LaMotte, A.E. 20230802 comma delimited https://doi.org/10.5066/F7765D7V This metadata record documents an ascii comma-delimited file representing estimated nitrogen in kilograms by NHDPlus v2.1 catchments for the conterminous United States. Nitrogen estimates were taken from Estimated nitrogen from septic for the conterminous United States, 2010 published by the U.S. Geological Survey. Nitrogen values by individual reach catchments (COMID) were determined by calculating a zonal mean in a GIS. This dataset was created by the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Project in support of USGS SPARROW modeling (SPAtially Referenced Regressions On Watershed attributes). The dataset also can be useful for other applications such as regional and (or) national watershed characterizations and modeling. 20101231 publication date Complete None planned -127.8873 -65.3455 51.5754 22.8720 ISO 19115 Topic Category inlandWaters None Nitrogen Septic USGS Metadata Identifier USGS:5d2f72f0e4b01d82ce821afa None conterminous United States None. Please see 'Distribution Info' for details. None. Users are advised to read the data set's metadata thoroughly to understand appropriate use and data limitations. Andrew E LaMotte U.S. Geological Survey, Northeast Region Geographer mailing address

5522 Research Park Drive

Baltimore MD 21228 United States 443-498-5549 443-498-5510 alamotte@usgs.gov catchments were spot checked to verify that nitrogen estimates aligned with the source data all values fall within expected range NA No horizontal accuracy tests were performed. The data did show up in the correct location. NA Andrew E LaMotte 2018 dataset https://www.sciencebase.gov U.S. Geological Survey https://doi.org/10.5066/p9qtgsi7 Digital and/or Hardcopy 20101231 publication date SepN_CONUS_bg_2010 nitrogen values Changed to: Downloaded raster dataset of estimated nitrogen for the conterminous United States (LaMotte, 2018) from USGS Science Base (https://doi.org/10.5066/P9QTGSI7), accessed 2018-05-06. The raster was then used in a GIS to derive a zonal mean for each MHDPlus v2.1 catchment. 20180506 Vector G-polygon 3109 Albers Conical Equal Area 29.5 45.5 -96.0 37.5 0.0 0.0 coordinate pair 0.6096 0.6096 meters North_American_Datum_1983 GRS_1980 6378137.0 298.257222101 Nsep2010.txt comma delimited text file. U.S. Geological Survey COMID NHDPlus v 2.1 unique identifier U.S. Geological Survey NHDPlus v2.1 unique catchment identifier U.S. Geological Survey NSEP2010 Estimated nitrogen from septic U.S. Geological Survey 0 451091 kilograms BASIN_AREA Area of NHDPlus v 2.1 catchment U.S. Geological Survey 900 65014443000 square meters NODATA Percent of NHDPlus v 2.1 catchment that contains missing source data U.S. Geological Survey 0.0 100.0 percent 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/F7765D7V None 20260326 Andrew E LaMotte U.S. Geological Survey, Northeast Region Geographer mailing address

5522 Research Park Drive

Baltimore MD 21228 United States 443-498-5549 443-498-5510 alamotte@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998