By Billy Birdwell, Senior Public Affairs Specialist
As the Savannah District continues designing and planning the Savannah Harbor Expansion Project (SHEP), some residents near the Corps reservoirs express concern the proposed deepening could increase downstream outflows.
Let me state the simple answer up front: The proposed deepening of the Savannah harbor will have no impact on outflows from the reservoir system. None.
The original legislation authorizing construction of dams on the Savannah River cited navigation as a purpose for building the dams. At the time that included the Savannah harbor and barge traffic on the river. Commercial traffic upstream of the Savannah Harbor ended in 1979 although an occasional barge will take something extraordinary upstream when other transportation modes are more difficult.
Today, supporting downstream navigation means keeping enough clean, fresh water in the Savannah harbor to maintain fish and other aquatic species particularly during routine maintenance dredging that keeps the channel and harbor open to commercial traffic. The harbor itself will always have sufficient volumes of water to float commercial shipping since the harbor is subject to ocean tides.
Keeping enough oxygen in the harbor without increasing reservoir discharges posed a challenge to SHEP planners. In studies leading up to the recommendation to deepen the harbor, they searched for ways to maintain adequate dissolved oxygen using the current water manual for the reservoirs. Planners determined oxygen could be injected into the river above and around the harbor to maintain current conditions. This proven method could be controlled with more precision than sending water downstream and could also react more quickly to changing conditions. It also protected the reservoirs. You can learn more about SHEP from our web pages by clicking here.
SHEP will impact the area around the New Savannah Bluff Lock & Dam. In order to reopen traditional habitat for sturgeon and other species, plans call for a large fish passage around the lock and dam. But even this fish passage will have no impact on the reservoir levels or even the pool behind the lock and dam.
Water is precious and getting more precious. By using an oxygen injection system at the harbor we reap the benefits of increased transportation efficiencies of a deeper harbor while still following the existing outflow restrictions.
Thanks for updating us. Many Lake Hartwell stakeholders have been pushing for reduced outflows from the system. Does the SHEP reduce the chances that this will happen? Can the oxygen injection process be used to help justify reduced outflows from the system?
Tom: By congressional direction, the SHEP environmental mitigation cannot be designed to improve water quality in the Savannah harbor, but must maintain current conditions. Therefore, the proposed oxygen injection system will not lead to a reduction in outflows. The SHEP was designed to have no impact on reservoir outflows – either by increasing them or decreasing them. Besides, the proposed injection system, near the bottom of the basin, would have no impact on water quality upstream of the harbor.
Thanks for asking.
BILLY E. BIRDWELL
Senior Public Affairs Specialist
Corporate Communications Office
Very glad to hear that SHEP will not increase the chances of our Upstate Reservoirs functioning as large mud holes any more often than they already do. Also gad to hear about the Oxygen Injection procedure to enhance water quality downstream….that could provide some solution to problems created by other issues, such as drought I suppose.
A couple of questions if I may……were the existing outflow restrictions altered when the newer reservoirs (Russell, Keowee, Jocassee and Bad Creek) were constructed? (they obviously help tremendously when it comes to flood event storage capacity)
Also, what period of time was used to determine the “average rainfall” data which is used to
guide the management of the reservoirs?
Thanks for commenting, Mark. I think in your first question you ask, “With the newer dams in place, do you really need the extra flood storage capacity you gain with the winter drawdown at Hartwell Lake and Thurmond Lake?”
I can only answer by saying “maybe, maybe not.” This is one of those topics we want to address in the Savannah River Basin Comprehensive Study (Comp Study). We realize weather patterns change over time. Designers used weather data they had dating from near the beginning of the 20th century to the late 1940s to create the dams a generation ago. These patterns may or may not have changed significantly (meaning “scientifically significant”) since the dams opened. The weather patterns may or may not change again before we complete the Comp Study.
We completed the initial study for the Comp Study and recently received permission to add The Nature Conservancy as another non-federal sponsor. Georgia and South Carolina are the other two non-federal sponsors. We hope to announce soon the beginning of the next interim study of the Comp Study.
Once scientists and engineers complete the full Comp Study we will have the data we need to make recommendations to Congress concerning changes to the way we manage the Savannah River basin. Until we have this data and can make the recommendations, we must follow the plans we have in place since we already know their impacts.
BILLY E. BIRDWELL
Senior Public Affairs Specialist
Corporate Communications Office
Savannah District, US Army Corps of Engineers
Thanks for your informative article. You have stated that oxygen content will be corrected but what about the salinity of the water in the harbor? By taking dirt out of the harbor and not increasing flows, sea water will replace the dirt as you state above. Are there any enviromental concerns about how salty the water in the harbor will be?
Your last paragraph about water being precious is the first time I have heard anyone from the Corp make that statement. If you truly mean what you say, then the next time the reservoirs are full like in 2011, please hold on to it as long as you can and do not open the generators wide open to 6500cfs while rainfall is not keeping up.
Thanks, Jimmy. Your questions gave us another opportunity to highlight the Savannah Harbor Expansion Project (SHEP). The SHEP will allow larger, more efficient ships to call on the port. We estimate the SHEP will net $174 million a year averaged over the project’s lifetime. Environmental mitigation is a large portion of the project’s expected costs.
The full answers to your salinity questions are much too long to include in this blog post, but we anticipated the effects of increased salinity and have planned some features to mitigate for it. Briefly stated, deepening the harbor will convert some fresh water marsh to brackish marsh. Plus under certain conditions of high tides and low river flows, chlorides threaten to reach the intakes of the City of Savannah water supply. We have plans to mitigate for these impacts.
You can read more about it in the “
Thanks, Jimmy. Your questions gave us another opportunity to highlight the Savannah Harbor Expansion Project (SHEP). The SHEP will allow larger, more efficient ships to call on the port. We estimate the SHEP will net $174 million a year averaged over the project’s lifetime. Environmental mitigation is a large portion of the project’s expected costs.
The full answers to your salinity questions are much too long to include in this blog post, but we anticipated the effects of increased salinity and have planned some features to mitigate for it. Briefly stated, deepening the harbor will convert some fresh water marsh to brackish marsh. Plus under certain conditions of high tides and low river flows, chlorides threaten to reach the intakes of the City of Savannah water supply. We have plans to mitigate for these impacts.
You can read more about it in the “Frequently Asked Questions” () section of the SHEP web site (). Scroll to FAQs 18, 20, 21, 22, and 23 where we discuss the topic. We also have the full, detailed reports online on the SHEP site. Be warned, however, the full reports, printed on two sides, placed in three-ring binders, and stacked, will reach nearly 13 feet high. (We measured it.)
I think you will find the answers you seek in the FAQs.
BILLY E. BIRDWELL
Senior Public Affairs Specialist
Corporate Communications Office
Savannah District, US Army Corps of Engineers
I believe that you have enough paperwork thru studies to mitigate the salinity issue. What I have a problem with is that salininity is one of the major issues listed in the reasons why lower flow rates weren’t approved in the recent request. In fact, it is one of the few issues listed that didn’t have a “may” or “might” in the listed reasons. So the question is, was the salinity issue a valid reason why the request was denied?
Also, economic reasons is not on the list of managing water but here again, downstream economic interest seem to be important while upstream economic impacts are ignored.