Coosa Basin Flood Control

1
Coosa Basin Flood Control

• Changes Submitted as Part of Relicensing Project
  2146

2
ACT Basin
Carters
Allatoona
3
Opportunities for Change

• Decades of operating history
• Changes in reservoir use
• FEMA flood mapping
• Comprehensive Study/Compacts
• Relicensing

4
How the Study Was Done

• Data from historical floods
• River cross sections
• ACT surface water database / Flood Frequency
  Analysis models
• Developed 100 year recurrence flows
• Developed new regulation procedures
• HEC-RAS unsteady flow models
• Coordination with USGS, OWR, COE

5
Flood Frequency Analysis

• Allatoona
• Carters
• Rome
• Weiss
• H Neely Henry
• Logan Martin
• Lay
• Mitchell
• Jordan
• Montgomery

6
Raise Winter Elevations

• Weiss 558 to 561

• Logan Martin 460 to 462

7
Flood Elevations
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Conclusions

• 4420 acres less flooding in 100 year event
• Winter levels raised
• Coordination planned with OWR to use findings
  from flood study for FEMA mapping

9
Operations
10
ACT/ACF Dispute

• 1990 lawsuit Alabama vs COE
• 1991 1998 Comprehensive Study
• 1998 2003/4 Compacts
• 2004 lawsuit Alabama Florida vs COE and
  Georgia
• September 2004 - Judge Bowdre added Atlanta
  Regional Commission and others
• December APC, Montgomery filed to join suit on
  side of Alabama.

11
Problem

• Corps would not finalize review and comment on
  flood study
• Corps will not participate in joint EA with FERC