LAKE LEVEL CONTROL 101

The current situation we find ourselves in at Lake Thurmond and Lake Hartwell provides an excellent example of how to balance the Savannah River Basin. 

 

What if we used the same method of control in flood stage that the Corps is using in drought stage.  If we did, release rates would be based totally on some feel good number for river flows. 

·         For example lets imagine that the NOAA asks that the river flows be held at 4,200cfs maximum until the lakes reach 5’ above full pool.  They could do so out of concern for critters in the river that will die because of high river flows and/or flooding downstream. 

·         If that were the basis the lakes could easily climb to levels that are hazardous from the standpoint of flooding and we would be in a massive problem both upstream and downstream.

This scenario is ridiculous and the Corps would quickly take the bull by the horns and explain to NOAA that meeting their request is simply not feasible.  That is what managers do.

 

Whether you are in a drought or in flood stage, the only reasonable method of control is to use lake levels as the basis for control rather than release rates. Holding lake levels to a maximum of 5’ above full pool in flood stage is no different than holding lake levels within 5’ of full pool in a drought.   The difference in what the Corps does in a drought is they control by release rates rather than holding lake level within a reasonable range.  Just as there is a maximum reasonable release rate based on downstream flooding there is a minimum reasonable release rate based on experiences downstream in past droughts.  Right now that lower limit is 3600cfs based on the experience gained in the drought of 2008.  In flood stage, everyone will agree that at 2’ above full pool lake levels should take precedence over release rates.  In drought stage the Corps needs to recognize 2’ below full pool is the point where lake levels take precedence over release rates. 

 

Lest anyone think lake levels are not a proper concern for the Corps, Congress added recreation and protecting fish and wildlife to the list of responsibilities in managing our lakes in 1988.  Recreation consists of the infrastructure required for recreation on the lakes not whether someone can fish a given spot on the lake or river.  That infrastructure includes the marinas, campgrounds, support businesses such as dock building, and all the real estate developed to provide access to the lakes. 

 

Looking at the full list of responsibilities the Corps has in managing our lakes, holding to reasonable minimums or maximums in release rates provides the protection needed for flood control, water supply/quality and fish and wildlife. Recreation is protected by keeping lake levels within 8 ft of full pool.  Power production is simply a goal the Corps has with SEPA.  Falling short of the power production goal from too low a release rate is simply an economic consideration.   Any deficiency in power production at the dams can be corrected by purchase of power off site.  The money involved in purchasing make up power is dwarfed by the destruction to the value of recreational infrastructure from excessive loss of lake level so recreation trumps power anytime the two are in competition.

 

Jerry Clontz, spokesman for Save Our Lakes Now

 

TEST OF CORPS' INTENTIONS TOWARD PROTECTING RECREATION HAS BEGUN

We wrote in our blog on May 25th, "TIME TO CORRECT DROUGHT PLAN IS NOW,  NOT AFTER THE LAKES HAVE DROPPED".  Apparently this fell on deaf ears because the current issue of Balancing the Basin indicates no intention of changing from past practices.  They project the lakes will drop 3.5 ft by mid August with no requirement to modify release rates until the lakes drop more than 4'.

As we've discussed many times a 4' drop in lake level before decreasing release rates causes destruction of recreation.  From that point the lake will drop more than 10' in a severe drought even if minimum release rates are initiated.  Following is a repeat of our recommendations for protecting recreation along with all the other concerns the Corps is supposed to be protecting for the Savannah River Basin.

1.  Maintain lake levels at full pool as long as this can be done without dropping release rates below 3600cfs.  In other words balance input and output in such a fashion that the lakes stay full rather than allowing the lakes to drop several feet before becoming concerned about lake levels.
2.  Once the lakes drop more than 2’ with a release rate of 3600cfs, maintain 3600cfs (3100 in winter months) until the lakes return to full pool.
3.  Anytime the lakes are down more than 2’ and the river is swollen from heavy rains, shut off flows from the dams until the river flows return to normal.  This will help minimize the amount of time reduced release rates are needed.

As noted before, all this would be a natural happening if the Corps followed the same logic Duke Power uses on Lake Keowee.  There the drought plan is based on never dropping the lakes more than 10' even in a severe drought.  They accomplish this by using the data gathered from the droughts of record to design their release rates.  Why we can't get the Corps to uphold their responsibility to protect recreation along with all their other concerns remains a mystery.

WHICH IS IT? DOES THE CORPS CONSIDER ECONOMICS IN SETTING RELEASE RATES OR NOT?

Repeatedly we have asked the Corps to decrease release rates because of the huge impact low lake levels have on the recreation infrastructure around the lakes.  By recreation infrastructure we mean real estate built for lake access and lake view, campgrounds, marinas, and all the many investments related to recreation around the lakes.  Each time the Corps has assured us they are not permitted to consider economics when determining release rates.

 

Now, in the most recent issue of balancing the basin, Billy Birdwell explains that the Corps is now able to hold a 3800cfs release rate because they have met their power quotas with SEPA.  The only reason power quotas are important is that power purchased to replace hydro power shortages costs more than hydropower produced by our lakes.  I may be confused but it seems to me that cost of power is nothing more than an economic consideration.  Surely I must be mistaken because the cost of monetary losses to recreational infrastructure from low lake levels dwarfs the added cost of power.  Matter of fact the total value of power produced on all three of our lakes is peanuts compared to the economic losses from low lake levels exceeding a drop of 10’.

 

What I see happening violates good engineering principles.  Good engineering means to use the information at hand to the full extent possible to perform a task such as managing our basins rather than wait for a perfect solution based on endless studies. The data from all the droughts of the past decade is more than sufficient to avoid drops in lake level in excess of 8-10’ while avoiding problems to downstream interests.  Instead the Corps makes endless excuses to avoid the changes needed.  While you can always learn more from further studies, there is no need to wait for these studies before making changes that will prevent the devastation we keep experiencing every time a drought occurs.  Save Our Lakes Now has outlined a sound approach to drought control in our previous blogs but to date there is no evidence that the Corps plans to incorporate these changes.

 

I ask again is Save Our Lakes Now the only organization concerned about this and other inconsistencies in the way the Corps is controlling our lakes.  Where are our congressmen and the other lake organizations when it comes to getting the Corps to optimize the drought plan for the Savannah River Basin.

LAST MINUTE REPRIEVE

Almost as if we caused it the projected release rates for Lake Thurmond have been throttled back to hold at 3800cfs on into June with the lake reaching almost full pool by June 7.  We don't know who is responsible but whoever it is, Col. Hall or someone else, we thank them.

WHO'S GONNA STOP THIS MADNESS

We need a champion to step forward and stop this madness of the Corps continually destroying recreation on our lakes.  The lake level is headed straight down and the Corps is increasing release rates.  The common sense thing to do would be for the Corps to hold off on increasing release rates and hold the lake levels as long as possible.   And we desperately need for the Corps to modify their drought plan along the lines of Save Our Lake’s proposals published on www.lakethurmondlevel.blogspot.com a few days ago. 

 

None of these is happening.  Why am I the only one upset about this?  Why are our congressmen not coming to our aide?  Why are the other lake groups silent on this?  Where are our champions who are going to get this madness stopped?

 

Jerry Clontz, spokesman for Save Our Lakes Now

THE TIME TO CORRECT DROUGHT PLAN IS NOW, NOT AFTER THE LAKES HAVE DROPPED

It is obvious that our current drought plans do not provide true balance for the Savannah River Basin.  Simple logic says the act of sending more water downstream than nature provides in rain is unbalanced.  And recent history shows repeated destruction to the recreational infrastructure around the lakes (marinas, campgrounds, houses built for recreation at the lake, dock builders, restaurants along the lake, etc.; not whether you can fish a given spot) with no similar destruction to downstream interests. 

 

Right now before the lakes begin to drop is a crucial time for achieving true balance of all the needs of the Savannah River Basin.  If you wait until the lakes begin to drop before you start corrections you lose balance.  First and foremost true balance requires that you factor in all the engineering knowledge you have about the system.  Following is a list of what we know from operations in past droughts:

 

·         The amount of rain over a year in the droughts between the year 2000 and 2010 was equivalent to 3600cfs inflow to Lake Thurmond.  Hence, in a drought matching those, you have to decrease releases to 3600cfs or you will lose continuity of lake levels.

·         Surveys of downstream interests in the drought of 2008 (all stakeholders were asked to comment on whether they could survive releases as low as 3100cfs) showed no significant impact from 3600cfs.  The only derogatory comments about 3600cfs came from NOAA and those comments were simply statements of concern over what might happen.  Since flows can be increased immediately if any of the possible concerns become real, there is no need to destroy recreation over something that might happen.

·         Recreation infrastructure is severely impacted when lake levels drop more than 10’.  Based on the droughts between 2000 and 2010, reducing releases to 3600cfs at the onset of a drought will prevent lake level drops of more than 10’.

·         The Army Corps of Engineers can control lake levels to within a fraction of a foot on a month to month basis using their hydrology models and knowledge and data on rain inputs.

·         Fears of low river flows impacting dissolved oxygen levels in the Savannah Harbor are unfounded.  Both measurements of dissolved oxygen at Clyo and the fact that ocean tides are 10x the input from the river say that dropping releases to 3600cfs is not harmful.

·         The critters in the river survived for thousands of years before the dams were built with river flows in severe droughts as low as 500cfs.  Additionally there are no endangered species threatened by releases of 3600cfs. 

·         The most important criteria for power production from our dams is peaking power.  As long as the lakes have plenty of water to permit power production during peak demand the other power needs for SEPA can be satisfied by purchases which are insignificant in cost compared to the cost to the recreational infrastructure when lake levels drop drastically.

·         Instrumentation at the dams shows the status of downstream flows permitting the Corps to safely stop releases when the river is flooded from rains.

·         Concern about unnecessary reduction in flows when we are not truly in a drought is unfounded.  Such reduction in flows will cause the lakes to refill quickly if we are not in a drought.

·         The time the river is at reduced flows will be minimized if we drop release rates at the beginning of a drought.  This is because it takes less time to refill the lakes when they contain more water at the end of the drought.

 

Factoring all these together yields a good engineering basis for developing a drought plan to protect all the various needs of the Savannah River Basin. This plan is different from the one currently in use by the Corps of Engineers because it corrects for low lake levels on day 1 of a drought rather than waiting until the lakes have already dropped several feet.  It should protect all aspects of the Savannah River Basin including the vast recreational infrastructure around the lakes.

 

1)      Maintain lake levels at full pool as long as this can be done without dropping release rates below 3600cfs.  In other words balance input and output in such a fashion that the lakes stay full rather than allowing the lakes to drop several feet before becoming concerned about lake levels.

2)      Once the lakes drop more than 2’ with a release rate of 3600cfs, maintain 3600cfs (3100 in winter months) until the lakes return to full pool.

3)      Anytime the lakes are down more than 2’ and the river is swollen from heavy rains, shut off flows from the dams until the river flows return to normal.  This will help minimize the amount of time reduced release rates are needed.

 

There is one further concern that needs to be addressed.  In the past the lakes were dropped 4’ after labor day. The reasoning is to provide better flood protection with heavy rains.  This was set up when Lake Thurmond was the only lake catching the runoff from the Savannah River Basin.  We now also have Lake Hartwell and Russell.  With the combination of all 3 lakes, 2’ drop should give the same protection as the 4’ drop used originally for Lake Thurmond.  Hence we recommend the Corps change the drop used after Labor Day  to  2’ instead of 4’.  During the months when the lakes are deliberately down 2’, releases should be 3600 anytime the level drops any significant amount.

ANSWER TO COLONEL'S ANSWER

The Corps has demonstrated time after time that they can balance lake levels to a high degree of accuracy.  In other words they have the engineering knowledge and models, etc. to permit them to do so.  Why then do they not follow the recommendations of Save Our Lakes Now which would keep the lakes within 8-10 ft of full pool while protecting downstream interests. Why have we destroyed the recreational infrastructure on the lakes 3 times in the past decade when we know how to prevent it. For example the Corps ignored the warnings of Save Our Lakes Now when the last drought started.  We pleaded for them to drop the release rate to 3600cfs but they argued that they did not want to cause any disruption to downstream flows until they were sure we were really in a drought.  We pointed out that if we were not in a true drought the lakes would refill quickly and normal releases could be resumed but they would not listen.

In his answer to one of our reader’s letters the Colonel claims immense difficulties with controlling the lakes in a drought.  However every reason given for the Corps not having latitude is now gone.  Yet they still refuse to adopt our proposals which simply achieve better balance by not sending more water to the ocean than nature provides averaged over the span of a year. 

For the record, our recommendation is to attempt to keep the lakes within 2’ of full pool by decreasing release rates to as low as 3600cfs.  Once the lakes drop more than 2’ below full pool using this approach, go to 3600cfs immediately until the lakes refill.  There are other ways refilling the lakes can be tweaked such as stopping all releases when the river below the dams is swollen from heavy rains and using 3100cfs rather than 3600 in cold months.  But first and foremost we need the release rates dropped to 3600 immediately when the lakes can no longer be held to within 2’ of full pool.

There is one other issue the corps failed to address in their answer.  We need for them to stop the practice of dropping the lakes 4’ in the winter months.  That was a provision in place to protect against flooding back when there was only one lake catching the runoff from winter and spring rains.  Now there are 3 lakes and a drop of 2’ provides the same margin of protection 4’ used to provide.