Year-end rainfall wrap-up

Annual rainfall for the Hartwell sub-basin in 2017. Six months out of the year experienced above average rainfall but the cumulative amount was still 2.2 inches below the annual average.

As 2017 came to a close, the Savannah River Basin seemed much like folks looking back at the year that was: It definitely has been worse, but still could have been better.

Building off a drought that started in January 2016 (which left the basin severely parched – Hartwell’s rain deficit was more than 19 inches below its 58-inch average), 2017 appeared to be a step in the right direction.

Each of the sub-basins recorded above average rainfall for six scattered months; and while Hartwell finished 2.2 inches below average, Russell and Thurmond were 2.36 and 2.45 inches above their annual averages, respectively.

I want to draw attention to this fact because context is important. Last week an anonymous user posted this in the “Rants & Raves” section of the Augusta Chronicle (Jan. 3):
While technically above average (Thurmond received 48.70 inches compared to its 46.25 annual average), it was hardly enough to mitigate the negative effects created by 2016’s nearly 15-inch deficit.

In a similar fashion (as shown in the graphic at the top of the page), October’s rainfall far exceeded the average (Hartwell: 7.68 inches versus a 4.04-inch average; Russell: 5.7 vs. 3.25-inch average; and Thurmond, slightly less pronounced at 3.98 vs. a 3.02-inch average), only to be outdone by November and December’s deficits.

Even with those huge October gains, Hartwell was still at 83% of its three-month average for October through December, while Russell and Thurmond sat at 87% and 81%, respectively.

As we have mentioned before, in order for the basin to fully recover from the drought, we need sustained, above average rainfall.

We also routinely answer questions about why other lakes in the region are at full pool while Hartwell and Thurmond languish 5-6 feet below winter guide curve.

The answer is as simple as it is complex.

In addition to still being in recovery mode from the drought, our reservoirs serve several different (and sometimes competing) functions outside of merely generating hydropower, which include flood storage, providing commercial and municipal water, recreation and environmental purposes.

We treat the Savannah River Basin as a system, not just individual reservoirs.

Looking ahead to 2018, meteorologists at the Southeast River Forecast Center called for a warmer than average, drier than average winter in their Dec. 13 Water Resource Outlook.

Put in perspective, they stressed an “average level of certainty” relating to this prediction and expect to update these forecasts in the coming weeks.

While no one knows what 2018 will bring, we’ll be the first ones cheering when sustained, above average rainfall finally comes.

~ Jeremy S. Buddemeier, Corporate Communications Office

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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