Watershed assessment of the Lake Allatoona/Upper Etowah River Basin
Author(s)
Stribling, James B.
Davie, Steven R.
Kubala, David M.
Jones, Jerry
Advisor(s)
Editor(s)
Carroll, G. Denise
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Abstract
There are multiple, complex, and cumulative
combinations of stressors throughout the Lake Allatoona/
Upper Etowah River watershed (LAUE). Recognition
of their presence and specific effects on the stream
biota in isolation from effects of all other potential stressors
is often difficult. An understanding can be developed
of the spatial and temporal characteristics of potential
stressor sources, the likelihood that stressors produced
would effect biological responses, and the variable magnitude
of those responses. We used ecological monitoring
and assessment results, combined with water quantity,
quality, and land use/land cover data, to evaluate ecological
condition as the response indicator, the physical,
chemical, and hydrologic stressors effecting biological
conditions, and point and nonpoint sources of those
stressors. The Georgia multimetric index (MMI), a biological
index using benthic macroinvertebrates, provided
assessments at four spatial scales: the watershed overall,
nested subwatersheds at two scales (10 and 12 digit hydrologic
unit code [HUC]), and individual streams.
Through the first 3 years of sampling (2006-07), approximately
44% of the basin has been assessed (n=158 sites,
and 23 out of fifty-three 12 digit HUC subwatersheds); of
that fraction, about 38% of the stream channel miles is
degraded, that is, with biological assessment results as
either “poor” or “very poor”. The most complete assessments
thus far are for the Upper Etowah River
(0315010401) and the Middle Etowah River
(0315010403) subwatersheds at 62 and 63 percent complete,
with 13.2 and 18.4% degraded stream miles, respectively.
The Upper and Middle Etowah River and Amicalola
Creek subwatersheds have the highest proportion of
assessments falling as either “good” or “very good”; those
subwatersheds having highest proportion as either “poor”
or “very poor” are Lower Etowah River, Little River, and
Upper and Lower Allatoona. Additional sampling and
analysis in the final 3 years of this rotating basin monitoring
program will ultimately result in 318 sites being assessed,
and will likely necessitate modification of assessment
results for some of the 10 digit HUC subwatersheds
and the LAUE overall. Inventory of potential stressors and
stressor sources found that there was a broad combination
of point and nonpoint sources, including urban/suburban
development, transportation corridors, combined animal
feeding operations (CAFO), silvicultural and mining activities,
and physical habitat degradation due to the reservoir
impoundment itself. These sources result in potential
elevated loadings of sediment (accelerated erosion), phosphorus
and other nutrients, multiple aspects of physical
habitat degradation to which the existing stream biota are
exposed. The combined knowledge of biological degradation,
most probable stressors, and the sources producing
those stressors, is serving as the foundation of a watershed
protection plan for the LAUE.
Sponsor
Sponsored by:
Georgia Environmental Protection Division
U.S. Geological Survey, Georgia Water Science Center
U.S. Department of Agriculture, Natural Resources Conservation Service
Georgia Institute of Technology, Georgia Water Resources Institute
The University of Georgia, Water Resources Faculty
Date
2009-04
Extent
Resource Type
Text
Resource Subtype
Proceedings