November rainfall continues October’s precedent

The chart shows hourly rainfall at Hartwell sub-basin for Nov. 1-12, 2015 (top) and 2014. Thus far in November, Hartwell has received 6.64 inches of rain compared to 0.14 inches in 2014. For more, visit http://ow.ly/UzK5s.

The chart shows hourly rainfall at Hartwell sub-basin for Nov. 1-12, 2015 (top) and 2014. Thus far in November, Hartwell has received 6.64 inches of rain compared to 0.14 inches in 2014. For more, visit http://ow.ly/UzK5s.

November rainfall at the projects has already exceeded the month’s averages on the heels of October’s record-setting pace.

To date, Russell outpaces the others by more than doubling its average of 3.5 inches in 12 days. Russell captured 7.4 inches, while Hartwell and Thurmond recorded 6.6 and 5.7 inches, respectively.

This week, Thurmond release rates were just shy of 30,000 cubic feet per second and will average approximately 25,000 cfs over the next few days, said Stan Simpson, a Corps water manager.

Increased outflows from Thurmond recently contributed to a rise in Savannah River levels. Some of the impacts have already been felt near Augusta with the closure of boat ramps, but Simpson said the up-tempo in rainfall and subsequent runoff will be balanced with flood management releases.

“From a seasonal perspective, [closures are] probably going to be a recurring theme through the spring,” said Simpson. “We are following the winter guide curve and providing more flood storage because there’s a very strong El Niño that has set up and is already affecting the Southeast.”

NOAA forecasters predict the El Niño pattern will bring above average rainfall to the Savannah River basin through the spring. With continued heavy rainfall predicted, Simpson said there is ample flood storage in the system and hopefully there will be no need to release water through any of the reservoir’s spillway gates.

But the reservoirs may see some temporary relief from the observed excessive rainfall as the current forecast is for less than an inch over the next week throughout the basin.

Having already eclipsed normal monthly averages with significant rainfall recorded every day to date, the sub-basins are potentially in for a record-breaking November. It will be interesting to see what kind of rainfall December and January will yield.

~Chelsea Smith, public affairs specialist

About US Army Corps of Engineers Savannah District

The U.S. Army Corps of Engineers Savannah District oversees a multi-million dollar military construction program at 11 Army and Air Force installations in Georgia and North Carolina. We also manage water resources across the Coastal Georgia region, including maintenance dredging of the Savannah and Brunswick harbors; operation of three hydroelectric dams and reservoirs along the upper Savannah River; and administration of an extensive stream and wetland permitting and mitigation program within the state of Georgia. Follow us on Twitter @SavannahCorps and on Facebook.com/SavannahCorps
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  • Ferris

    Chelsea, the amount of Oct and Nov rainfall is impressive. The basin weighted chart shows that cumulative rainfall in Oct and so far in Nov exceeds every year on record from 1948 for all of Oct and Nov, and exceeds the average strong El Niño event for Oct, Nov, and Dec. I do hope the forecast heavy rainfall along the Mississippi River does not drift closer to us; 0.5″ to 1″ will be plenty of rain for next week. I very much appreciate the water managers staying on top of the El Niño situation. ~ Ferris

  • Ferris

    The Projection today demonstrates USACE respect for the lakes and for recreation by not counting precipitation until it happens and by planning to exit Flood Storage and no more. Even with recent and forecast heavy rainfall events and a continuing strong El Niño through Spring, the Projection uses only 75% of normal local inflows at 10 weeks out although 125% could be easily justified.

    Strong El Niño events have the greatest visible effect on the SRB from Jan through Apr. Rainfall in Oct through Dec saturates the ground upstream and downstream of Thurmond Dam. The resulting higher runoff rates in Jan through Apr and an average 4″ of additional precipitation add about 8′ to lake levels without higher release rates. Higher Thurmond release rates add to higher local runoff rates, raising the river to dangerous and even flood levels.