Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking (simulation depth 50 meters) -- Input data set for sandstone and carbonate rocks (gwava-dw

Hitt, K.J. 2007 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking (simulation depth 50 meters) -- Input data set for sandstone and carbonate rocks (gwava-dw_sscb) 1 Raster digital data Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?gwava-dw_sscb Nolan, B.T. Hitt, K.J. 2006 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States Environmental Science and Technology Volume 40, Number 24, pages 7834-7840 http://water.usgs.gov/nawqa/nutrients/pubs/est_v40_no24/ http://pubs3.acs.org/acs/journals/doilookup?in_doi=10.1021/es060911u This data set represents the presence or absence of sandstone and carbonate rock aquifers in the conterminous United States. The data set was used as an input data layer for a national model to predict nitrate concentration in ground water used for drinking. Nolan and Hitt (2006) developed two national models to predict contamination of ground water by nonpoint sources of nitrate. The nonlinear approach to national-scale Ground-WAter Vulnerability Assessment (GWAVA) uses components representing nitrogen (N) sources, transport, and attenuation. One model (GWAVA-S) predicts nitrate contamination of shallow (typically less than 5 meters deep), recently recharged ground water, which may or may not be used for drinking. The other (GWAVA-DW) predicts ambient nitrate concentration in deeper supplies used for drinking. This data set is one of 14 data sets (1 output data set and 13 input data sets) associated with the GWAVA-DW model. Full details of the model development are in Nolan and Hitt (2006). For inputs to the model, spatial attributes representing 13 nitrogen loading and transport and attenuation factors were compiled as raster data sets (1-km by 1-km grid cell size) for the conterminous United States (see table 1). >Table 1.-- Parameters of nonlinear regression model for > nitrate in ground water used for drinking (GWAVA-DW) > and corresponding input spatial data sets. > [kg, kilograms; km2, square kilometers.] > >Nitrogen Source Factors Data Set Name > 1 farm fertilizer (kg/hectare) gwava-dw_ffer > 2 confined manure (kg/hectare) gwava-dw_conf > 3 orchards/vineyards (percent) gwava-dw_orvi > 4 population density (people/km2) gwava-dw_popd > >Transport to Aquifer Factors > 5 water input (km2/cm) gwava-dw_wtin > 6 glacial till (yes/no) gwava-dw_gtil > 7 semiconsolidated sand aquifers gwava-dw_semc > (yes/no) > 8 sandstone and carbonate rocks gwava-dw_sscb > (yes/no) > 9 drainage ditch (km2) gwava-dw_ddit > 10 Hortonian overland flow gwava-dw_hor > (percent of streamflow) > >Attenuation Factors > 11 fresh surface water withdrawal gwava-dw_swus > for irrigation (megaliters/day) > 12 irrigation tailwater recovery (km2) gwava-dw_twre > 13 Dunne overland flow gwava-dw_dun > (percent of streamflow) > 14 well depth (meters) - "Farm fertilizer" is the average annual nitrogen input from commercial fertilizer applied to agricultural lands, 1992-2001, in kilograms per hectare. "Confined manure" is the average annual nitrogen input from confined animal manure, 1992 and 1997, in kilograms per hectare. "Orchards/vineyards" is the percent of orchards/vineyards land cover classification. "Population density" is 1990 block group population density, in people per square kilometer. "Water input" is the ratio of the total area of irrigated land to precipitation, in square kilometers per centimeter. "Glacial till" is the presence or absence of poorly sorted glacial till east of the Rocky Mountains. "Semiconsolidated sand aquifers" is the presence or absence of semiconsolidated sand aquifers. "Sandstone and carbonate rocks" is the presence or absence of sandstone and carbonate rock aquifers. "Drainage ditch" is the area of National Resources Inventory surface drainage, field ditch conservation practice, in square kilometers. "Hortonian overland flow" is infiltration excess overland flow estimated by TOPMODEL, in percent of streamflow. "Fresh surface water withdrawal for irrigation" is the amount of fresh surface water withdrawal for irrigation, in megaliters per day. "Irrigation tailwater recovery" is the area of National Resources Inventory irrigation system, tailwater recovery conservation practice, in square kilometers. "Dunne overland flow" is saturation overland flow estimated by TOPMODEL, in percent of streamflow. "Well depth" is the depth of the well, in meters. Well depth was not compiled as a spatial data set. Well depth equals 50 meters for the model simulation being presented. Reference cited: Nolan, B.T. and Hitt, K.J., 2006, Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Environmental Science and Technology, vol. 40, no. 24, pages 7834-7840. This particular data layer was created to help characterize nitrogen transport factors at a national level for input to a national model to predict nitrate concentration in ground water used for drinking. Nitrate