[Federal Register Volume 73, Number 59 (Wednesday, March 26, 2008)]
[Notices]
[Pages 16008-16009]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-6166]


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ENVIRONMENTAL PROTECTION AGENCY

 [FRL-8546-7]


Causal Analysis of Biological Impairment in Long Creek: A Sandy-
Bottomed Stream in Coastal Southern Maine

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of availability.

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SUMMARY: EPA is announcing the availability of a final report entitled, 
``Causal Analysis of Biological Impairment in Long Creek: A Sandy-
Bottomed Stream in Coastal Southern Maine'' (EPA/600/R-06/065F), which 
was prepared by the National Center for Environmental Assessment (NCEA) 
within EPA's Office of Research and Development (ORD).

ADDRESSES: The document is available electronically through the NCEA 
Web site at: http://www.epa.gov/ncea. A limited number of paper copies 
will be available from the EPA's National Service Center for 
Environmental Publications (NSCEP), P.O. Box 42419, Cincinnati, OH 
45242; telephone: 1-800-490-9198; facsimile: 301-604-3408; e-mail: 
lmit.com">nscep@bps-lmit.com. Please provide your name, your mailing address, the 
title, and the EPA number of the requested publication.

FOR FURTHER INFORMATION CONTACT: Information Management Team, National 
Center for Environmental Assessment (8623P), U.S. Environmental 
Protection Agency, 1200 Pennsylvania Avenue, NW., Washington, DC 20460; 
Telephone: 703-347-8561; e-mail: [email protected].

SUPPLEMENTARY INFORMATION: This assessment presents results from a 
complex causal assessment of a biologically impaired, urbanized coastal 
watershed--the Long Creek watershed. The primary goals of this case 
study include the following.

[[Page 16009]]

    First, the assessment serves as an example EPA Stressor 
Identification (SI) case study, whereby the report may help future 
assessors understand the SI process for other biologically impaired 
ecosystems and the scientific community better understand urban-related 
stressor interactions. Target audience members may include government 
agency and consulting firm scientists attempting to conduct their own 
case studies and managers interested in learning what the SI process is 
capable of.
    Second, the assessment provides useful information for the specific 
environmental improvement of the Long Creek watershed. This is 
especially timely, as managers are currently considering options for 
promoting ecological recovery of the watershed.
    The Long Creek watershed is biologically impaired and located 
primarily in South Portland, Maine. A relatively unimpaired upstream 
portion of the Red Brook watershed, adjacent to and immediately south 
of Long Creek, provides a reference condition and is also discussed in 
the report. The contributing watersheds of both streams are urbanized, 
home to industrial, commercial, and residential land uses. The Long 
Creek and Red Brook watersheds showcase a wide range of topics related 
to resource management including the environmental implications of 
urban land use for coastal regions and the interactions among multiple 
causes linked to biological impairment.
    The Long Creek project team, consisting of the U.S. EPA and Maine 
Department of Environmental Protection, followed U.S. EPA's SI guidance 
to conduct the case study. A rudimentary knowledge of the SI process 
may assist report readers; U.S. EPA's CADDIS (Causal Analysis/Diagnosis 
Decision Information System) Web site, http://www.epa.gov/caddis/, 
provides causal assessors with the most recent SI methodology.
    The project team identified four specific biological effects 
defining impairment and seven candidate causes of impairment. The 
biological effects include decreased Ephemeroptera, Plecoptera, and 
Trichoptera (EPT) generic richness, increased percentage of non-insect 
taxa individuals, increased Hilsenhoff Biotic Index (HBI) score, and 
absence of brook trout. Candidate causes include increased onsite 
organic production (or autochthony), decreased dissolved oxygen, 
altered flow regime (increased hydrologic flashiness, including 
decreased baseflow and increased peaks), decreased large woody debris, 
increased sediment, increased temperature, and toxic substances 
(including, e.g., metals and ionic strength).
    Specific biological effects and candidate causes were evaluated at 
three impaired sites on Long Creek. Implications associated with 
interactions among probable causes of impairment are discussed in terms 
of this case study and causal assessment in general.

    Dated: March 14, 2008.
Rebecca Clark,
Acting Director, National Center for Environmental Assessment.
 [FR Doc. E8-6166 Filed 3-25-08; 8:45 am]
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