Chickamauga
Reservoir
Ecological
health rating
The ecological health of Chickamauga Reservoir rated fair in 2007, compared to good in previous years. Three indicators (dissolved oxygen, chlorophyll, and bottom life) either rated at the low end of their historic range or lower than in previous years. The lower ratings were largely due to low reservoir flows in 2007, which was the driest year in 118 years of record.
TVA monitors four locations on Chickamauga Reservoir—the deep, still water near the dam, called the forebay; the middle part of the reservoir; the Hiwassee River embayment; and the riverlike area at the extreme upper end of a reservoir, called the inflow—usually on a two-year cycle.
Chickamauga
Reservoir Ecological Health Ratings, 1994-2007
Click chart for raw
data.
The table below
shows the ratings for individual ecological health indicators at Chickamauga
in 2007. These ratings are briefly explained in the paragraphs that follow.
|
Ecological
Health Indicators at
Chickamauga Reservoir, 2007
|
|
Monitoring
locations
|
Dissolved
oxygen
|
Chlorophyll
|
Fish
|
Bottom
life
|
Sediment
|
| Forebay |
|
|
|
|
|
| Mid-reservoir |
|
|
|
|
|
| Hiwassee
River embayment |
|
|
|
|
|
| Inflow |
|
|
|
|
|
Dissolved oxygen
Dissolved oxygen rated good at the mid-reservoir and Hiwassee River embayment monitoring locations and fair at the forebay. Dissolved oxygen typically rates good at all locations, except during extremely dry, low flow years such as 2007, which can result in the development of low dissolved oxygen conditions near bottom.
Chlorophyll
Chlorophyll rated poor at all monitoring locations because of elevated chlorophyll concentrations. Similar to dissolved oxygen, chlorophyll typically rates good or at the high end of the fair range in Chickamauga Reservoir, except in extremely dry years when low flows through the reservoir allow more time for algae to grow.
Fish
The fish community rated at the high end of the fair range at all monitoring locations. The fish community typically rates good or at the high end of the fair range.
Bottom life
Bottom life rated fair at three monitoring locations and poor at the Hiwassee embayment location. Bottom life at the forebay and embayment monitoring locations rated lower than in previous years (at the low end of the fair range and poor, respectively) because overall abundance and diversity of animals were lower. Prior to 2007, ratings varied between good and fair at each location.
Sediment
Sediment quality rated good at all monitoring locations. No PCBs or pesticides were detected, and all metal concentrations were within the expected range. Elevated concentrations of PCBs and selected metals—generally zinc and copper—have been detected in sediment samples from the forebay and Hiwassee embayment monitoring locations in some previous years.
See definitions of
ecological health indicators and monitoring locations.
|
|
Fish
consumption advisories
There are no fish
consumption advisories for Chickamauga Reservoir. TVA collected channel catfish and largemouth bass from the reservoir for tissue analysis in fall 2005. The results, which were similar to those of previous years, will be provided to state agencies in Tennessee. TVA will analyze fish from the reservoir again in autumn 2007.
Tennessee Valley Authority
