atmospheric deposition and the role of the chesapeake bay program

Atmospheric Deposition and the Role of the

Chesapeake Bay Program

Jeffrey S. SweeneyUniversity of Maryland

Chesapeake Bay Program [email protected]

410-267-9844

Nutrient Subcommittee MeetingMD NRCS Office

December 13, 2006

21.0 18.2 17.8 17.2 17.1 12.6

120.1109.2 108.4 106.6 105.7

71.9

8.3

3.6 4.1 3.5 2.9

2.4

82.4

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1985 2002 2003 2004 2005 2010 Cap LoadAllocation

(million lbs

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/year)

NY PA DC MD WV VA DE

Nitrogen Loads Delivered to the Chesapeake Bay By Jurisdiction

Point source loads reflect measured discharges while nonpoint source loads are based on an average-hydrology year

337.5

277.7 275.1 270.2

183.1

266.3

From 2004:All jurisdictions decrease

87.758.4 61.2 57.3 54.0

183.1

149.4

113.9 108.2 106.7 105.9

38.7

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30.6

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1985 2002 2003 2004 2005 2010 Cap LoadAllocation

(million lbs

TN

/year)

Point Source Agriculture Forest Urban Runoff Mixed Open Septic Water Dep

Nitrogen Loads Delivered to the Chesapeake Bay By Source Point source loads reflect measured discharges while

nonpoint source loads are based on an average-hydrology year

337.5

277.7 275.1 270.2

183.1

266.3

From 2004:Point source = -3.3 million lbs.Agriculture = -0.9 million lbs.

Slight increase from all other sources except non-tidal water deposition

2005 Annual Model Assessment

Continuing Issues• Atmospheric Deposition

o All jurisdictions credited with lower atmospheric deposition of nitrogen as assessed through trends in monitoring data used in calibration of the Phase 5 Watershed Model.

Benefits of NOx SIP Call and other air programs. o Nutrient Subcommittee Discussion

How should deposition component be accounted for and reported?

Environmental Indicators:Reducing Pollution

Answer two questions:• How is the Bay/Watershed doing?

• What’s being done and are we on track in our efforts to restore the Bay?

Provide accountability• Connecting efforts with results

Provide guidance for future efforts• Intended audience is “interested public” and environmental managers

Historic and Projected Atmospheric Deposition to the Chesapeake Bay Watershed

229

275

391394396

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350

400

1990

1992

1994

1996

1998

2000

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2004

2006

2008

2010

2012

2014

2016

2018

2020

(million lbs.

TN

/year)

Monitored ModeledCAIR+CAMR+BAR

T

NADP/NTN + Atmospheric Integrated Research Monitoring Network

(AirMoN)

Models-3/Community Multi-scale Air Quality (CMAQ) Modeling System)

• Provides estimates of N deposition resulting from changes in precursor

emissions from utility, mobile, and industrial sources due to management actions or

growth. • Adjusts deposition determined by wet-fall

concentration model and precipitation volumes

• Predicts the influence of source loads from one region on deposition in other regions. • Provides estimates of wet:dry for NO3

- and NH4

-.

Atmospheric Deposition and the Response in LoadsHow do emission controls impact deposition to the watershed and loads to the

Chesapeake Bay?

395.8 393.9 390.8

274.7

229.4

189.9 189.7 189.3175.3 169.9

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Cap Load Allocationw/ 1990 Deposition



Cap Load Allocationw/ Projected 2010

Deposition

Cap Load Allocationw/ Projected 2020

Deposition

(million lbs.

TN

/year)

Atmospheric Deposition Chesapeake Bay Loads

Goal is nitrogen load reduction from all air programs from 1996 = 15 million lbs.NOx SIP call, etc. = 7 million lb. reduction

Other air programs, i.e., CAIR = 8 million lbs.

Reducing Pollution Environmental Indicator:Air Pollution

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Controlling Nitrogen

Accounting Begins

Monitored/

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ModeledProjection

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Goal is nitrogen load reduction from all air programs from 1996 = 15 million lbs.

Projected reduction primarily from NOx SIP Call = 7 million lbs.Projected reduction from other air programs, i.e., CAIR = 8 million lbs.

