I received this email from Save our Lakes Now explaining (in basic terms) how lake levels are managed on Lake Hartwell and Lake Thurmond and the Savannah River Basin. If you own or are planning to buy Lake Hartwell Real Estate, the article below can shed some light on lake level management and what options are being presented to the US Army Corps of Engineers. In my opinion, they really make sense.
Where we are on Lake Thurmond and Hartwell Levels:
How we got here and How we can avoid in the future.
It's been sometime since we discussed the essential elements of avoiding low lake levels in Lake Hartwell and Lake Thurmond. A lot of you have been with us from the start but there are many who are just now getting into the fray and there is a good bit of confusion over why we are seeing these huge drops in lake level. The purpose of this blog posting is to go back over the basic elements of the problem and how it can be improved.
First, many at Lake Hartwell wonder why all they hear about is release rates from Lake Thurmond. They naturally wonder why we aren't concerned about release rates from Lake Hartwell. The reason for this is that both Hartwell and Thurmond are kept in balance such that Hartwell drops 1ft for every 1ft drop in Thurmond. The only difference between Thurmond and Hartwell is that Thurmond is where the water is ultimately released and the release rates at Thurmond control the levels for both lakes.
Going back to basics, the thinking that the dams along the Savannah River do nothing but cause problems for people downstream is incorrect. Just the opposite is true. The dams in the Savannah River Basin actually have made major improvements for the river downstream of Lake Thurmond. First the dams prevent the destructive flooding that used to occur during periods of heavy rain. Second the dams have completely eliminated the severe droughts that used to occur in the river during times of drought. Before the dams were constructed river flows as low as 500cfs could occur in a severe drought. Now the river never experiences flows of less than 3600cfs even in the droughts of record.
Continuing with basics, the average amount of rain that comes into the basin upstream of Lake Thurmond during droughts of record is 3,600cfs. And the basis for pollution release limits along the river is 3,600cfs releases from Thurmond Dam. And during the drought of record in 2008 the releases from Lake Thurmond were held at 3600cfs for over 18 consecutive months with no reports of problems from downstream stakeholders. Hence Save Our Lakes Now and other lake stakeholder groups have recommended that the Corps drop immediately to a release rate of 3600cfs anytime the lakes drop 2ft below full pool. Following this approach we should not experience drops of 16ft and more like we did in previous droughts of record. The Corps now is using a release rate of 3800cfs which sounds similar but the problem is they started way later than when the lakes were down 2ft and 3800cfs vs 3600cfs results in an additional 2ft drop each year.
In the past numerous excuses and or reasons have been used to justify refusal to go to 3600cfs at the start of a drought. Investigation into each one revealed that these reasons were not founded on good science. For the sake of brevity I will hold off on going into each and every one but let me give the example of power generation and oxygen levels in the harbor. Initially the Corps claimed their power contracts with SEPA prevented them curtailing releases to the rates we were recommending. Save Our Lake Now discussed this with officials from SEPA and discovered that they prefer the lakes be kept as full as possible because they depend on us for peaking power rather than long term total watts generated. The worst thing that could happen for them is to need peaking power and the lakes be so low it can not be provided. Failure to meet planned power totals are easily made up by rebalancing power from the other 7 lakes in our grid. And so far as dissolved oxygen in the harbor, fears that lowered releases from Thurmond might decrease already poor oxygen levels in the harbor are unfounded. However in fact the tide from the Atlantic Ocean is so much larger than our river flows that the oxygen levels in the harbor are determined by the ocean rather than our release rates.
Let me summarize what we would like the Corps to do. Following these recommendations we should never reach the levels we are at now regardless of how long a drought lasts. We ask that they respond to any unexplained drop of 2ft in lake levels with an immediate drop in release rates from Thurmond dam to 3600cfs. Further we recommend that during the winter months when that rate can be reduced further without detriment that the release rates be dropped to 3100cfs. And finally, when the river is swollen from heavy rains during periods of severe drought that releases from Thurmond Dam be reduced to zero as long as the river remains swollen.
Responses to incorrect thinking:
Wrong- lake stake holders are just selfish and want more than their share of the water.
Right- the Corps is sending more water downstream during a drought than nature is providing by rain hence river stake holders are receiving more than their fair share of the water.
Wrong- dropping release rates to 3600cfs too soon would result in people downstream suffering unecessarily.
Right- if release rates are dropped to 3600cfs because of a 2ft drop and we are not really in a drought the lakes will refill quickly and normal releases resumed.
Wrong- dropping release rates to 3600cfs is inconsiderate of environmental protection
Right- if the dams were kept full at all times the environment would experience exactly the same river flows it did before constructing the dams. 3600cfs already is a huge benefit to environmental protection by preventing the river from ever experiencing severe droughts again.
Wrong- flows in excess of 3600cfs should be used to keep the river as healthy as possible
Right- since we can not make water out of thin air, flows greater than we are receiving from rain could easily destroy the system. By averaging the rainfall over a years time we are already providing maximum possible benefits to the river.