is considered to be the most widespread contaminant in ground water. High nitrate concentration in ground water is a concern for human health, and protecting drinking water sources is a national priority. The U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program monitors the occurrence and distribution of nitrate and other contaminants in ground water and streams. However, because monitoring everywhere for the occurrence and distribution of nitrate in ground water is impractical, national water-quality models are used to address data gaps. The goal of the current study was to predict ground water vulnerability to nitrate at the national scale, to complement measured data. The data set is provided as native ESRI ArcInfo Workstation GRID and as ASCII text (plain text) format. The file "gridname".tgz file contains the GRID in a directory (folder) called arctar00000, where "gridname" is the name of the data set. For example, a GRID without a VAT (value attribute table) has the following files: >arctar00000/ >arctar00000/gridname/ >arctar00000/gridname/dblbnd.adf >arctar00000/gridname/hdr.adf >arctar00000/gridname/log >arctar00000/gridname/metadata.xml >arctar00000/gridname/prj.adf >arctar00000/gridname/sta.adf >arctar00000/gridname/w001001.adf >arctar00000/gridname/w001001x.adf >arctar00000/info/ >arctar00000/info/arc.dir >arctar00000/info/arc0000.dat >arctar00000/info/arc0000.nit >arctar00000/info/arc0001.dat >arctar00000/info/arc0001.nit >arctar00000/log A GRID with a VAT (value attribute table) (gwava-dw_orvi, gwava-dw_hor, gwava-dw_gtil, gwava-dw_semc, gwava-dw_sscb, gwava-dw_dun) these files: >arctar00000/ >arctar00000/gridname/ >arctar00000/gridname/dblbnd.adf >arctar00000/gridname/hdr.adf >arctar00000/gridname/log >arctar00000/gridname/metadata.xml >arctar00000/gridname/prj.adf >arctar00000/gridname/sta.adf >arctar00000/gridname/vat.adf >arctar00000/gridname/w001001.adf >arctar00000/gridname/w001001x.adf >arctar00000/gridname.aux >arctar00000/info/ >arctar00000/info/arc.dir >arctar00000/info/arc0000.dat >arctar00000/info/arc0000.nit >arctar00000/info/arc0001.dat >arctar00000/info/arc0001.nit >arctar00000/info/arc0002.dat >arctar00000/info/arc0002.nit >arctar00000/info/arc0002r.001 >arctar00000/log To extract the ArcInfo Workstation GRID from the "gridname".tgz archive file, use TARARC, WINZIP, or the following commands: >gunzip gridname.tgz >tar xvof gridname.tar The data set is provided in ASCII text format in addition to the native ESRI ArcInfo Workstation GRID format in case the user's software cannot access the data in ArcInfo Workstation GRID format. The ASCII file is compressed using gzip as "gridname".txt.gz, where "gridname" is the data set name. 1991 2003 Water-quality data used in this study were collected during 1991-2003 and represent the first full decade of sampling by the NAWQA program. The input data layers describe conditions in the mid 1990's, and so the predictions represent mid 1990's land-use and nitrogen-loading conditions. Complete None planned. -127.97736605 -65.11883061 51.691800 23.09338233 None Ground water Ground water contamination Ground water pollution Ground water susceptibility Nutrients Nitrate National Water-Quality Assessment Program NAWQA Nonlinear model Nitrate concentration Drinking water inlandWaters Sandstone and carbonate rocks None Conterminous United States None None None None None. This spatial data set is one of a group of data sets developed specifically for use in a national model of nitrate in ground water. The data set should be used at the national or regional level, not at the local level. Users should consider the various assumptions that went into generating each spatial data set and the limitations inherent in the source data materials in deciding whether the data set is appropriate for use in other national or regional applications. Please acknowledge the U.S. Geological Survey in products derived from these data. Thanks to Michael E. Wieczorek who reviewed the metadata and provided useful comments. Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.0.0.535 Nolan, B.T. 2001 Relating nitrogen sources and aquifer susceptibility to nitrate in shallow ground waters of the United States 1 Ground Water Volume 39, Number 2, pages 290-299 http://water.usgs.gov/nawqa/nutrients/pubs/gw_v39_no2/ Nolan, B.T., Hitt, K.J., and Ruddy, B.C. 2002 Probability of nitrate contamination of recently recharged groundwaters in the conterminous United States 1 Raster digital data Environmental Science & Technology Volume 36, Number 10, pages 2138-2145 http://water.usgs.gov/nawqa/nutrients/pubs/est_v36_no10/ http://water.usgs.gov/lookup/getspatial?gwrisk Nolan, B.T. Hitt, K.J. 2006 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States Environmental Science and Technology Volume 40, Number 24, pages 7834-7840 Denver, Colorado U.S. Geological Survey http://water.usgs.gov/nawqa/nutrients/pubs/est_v40_no24/ http://pubs3.acs.org/acs/journals/doilookup?in_doi=10.1021/es060911u Hitt, K.J. 