DOlive Creek Watershed Sedimentation Assessment

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Baldwin County Erosion and Sediment Transport
The Horse is out of the Barn but can we put him
back in?
Marlon Cook
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• Sources of sediment
• Natural stream channel erosion
• Man-made sources from land disturbance

• Sediment transport mechanisms
• Geologic uplift
• Falling sea level
• Lowered water table
• Increased runoff

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Acknowledgements

• Mobile Bay National Estuary Program
• Alabama Department of Conservation and Natural
  Resources
• Lake Forest Property Owners Association
• City of Daphne (Ashley Campbell)
• DOlive Creek Watershed Working Group
• GSA Groundwater Assessment Program (Neil Moss and
  Steve Jennings)

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DOlive Creek Watershed Working Group
City of Daphne City of Spanish Fort Alabama
House of Representatives U.S. House of
Representatives Mobile Bay National Estuary
Program Lake Forest Property Owners
Association Baldwin Co. Soil and Water
District Alabama Department of Environmental
Management Alabama Department of Conservation and
Natural Resources Alabama Department of
Transportation Geological Survey of
Alabama Cypress/Spanish Fort ILP ATT Malbis
Properties Thompson Engineering
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Coastal Alabama
Urban
Baldwin County
Mobile County
Forest
DOlive Creek Watershed
Agriculture
Magnolia River
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Southwest Alabama Geologic Structure
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Baldwin County Elevations
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Eastern Shore Geology
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DOlive Creek
Magnolia River
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Sediment Loads
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Geological Survey of Alabama Sedimentation
Monitoring Sites
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Sedimentation
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11
4
5
3
10
2
1
DOlive Creek
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Tiawasee Creek
9
8
DOlive Bay
12A
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GSA Sedimentation Assessment Sites
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Precipitation in the DOlive Creek Watershed

• October 2006-October 2007 44.7 inches
• October 2007-October 2008 74.1 inches

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Suspended Bed
Suspended Bed
10/06-10/07 10/07-10/08
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Suspended Bed
Suspended Bed
10/06-10/07 10/07-10/08
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Sedimentation

• Total Sediment Load to the lake at Lake Forest
  for normal annual precipitation 8,200 tons per
  year
• Sedimentation will occur in two phases
• Multiple sources during development and
  construction.
• Channel degradation due to increased impervious
  surfaces, increased stream discharge, and
  increased stream discharge velocity.

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DOlive Creek Watershed 2003 Land Use
Agriculture
Commercial
Residential
Forest
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Water Quality
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Choctawhatchee River
Yellow River
Conecuh River
Terrapin Creek
D'Olive Creek
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Choctawhatchee River
Yellow River
Terrapin Creek
D'Olive Creek
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Choctawhatchee River
Yellow River
Tuscaloosa storm water
Terrapin Creek
Conecuh River
D'Olive Creek
Agricultural, forest, and urban
Agricultural and forest
Urban land use
Agricultural and forest
Agriculture and forest
Transitional from residential agriculture and
forest land use to urban
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Sedimentation Magnolia River Watershed
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Coastal Alabama
Urban
Baldwin County
Mobile County
Forest
DOlive Creek Watershed
Agriculture
Magnolia River
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DOlive Creek
Magnolia River
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Magnolia River Monitoring Sites
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9
2
3
4
5
6
10
7
8
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Tuscaloosa storm water
Terrapin Creek
Gantt-Point A
D'Olive Creek
Magnolia River
Choctawhatchee River
Yellow River
Bear Creek
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Can we put the horse back in the barn?

• DOlive Creek watershed- 20 mi2
• Magnolia river watershed- 40 mi2
• DOlive Creek watershed total sediment load-
  8,200 tons/year 410 tons/mi2/year.
• Magnolia River watershed total sediment load-
  3,550 tons/year 89 tons/mi2/year.
• DOlive Creek Watershed Working Group coordinated
  by the Mobile Bay National Estuary Program has
  initiated a remediation plan for corrective
  actions in the watershed.
• Magnolia River watershed was recently granted the
  Outstanding Water designation.