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Reducing Pollution Environmental Indicator:Air Pollution

Controlling Nitrogen

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5% of Goal Achieved

Accounting Begins

Reducing Pollution Environmental Indicators:Air Pollution, Agriculture, Urban/Suburban Lands

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Air Nitrogen Pollution

5% of Goal

44% of Goal

-88% of Goal

Agriculture Nitrogen Pollution

Urban/Suburban Lands Nitrogen Pollution

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Wastewater Agriculture Developed Lands

Individual SourcesNitrogen

Reducing Pollution Environmental Indicators:Current (2004) Restoration Efforts

All SourcesNitrogen

How important is urban versus agriculture versus wastewater versus air?


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Should 2005 include impact of reduced deposition?


For reporting purposes, it’s necessary to account forthe air piece, but how?

The Impacts of Emission Controls on Chesapeake Bay Watershed Deposition and Loads

DISCUSSION• How do emission controls impact deposition to the watershed

and loads to the Chesapeake Bay? o 7 million lb. load reduction goal is built into jurisdictional

Tributary Strategies. Comparison is made between baseline and 1990 Clean Air Act

projected benefits – as assessed during the time of allocating the nutrient cap loads. Primarily Tier II tail pipe standards on light duty vehicles. Utility emissions with Title IV (Acid Rain Program) fully

implemented. 20-state NOx SIP call reductions at 0.15 lbs/MMbtu during the

May to September ozone season only. o 8 million lb. load reduction goal is EPA’s commitment beyond

what’s built into jurisdictional Tributary Strategies. Comparison is made between 1990 Clean Air Act projected

benefits and projection from CAIR + CAMR + BART.



and loads to the Chesapeake Bay? o The benefits in load reductions to the Chesapeake Bay – from

reductions in emissions and deposition – are dependent on the land cover the air flux falls on.

o For most Bay Program air impact assessments, this land condition is held constant so only changes in loads to the Bay due to changes in deposition are quantified.

Scenarios are run with the same watershed conditions for landuses, manure and chemical fertilizer applications, nonpoint source BMPs, point sources, septic, etc. The baseline watershed condition is a scenario where each

jurisdictional portion of the major tributaries hits their cap load allocations for nutrients and sediment exactly.

The baseline landuse is not the strategies’ condition exactly. Strategies were developed at different times over several years. It is not prudent to do the entire suite of air impact scenarios every

time a jurisdictional plan is finalized or revised. There would be confusion among stakeholders and decision-makers

working with air programs if the deposition-to-load cause-and-effect relationship changed constantly because of landuse changes.



and loads to the Chesapeake Bay? o The benefits in load reductions to the Chesapeake Bay – from

reductions in emissions and deposition – are dependent on the land cover the air flux falls on.

Forests, on average, retain more than 85% of the nitrogen deposited on them from the air. “If all of the 5.5 million acres of the forest that both

maximizes water quality but is vulnerable to development is lost, an additional 29 million lbs. of nitrogen annually will reach the Bay.” (Forest Sector Issue Paper, Expansion and Retention of Forested Area, Chesapeake Bay Program Implementation Committee, 10/19/06)

Impervious surfaces don’t retain nutrients but channel the load directly to adjacent land or water.

Inputs of Nitrogen to the Watershed and Loads Delivered to the Chesapeake Bay

394

103 76

489

9174

461

6851

63

6357

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Inputs Load to Local Waters Load Delivered to Bay

(million lbs.

TN

/year)

Atmospheric Deposition Chemical FertilizersManure Municipal & Industrial WastewaterSeptic

Nitrogen Attenuation

Uptake by vegetation• Soil storage

• Denitrification28% of nitrogen load from atmospheric deposition

Rooted in relative proportion of inputs Does not include deposition to tidal water

Agriculture40%

Forest15%

Atmospheric Deposition to Non-

Tidal Water1%

Urban & Suburban Runoff18%

Municipal & Industrial

Wastewater21%

Septic5%

Agriculture - manure19%

Agriculture - chemical fertilizer

16%

Agriculture - Atmospheric Deposition - livestock & fertilized soil

emissions6%

Atmospheric Deposition - mobile (on-road + non-

road) + utilities + industries

21%

Natural - lightning + forest soils

1%

Urban & Suburban Runoff - chemical

fertilizer11%

Municipal & Industrial Wastewater

21%

Septic5%

• Based on year 2004 estimates from the Chesapeake Bay Program Phase 4.3 Watershed Model. • Sources of nitrogen loads in the break-out chart are rooted in the relative inputs of natural and

anthropogenic sources. • Contributions exclude atmospheric deposition directly to tidal waters of the Chesapeake Bay.

