Environmental Impact of Impoundment of the Snake Creek Reservoir Keith Rice, Bryan Victor, Dr. Julie K. Bartley, and Dr. Rebecca Dodge; Department of Geosciences, University of West Georgia, Carrollton GA 30118

1
Environmental Impact of Impoundment of the Snake
Creek Reservoir Keith Rice, Bryan Victor, Dr.
Julie K. Bartley, and Dr. Rebecca Dodge
Department of Geosciences, University of West
Georgia, Carrollton GA 30118

Water Quality Upstream-Site 49
Downstream-Site 111

• Landsat Satellite Images

• Background
• The Snake Creek Reservoir was impounded in
  late 2001. It is located just east of Carrollton
  Georgia and provides part of the countys
  drinking water supply. It is the newest and
  largest reservoir in Carroll County.
• Concerns
• Temperature will increase in flooded areas, due
  to decreased flow and increased surface area.
• Turbidity will increase due to upstream erosion.
  The reservoir will gradually fill with sediments.
• Dissolved oxygen levels will become lower and may
  result in a fish kill, upstream of the reservoir.
  
• Bacterial activity will increase.
• Project Goals
• Assess environmental and water quality change
  during and after impoundment. Data sources
  Landsat satellite (1999, 2001, 2003) water
  quality data from the Center for Water Resources
  (2001, 2004), and from USGS (2001), and newly
  collected data during the project.

1999
2003
2001
Temperature is higher after impoundment at both
sites. After impoundment, summer water
temperature exceeds air temperature.
Average turbidity is higher upstream after
impoundment and lower downstream. Note that
clear-cutting had begun in the reservoir area by
2001.
These three scenes capture the intervals of the
reservoir impoundment. The central portion of
the subset, shows substantial change from 1999 to
2001 and again from 2001 to 2003. (Green
represents vegetation pink shows areas of bare
ground and black represents water) The image is
17.16 km wide.
Dissolved Oxygen is lower after impoundment,
upstream of the reservoir.
Unsupervised Classifications
1999
2001
2003
The images above group areas of similar land
cover to better visualize land use change from
year to year. GreenGrass, OrangeBare Ground,
TurquoiseEvergreen Trees, Dark GreenDeciduous
Trees, BlueWater, PinkResidential, RedRoads,
and WhiteClouds
Fecal coliform bacteria levels are higher
upstream after impoundment and lower at the
downstream sites
(site 50 is downstream from site 111).
Change Detection
2001-2003

• Conclusion
• Satellite images show substantial change over the
  study period. Pre-impoundment clear cutting and
  subsequent impoundment are visible.
• Water temperature increase upstream of the
  reservoir contributes to a drop in dissolved
  oxygen.
• Upstream increase and downstream decrease in
  turbidity is consistent with sediment erosion and
  entrapment in the reservoir. Over time, the
  reservoir will accumulate sediment, decreasing
  its volume.
• Fecal coliform bacteria levels show a pattern
  similar to turbidity, consistent with increased
  runoff and higher temperature upstream of the
  reservoir, and entrapment of sediment in the lake.

1999-2003
These images evaluate change between two
time intervals. Green represents a 20 increase
in reflectance and the red shows a 20 decrease
in reflectance. Black areas show lt20 change. The
1999 image was taken during a drought, causing
change to appear anomalously high.
Acknowledgements John Congleton, Randa Harris,
Curtis Hollabaugh, Patrick Gilliland and Andrew
Boothe. Funded by NSF STEP grant   DUE-03365
71