AN EVALUATION OF THE COMPATIBILITY BETWEEN NAVIGATION AND ENVIRONMENTAL RELEASES FROM THE ACF RESERVOIR SYSTEM

ELEVATION IN FEET JIM WOODRUFF L&D APALACHICOLA RIVER MILESPROFILEAPALACHICOLAAND CHATTAHOOCHEE RIVERS Head of Navigation Head 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 System May 2011 Compacts expired 2004 IOP 2007 – ESA Drought of RIOP 2008 Magnuson decisions th circuit appeal 2011 Draft basin manuals On/off state negotiations ACF Stakeholders groups

State of the River May 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 Exceeded90 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 Dredging 250,000 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)

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

Lake Lanier RIOP – No Withdrawals RIOP - + Navigation RIOP % Increase Demands

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