THE COMPATIBILITY BETWEEN ENVIRONMENT AND NAVIGATION IN THE ACF BASIN

THE COMPATIBILITY BETWEEN FLOWS FOR ENVIRONMENT AND NAVIGATION IN THE ACF BASINSteve Leitman2011 Alabama Water Resources ConferenceFunded under a USDA Rural Development Grant.

Steve Leitman, Apalachicola Riverkeepers

Charles Stover and Stacey Graham, Alabama Power

Information in this presentation represents only my views.For the past several decades, navigation and environment interests in the Apalachicola-Chattahoochee-Flint (ACF) basin have had what can only be called a contentious relationship.One of the major causes of this conflict has been the expectations of navigation interests from the project: a reliable, year-round channel at the design flow of 9,300 cfs.

When the channel was first developed that it was believed that :

1) the 95% exceeded flow was at least 9,300 cfs

2) that a 9-foot channel could be provide at this flow after the channel was maintained.The 9,300 cfs design flow has not been available 95% of the time.

Observed flow available 95% of the time from 1922 to 2011 for the Apalachicola River at Chattahoochee was 6,580 cfs.

Frequency of the availability of the 9,300 cfs flow was about 85%.In addition, the flow needed to provide a 9-foot channel has exceeded the 9,300 cfs design flow.

Estimates by the Corps of Engineers of how much water was needed to provide the 9-foot channel when the channel was being maintained ranged from 13,000 cfs to 16,000 cfs since the 1970s.In summation, there was no way that the ACF navigation channel could have been available 95% of the time and navigation interests were left with unreal expectations from the project. Ultimately, Florida denied water quality certification to maintain the Apalachicola Rivers navigation project.

Corps stopped making releases to support the navigation channel.

Situation best described as a lose-lose solution.At the base of our current project is a mutually held belief that the problem has been with how the navigation project was approached, not that navigation and the environment are mutually incompatible. In spite of this long history of confrontation, navigation interests and environmental interests do have a common interest in the Apalachicola River:

They both want more water coming down the river.In our project we are exploring how much overlap there is between the water that navigation interests want and the water that environmental interests want. Can the lose-lose situation be changed to a win-win situation?To accomplish this task there are several critical questions which need to be addressed:

1) What are the interests of navigation and environmental stakeholders in the ACF basin? Navigation interests want to have the 9-foot channel available as many consecutive days each year as possible without either causing significant environmental damage or impacts to other users of the federal storage reservoirs.Environmental interests in turn simply want to see the aquatic ecosystems sustained or enhanced in the future.2) What are realistic expectations from the ACF system in terms of reliability of the navigation project?AVAILABILITY OF THE NINE-FOOT NAVIGATION AT VARYING LEVELS OF FLOW NEEDED TO PROVIDE THENINE-FOOT CHANNEL

3. Where is the common ground between environmental and navigation interests in the ACF basin?Dredging can increase the availability of the navigation. HEC-RAS analyses show that without dredging the 9-foot channel can be provided at 21,000 cfs, whereas with 250,000 cubic yards of dredging it would take 14,000 cfs to provide a 9-foot channel.

There are multiple, perhaps too many, ways to represent the relationship between flow and the aquatic ecosystem. One way is to evaluate the extent of floodplain inundation.

PERCENT OF TIME 15,000 cfs EXCEEDED UNDER REVISED RELEASE RULES3) What are the possible areas of conflict between navigation and environmental interests?One issue which needs to be balanced is the fact that environmental interests want as little dredging as possible (some say none) but an increase in the frequency of mid-range flows (15,000 to 21,000 cfs) while navigation interests want the channel available as much as possible and would prefer the 14,000 cfs option with 250,000 cubic yards of dredging.Is there a common ground solution that allows for reduced dredging, reduced impact on reservoirs, yet increased inundation of the floodplain?4) What are the limits of the system to support navigation and environmental interests mutual flow needs in the Apalachicola River?

MEDIAN ELEVATIONS AT LAKE LANIER

90% EXCEEDED ELEVATIONS AT LAKE LANIERWe are at the stage of writing up our material and will have a report available this fall.