PROJ00527

• Contract/PO #: FS0024X
• Contractor Name: Florida Water Conservancy District
• Contract Type: Loan
• Water District: 0
• County: La Plata
• Loan Projects - Doc Type: Feasibility Study

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to close the outlet which consists of lowering the existing
concrete plug in the intake structure to cover the outlet pipe.
The plug or bulkhead is shown in Drawing 519-D-12 in Appendix B.
The plug is an 8.5 foot diameter, 19-inch thick piece of concrete
with four "flaps" at 90 degree angles to each other. The plug
currently is resting on the "flaps" about ten feet above the
entrance to the outlet pipe.

The plug would be lowered 'onto the pipe entrance by removing
the four support pins and blocks, raising the plug one to two
inches, and rotating it about ten degrees so that the "flaps" are
away from the supports. The plug would then be lowered ten feet.

The plug weighs about 14,000 pounds in the air and 8,000
pounds submerged. (Reclamation documents incorrectly list the
plug as weighing 6,500 pounds.) Several methods for lifting the
plug were considered: l) a helicopter, 2) a barge with a hoist,
and 3) a frame structure which would rest on the intake structure.
Reclamation has not closed an outlet of this design at any other
dam so a precedent has not been set.

The nearest helicopter with the capability to lift the plug
is in the northwest United States and costs $2,000 per hour; the
cost for two flights to Lemon Dam and the actual lifting time have
been estimated to be approximately $40,000. A barge with a hoist
was suggested by Reclamation but the barge would have to be con-
structed specifically for the job and would have to be quite large
to provide adequate buoyancy.

The frame would be constructed and placed on the intake, with
a winch at the top of the frame. (Underwater winches are not
commonly available for this weight and if utilized would be

6.0-3