Atlanta Water Shortage

It’s August, so it’s time to welcome back the scorching temperatures.  The Lawrenceville Weather Blog is reporting that today was unofficially the hottest day of the year so far.  Last August was brutally hot across Georgia, resulting in a significant drop in Lake Lanier’s water level.  It’s unlikely that this year will be quite that hot, as it was the one of the hottest Augusts since 1980.

Despite the cooler temperatures, we could still see another large drop in Lanier’s level.  As rkolter pointed out, last year we had a ton of restrictions and people were very water-conscious.  This year there are fewer restrictions in place and water is rarely in the news.

Last August saw a drop of 2.37 feet (1064.14 to 1061.77).  Do you think August will see a greater drop, a lesser drop, or no drop at all?

It’s been a few months since I’ve done one of these charts, but I thought it was probably time to do another one.  These next few months will be very interesting, so here’s where we stand right now.

I won’t say much else, since our previous post covered it pretty well.

As seen in Ken Cook’s blog, July was the rainiest month we’ve had in nearly two years, with a total of 7.17″ at the Atlanta airport, which is 2.05″ above average.  It also cuts our rainfall deficit for the year to just five inches, compared to the 14 inch deficit we were facing at this point last year.

The bad news is that Lanier continues to drop.  It went from 1056.23′ on July 1 to 1055.15′ on August 1, or a drop of just over a foot. Last year on August 1 we were at 1064.14′, so we’re quite a bit behind that.

Last August is when the lake really began to drop, losing nearly 2.5 feet in August, and over three feet in both September and October.  The record low is 1050.79, set on December 26 last year.  If we see similar drops in the next few months, we’ll blow past that record.

This month should be very telling…

With Lanier at its lowest level for this time of year since it was built in the 1950s, the Corps has issued a warning to anyone planning to use the lake over the holiday.  The statement from E. Patrick Robbins reads, in part:

“The shallower water conditions could expose sandbars or stumps to those swimming or boating,… Boaters should be cautions as declining levels may reduce clearance over underwater obstructions.”

The article in the AJC brought up some interesting facts:

• The lake is about 15 feet below full, something we’re all well aware of.
• Of the 39 public docks, only two are usable.
• Of the 100 lanes of public boat ramps, only 12 are usable.

Also, the article claims that the corps expect Lanier to drop another foot by July 25.  Considering we lost about 1.5 feet in the month of June, that sounds like a pretty reasonable guess.

According to an article in the AJC, the sun is responsible for about 2/10″ drop in lanier every day.  It’s been losing about an inch/day lately (0.84 the last few days), a trend which seems likely to continue for a while.  Yesterday, that 2/10″ amounted to over 193 million gallons.

The weather is cooling off a bit, which should help, but no major rain is anywhere in the forecast.

The various rivers and streams that flow into Lake Lanier are at (or near) their all-time lows, which isn’t a good sign for the lake.

According to 11Alive, the Chattahoochee River north of the lake is at 28% of its normal flow.  Other than the 28% figure, the article didn’t give any other numbers, just quotes from local residents talking about how low it looks.

So far this year, the lake has done pretty well.  It even surprised some folks (like myself) when it rose a few inchdes last month.  This month has been a slow but steady drop, down about 4 inches so far.  Last June, the lake dropped by about 21 inches, so at least we’re still dropping at a slower rate.  Of course, we’re already about 10 feet lower than this time last year…

If the inflow continues to dwindle, this could create some big problems, even with the revised operating plan in place.

The Lawrenceville Weather Blog has a nice look at the current state of the drought.  From their site:

And, indeed the latest drought monitor for Georgia shows an area of extreme drought in the northeast corner of the state enlarging to the west, including portions of Gwinnett county, and virtually all of the Lake Lanier drainage basin. As of Tuesday, 8.9% of Georgia was in extreme drought, compared to 2.3% last week. 61% of the state is classified as being in a moderate drought. However, as the comparison below shows, we’re still better off than we were at this time last year. On June 12, 2007, 47% of Georgia was in extreme drought and 96.1% was in at least a moderate drought.

Hopefully we’ll get some lucky downpours over the next few weeks to help prop us up, then a slow moving tropical storm later this summer.  We can dream, can’t we?

(so sad, having to dream about tropical storms…)

(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

It’s time again for our Lanier status update, and just like last month I’m quite pleased with the results.  I had predicted that the lake would “drop a few feet” by June, but it actually rose by a few inches.

There are a few conclusions to be made from this:

• It’s wonderful that the lake held steady for the month.  In the past two years, May saw an average drop of about 1.5 feet.
• We’re still nearly 10 feet lower than this time last year.  With as bad as things got last year, it’s not good to be 10 feet below there.
• We’re closing the gap.  A month ago we were about 11 feet lower than last year and we’ve inched a bit closer.

I’ll once again predict a drop of a couple feet for the coming month, but I say it with much less confidence.

Any predictions from you?

According to an article in the Gwinnett Daily Post, the Army Corps of Engineers expect Lake Lanier to fall around six feet this summer if the weather is similar to 2007.

On the other hand, he said that it could possibly refill by the end of the year if there were heavy rains.  From what I can gather, the only way it’ll fill by the end of the year is if those “heavy rains” are from hurricanes and/or tropical storms, which is certainly possible.

A drop of six feet from our current level would put the lake at roughly 1051′.  While that would be bad for business at the lake (as they mentioned in the article), there really wouldn’t be any impact on our water supply.  Even dropping below the dead pool would have a minimal effect.

I’m curious why they say it would only be a six foot drop if the weather was similar to last year.  Last year from this time to the end of the year we saw about a 15 foot drop.  We’re starting lower this year, would means that water would drop more quickly.  Why just six feet?  Anyone know the answer?

On another note, I apologize for the lack of posts lately — there simply hasn’t been much news.  If you know of a story that we should mention on the site, please feel free to contact me.  Thanks!