AN EVALUATION OF THE COMPATIBILITY BETWEEN NAVIGATION AND

ENVIRONMENTAL RELEASES FROM THE ACF RESERVOIR SYSTEM

#

#

#

#

Flint River

# Apalachicola River

Atlanta

Albany

Columbus

Gulf of Mexico

AtlanticOcean

#

Chattahoochee River

ELEVATIONIN FEET

1200

1000

800

600

400

200

0

400

200

0JIM WOODRUFF L&D

APALACHICOLA RIVER

MILES

PROFILEPROFILEAPALACHICOLA APALACHICOLA

AND AND CHATTAHOOCHEE RIVERSCHATTAHOOCHEE RIVERS

Head of NavigationHead of Navigation

BUFORD DAM (Lake Sidney Lanier)

CHATTAHOOCHEE RIVER

WEST POINT LAKE

WALTER F. GEORGE L&D

GEORGE W. ANDREWS L&D

Atlanta, GA

Columbus, GA

A big river system with limited reservoir control

State of the SystemMay 2011

• Compacts expired 2004• IOP 2007 – ESA• Drought of 2007-2008• RIOP 2008• Magnuson decisions 2010• 11th circuit appeal 2011• Draft basin manuals - 2011• On/off state negotiations• ACF Stakeholders groups

State of the RiverMay 2011

• Navigation dead in the water

while• Water use continues to

grow despite legal uncertainty

• Lack of flow targets in the mid-Chattahoochee

• Angst of both lake users and oyster men

Frustrated ?

How do we get out of this?

RELATIONSHIP BETWEEN FLOW AND CHANNEL AVAILABILITY

25 Exceeded Median

75 Exceeded 90 Exceeded

Outflow at Jim Woodruff varying water flow levels with and without navigation releases

HEC RAS

Channel Model

New Soundings

Mile 39

Conversion from HEC2

Channel Description

No Dredging

• 7’ – 17,000 cfs• 9’ – 21,000 cfs

Reference Dredging250,000 yards

• 7’ – 10,000 cfs• 9’ – 14,000 cfs

With about 250,000 cubic yards of dredging a 9-foot channel could be provided with 14,000 cfs flow and a 7-foot channel with 10,000 cfs flow.

Flow Augmentation Plan

• In our re-coding of the RIOP release logic in the models we included a provision of where a release is made when the 7-day basin inflow was a specified amount (x) below the required flow to provide a navigation channel.

• To evaluate augmentation levels multiple model runs were done at varying levels of augmentation and for varying navigation scenarios depending on the level of dredging needed to provide the channel.

How It Works

Flow for a given channel depth

Levels of augmentation

Threshold flow

7 day basin inflow

RIOP

The RIOP operations were designed to provide for the flow needs of federally listed species (sturgeon and mussels)

Months Composite Storage Zone

Basin Inflow (BI) (cfs) Releases from Woodruff Dam (cfs)

Basin Inflow Available for Storage

March - May Zones 1 and 2 >= 34,000 >= 25,000 Up to 100% BI > 25,000

>= 16,000 and < 34,000 >= 16,000 + 50% BI > 16,000

Up to 50% BI > 16,000

>= 5,000 and < 16,000 >= BI < 5,000 >= 5,000 Zone 3 >= 39,000 >= 25,000 Up to 100% BI >

25,000 >= 11,000 and < 39,000 >= 11,000 + 50% BI

> 11,000 Up to 50% BI > 11,000

>= 5,000 and < 11,000 >= BI < 5,000 >= 5,000 June - November

Zones 1,2, and 3

>= 24,000

>= 16,000 Up to 100% BI > 16,000

>= 8,000 and < 24,000 >= 8,000 + 50% BI > 8,000

Up to 50% BI > 8,000

>= 5,000 and < 8,000 >= BI < 5,000 >= 5,000

December - February

Zones 1,2, and 3

>= 5,000

>= 5,000 (Store all BI > 5,000)

Up to 100% BI > 5,000

< 5,000 >= 5,000 At all times Zone 4 not applicable >= 5,000 Up to 100% BI >

5,000 At all times Drought Zone not applicable >= 4,500 Up to 100% BI >

4,500

RIOP

ResSim and Stella Calibration

• Flows and elevations throughout the basin

Sensitivity Analyses

• Demands (current to 50% increase)• Augmentation Thresholds (1,000 to 10,000 cfs)• Navigation flows for different channels (9-FOOT

FLOW 14,000 – 21,000 cfs)• Columbus target (active vs. inactive)

Used Stella for making large number of runs required for ranges of alternatives because of its quick run-time.

Navigation Patterns

• Navigation Season January – May

• Low flow period June to November– Much lower availability– Regularity of shipping service a major concern

Navigation Performance Measures

• Percentage availability by month• Consecutive days with a channel• Consecutive days without a channel

• 7 and 9 foot channels• Dredging and without dredging

Availability of a 9-foot channel

Availability of a 7-foot channel

Mid – Chattahoochee Minimum Flows

• Columbus– Continuous 850– Daily 1,350– Weekly 1,850

• Columbia– 2,000

• Woodruff– 5,000

Mid-Chatt. Flow

• No set augmentation in the RIOP mode

• Set daily target

J an Mar May Jul Sep Nov Jan2007

Flow

(cfs

)

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

Columbus

RIOP Baseline 1350 Target

Lake Lanier

RIOP – No Withdrawals

RIOP - + Navigation

RIOP - + 50% Increase Demands

Just the Highlights

Report to follow