year pct_irrig_ag Percent of watershed in irrigated ag from GAGES-2 USGS Defined 0.0 19.43 percent power_num_pts Number of power plants from GAGES-2 USGS Defined 0 28 power_sum_mw Watershed total power plant megawatts from GAGES-2 USGS Defined 0.0 5868.9 megawatts devnlcd06 NLCD2006 developed percent from GAGES2 USGS Defined 0.0 95.87 percent forestnlcd06 NLCD2006 forested percent from GAGES2 USGS Defined 1.21 100.0 percent plantnlcd06 NLCD2006 cultivated percent from GAGES2 USGS Defined 0.0 88.69 percent waternlcd06 NLCD2006 water percent from GAGES2 USGS Defined 0.0 16.68 percent snowicenlcd06 NLCD2006 snow and ice percent from GAGES2 USGS Defined 0 0 percent impnlcd06 NLCD2006 impervious percent from GAGES2 USGS Defined 0.0 50.1 percent elev_mean_m_basin Mean watershed elevation from GAGES2 USGS Defined 10.17 1029.73 meters slope_pct Mean watershed slope from GAGES2 USGS Defined 0.0 33.31 percent awcave Mean watershed available water capacity from GAGES2 USGS Defined 0.07 0.16 meters permave Mean watershed permeability from GAGES2 USGS Defined 0.98 11.86 inches per hour clayave Mean watershed clay fraction from GAGES2 USGS Defined 5.73 31.43 percent siltave Mean watershed silt fraction from GAGES2 USGS Defined 14.97 62.54 percent sandave Mean watershed sand fraction from GAGES2 USGS Defined 14.12 79.3 percent major_dams Number of major dams from GAGES2 USGS Defined NA No Data USGS defined 0 33 count acc_nid_storage Accumulated total watershed dam storage from GAGES2 USGS Defined NA No Data USGS defined 0.0 2640883.84 acre feet impervious_area Multiple timesteps of impervious area percent from GAGES-2 timeseries USGS Defined NA No Data USGS defined 0.08 43.51 percent water_use Multiple timesteps of total watershed water use from GAGES-2 timeseries USGS Defined NA No Data USGS defined 0.0 323.93 millions of gallons per day per square kilometer GS ScienceBase U.S. Geological Survey mailing address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.5066/P92UYECV None 20200821 John C Hammond U.S. Geological Survey, NORTHEAST REGION Hydrologist mailing address

5522 Research Park Drive

Catonsville MD 21228 US 443-498-5568 443-498-5510 jhammond@usgs.gov FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata FGDC-STD-001.1-1999