Public Information Statement
Issued by NWS Jackson, MS

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NOUS44 KJAN 172159
PNSJAN

Public Information Statement
National Weather Service Jackson MS
359 PM CST Mon Feb 17 2020

....Flood of February 2020 is similar in flow to the Flood May of
1983...

On Tuesday May 24, 1983, Ross Barnett Reservoir began discharging
78,000 cubic feet per second (CFS) of water into Pearl River
below. This discharge continued for 15 hours. The Pearl River at
Jackson crested at 39.48 feet on Wednesday May 25th which
corresponds to a flow past the river gage of 79,500 cubic feet per
second.

On early Sunday February 16th,2020, Ross Barnett Reservoir began
discharging 78,316 cubic feet per second (CFS) of water into the
Pearl River below. This discharge continued for 6 hours. The
Pearl River is near crest this afternoon around 36.60 feet which
corresponds to a flow past the river gage of 76,550 cubic feet per
second.

Comparing our current flood event with the May of 1983 flood
event, they both have nearly the same discharges from the
reservoir and similar discharges at the river gage on Highway 80.
The biggest difference occurs when we look at the stage (water
level). At Highway 80, the crest of May 1983 was 2.88 feet
higher. Why is Jackson not as high during our current flood event?
For one reason, the river is more efficient which means the river
could be much deeper after past floods have carried away the silt
out of the bottom of the stream. Another possibility, the
clearing of trees along the flood plain after the 1983 flood. This
would allow the river to flow faster not being impeded by trees.

This situation has benefited those in downtown Jackson where the
river is much lower than expected. Most would ask, "What about
the areas that flooded in Northeast Jackson?" Most people north of
Lakeland Drive experienced similar flows as the 1983 flood;
however, looking at the Ross Barnett river gage below the dam and
the height of the water that backed up into Hanging Moss Creek,
the river looks to have crested at least 1.5 feet lower than 1983
which is equivalent to a 38 foot river on the Highway 80 gage in
the past. The lower river levels in this area were not as great as
at Highway 80. One possible reason for not seeing an even lower
river in these areas may be due to the continued build up of
properties along Lakeland Drive to the 1 percent flood level (100
year flood). A second possibility is the narrowing of the river
channel by levees from Lakeland Drive to the Highway 80 bridge. A
lot of the water being discharged from Ross Barnett has to wait
to flow through the levees towards Jackson. The water ponds or
goes into storage on the Rankin County side of the river waiting
to flow south. This storage of water will keep the river level
high for a longer time period from the dam to Highway 80 as the
water drains.

Other past floods have also shown this tendency to store water
even before there was as much development on Lakeland Drive. This
flood just made it more pronounced. This flood will go down as the
3rd highest flood on record for the Jackson area. It will also be
the flood that most likely recognizes that we can have 2
significantly different flood impacts along the Pearl River in
Jackson, one north of Lakeland Drive and another in the city and
areas just south of Highway 80.

Will this difference always exist? River channels that efficiently
carry flow downstream can silt up and become inefficient carriers
of water. Will other changes in the flood plain occur which will once
again impede flow? All of these are possible. One area that will
not change is the continued growth of Lakeland Drive and the
narrowing of the river channel by the levee system from Lakeland
Drive to Highway 80. These questions and more will be studied
after this event.

$$
MVP



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