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

PDF Version (2 pp, 57K, About PDF)

[Federal Register: March 26, 2008 (Volume 73, Number 59)]
[Notices]
[Page 16008-16009]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr26mr08-62]

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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:
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: nceadc.comment@epa.gov.

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]
BILLING CODE 6560-50-P

 
 

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