ponds in an estimated 1 to 10 years. Lowering of
water levels should lead to in-situ WP degradation
a U.S. Army artillery training range for the past
and natural attenuation as pond sediments dry.
40 years.
Annual sedimentation rates in some ponds and
Landcoverlandform classification and map-
marshes are sufficient to bury WP in several years or
ping was conducted using aerial photos for the
more and thereby reduce the exposure to feeding
entire salt marsh at two scales to show seven
waterfowl. Ice and water are also effective trans-
physiographic zones at a scale of 1:55,000 and
porters of WP, moving it about ERF and into Eagle
more detailed waterbody and vegetation types at
River, and eventually into Knik Arm, where its fate
a scale of 1:27,000. Quantitative sampling of vege-
is unknown. Certain areas of ERF will require artifi-
tation, avifauna, and macroinvertebrates
cial drainage, but natural conditions can be restored
included a daily population census of waterfowl,
425 1-m2 plot samples of vegetation, and 82
following treatment. Recommendations are made
for the use of natural attenuation and additional
macroinvertebrate sediment samples obtained in
studies that are required to ensure the successful
May, July, and August. Comprehensive species
cleanup of ERF.
inventories as well as relative abundances and
habitat relationships are presented here.
The flora of ERF includes over 65 species of
Lawson, D.E., L.E. Hunter, S.R. Bigl, B.M.
Nadeau, P.B. Weyrick, and J.H. Bodette (1996)
vascular plants, including halophytic species
Physical system dynamics and white phosphorus
characteristic of mud flat salt marsh, aquatic sub-
fate and transport, 1994, Eagle River Flats, Fort
merged, and emergent marsh species. The avi-
Richardson, Alaska. USA Cold Regions Research
fauna of ERF includes about 68 species of birds,
and Engineering Laboratory, CRREL Report 969.
including dabbling ducks, shorebirds, raptors,
Eagle River Flats (ERF) is a subarctic estuarine
and granivores. Over 30 species of sediment
salt marsh where human and natural forces are
macroinvertebrates were sampled from the bot-
causing significant changes in the environment.
toms of ponds and tidal creeks. The dipteran lar-
Multiple internal and external forces govern the
vae Chironomus salinarus is the most common and
physical and chemical processes by actively alter-
abundant species particularly in shallow ponds
ing surface conditions, sometimes in unpredict-
with high salinites but less common in deeper
able ways. ERF is also used as an artillery range by
ponds and tidal creeks.
the U.S. Army, where past use has resulted in
Although small in area, ERF contains many of
the same habitats and species found in other
sediments within ponds and mudflats. Bottom-
much larger estuarine salt marshes on Upper
feeding waterfowl ingest this WP, which causes
Cook Inlet but does not contain extensive tidal
rapid death. This report documents analyses of the
mudflats along the coastal edge, which likely
physical environment, describing the nature of the
affects the abundance of both waterbirds and
physical systems and factors controlling them. It
invertebrates species.
includes data on sedimentation, erosion and
hydrology. These investigations provide knowl-
Racine, C.H., M.E. Walsh, C.M. Collins, D.J.
edge necessary to designing and evaluating reme-
Calkins, and B.D. Roebuck (1992) Waterfowl
dial technologies. They also help determine the
mortality in Eagle River Flats, Alaska: The role of
munition residues. USA Cold Regions Research
system's capacity to naturally attenuate the WP
contamination.
and Engineering Laboratory, CRREL Report 925.
The deaths of hundreds of migrating dabbling
ducks and 1050 swans have been documented
Racine, C.H., B.B. Steele, L. Reitsma, and C. Bouw-
kamp (in press) Biodiversity inventory of Eagle
annually for the last 10 years in Eagle River Flats
River Flats, Upper Cook Inlet Alaska. USA Cold
(ERF), an estuarine salt marsh on Ft. Richardson,
Regions Research and Engineering Laboratory,
Alaska. This marsh has been used for the past 40
CRREL Report.
years as an artillery impact range by the U.S.
An inventory of landcover-vegetation, flora,
Army. During May and August 1990, CRREL col-
bird, and sediment macroinvertebrate faunas of
lected 250 sediment and water samples and anal-
Eagle River Flats (ERF), an 865-ha salt marsh on
yzed them for munitions residues. We found 2,4-
Upper Cook Inlet near Anchorage, Alaska, was con-
DNT in a limited area of Eagle River Flats not
ducted between 1991 and 1995. This work was car-
used by waterfowl and white phosphorus in sed-
ried out as part of an ecological risk assessment for
iments from the bottom of shallow ponds where
84
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