Eutrophication of Estuaries and Acidification of Freshwater Bodies

in the United States The Benefits and Costs of

the Clean Air Act 1990 -2010& New Developments

Linda M. Chappell, PhD

U S Environmental Protection Agency

October 3, 2002

• Acid deposition is still a regional problem

• Highest sulfate deposition occurs in the Midwest and northeastern United States, both

adjacent to and downwind of the highest emitting areas

• Impacts occur in both the eastern U.S. and mountainous areas of the West

Acid Rain: Overview

Deposition data measured by CASTNet and NADP, 1997-1999

Acidic surface waters in regions surveyed by the National Surface Water Survey

• Effects of acid deposition

include:• Acidification of lakes and

streams, making them unsuitable for fish and other aquatic life

• Damage to forests through acidification of soil, depletion of soil nutrients, and direct injury to tree leaves and needles

• Harm to material and cultural resources, including buildings, statues and monuments

Acidic Deposition Predominant causes are sulfuric and nitric acid formed

from sulfur dioxide and nitrogen oxides Deposition occurs through three pathways: wet

deposition, dry deposition, and cloud-water Sources of sulfur dioxide are primarily coal and

residual oil combustion (utilities are major contributor) Sources of nitrogen oxides are internal combustion

engines, furnaces, boilers, engines Results in acidic surface waters, negative impact on

acid sensitive fish populations, competitive advantage for acid-resistant species

1999 NOAA Report. National Estuarine Eutrophication Assessment

Estuarine Eutrophication Nutrient Sources and Effects on Estuaries

1999 NOAA Report. National Estuarine Eutrophication Assessment.

Estuaries with High Levels of Eutrophication

The Cost and Benefits of the Clean Air Act 1990 - 2010 Assess the benefits and costs of the Clean

Air Act Amendments (CAAA) for freshwater acidification and estuary eutrophication for the period 1990 - 2010

Benefit Assessment Approach: Identify endpoint – service flow Provide a defensible link between changes in air

pollution and quality or quantity of service flows Quantitative models to monetize these changes

Acidification of Freshwater Lakes and Streams Evaluated recreational fishing benefits in the

Andirondacks regions of New York Scenario specific (with and without CAAA) acid

deposition modeled using Regional Acid Deposition Model (RADM)

Model of Acidification of Groundwater in Catchments (MAGIC) used to estimate impact of sulfur and nitrogen deposition on lake acidity (pH and Acid Neutralizing Capacity (ANC))

Benefits of CAAA relating to recreational fishing in the Andirondacks

Benefit Monetization -Random Utility Model for recreational fishing that allows for substitution among sites and fisheries in the region based upon water quality parameter changes (Montgomery and Needelman (1997))

Annual benefits range from $12 to $88 million (mean $50 million) in 2010 (1990$)

Caveats, limitations, and uncertainties

Eutrophication of Estuaries Illustrative estimate of potential benefits from

nitrogen air deposition reductions to US estuaries Assesses changes in nitrogen air deposition

directly to estuary water bodies using a geographical information system (GIS) approach and land use pass through factors for deposition to watershed areas for the Chesapeake Bay, Tampa Bay, Long Island Sound

Decreases in nitrogen deposition range from 38 to 43 percent for the estuaries evaluated

Benefit Estimation Uses an avoided cost benefit estimation approach for the

three estuaries Monetary benefits for the three estuaries range from $376

million to $1.5 billion annually in 2010 (1990 $) Benefits are extrapolated to US east coast estuaries that

are ranked as moderately or highly susceptible to eutrophication and benefits for nitrogen deposition reductions for these additional estuaries range from $262 million to $2.8 billion annually in 2010 (1990$).

Key issue - benefit estimate are illustrative and not added to the overall monetary benefits of the CAAA in 2010.

Next Steps in the Process Damage function approach Ideally wish to establish a platform that links:

Air deposition – Evaluate air deposition changes Watershed/Estuary Models – Evaluate water quality impacts Biological and Economic Endpoints Economic Valuation – Estimate monetary benefits

Challenging Task!

Progress to Date Air deposition models are available – Regulatory

Modeling System for Aerosols and Deposition (REMSAD) Regional Acid Deposition Model (RADM)

National Water Pollution Control Abatement Model (NWPCAM) – water quality model developed by the US EPA Office of Water

National water quality model for freshwater rivers and streams

Used to evaluate policy alternatives Linked to economic valuation study (Carson - Mitchell)

Next Steps Add air deposition modeling to NWPCAM Expand capabilities to watershed/estuaries to

model potential water quality improvements Establish relevant biological and economic

endpoints Valuation studies – studied planned for California

coast by US EPA National Center for Environmental Economics