Lake Update: July 9, 2013

LATEST ELEVATIONS:

As this is written a thunderstorm is hitting the Lake Thurmond area.  Current levels are 664.44 ft-msl (Hartwell) and 331.88 ft-msl at Thurmond.   Lake Russell is also above full pool flood storage at 478.73 ft-msl.  All three lakes remain over full pool!

This has resulted in the need to increase releases from the lakes to maintain some of the flood storage requirements.  Many of you may have seen the news reports from Augusta of the flooding in the river.  With the increased rain below Augusta coupled with the increased releases from the lakes there will be additional flooding as the flows in the lower river hit 20,000 to 30,000 cfs.  Everyone will be watching Tropical Storm Chantal to see how it tracks over the next several days. The models project its track to be off the coast of the GA and SC border by Sunday afternoon.  The unknown is how close to the coast the storm actually tracks.  This will determine how much rain the SRB gets from the storm.

SPILLWAY GATE TEST REMINDER:

A reminder that the spillway test at Hartwell will be conducted on July 10 from 1:00 PM to 3:30 PM.  The test at Thurmond will be on Thursday afternoon, July 11 from 1:30 to 4:00 PM.  As of this morning, they are still scheduled (see below press release).  Visitors can watch the test at Thurmond from below the Dam. Park on the South Carolina side of the river. For questions, contact the Visitors Center at 800-533-3478. If you have never seen the gates open, it will worth the trip.

PRESS RELEASE ON INCREASED WATER RELEASES:

We received the following Press Release from the corps concerning the increased releases from the Lakes:

For Immediate Release

July 9, 2013

News Release No. 13-18

Continuing rains lead to increased water releases from Savannah River reservoirs

SAVANNAH, Ga. – Following extensive rain in the upper Savannah River basin and more forecasted, the U. S. Army Corps of Engineers Savannah District began releasing stored floodwaters from Hartwell, Richard B. Russell and J. Strom Thurmond lakes Monday. Inflows from the recent rainfall pushed elevations into the flood control storage pool at all three reservoirs. Water managers directed the release of water through the spillway gates at Hartwell Dam Tuesday morning to lower the reservoir to below 665 feet above mean sea level (ft-msl), the top of the spillway gates.

As of noon Tuesday, elevation at Hartwell Lake was 664.8 ft.msl, at Richard B. Russell, 477.5 ft.-msl, and at J. Strom Thurmond 331.8 ft.-msl.

For the next several weeks water will be released from the flood storage pools at Thurmond, Russell and Hartwell Dams until all flood storage pools drop to near guide curve for this time of year, or 660 ft.-msl at Hartwell, 475 ft-msl at Russell and 330 ft.-msl at Thurmond. The flood storage pools are the capacity of the reservoirs above “full pool.” The flood storage pools temporarily store excess storm runoff in the three-lake Savannah River Basin system.

“Our first concern is public safety,” said Corps hydrologist Stan Simpson. “We activated our standard plans for reducing reservoir levels with controlled releases first through our generation turbines. When more rains came Monday night above Hartwell Lake we needed to increase our releases by passing water through the spillway gates – also part of our standard water management plans.”

“We also must consider the possibility of additional rainfall that could hit our area as tropical storm Chantal approaches the East Coast,” Simpson said. Flood risk reduction is a primary mission of the reservoirs.

Daily average flows out of Thurmond Dam will be managed to approximately 25,000 cubic feet per second (cfs) averaged over each 24-hour period this week. The Corps of Engineers plans to manage flows at or less than 30,000 cfs at Augusta. However, with downstream inflows, river flows at the New Savannah Bluff Lock and Dam gauge may exceed 30,000 cfs –within river channel capacity. Some minor flooding of docks is expected downstream of Thurmond Dam. Agricultural interests may have some flooding at flows below 30,000 cfs.

With above normal releases, river velocities will be much higher than normal. Boaters, anglers, and others using the river below the Thurmond Dam should exercise extreme caution and should wear a life jacket at all times when on or even near the river. Some low-lying areas could be inundated. Dock owners at all locations should be prepared to adjust their docks if necessary. The Corps of Engineers has received reports of large debris in the reservoirs and in the Savannah River as well as some inundated signs. Some recreation areas and facilities including boat ramps and courtesy docks have closed due to high water.

Spillway gate tests previously scheduled for July 10 at Hartwell Dam and July 11 at Russell Dam and Thurmond Dam remain on schedule.

The public can follow the management of its reservoirs and the Savannah River through the Corps of Engineers blog Balancing the Basin athttp://balancingthebasin.armylive.dodlive.mil/.

Harry and Barb Shelley
FSRB
hbshelley@wctel.net

Leave a Reply

Your email address will not be published.