Clear Water Alabama Field Day
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One of the bottomless culverts at the
Tannehill Preserve subdivision that allows construction practices above
creeks and streams without disturbing them. |
By Matthew D. Collins, Communications Specialist, NRCS, Auburn, AL
The Alabama Erosion and Sediment Control Partnership recently held the 2008
Clear Water Alabama Field Day in Bessemer, Alabama. The field day highlighted
many erosion and sediment control practices and gave participants a chance to
observe and discuss many on-site practices. Some of the practices included
new sediment basin technology that reduces the suspension of soil particles in
water, called turbidity.
Two of the demonstration sites, the Colonial Promenade Shopping Center of
Bessemer and Tannehill Preserve subdivision, showcased bottomless culverts, an
innovation aimed at allowing construction of roads over creeks and streams
without having to alter or destroy the ecosystem of that creek or stream.
Tannehill Preserve also demonstrated a low-impact planned urban development
designed to preserve wildlife habitats as well as soil and water quality through
practices such as stream buffers, narrower streets, and sidewalks on only one
side of the road.
The field day also exhibited a new sediment basin for construction sites, the
first of its kind built in Alabama. The basin includes baffles, a skimmer, and
chemical treatment with polyacrylamide. The basin’s components slow the flow of
the water, promote rapid settling of the fine soil particles that otherwise stay
in suspension for days, and discharge the water from the surface rather than the
bottom of the basin. The end result is clearer, cleaner water leaving the basin.
The basin was installed at the Cedar Creek subdivision in Bessemer just days
before Tropical Storm Fay brought heavy rainfall to the area. "The basin
performed perfectly," said Natural Resources Conservation Service State
Conservation Engineer Perry Oakes. "Turbidity levels were reduced over 95
percent. The new sediment basin technology will be introduced into the Alabama
Handbook for Erosion Control and Stormwater Management on Construction Site
soon. Look for these type basins to be constructed on construction sites
throughout Alabama."
The Clear Water Field Day demonstrations were presented by representatives
from private firms working in erosion and sediment control as well as presenters
from the Alabama Department of Transportation, Auburn University, the Alabama
Soil and Water Conservation Committee, and the Natural Resources Conservation
Service.
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Sediment basin demonstration at the Cedar Creek
subdivision construction site in Bessemer. |

The sediment basin at near capacity after the heavy rainfall from
Tropical Storm Fay. The difference is turbidity becomes visible as
the water passes through the basin’s baffles from left to right. |
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