Sediment Challenges in the

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