Geoscience Reference
In-Depth Information
This 1130 km 2 area of the southern Appalachian
Mountains is predominantly forested (79% forest
cover, Plate 13). The valley is largely within
the Tallulah Falls geological formation, which
mostly comprises metasedimentary gneiss, schist,
and metagraywacke. The regional geology is
characterized by metamorphic rocks (largely
gneiss, schist, and metagraywacke) with scattered
windows of older basement rocks (mainly
granitic gneiss) with similar hydraulic properties
and yielding low levels of dissolved solids in
groundwater (Hatcher, 1988; Velbel, 1988; Daniel
and Payne, 1990; Robinson et al ., 1992; Mesko
et al ., 1999). Soils within the area are generally
classified as Inceptisol and Ultisol soil orders. Soils
are approximately 1 m deep and underlain by
regolith of saprolite (Velbel, 1988). The saprolite
mantle is 1-30 m thick and drapes the ridges and
slopes (Hewlett , 1961), and substantial colluvial
deposits are present on benches, coves, and
footslopes (Southworth et al ., 2003; Leigh and
Webb, 2006).
The regional climate is considered humid sub-
tropical at the lowest elevations and marine
humid temperate at higher elevations, with mild
winters with little snowfall and mild summers
with temperatures seldom exceeding 30 C. Rainfall
is distributed rather evenly throughout the year.
The regional average annual precipitation is
about 1400 mm, but there is considerable spatial
variability related to elevation and considerable
annual
areas, while the balance of nearly 20% resides in
rural areas. However, what is not revealed in the
US Census by virtue of how 'urban' and 'rural'
are defined is that an increasingly large segment of
the United States population (37%) now live in the
urban-rural interface (Sutton et al ., 2006).
Traditionally, people living in the Upper Little
Tennessee River Basin had farms and lived in the
valleys. In contrast, people moving from the cities
or building second homes frequently purchase land
and build on the sides and tops of mountains.
The objective of this study was to determine
how development, and particularly mountainside
development, is affecting stream chemistry in the
Upper Little Tennessee River Basin.
The terms 'land cover' and 'land use' have
often been used interchangeably, or, even when
the difference is acknowledged, land cover has
been used as a surrogate for land use. A few
studies have integrated some land-use information
into land-cover data (Osborne and Wiley, 1988;
Groffman et al ., 2004) but land cover and land use
were not analysed separately. Turner and Meyer
(1994) noted that land cover is principally the
concern of natural science, while land use is the
concern of social science. While land cover denotes
the physical state of the land, land use denotes the
human deployment and accompanying property
rights associated with the land (Turner and Meyer,
1994). A number of studies have examined how
economic and other social factors influence land
cover (Turner et al ., 1996), but we are not aware
of previous studies where the conjoint effect of
land use and land cover have been examined. In
this collaboration of natural and social scientists,
land-cover data based on satellite imagery, and
land-use data, based on tax records tied to parcel
boundaries within catchments, were used as
independent variables to examine their effect on
stream water quality.
variability
related
to
drier
and
wetter
climatic periods.
The basin includes two towns, Franklin and
Highlands. Franklin has a population of 3931
within the town limits, but the population in
Macon County, which contains Franklin, is 32 607.
Highlands has a resident population of 1058 but a
summer population of about 18 000.
Methods
Site description
Fifty-eight synoptic stream sites in the Upper
Little Tennessee River Basin (Plate 13) were
sampled in February and June 2009 during periods
of
The Upper Little Tennessee River Basin is located
in western North Carolina and north Georgia,
USA, in the Blue Ridge Physiographic Province.
baseflow
to
characterize
both
growing
and
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