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The Tully Valley (fig. 2) is within the Finger Lakes Region of the
Allegheny Plateau. The small (2 acre) wetland is in the northwestern part of
the valley at the base of Bare Mountain. Ground-water flow feeding the
wetland is from a series of fresh- and brackish-water springs at the foot of
the mountain. Freshwater springs are fed by precipitation infiltrating the
hillside slopes, whereas brackish springs are fed from the deep shale-bedrock
flow system. Concentrations of sulfate, sodium, and chloride in brackish
flows are naturally high because they leach into the groundwater as it moves
slowly through fractures in the mineralized bedrock. Flow from the
freshwater springs typically is least during summer, increases in fall, remains
fairly constant throughout winter, and increases again during the spring in
response to rain and snowmelt. Brackish discharge is more uniform than
freshwater discharge, although brackish flow generally also is greatest during
the spring. Thus, fresh and brackish waters flow into the wetland during the
spring, but brackish discharge predominates during summer. Several small
drainageways in the wetland form a small stream that carries outflow to the
northeast. Flow of this stream is entirely from the fresh- and brackish-water
springs at the base of Bare Mountain.
A considerable saltworks industry developed by the mid 1800s along the
western side of Syracuse. Over-exploitation of local salt reserves spurred the
discovery in the late 1880s of salt layers approximately 1000-1400 feet
below land surface at the southern end of the Tully Valley. Mining operations
began in 1889 and continued until the late 1980s, during which
approximately 200 million tons of salt were removed. In order to mine the
salt, operators injected surface water into the salt layers through a series of
wells and then lifted the dissolved salt (brine) to the surface. Company
records from the turn of the century estimated that 40-60% of injected waters
were "lost" to the surrounding bedrock and/or glacial deposits. Injection
practices were abandoned in the late 1950s because it was determined that
groundwater flow into the caverns were sufficient to dissolve additional salt
deposits. Up to one billion gallons of brine per year were pumped after
injection practices were abandoned. Mining activities were reduced greatly
in 1986 and ended in 1988.
Removal of nearly 150 feet of salt caused the land surface to collapse in
parts of the brine fields as early as the 1920s. Large collapses occurred
during the 1940s, and surface subsidence of 5 to over 40 feet has occurred
since the 1950s. No subsidence was documented as far north as the study
wetland, however.
White pine trees generally are clustered near the center of the wetland on
moss-covered hummocks at slight elevations above the series of small
drainageways. Only a few pines grow in northern and southern parts of the
wetland. Pines range in age from 20 to 130 years, in diameter from 7 to 20
inches, and in height from 15 to 30 feet. Numerous trees were in poor health
in late 1994, particularly within the central part of the wetland, and at least
four died during the ensuing year. Two pencil-sized corings from each of 17
white pines were collected with a steel increment borer designed to extract
samples of rings without harming the tree. Cores were placed to dry in paper
drinking straws and subsequently sanded to make the rings easier to see. The
rings of each paired cores were measured and crossdated with each other (the
process whereby each ring is assigned an exact year of formation) and
averaged together to form one composite ring-width series for each tree.
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