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A broad swath of North Carolina that
includes Wake County is in a severe
drought with no substantial rain
expected soon, and the county’s major
water supply, Falls Lake, is predicted
to shrink as the summer progresses.
“What’s really important is
to look at the inflows,” Thomas E.
Freeman, the operations manager at Falls
Dam for the U.S. Army Corps of Engineers
said Tuesday.
Those inflows are miniscule
in comparison to normal. Between April 1
and 16, the water coming into the lake
from the Eno, Flat and Little rivers was
78 cubic feet per second while the
inflow in a normal month of April is 879
cfs.
“If the inflow trend for
Falls Dam continues, April will be a
record low month for inflows,” Terry M.
Brown, the water control manager for the
Wilmington district of the corps, wrote
on Monday in his regular update about
reservoirs and the drought. The
prediction is for inflow to be only 9
percent of normal.
“So far for 2006, and out of
79 years of records, January was in 14th
place with 368 cfs average for the month
(normal is 970 cfs), February was in 6th
place with 343 cfs (normal is 1,351 cfs),
and March was the driest March of record
with 110 cfs (normal is 1,287 cfs),”
Brown wrote.
Brown noted that Raleigh had
a 6.93-inch rainfall deficit for the
year as of Monday with only small and
scattered rain anticipated. Across most
of the state, streamflows are at less
than 5 percent of usual.
There was a rainfall deficit
of 5.5 inches during 2005, giving a
total rainfall deficit since Jan. 1,
2005, of 12.43 inches. The National
Weather Service predicts lower than
average rainfall and higher than average
temperatures for the next 30 to 90 days.
Currently, Falls Lake, at
its level of 250.5 feet above mean sea
level, holds 78 percent of its normal
water supply and 97 percent of its water
quality storage pool. That is before
area residents increase water use for
summer activities.
“Our water usage at this
time of the year is always low,” Freeman
said. “As warmer weather approaches, the
normal summer activities will increase
and Raleigh’s pumpage will increase.”
Raleigh is pumping just over 60 million
gallons a day from the lake to supply
its residents and those in Wake Forest,
Rolesville, Garner, Wendell, Knightdale
and Zebulon with water.
On April 5, the Wilmington
district received approval from the
Corps’ division office in Atlanta to
limit the flow from the dam to a minimum
of 60 cfs. The Corps and those who use
the Falls Lake and Neuse River water
will monitor that release as the summer
proceeds. Brown holds a conference call
with stakeholders every Tuesday and
meets with them every month.
Brown’s Monday message
included information about the projected
amount of water storage and water
quality storage and lake levels through
the end of September with and without
the limited releases, assuming that the
inflows into Falls continue at 10
percent of normal.
At the end of April, that
projection shows the water supply pool
shrinking to 75 percent of normal for
both modes of operation and the lake
level dropping slightly.
By the end of September,
with or without the limited release at
the dam, there will be only 13 percent
of the water supply pool remaining,
according to the projection. The lake
level with the limited release would be
at 241.5 feet, at 239.6 with normal
releases.
Brown also presented another
scenario based on a repeat of the 2002
drought and inflows. In that model,
there would only be 8 percent of the
water supply storage pool left in the
lake and 24 percent of the water quality
storage. The lake level would be at
240.5 feet.
“In 2002, very heavy rains
helped Falls Lake recover quickly in
mid-October,” Brown wrote. “Just prior
to recovery, water supply storage would
drop to 3 percent remaining and water
quality to 4 percent remaining.
“The conservation pool
containing the water supply and water
quality storage is from the 236.5 to
251.5 level in Falls Lake. In this 15
feet of water, about 50 percent of the
storage is in the top five feet,” Brown
concluded his discussion of Falls Lake.
Back in 2002, the lake went
down to 244.09 feet on Oct. 31, but
there was a heavy widespread rain
shortly afterward, and by Nov. 3 and 4
the lake was back to its normal pool,
251.5 feet, and rising.
Last year Falls Lake shrank
down to 244.20, again on Oct. 31. But
the rains did not come in 2005 as they
did in 2002. The lake has been slowly
recovering, but has not reached the
normal pool level since last fall.
Between Monday and Tuesday of this week
it shrank by a tenth of a foot from
250.5 to 250.4 feet.
Keep track of the daily
inflows and releases at Falls Lake at
http://epec.saw.usace.army.mil/neuse.htm.
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