A CHEMICAL ENGINEER LOOKS AT MANAGEMENT OF LAKE THURMOND

Managing complex water systems from raw sewage to waters heavily contaminated with nuclear waste is routine for Chemical Engineers.  Both the many years of education they receive on such matters and their experience from decades of handling these issues in real life fully equip them for handling something as mundane as managing the Savannah River system.  We have interviewed one of the Chemical Engineers in our group who is very familiar with the Savannah River Basin about how he feels the basin should be managed, especially with respect to release rates and level control during major droughts.

His first step was to list the various issues that the Corps has to deal with along these lines and prioritize each consideration.  Here is his list of priorities:

1. Fresh water is one of the most valuable commodities on earth and maximizing the amount of fresh water in the system at all times should be top priority
2. Quality of water for human consumption comes second
3. Environmental concerns come next
4. Economic impact on the lakes and surrounding communities comes next
5. Impact on the various production facilities along the river that use water to dilute their waste comes next
6. Impact on power production comes next
7. Impact on oxygen levels in the harbor comes next

And so on with any other concerns people have along the basin.

Looking at priority one, this demands the lakes be kept as full as possible because all the water released from the lakes becomes salt water as it reaches the harbor. This then dictates that release rates should be reduced as much as possible during a drought to preserve the fresh water in the system.

 Looking at priority two, past experience has shown water quality to be satisfactory with release rates as low as 3600cfs from Thurmond.  Hence in the event of a drought it is recommended the release rate from Thurmond be dropped to at least 3600cfs when lake levels start dropping to maintain as much fresh water in the system as possible.

Environmental concerns are a little less obvious.  Depending on who is dictating what the concerns should be and how reasonable they are this can vary over a very wide range.  Again, it has been demonstrated that even the most extreme environmental concerns can be met with release rates as low as 3600cfs when the lake levels start dropping.  And here again priority 1 dictates that this should be done.

Economic impact on the lakes and surrounding communities becomes severe when the lakes drop more than 8’ from full pool.  Experience from the droughts over the last decade show the lake levels will not drop more than 8’ if release rates are dropped to 3600cfs when the lake levels start down.

Economic impact on downstream commercial operations is a sleeping giant.  As every chemical engineer knows the quantity of waste being released is a function of how much you want to clean the water before it is released to the river.  Any challenges here should be met with tighter release limits, not increased river flows.  Hence here again 3600cfs makes sense.  Even lower release rates are possible if tighter controls are set on production releases.

The impact on power production is almost not worth our consideration.  To destroy good fresh water just to save a few cents off our power bills is foolhardy.  Besides it can be argued that this is purely an economic consideration since power can be obtained elsewhere when we are in a drought.  As an economic concern, the cost to the recreational infrastructure around the lakes from low lake levels far exceeds any savings in power costs.

Impact on oxygen levels in the harbor is no match for priority one.  First the water from Thurmond dam is pristine as it comes from the dam having gone through the vast settling basin our lakes present.  Second the water from Thurmond dam is fully oxygenated (100% saturated with oxygen) after it crosses the rapids north of Augusta.  Besides the only impact flows from Thurmond dam have on oxygen levels is the fact that they dilute production wastes. And as noted previously this is best controlled by the release standards for the various production facilities along the river.  And one other factor making our release rates inconsequential to the oxygen levels in the harbor is that the tide contributes 10 times the water to the harbor that the river does.  Hence oxygen levels in the harbor are controlled primarily by the ocean rather than the river.

 

Jon Clerry, spokesman for Save Our Lakes Now