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A Multi-Agency Critical Loads Development and Implementation Process for the Northeast U.S

Gary Kleiman
Science and Technology Program Manager
101 Merrimac Street, 10th Floor, Boston, MA 02114


The Northeast U.S. has been challenged by acid deposition for more than 40 years. Given the geologic, ecosystem, and land-use diversity of the region, management approaches based upon critical loads are well suited for application in the Northeast. The development and implementation of a successful management framework, however, will depend upon multi-agency support for a scientific approach for establishing critical loads across the region. A pilot initiative is being undertaken by 11 Eastern States, The U.S. EPA, U.S. Forest Service, U.S. Geologic Survey, and the U.S. National Park Service to develop a scientific foundation for determining critical loads for both terrestrial and aquatic ecosystems utilizing steady-state and dynamic modeling approaches on a regional basis.

This talk will review the development of critical loads in New England through the New England Governors/Eastern Canadian Premieres Acid Rain Steering Committee and briefly discuss how these products are informing policy decisions in the region. For example, New Hampshire’s Fish and Game Department has used the critical loads maps to survey forests at risk for their statewide assessment of ‘habitats at risk’ and Canadian officials have used the critical loads estimates in assessing the sensitivity of ecosystems to deposition for the PM Annex to the Canada-U.S. Air Quality Agreement.

In addition, the Northeast States’ perspective on acid deposition issues and the need for additional ecosystem protection will be presented as context for why various management approaches based upon critical loads are now being considered. With the advent of market based approaches under the Title IV Acid Rain Program, the Eastern U.S. saw broad reductions which have resulted in substantial signs of recovery in up to one-third of acidified Northeast Lakes and Streams [U.S. EPA, 2003]. Unfortunately, this means that we have seen a lack of substantial recovery in over two-thirds of acidified surface waters to date. Future management approaches based on critical loads may provide resource managers with options that would enable them to address individual ecosystems by identifying the specific stresses that are affecting each unique system. Existing air quality programs such as the Regional Haze program may provide useful analogs for using physically-based environmental targets (e.g. natural visibility conditions versus critical loads) as a basis for setting program goals.

Finally the presentation will review the multi-agency process for developing a scientific basis for establishing regional critical loads and the important role that state agencies and the federal partners will play in establishing regional critical loads protocols in the Eastern U.S. This process will include the formation of a stakeholder working group representing state air agencies and other environmental management agencies as needed and multi-agency federal partners. The focus of this pilot will be on identifying approaches that are easy to calculate with regional consistency, have credibility based on current knowledge, and are flexible enough to allow for changes as our scientific understanding improves. The process will include an initial meeting to explain the technical approach and achieve buy-in to the process followed by a series of quarterly calls and meetings to detail progress, explain decision-points and achieve group consensus on a path forward.