tiles or other ground covers, and enhancing sedi-
mentation, will affect the physical ecosystem of
ERF in ways that are largely unknown. Likewise,
both the short- and long-term viability of these
Eagle River Flats is one of several estuarine
treatments will be influenced by the physical sys-
tidal flats and salt marshes within the upper
tem, where the occurrence, intensity and interac-
Cook Inlet region of south-central Alaska (Fig. 1).
tion of the physical processes remain poorly
It lies at the mouth of Eagle River on the south-
understood. Baseline data are still required to de-
east side of Knik Arm and is about 2.75 km wide
fine the sensitivity of the Flats to perturbations
at the coast, narrowing inland. This region has a
and to evaluate its responses to potential reme-
transitional maritime to continental climate, with
generally moderate annual temperatures (daily
mean 1.9C; minimum mean 2.2C) and precipi-
methods chosen, but ultimately they must be
compatible with the physical system.
tation (330 to 508 mm) (Evans et al. 1972).
In this report, we present the initial analysis of
A high tidal range with semi-diurnal fluctua-
the physical system of Eagle River Flats, focusing
tions of 9.1 to 11 m and sediment-laden glacial
on the interrelationships of the hydrological and
discharges are critical factors affecting ERF
sedimentological processes. Although prelimi-
hydrology and sedimentology (Lawson and
nary, these initial results clearly demonstrate the
Brockett 1993). Inundation results from both the
complexity of the Flats' physical system and the
tides in Knik Arm and the resultant overflow
need for further quantitative studies.
from the Eagle River as it meets the rising tide.
Figure 2. General distribution of ponds (shaded areas) and the primary
drainage system of gullies and vegetated channels within ERF. The primary
study area was within the northeastern area marked by the rectangle.