Agricultural Nonpoint 

Source Pollution: 

Agenda for the Future

Farm, Ranch, and Rural Communities

Federal Advisory Committee

February 23, 2009
Why is This on the Agenda?

• Nonpoint source (NPS) pollution is a significant 

problem for the Nation

• Water quality/ecological consequences

• Hypoxia and eutrophication

• Impairment

• Leading sources and trends

• Human-health concerns for drinking water

• Addressing nutrients is a top priority for EPA

• Current efforts are not sufficient

• Future actions: Are we heading toward regulation?

• The agricultural community should be involved 

in future decision-making
Hypoxia Areas Have Increased 

Dramatically over the Last 50 Years

Source: Science/World Resources Institute.
Gulf of Mexico Hypoxia
“Failing the Chesapeake Bay”

-- Washington Post, December 2008

• EPA Chesapeake Bay Program’s 2007 

Annual Assessment found most of the 

Bay's waters are degraded:

• 12% of the Bay and its tidal tributaries met 

dissolved oxygen standards during the 

summer months

• 26% of the Bay's waters had acceptable 

concentrations of chlorophyll a

• 12% of the Bay's waters had acceptable water 

clarity. 

• Fish kills in a number of rivers leading to the 

Bay

“Stepped-up Regulation Backed as 25-Year Effort Fails to Meet Long-Term 

Deadlines” -- Washington Post, December 9, 2008
Other Areas of the Country

• Although smaller in size, many other 

watersheds exhibit significant water 

quality challenges caused largely by 

agricultural runoff.

• Selenium discharges from irrigation return 

flows in the Central Valley of California

• Runoff of unusually large sediment loads in 

eastern Washington (Palouse Region) due 

to agricultural activities on highly erosive 

lands 

• Grazing impacts throughout much of the 

West from both upland and riparian erosion
Nutrients, Organic Enrichment, 

and Pathogens are Leading 

Causes of Impairment

Rivers and 

Streams 

(23%

assessed)

Lakes, Ponds 

and Reservoirs 

(40%

assessed)

Estuaries 

(32%

assessed)

Pathogens Mercury Pathogens

Sediment Nutrients Organic 

enrichment

Nutrients Organic 

enrichment

PCBs

Source: Most recent state 305(b) reporting in ATTAINS (mix of 2006, 2004, and 2002).
Agriculture and AtmoDep are 

Leading Sources of Impairment

Rivers and 

Streams 

(23% assessed)

Lakes, Ponds 

and Reservoirs 

(40% assessed)

Estuaries 

(32%

assessed)

Agriculture Unknown/

Unspecified*

Unknown/

Unspecified*

Unknown/

Unspecified*

Atmospheric

deposition

Atmospheric

deposition

Hydromodification Agriculture Municipal 

discharges

*Source unknown or undocumented due to insufficient information

Source: Most recent state 305(b) reporting in ATTAINS (mix of 2006, 2004, and 2002).
Highest Concentrations of Nitrogen are 

Geographically Focused
Nitrogen Concentrations Increase 

with Percent Agriculture in Watershed

Ecological Regions

CPL

NAP

SAP

UMW

NPL

SPL

TPL

WMT

XER

WSA Watersheds

% Ag in Watershed

0 10 20 30 40 50 60 70 80 90

T

otal Nitro

g

e

n (u

g/L)

50,000

45,000

40,000

35,000

30,000

25,000

20,000

15,000

10,000

5,000

0
2002 Ammonia Emissions from 

Animal Agriculture
Poor Stream Biology is Twice as 

Likely in Streams with High Levels of 

Nitrogen, Phosphorus or Sediments

From the December, 2006 Wadeable Streams Assessment

National Summary

Biological Condition of

Wadeable Streams
Year

1960 1970 1980 1990 2000

DIN, 

M

L

-

1

50

100

150

200

250

300

350

DIP, 

M

L

-

1

0

5

10

15

20

25

30

DIN

DIP

1960-62

Dissolved Inorganic Nitrogen (DIN)

Dissolved Inorganic Phosphorus (DIP)

Nutrient Trends for Mississippi River
Agriculture is the Predominant 

Nutrient Source to Gulf

• Ag contributes more than

70% of the N and P

delivered to the Gulf

• AtmDep contributes16%

of N

• Urban sources represent

only 9-12%

• Watersheds contributing 

highest load include Central 

Mississippi and Ohio (IL, IA, 

IN, IS, AR, KY, TN, OH, MS)

• Greatest reduction in load to 

the Gulf predicted from 

targeting sources near large rivers or small streams that 

flow quickly to large rivers

Source: USGS SPARROW Model for Mississippi/Atchafalaya Basin
Effects of Excess Nutrients on 

Drinking Water Quality 

• Nutrients can stimulate algal growth –

elevated levels of organic matter

• Creates taste and odor problems

• Possible health effects from algal toxins

• Organic matter + disinfectants = disinfection 

byproducts

• Runoff of nitrogen-based fertilizers leads to 

elevated nitrate levels in surface and 

ground water

• Acute health risks for children (blue babies)
Current Voluntary Approaches 

Alone are not Sufficient to Deal 

with the NPS Problem

Source: EPA’s Chesapeake Bay 2007 Health and Restoration Assessment Report

For Example: Chesapeake Bay
Numeric WQS for Nutrients are Not 

Being Adopted Fast Enough 

• Florida Determination

• On January 14, EPA issued a formal determination under the 

CWA that numeric nutrient water quality criteria are necessary in 

Florida.

• EPA expects to propose numeric nutrient standards for lakes 

and flowing waters within 12 months, and for estuaries and 

coastal waters within 24 months. 

• Mississippi River Petition

• On July 30, 2008, various environmental groups petitioned EPA 

for Rulemaking under the CWA for numeric water quality 

standards for N and P and TMDLs for the Mississippi River and 

the Gulf of Mexico.
Is it Time to Regulate NPS Pollution?

• What’s the tipping point?

• More hypoxic “dead” zones?

• Fisheries collapse?

• Are we there now?
Your Help is Needed

• We need YOUR HELP to:

• Better connect the water quality message with 

the farming community

• Assure that we all understand how we can 

better support farmers in their nutrient 

reduction efforts

• Make sure our solutions make financial sense 

to the farmer

• Figure out a way to start getting significant 

reductions sooner rather than later!
Joseph T. Piotrowski

Office of Wetlands, Oceans, and Watersheds

U.S. Environmental Protection Agency