Lake Panorama Association Gets Improved Dredge
This aerial view of the old dredge, taken several years ago, shows the upper part of the lake and surrounding terrain.
Photos courtesy of Lake Panorama Association
On May 6, the Lake Panorama Association’s (LPA) new dredge arrived from DSC, and representatives from DSC supervised its assembly by LPA staff.
The dredge is a 7650 series Barracuda swinging ladder dredge that can also be operated conventionally by locking the ladder in place and pivoting on the stern spud using swing wires and anchors.
Lake Panorama is a 1,400-acre lake in West Central Iowa – the largest private lake in the state, with 1,000 homeowners belonging to the association. Formed in 1970 by a dam on the Raccoon River, the lake has an annual influx of 250,000 to 300,000 cubic yards of sediment. In 1999, the association purchased a 14-inch Barracuda from DSC, and this year is replacing that dredge with a new 16-inch Barracuda and a booster station. The order for the $2 millionplus dredge and booster station was signed in early 2013, with delivery scheduled for late March 2014, pushed to early May.
Assembling the spuds, which are 20 inches square and 25 feet long.
The dredge was assembled at the lake and ready to launch by Mother’s Day – May 11. That night, two tornados hit the area, causing several million dollars in damage to homes, condominiums and trees, but no one was injured or killed, Association General Manager John Rutledge said. The tornados were EF2 (111 to 135 mph) and EF1 (86 to 110 mph) in intensity. The EF2 passed directly over the newly assembled dredge, which had not yet been launched, Rutledge said. It touched down a few hundred yards past the dredge and destroyed eight condos, leaving the dredge untouched and able to be launched the following day.
Attaching the ladder assembly to the hull. The cutter is 38-inches i.d. with weld-on heavy-duty replaceable edges.
Though it is a private lake, Lake Panorama is not a wealthy community, Rutledge said. In the middle of an agricultural area, it has a boat ramp and three beaches, and owners of bare lots can be members and have access to the lake. The lake is long and narrow, and the dredging is confined to the upper end, which is not developed. It is maintained at 15 feet deep, and dredging continues through the summer to Thanksgiving.
“We did not start dredging this year with the old dredge,” Rutledge said. “It is not worth mobilizing it when the new dredge will soon be ready to work.”
“The booster station provides the necessary head to pump the required distance. We’re pumping around 7,500 feet with 90 feet of head. Essentially, the booster will provide us for more efficient operations,” Rutledge said.
The dredge is equipped with features DSC designs into its dredges to improve efficiency and safety. The dredge pump is an in-hull Metso Thomas 16 x 16 – 40 three-vane dredge pump, with an oil-lubricated bearing assembly.
The dredge was launched from shore on May 12. It was narrowly missed by a tornado the night before.
A marine style reduction gear is coupled to a DSC Model CD50 cutter drive. The cutter is a 38-inch i.d. basket style cutter with weld-on heavy-duty replaceable edges for digging the silt, sand and gravel in the lake. There are three spuds – two side spuds and one stern kicking spud. The kicking spud is controlled by the operator by fingertip controls, as are the other dredging functions. A panel contains additional control switches, gauges and metering displays. The elevated lever room allows excellent operator visibility for dredge functions and surrounding conditions.
The standard DSC dredge control system protects against pump engagement and disengagement at high speed, and locks out all hydraulic functions during start-up and control activation. It sounds alarms for electrical faults, hydraulic problems and the like. The control systems records and displays operating hours of all major dredge systems, including major equipment hours, dredge pump, cutter, swing/positioning winches, stern winch and ladder winch – all useful for scheduling service for the equipment.
A DSC Degassing System protects the pump by removing gas bubbles in the slurry before it reaches the impeller.
The six-foot by eight-foot control room is lifted into place.
The booster is a custom 7650 Series diesel booster station mounted on a 21-foot, 11-inch long by 7-foot, 11-inch-wide barge. The pump is a 16-inch x 16-inch-40 Metso Thomas Dredge Pump, powered by a CAT C27 Acert 950 hp diesel engine with a hospital grade silencer.
DSC’s safety systems include handrails, equipment guards and fire extinguishers. Grease manifolds are in safe locations where crew members will not come in contact with the operating equipment.
The control cabin is six feet by eight feet, large enough for a two-person crew and countertops that can hold a small refrigerator and small appliances, plus space for tool storage. A reciprocating piston-type air compressor provides ample air supply for air-operated maintenance tools.
The hydraulic system is designed with a series of independent circuits allowing proper operation of the swing, spud, ladder, cutter and service water functions. Suction relief is by DSC’s Maximizer valve. It incorporates a hydraulically-controlled butterfly valve connected to the suction pipe, and is automated to respond to changes in vacuum and discharge pressure.Edit Module