I thought it would be beneficial to put what we've learned in one place so anyone trying to catch up to date will have one site where they can get the facts quickly. Our findings are based on Corps of Engineers data during one of the worst droughts of record and the comments solicited by the Corps from all lake and downstream stakeholders as the drought progressed. This information was gathered during the drought of 2008 with releases from Thurmond held to 3,600 cfs for the full 12 months of that year.
First and most important the data show that the average rainfall over a 12month period of time during the droughts of worst record is 3,600cfs. Because of this release rates from Thurmond of 3600cfs will keep the lake in balance over the course of a year. Lake Thurmond will drop in level during the dry months but return to full pool during the periods of higher rainfall. If we had started the year with the lake at 328ft the minimum level would have been in excess of 322ft and the economic disaster to lake interests would have been avoided. Not only would this benefit lake interest economics but avoiding drastic drops in lake level protects against losing predictable river flows. Based on this we have requested that the Corps modify the drought plan as follows:
o To minimize the overall drop in lake level during times of drought initiate a release rate of 3600cfs anytime the lake drops below 328'.
o Maintain the 3600cfs flow rate until the lake returns to full pool (330').
o During the cooler weather months of October through March, we recommend a release rate of 3100cfs to further minimize level fluctuations.
Second we learned that there are additional knobs that can be turned during a drought to further minimize level fluctuations.
o Flow and stream level information is available to the dam operators. If stream flows to the river were used as the criteria on what releases are needed from the dam there were many times in 2008 when dam releases could have been throttled below 3600cfs without any harm downstream.
o Environmental interests currently require a minimum flow across the rapids at Augusta and this flow is the difference between what is released from the dam and what flows through the Augusta Canal. Hence lower flows through the Augusta Canal would permit lower release rates at the dam anytime the rapids are the pinch point in flow needed.
If these findings would be incorporated into the Corps' drought management plan we could eliminate future economic disasters like those that have occured repeatedly since 1985 during Savannah River Basin droughts. The Corps states that they are not responsible for economics but this is in direct contradiction to 1993 court decisions arising from major droughts along the Missouri River. Furthermore the recommended changes to the drought plan offer as much benefit to downstream interests as they do to lake interests. At one point in the drought of 2008 we almost lost the ability to manage release rates. We came close to reaching levels where the drought plan calls for releases equal to what is coming in from rain. Such release rates could be as low as 500cfs which would be very destructive downstream of Thurmond Dam.
Further improvements beyond those from our recommendations above could come from developing models of the Savannah River Basin which predict lake levels, river flows, etc. from all the variables mother nature can throw at us. I understand that such a model may already exist. One study that would be illuminating would be to look at what happens if you keep Lake Hartwell full at times of drought. At first glance this looks bad because Thurmond levels would drop faster due to less input. But it may well be that more rapid refilling of Thurmond when rains occur could offset this negative.
What is desperately needed is input to the Corps' on drought management from lake interests. Comments such as "we can't factor in economics" should no longer be tolerated. At present the Corps has no legitimate representation of lake interests in their decision making meetings. They quote what the NOAA, DNR, DHEC etc. want but they do not incorporate inputs from lake interests such as Save Our Lakes Now which is a 501c3 non profit organization representing Lake Thurmond interests or the Lake Hartwell Association which represents Lake Hartwell interests. What would also be excellent is to incorporate the model of the Savannah Basin assuming it exists into decision making. Excuses such as we need more study are out of line. Throwing money at a problem that can already be solved is not what we need.
