WILMINGTON — Earlier this week, the U.S. Army Corps of Engineers announced it was dramatically increasing the outflow from Jordan Lake into the Cape Fear River; the announcement triggered upset reactions on social media, particularly from residents in southeastern N.C. already dealing with flooding issues.
The Corps of Engineers controls the outflow from Jordan Lake, located just south of Chapel Hill, into the Cape Fear River by regulating outflow at the dam. While outflow varies, in the winter it frequently maintained between 1,000 and 2,000 cubic feet per second (cfs), roughly 450,000 gallons per minute — the outflow discharged into the Haw River, shortly before it joins the Deep River to form the Cape Fear River.
However, recent rainfall has pushed the lake to its limits; according to the Corps of Engineers, a month after Hurricane Florence the lake was still six feet over its normal level; after Hurricane Michael, and heavier recent rains, the lake is now 16 feet over its normal level.
Increased outflow into the Cape Fear River
On Monday, the Corps of Engineers announced it was increasing outflow to around 6,500 cfs, and on Tuesday evening, announced a further increase to over 10,000 cfs – sending about 4.5 million gallons per minute downstream along the Cape Fear River.
“Water Management Update: We’ve increased discharges from Jordan Lake to 10,400 cubic feet of water per second, nearly 4.5 million gallons per minute. This decision was made with careful consideration of downstream communities – much research and calculation occurs before making such decisions. As mentioned with a previous post, these waters take the better part of a week before they reach the Wilmington area,” the Corps of Engineers posted.
For those still reeling from flooding in the wake of Hurricane Florence, this was upsetting news; several posts claimed the Corps of Engineers was ignoring low-income rural areas in its analysis, and also that the increased outflow was done to protect real estate neighboring Jordan Lake.
In a response, the Corps of Engineer wrote, “we are lucky in that by design of the lake, all of the land directly bordering the lake is government owned and managed. This means that when we are holding back waters, we do not need to worry about damaging homes on Jordan Lake as there is no private ownership directly on the lake. There are some neighborhoods bordering the forests surrounding the lake that face roads flooding that we must consider when holding on to flood waters, but the worries to downstream communities are far more numerous.”
Several of those concerned live in Pender County, where flooding from the Northeast Cape Fear River has been devastating.
However, the Northeast Cape Fear joins the Cape Fear at Eagle Island, along Wilmington’s downtown riverfront, far south of Burgaw. While it is possible that the increased volume of the Cape Fear River could cause its tributaries – including the Northeast Cape Fear – to back up, gauges monitoring those rivers have shown this isn’t happening, according to the Corps of Engineers.
Lastly, the Corps of Engineers pointed out that – without the Jordan Lake and dam – an additional 16 feet of water would be headed downstream, dwarfing the amount released this week.
“10,500 cfs, is a seep comparatively speaking in terms of just how much water moves through the Cape Fear. If the dam weren’t here, the Cape Fear would have been receiving near 60,000 cfs with the recent peak flows,” the Corps of Engineers wrote.
According to online reports, the outflow has been reduced back down to around 6,000 cfs; further reduction is expected as the Lake Jordan water level returns to normal.
Send comments and tips to Benjamin Schachtman at firstname.lastname@example.org, @pcdben on Twitter, and (910) 538-2001.