[Bristol-Birds] South Holston shorebird habitat vansishing
- From: "Wallace Coffey" <jwcoffey@xxxxxxxxxx>
- To: "Bristol-birds" <bristol-birds@xxxxxxxxxxxxx>
- Date: Tue, 18 Sep 2007 22:10:11 -0400
South Holston Reservoir suffers
serious low levels due to drought.
shorebird habitat vanishing
In the next 48 hours the lake level at the
impoundment will drop under 1700 feet.
This is several feet lower than the midwinter
mark observed in late January of this year.
The red line on the chart shows the actual
impoundment elevation for this year by feet and
by months. The black line shows the 2006 levels.
The present lake levels is down about 20 feet below this date last year. That
is a
major departure.
The shaded area represents the reservoir's expected elevation throughout the
year.
Based on computer simulations using more than 100 years of historical rainfall
and
runoff data, the reservoir's elevation is expected to be in the shaded area an
average
of eight out of every 10 years on any given date. For this reason, it is also
referred to as
the 80 percent probability bound. The green line is used to project drawdown
for
current discharges in relationship to other TVA impoundments.
At the current stage, birders visiting Musick's Campground will notice the lake
level is
probably far below lower almost anything seen for late summer.
The shorebird habitat of wet muddy areas with more shallow, rocky, shorelines
is gone. The
useable mudflats are dry or nearly dry. It is doubtful if any significant
shorebird usage
will continue this fall. Late September and early October are still good times
for such migrants
but the habitat is also necessary. It will be an interesting development to
watch and will
probably reveal good information about habitat usage by late summer shorebirds
at this
site.
The lack of water levels reaching high enough and staying long enough to
inundate some
habitat has caused extensive vegetation growth in areas that might have
otherwise been used by
some shorebirds.
Arrival of coots, grebes, waterfowl and such during the next two to three weeks
should not
be affected.
Let's go birding......
Wallace Coffey
Bristol, TN
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