• Point source loads reflect measured discharges while nonpoint source loads are based on an average-hydrology year.

Sources by Watershed ModelMajor “Landuse” Category

Sources with the Break-out for Atmospheric Deposition

Sources of Nitrogen Loads to the Chesapeake BayHow much of the nitrogen load delivered to the Chesapeake Bay is from

atmospheric sources?


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DISCUSSION• Is it necessary to isolate the air piece from agriculture and

urban/suburban land and, if so, how? o Keep the air component as part of agricultural and

urban/suburban lands? CAA reductions were built in during the development of Tributary

Strategies. Typically report loads by model landuses – rather than as the

more-fundamental manure, chemical fertilizers, and atmospheric deposition. Model is calibrated by model landuse “source”, not the more-

fundamental sources. “Lands” are managed by states and localities while air emissions are

typically, but not entirely, regulated at the federal level (CAA, CAIR, etc.).

Emission controls from as distant as Texas, Canada, and the Bahamas can impact the Bay watershed’s deposition.

But an indicator specifically for air is necessary.



urban/suburban land and, if so, how? o Up until this point, the agriculture and developed sectors are

not moving closer to their goals much because of reductions in atmospheric deposition since deposition is largely unchanged.

Regulated reductions mostly from the EGUs have been offset by increases in emissions from the mobile sector (primarily) and increases in ammonia emissions from the agricultural sector (secondarily).

o As net reductions in deposition increase through CAIR, as projected, need to determine how to best account for this in reporting.



urban/suburban land and, if so, how? o Completely isolate the air component from agriculture and

developed lands? Issue, in itself, is complicated and goes far beyond a new need to

look at Tributary Strategies in a different manner with the air component separated.



urban/suburban land and, if so, how? o Completely isolate the air component from agriculture and

developed lands? Some jurisdiction’s interest in getting “credit” for state emission

controls that go beyond, for example, ozone-season NOx SIP or Tier II tail pipe standards. Reductions in deposition are determined through monitoring program

information coming from sites throughout and just beyond the watershed.

The root cause and location of the emission controls that yield deposition reductions to the watershed are difficult to ascertain accurately.

How do you “credit” emission controls in one watershed state that also benefit other states’ deposition?

Who gets “credit” for emission controls outside the Bay watershed boundary that yield deposition reductions to the watershed?

Bay Program partners have been considering – and working at answering – these questions for a few years through the development of more-local tools relating emissions, deposition, and loads.

Peer-Review

• Meeting of regional air experts will be convened in early January to discuss air issues:

o Robin Dennis, NOAA/EPAo John Sherwell, MD DNRo Mark Garrison, Environmental Resources Management o Jeff Stehr, UMDo Dan Salkovitz, VA DEQo Mike Kiss, VA DEQo Kenn Pattison, PA DEP (invited)o Jeff Grimm, Penn State (invited)o etc.

• Need direction from NSC and TSWG now on how to determine air environmental indicator for 2006 Chesapeake Bay Restoration Assessment.


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Peer-Review and the Nutrient Subcommittee’s Role with Air at the Chesapeake Bay Program

DISCUSSION• Need for a Peer-Review Process

o Is it the NSC’s job to put a peer-review process in place?o How do we establish a peer-review process?o Who could serve as peer-reviewers?

STAC? Air experts from jurisdictions?

• What role, if any, should the NSC have in addressing air issues?• What are NSC recommendations concerning air?

atmospheric deposition and the role of the chesapeake bay program

Documents

source point source

nonpoint source loads

influence of source

reductionother air programs

deposition component

chesapeake bay programjeffrey

nitrogen load reduction

estimates of n deposition