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Solar
Powered Pumps Come to the
Inland Bays Watershed
Did a wandering spacecraft land in the Inland Bays
this autumn? The alien-looking machines that can be seen
submerged in the Torquay Canal and Bald Eagle Creek are actually
six huge water pumps leased by the Committee for the Betterment
of Bald Eagle Creek and Torquay Canal with grant funds
from the Sussex
County Soil Conservation District and the Center
for Inland Bays, combined with private donations from landowners
along the canal. The pumps were placed in these two tributaries
as a year-long experiment to try to stop the summertime fish kills.
Bald
Eagle Creek and Torquay Canal are man-made tributaries of
Rehoboth Bay, averaging seven feet deep with holes 10-18 feet
deep. Water
quality concerns in these waterways are caused by nutrient overenrichment.
Organic matter builds up in the holes then breaks down, forming
hydrogen sulfide gas.
 The
committee developed a solution to this problem featuring the floating
pumps, called SolarBees,
which were provided and installed in October by Pump
Systems, Inc. a company located in Dickinson , North Dakota
. The
pumps circulate water from the bottom to the top of the canals
increasing dissolved oxygen levels and eliminating the dead-spots
that plague the canals. These dead-spots, typically near
the holes, are oxygen poor. Pockets of hydrogen sulfide ,
toxic to fish, bubble up to the surface and break, causing an unpleasant
rotten egg smell. Fish can sicken and die when they swim
into these pockets when the conditions are at their worst. Millions
of young fish have been killed this way in recent summers.
While the pumps will not solve overall water
quality concerns in the bays, they provide a good interim solution
for helping reduce or eliminate fish kills and the odors caused
by decaying material. The combined odors of hydrogen sulfide and
dead fish has been one of the biggest concerns of residents
along the tributaries. With the pumps in place the labor
costs of cleaning up after a fish kill are also avoided.
 The
SolarBee's stainless steel circulator has a diameter of 16 feet,
and has three solar panels that power a 3-foot propeller that is
located just below the water's surface. The devices are anchored
and navigation lights warn boaters of their presence. Splayed
wires bounce in the wind to discourage birds from landing on the
solar panels and covering them with droppings. The direct
flow of the pumps is 3,000 gallons per minute and the total flow
is 10,000 gallons per minute, basically duplicating a slow moving
stream in an enclosed body of water. Plastic water tubing
lowered from the pumps into the deep holes helps mix the existing
hydrogen sulfide gases, avoiding bringing large pockets to the
surface and preventing fish kills. The pumps
continue to circulate the water so the hydrogen sulfide does
not build up again in the holes. SolarBees also have solar
powered battery packs for night operation,
which is when hydrogen sulfide tends to bubble to the surface
with adverse impacts on fish.
 Prior
to the installation of the SolarBees, students from the University
of Delaware's College of Marine Studies performed baseline
water testing to compare to frequent testing that
will take place while the pumps are operating. Water quality
will continue to be monitored by the UD College of Marine Studies
and by the Department of Natural Resources and Environmental Control.
The
total cost estimate for the year-long experiment is $190,000. If
successful, and the group decides to purchase
the pumps, the money spent during the lease period will be applied
to the total cost. The Inland
Bays project is a new test use for this equipment, which is usually
used in ponds, sewer plants, and irrigation lakes for circulation
and aeration. There are currently over 450 SolarBee pumps
being used around the country.
One long term solution
may be to fill in the holes. The U.S.
Army Corps of Engineers have been approached for expertise
and assistance with filling in the holes, which were dug during
construction of the Rehoboth Beach Country Club development.
You can read more about fish kills in
this article from our September-October issue of Tributary
Times.
More information on the SolarBee pumps
and their use in Sussex County from this
series of articles on the Pond Windmills
web site.
The
News Journal had an article
titled, Solar
Pumps Could End Fish Kills on October 21, 2003.
The
Cape Gazette published an article titled,
Solar
Powered Pump May Aerate Dead-End Canals on October 3,
2003.
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