2007 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking (simulation depth 50 meters) -- Model output data set (gwava-dw_out) 1 Raster digital data Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?gwava-dw_out Hitt, K.J. 2007 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking -- Input data set for farm fertilizer (gwava-dw_ffer) 1 Raster digital data Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?gwava-dw_ffer Hitt, K.J. 2007 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking -- Input data set for confined manure (gwava-dw_conf) 1 Raster digital data Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?gwava-dw_conf Hitt, K.J. 2007 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking -- Input data set for orchards/vineyards (gwava-dw_orvi) 1 Raster digital data Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?gwava-dw_orvi Hitt, K.J. 2007 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking -- Input data set for population density (gwava-dw_popd) 1 Raster digital data Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?gwava-dw_popd Hitt, K.J. 2007 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking -- Input data set for water input (gwava-dw_wtin) 1 Raster digital data Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?gwava-dw_wtin Hitt, K.J. 2007 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking -- Input data set for glacial till (gwava-dw_gtil) 1 Raster digital data Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?gwava-dw_gtil Hitt, K.J. 2007 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking -- Input data set for semiconsolidated sand aquifers (gwava-dw_semc) 1 Raster digital data Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?gwava-dw_semc Hitt, K.J. 2007 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking -- Input data set for drainage ditch (gwava-dw_ddit) 1 Raster digital data Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?gwava-dw_ddit Hitt, K.J. 2007 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking -- Input data set for Hortonian overland flow (gwava-dw_hor) 1 Raster digital data Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?gwava-dw_hor Hitt, K.J. 2007 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking -- Input data set for fresh surface water withdrawal (gwava-dw_swus) 1 Raster digital data Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?gwava-dw_swus Hitt, K.J. 2007 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking -- Input data set for irrigation tailwater recovery (gwava-dw_twre) 1 Raster digital data Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?gwava-dw_twre Hitt, K.J. 2007 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking -- Input data set for Dunne overland flow (gwava-dw_dun) 1 Raster digital data Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?gwava-dw_dun Hitt, K.J. 2007 Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in shallow, recently recharged ground water -- Model output data set (gwava-s_out) 1 Raster digital data Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?gwava-s_out The model results were checked using standard USGS review procedures. Not applicable for raster data. The data spans the conterminous United States. An output cell was assigned a value of "no data" if any of the corresponding input data cells at that location was "no data." U.S. Geological Survey 200310 Principal Aquifers of the 48 Conterminous United States, Hawaii, Puerto Rico, and the U.S. Virgin Islands Version 1.0 map Madison, Wisconsin, USA U.S. Geological Survey http://www.nationalatlas.gov/metadata/aquifrp025.faq.html On-line 2003 Publication date of principal aquifers data USAQV2 The 2,500,000-scale map of principal aquifers in the National Atlas of the United States is the source for sandstone and carbonate-rock aquifers. [Retrieved June 2004.] Spatial data sets representing nitrogen (N) loading and transport and attenuation factors were compiled for the conterminous United States. N source variables include farm fertilizer, manure from confined animal feeding operations, and loading surrogates that reflect additional sources of N. For example, population density is a surrogate for nonagricultural sources of N from septic tanks, sewers, and domestic animal waste in urban areas. Transport factors include water input, sediments, rock type, and selected management practices. "Water input" is an interaction term expressed as the ratio of the total area of irrigated land to precipitation. Attenuation factors include variables that are surrogates for dilution and/or denitrification. Each of the variables in the model was compiled within 1-km by 1-km grid cells for prediction of nitrate concentration at the national scale. >Table 2.