Sediment Challenges in the

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21 févr. 2014 (il y a 2 années et 9 mois)

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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