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GIS Coverage for the National Water-Quality Assessment (NAWQA) Program Retrospective Database for Nutrients in Surface Water: Monitoring Locations

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Abstract: The retrospective database is a compilation of historical water-quality and
ancillary data collected before NAWQA Study Units initiated sampling in 1993.
This coverage contains the point locations of monitoring locations where
historical water-quality data was collected. Water-quality data were obtained
by study-unit personnel from the U.S. Geological Survey (USGS) National Water
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Related URL
Description: Access data from the USGS National Water Quality Assessment Data Warehouse.

Description: Homepage of the USGS National Water Quality Assessment Program (NAWQA).
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Caption:  NAWQA Retrospective Database for Surface Water Nutrients: Monitoring Locations
Geographic Coverage
Spatial coordinates   
  N: 48.25   S: 22.87   E: -65.35   W: -127.88

Data Set Citation
Dataset Originator/Creator: Hitt, K.J. and Nakagaki
Dataset Title: National Water-Quality Assessment (NAWQA) Program Retrospective Database for Nutrients in Surface Water : Monitoring Locations
Dataset Release Date: 1999-07-01
Dataset Release Place: Reston, VA
Dataset Publisher: USGS
Data Presentation Form: Map
Location Keywords
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Quality Mueller and others (1995) used this data to determine preexisting
water-quality conditions in the first 20 NAWQA Study Units that began
in 1991. Also, Nolan and Ruddy (1996) used the data to describe areas
of the United States at risk of nitrate contamination of ground water.

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Access Constraints None
Use Constraints Historical data can be of limited use in national assessments
because of inconsistencies between and within agencies in database
structure and format and in sample collection, preservation, and
analytical procedures. For example, changes in sample collection and
analytical procedures can cause shifts in constituent concentrations
that are unrelated to possible changes in environmental factors. See
Mueller and others (1995) for assumptions and limitations associated
with the retrospective database.
Data Set Progress
Originating Center
Data Center
Clean Air Markets Division, U.S. Environmental Protection Agency Supplemental Info
Data Center URL:

Data Center Personnel
Phone: 202-564-9180
Email: camdgis at
Contact Address:
Clean Air Markets Division
1200 Pennsylvania Avenue, NW
Mail Code 6204J
City: Washington
Province or State: DC
Postal Code: 20460
Country: USA
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Distribution Media: FTP
Distribution Size: 6184720
Distribution Format: ArcInfo export format
Fees: No fees

Distribution Media: FTP
Distribution Size: 16303646
Distribution Format: ArcView shapefile
Fees: No fees
Anderson, J.R., Hardy, E.E., Roach, J.T., and Witmer, R.E., 1976, A
land use and land cover classification system for use with remote
sensor data: U.S. Geological Survey Professional Paper 964, 28 p.
Fegeas, R.G., Claire, R.W., Guptill, S.C., Anderson, K.E., and Hallam,
C.A., 1983, Land use and land cover digital data: U.S. Geological
Survey Circular 895-E, 21 p.
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Extended Metadata Properties
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Creation and Review Dates
DIF Creation Date: 2002-11-15
Last DIF Revision Date: 2017-08-23