Nitrogen and Phosphorus Pollution Data Access Tool (NPDAT)

epa.gov/nutrientpollution/npdat

xvEPA

United States
Environmental Protection
Agency

Introduction to NPDAT

Over the last 50 years, the
amount of nitrogen and phos-
phorus pollution entering our
nation's waters has escalated
dramatically. For example, 30
percent of U.S. streams have
high levels of nitrogen (N) and
phosphorus (P) pollution. Re-
ported drinking water violations
for nitrates have doubled in the
last eight years N and P pollu-
tion threatens human health,
aquatic ecosytems, and eco-
nomic prosperity. The U.S. Envi-
ronmental Protection Agency's
new tool, NPDAT, is designed
to help states develop effective
state N/P reduction strategies to
combat this serious and grow-
ing environmental problem.

What is the Nitrogen and Phosphorus
Pollution Data Access Tool?

EPA's new"Nitrogen and Phosphorus Pollution Data Access Tool" (NPDAT)
helps states, other partners, and stakeholders to:

(1)	Prioritize watersheds on a statewide basis for nitrogen
and phosphorus loading reductions, and

(2)	Set watershed load reduction goals based upon best
available information.

The NPDAT consists of an introductory Website, geospatial viewer, data
downloads, and datasets available publicly elsewhere. The Data Access Tool
aggregates data at a single location. With these data "pre-assembled," states
and others can readily use this data, gather additional, less-accessible data and
develop effective nitrogen and phosphorus source reduction strategies.The
NPDAT leverages the common code base used by the EPA's Recovery Mapper,
MyWATERS Mapper, and Beaches Mapper Web mapping applications. In doing
so, it supports the basic tenets of the EPA Geo-Spatial Platform initiative.

How can states and others use the Data Access Tool?

The NPDAT can help support states in analyzing nitrogen and phosphorus pol-
lution by providing key data in a readily-accessible and easy-to-use format on:

1)The	extent and magnitude of nitrogen and phosphorus pollution,

2)	Water quality problems related to this pollution, and

3)	Potential pollution sources.

Upper Sandusky

Bucyrus

Map Layers (zoom in to view all layers)

Nitrogen / Phosphorus (N/P) Lay ere

B SPARROW Total N/P Yields

^ N Incremental 2002 (Major River Basins)
P Incremental 2002 (Major River Basins)
N Incremental 1992 (Mississippi Basin)
P Incremental 1992 (Mississippi Basin)
N Delivered Incremental 1992 (Mississippi Basin)
* P Delivered Incremental 1992 (Mississippi Basin)
¦ Water Quality Monitoring Sites with N/P (STORED
¦I Water Quality Monitoring Sites with N/P i.NWISl
H| NARS N/P Values for Streams
lH NARS N/P Values for Lakes
ffl Facilities Ukely to Discharge N/P to Water
H Hatlonal Land Cover D-ataset
8M .'.Waters Listed for N/P Impairments
IB Raters with N/P TMDLs

Screenshot of the Data Access Tool which shows that the Total Nitrogen yield varies among 818 watersheds in the Mississippi River
Basin (U.S. Geological Survey SPARROW model).

Van Wert

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What type of information is available
through the Tool?

Data available on the NPDAT include:

Nitrogen arid Phosphorus Loading information

from U.S. Geological Survey SPARROW model
(SPAtially Referenced Regressions On Watershed
attributes)

Water Quality Data and Information (e.g.,

Water quality monitoring sites with nitrogen and
phosphorus data and National Aquatic Resource
Surveys (NARS) Phosphorus/ Nitrogen Values
data layers)

Setting Watershed Load Reduction Goals /

Source Control Priorities (e.g., Facilities that are
likely to discharge nitrogen and phosphorus to wa-
ter, waters with N/PTMDLs [Total Maximum Daily
Loads], and drinking water sources.)

The NPDAT includes the best information currently
available in EPA and related federal databases. While
making these data layers viewable and downloadable
through NPDAT, EPA does not draw conclusions or
make any recommendations or determinations as to
sources of nitrogen or phosphorus in individual states.

How can states and others obtain data
through the Tool?

Users can obtain data through the NPDAT's geospatial
viewer and data downloads at the website at:
www.epa.gov/nutrientpollution/npdat.

The NPDAT Tutorial, available on the website, follows
the recommended elements of EPA's March 16, 2011
memorandum "Working Effectively in Partnership
with States to Address Phosphorus and Nitrogen
Pollution Through Use of a Framework for States
Nutrient Reductions"and includes narrative text and
screenshots.

How can you get help or provide feedback?

Users may also submit questions and comments to EPA via NPDAT "Contact Us" links or by email at:
npdat-hq@epa.gov. EPA will consider user feedback and may provide updated data in the future.

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Waters that are listed as impaired by nitrogen and/or phosphorus under the Clean Water Act Section 303(d) list, as well as TMDLs for
nitrogen and/ or phosphorus, can be viewed and downloaded to help prioritize watersheds.

SEFft

United States
Environmental Protection
Agency

Information and resources on nitrogen and phosphorus pollution can be found at
http://epa.gov/nutrientpollution

Additional information on nitrogen and phosphorus pollution in the Mississippi River
Basin can be found at http://epa.gov/msbasin

U.S. EPA, Office of Wetlands, Oceans and Watersheds Watershed Branch (4503T),
1200 Pennsylvania Ave. NW, Washington, DC 20460
January 2012, EPA 841 -F-1 1 -003


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