-- Variables compiled for regression model GWAVA-DW, > units and estimated coefficients > [kg, kilograms; km2, square kilometers.] > >Nitrogen Loading Units Estimated coefficient > 1 farm fertilizer kg/hectare 0.1068 > 2 confined manure kg/hectare 0.1416 > 3 orchards/vineyards percent 0.2999 > 4 population density people/km2 0.0021 > >Transport Factors > 5 water input km2/cm 86.55 > 6 glacial till presence/absence -0.8658 > 7 semiconsolidated sand aquifers presence/absence 0.5057 > 8 sandstone and carbonate rocks presence/absence 0.3641 > 9 drainage ditch km2 -5.080 > 10 Hortonian overland flow percent of streamflow -0.0330 > >Attenuation Factors > 11 fresh surface water withdrawal megaliters/day -1.334 > 12 irrigation tailwater recovery km2 -13.84 > 13 Dunne overland flow percent of streamflow -0.1443 > 14 well depth meters -0.00163 200512 Areas of ROCK_TYPE = 500 (sandstone and carbonate-rock aquifers) in the principal aquifers map (USGS, 1998) were converted to a preliminary national grid with "500" coded as 1 (presence of sandstone and carbonate-rock aquifers) and everything else coded as 0 (absence of sandstone and carbonate-rock aquifers). Areas that were in sandstone and carbonate-rock aquifers and did not overlap with areas of till were retained in the final grid representing sandstone and carbonate-rock aquifers. 200512 To make the national map of predicted nitrate concentration, the values from the 1-km by 1-km grid cells for each of the input data layers were put in to the model equation to calculate a predicted concentration for each output cell. An output cell was assigned a value of "no data" if any of the corresponding input data cells at that location was "no data." The following ArcInfo Workstation GRID commands produced the predicted nitrate concentration grid: >/*Nonlinear regression model 2 for nitrate in drinking water wells. Depth 50 meters. >/*Fertilizer and manure units are kg/ha (usegha) >/*Feb 01 2006 >/*Remove filter on fertilizer, manure, population. Revise filter on precip to be 99x99 rectangle, >/* instead of 9x9 kernel. >setwindow -2380000.000 260000.000 2265000.000 3200000.000 orchvin >setcell 1000 >/*Set directory housing the filtered input grid for precip. >&s fdir = d:/ancill/model2005/dec2005/filtered >/* >gwava-dw_out = ((0.106751 * gwava-dw_ffer) + (0.141597 * gwava-dw_conf) + (0.299863 * gwava-dw_orvi) + (0.0021 * gwava-dw_popd)) * ~ >exp ((-5.08005 * gwava-dw_ddit) + (-0.03299 * gwava-dw_hor) + (-0.86585 * gwava-dw_gtil) + (0.505704 * gwava-dw_semc) + (0.364065 * gwava-dw_sscb) + ~ > (86.54621 * %fdir%/gwava-dw_wtin)) * ~ >exp ((-1.33354 * gwava-dw_swus) + (-13.8388 * gwava-dw_twre) + (-0.14432 * gwava-dw_dun) + (-0.00163 * 50)) GRID cells were randomly selected from this data set and were checked by hand to ensure the correct values were calculated using the model equation and the input data layers. Areas with high N load, low to moderate clay content, sufficient water input, and low denitrification potential have the highest predicted nitrate concentration in ground water and therefore may be vulnerable to nitrate contamination. The most extensive areas of predicted, severe contamination (nitrate greater than 10 mg/L) occur in the High Plains, and areas of predicted, moderate contamination (more than 5 to 10 mg/L nitrate) occur extensively in the northern Midwest. 200512 The GRID was converted to ASCII (plain text) for distribution using ArcInfo Workstation command: >gridascii gwava-dw_sscb gwava-dw_sscb.txt 2007 Revised metadata concerning Principal Aquifers source citation. No change to data set. 20080616 Raster Grid Cell 2887 4633 1 Albers Conical Equal Area 29.5 45.5 -96 23 0.00000 0.00000 row and column 1000.0 1000.0 METERS North American Datum of 1983 GRS80 6378137.000000 294.257222 Each 1-km by 1-km grid cell stores presence (1) or absence (0) of sandstone and carbonate rocks. Data Type: Integer Number of Values = 2 Minimum Value = 0.000 Maximum Value = 1.000 Mean = 0.043 Standard Deviation = 0.204 A VAT is present. VALUE is 1 or 0, and COUNT is the number of cells of each VALUE. In the ASCII text file, "no data" is indicated as -9999. None. U.S. Geological Survey Ask USGS -- Water Webserver Team mailing

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Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+gwava-dw_sscb Although this data set has been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data and related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. ArcInfo Workstation GRID gzip -d; gunzip 132453 bytes http://water.usgs.gov/GIS/dsdl/gwava-dw/arctar/gwava-dw_sscb.tgz ASCII file gzip -d; gunzip 191365 bytes http://water.usgs.gov/GIS/dsdl/gwava-dw/gascii/gwava-dw_sscb.txt.gz Index to all files related to the GWAVA-DW model to facilitate downloading all the GIS data sets Web page with links to all data sets HTML 5 bytes http://water.usgs.gov/GIS/dsdl/gwava-dw/index.html None. This data set is provided by USGS as a public service. 20080616 U.S. Geological Survey Ask USGS -- Water Webserver Team mailing

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Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://water.usgs.gov/user_feedback_form.html FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998