Understanding the revised interim operating plan
(Note: This is a guest post by Rich S.)
On June 2nd, the U.S. fish and wildlife service gave their blessing to the Corps of Engineers Revised Interim Operating Plan (PDF).
So for the foreseeable future, this plan defines how decisions will be made concerning water retention in the ACF system including Lake Lanier. This plan is a modification of the operating plan the corps has been using for the last several years. The modifications are intended to favor retention or storage in the reservoirs of the ACF above the old plan which clearly released too much water during the recent drought.
I was surprised to see that the plan doesn’t really address Lanier or any of the other lakes individually, but mainly addresses the release from Jim Woodruff dam because of course everything that isn’t released from that Dam is held in the five reservoirs of the ACF.
Decisions about how much water is to be released vs. stored are based on three factors: Composite action zone, season, and inflow.
The composite action zone is similar to the one you are likely familiar with from this lake Lanier forecast chart - http://water.sam.usace.army.mil/lanfc.htm
The composite chart adds the storage from all five reservoirs and treats it as a sum of the entire system. The action zones are similar with zone one being relatively good and zone four being very low water levels. They also added a fifth zone that they call the “drought zone”.
Release levels vary by three seasons: spawning season (March-May); non-spawning season (June-November); and winter (December-February). Regardless of the season, when the composite level reaches zone four, releases from Woodruff dam are reduced to 5000 cf/s. Any inflow above that level can be retained as storage. Likewise, when the composite level reaches the drought zone, releases are reduced to 4500 cf/s.
During the winter period, releases are reduced to 5000 cf/s regardless of the composite zone (except 4500 cf/s in the drought zone). All additional inflow is stored.
Aside from the above situations, releases from Woodruff dam are based on season, zone, and inflow with some portion of any inflow above 8000 cf/s retained for storage.
Compared to the old plan, this one lets us release a little less water when times are bad, and store a little more of the excess when times are good. It’s not going to solve all of our problems, but it may actually be sustainable over time, which the old plan clearly proved not to be.
Rich
Tags: army corps, lake lanier, operating plan, woodruff dam
June 11th, 2008 at 11:41 am
Excellent summary, Rich.
Even with these interim changes, however, the USACE policy regarding minimum flows in the Apalachicola River remains an incorrect and perverted interpretation of the Endangered Species Act.
The intention of the Endangered Species Act was to prevent federal agencies from altering the natural environment in such a way that endangered species were adversely affected. This USACE policy, however, turns the intention of the act upside-down by incorrectly assuming that the act requires the agency to actively alter the natural environment to save endangered species. Under a correct interpretation of the Endangered Species Act, during times of drought the USACE is obligated to maintain only those minimum Apalachicola River flows that would have naturally occurred if the Georgia dams did not exist.
In other news, Lanier’s year to date total inflow (through 6/10/08) is now the third lowest in Lanier history, having passed from fourth to third lowest on 6/4/08. If the Lanier basin doesn’t receive significant rains in the next two weeks, the total year to date inflow could well slip another notch to the second lowest in Lanier history. The drought continues…
– DSO –
June 11th, 2008 at 12:59 pm
Just to jump on the bandwagon, the total reseveroir(bad sp) volume for Lanier did not change from May 1 thru May 31, and the total height actually grew by 0.06 feet.
I’ve restarted the predictions spreadsheet I use as of June, since May was a wash (pun intended).
The first set of five days in a row of regular volume drops occurred in June, and the first five days in a row of regular height drops occurred in the end of May and start of June.
I think we may be surprised by how quickly Lanier drops this summer.
June 12th, 2008 at 5:56 am
BGGGAAWWWKKKK
WHEN DO I GET A GUEST POST?
June 12th, 2008 at 7:03 am
Is the gauge at Buford Dam broken? It’s swinging wildly by several hundredths of a foot.
June 15th, 2008 at 7:02 am
There is no accountabilty…just keep on draining it out….I’m glad I did not pay all that money for lake front property…..
August 11th, 2008 at 6:43 pm
Joe Says:
June 15th, 2008 at 7:02 am
There is no accountabilty…just keep on draining it out….I’m glad I did not pay all that money for lake front property…..
–
lake front property? who you kidding, you can barely make RENT
BGAWWWKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK