Sediment Challenges in the
Tombigbee River Basin
Peter J. Grace, USACE
William H. McAnally, MSU
Purpose of Presentation:
To Highlight
-
•
Some sediment issues in the Tombigbee River
basin.
•
Needs for data to address those challenges.
•
Need for a regional sediment management
approach.
•
Opportunities for improved coordination between
basin stakeholders.
The
Tombigbee
River Basin
•
Tennessee, Mississippi and Alabama
•
Tennessee
-
Tombigbee Waterway
•
40% of flow to Mobile Bay
•
40% of sediment supply to Mobile Bay?
The
Tenn
-
Tom
Waterway
•
A route to the Gulf of Mexico for the
inland waterway system
•
Connects the Tennessee River to
Mobile Bay
•
The Waterway:
–
aids inland navigation
–
stimulates economic development
–
provides outdoor recreational
opportunities
–
enhances wildlife habitat
Sedimentation
Challenges
•
Tributary erosion and sediment supply.
•
Deposition in the river, waterway, and ports.
•
Dredging, dredged material placement, and beneficial uses.
•
Impacts on cultural preservation and environmental quality.
•
Downstream sediment supply effects.
Tributary
Erosion
•
Tributaries are experiencing bed and bank erosion, which contribute
to excess sediment loads downstream.
–
Flood Control Projects (Big Brown, Donivan, Twenty
-
Mile, and
Mantachie Creeks).
–
Old Tombigbee River and Town Creek.
–
Matubby Creek and James Creek
–
Buttahatchie River
–
Others
•
Upstream erosion threatens landowners and infrastructure, reduces
projects effectiveness.
•
Sediment inflows to the river deposit in the waterway and ports and
move to downstream areas.
Tombigbee River
–
East Fork Tributaries
Donivan Creek
Twenty
-
Mile Creek
Mantachie Creek
James Creek
–
Columbus Pool
Other Issues
–
Mussel Habitat
•
Five Listed Species of Mussels
•
Requirement to Pass 70 cfs at
Hwy 78
-
Fulton
Other Issues
–
Cultural Resources
Dredging, Placement, and Beneficial Uses
•
Waterway Dredging: >800,000 cu
yd/yr
•
Port Dredging: >30,000 cu yd/yr
•
Upland Disposal Areas (DA’s):
Limited DA capacities, and critical
space limitations in some areas.
•
Possible beneficial uses:
–
common fill material
–
concrete and asphalt
aggregate
–
capping materials
–
commercially sold home
improvement materials
–
marsh construction
–
beachfill material
–
armor unit construction
materials
Sediment Management
Downstream Sediment Supply
•
Insufficient Sediment Supply
–
Wetlands losses
–
Beach erosion
•
Excess Sediment Supply
–
Oyster reef & other habitat sedimentation
–
Port and channel dredging
Upper photo courtesy of Scott
Douglass, U. So. Ala.
USACE Data and Resources
•
GIS capabilities at CESAM and TTWW Management Center (ARCGIS 9.1)
•
Types of data include: Geospatial data
Hydrographic surveys
Dredging and dredged disposal area information
Water surface elevations
Spillway discharge data
Precipitation
Limited water quality data
Habitat management information
Recreation information
•
2005 EPA water quality investigation of Aliceville Pool.
•
1991 East Fork sedimentation study.
•
Possible new effort related to Dredging Operations and Environmental
Research (DOER) Program.
Data Needs
•
Land
-
Use data
•
Best Management Practices
•
Non
-
federal maintenance dredging information
•
Water quality data
•
Top of bank surveys
•
Aerial photographs
•
Historical information related to erosion and
sedimentation
Summary
•
Upstream sediment issues are known in part
and are significant.
•
Downstream sediment issues are known in part.
Are they significant?
•
Linkage between upstream and downstream
issues exists, but is it understood?
•
What kind of information will resolve the
unknowns?
•
Will regional management/collaboration address
issues better?
Questions/Discussion
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