Lake Restoration Operation Receives High Marks
An erosion control project at Lake Panorama, near Panora, Iowa, required the removal of 446,250 cubic yards of silt and sediment from the bottom of this privately owned 1400-acre lake. The operation is a joint endeavor of the Central Iowa Energy Cooperative (CIECO), the owner of the lake, and the Lake Panorama Association (LPA), the local homeowners group. CIECO is a subsidiary of Central Iowa Power Cooperative (CIPCO), Cedar Rapids, Iowa, an electric generation and transmission cooperative serving over 250,000 Iowans across the state.
CIECO purchased Lake Panorama and associated properties from bankruptcy court. The major interest in the lake at that time was as a water resource for future construction of an electric generating plant. Plans for building a power plant have since been canceled.
In the meantime, the lake region, located 40 miles from a major metropolitan area in wet central Iowa, has become a thriving site for development. Approximately 40 new homes are being built on the lake annually. The electric needs of the Lake Panorama area are served by Guthrie County Rural Electric Cooperative, a member system of CIPCO. Therefore, the community and the cooperatives have a continuing interest in the success of Panorama National Golf Course and Conference Center on the lake. This property generates additional revenues for the community. The continuing growth in the lake region affirms the cooperative’s decision to make long term investments such as a dredging operation.
CIECO and LPA’s agreement for the joint erosion control program commits LPA to operating and maintaining the dredge used on the lake. The silt is pumped at a flow rate of approximately 4000 GPM from the lake by the dredge into containment basins constructed by CIECO. This spirit of cooperation guarantees that the integrity of the lake is maintained and the future development potential of the area is assured.
The Lake Panorama Association has maintained exceptional records on the entire dredging operation over the last 23 months. The following is a "report card" of this project which covers the dredging operation, job-site parameters and actual dredging costs.
The Dredge
The Ellicott Series 370 "DRAGON™" dredge, named "CIECO’s Pride", features 20 ft. digging depth capability, a 40 hp basket cutter with chisel teeth, 12 inch high density polyethylene discharge pipe rated SDR 17, and a spud operation with true freefall.
Dredge Operation
(10/90 - 7/92 inclusive)
A) Two-man crew plus supervisor
B) Three shifts per day, 5 days per week, 7 months per year
C) Total hours on Caterpillar 3406 diesel engine rated 309 HP continuous: 3,000
D) Fuel used: 35,295 U.S. Gallons
E) Cubic yards of material pumped: 446,250
F) Fuel consumption: 11 U.S. gallons per hour
G) Operating cost - (fuel, maintenance, labor, insurance, spare parts and pipeline depreciation) - $190,102
H) Unit dredging costs: $0.426 per cubic yard
I) Average dredge production: 150 cubic yards per hour
J) Average cutting depth: 7-12 feet
Pumping Distances
A) Average pipeline length is 3,000 feet at +40 feet elevation rise to the disposal area
B) Dredge has pumped a maximum of 4,800 feet with a +20 feet elevation rise
C) Peak dredge output has been verified at 300 cubic yards per hour in material that is lake sediments (90%) with the balance consisting of sand, gravel and clay
The Lake Panorama Association conducted a cost-effective dredging program since operating costs are in the 42.6 cents per cubic yard range, which is far below standard industry costs, less dredge depreciation. The initial goal for the Series 370 is 1,000,000 cubic yards so the dredge will be required to operate for a few more years. When you factor in the depreciation of the dredge, this adds only $0.15 to $0.25 per cubic yard depending on whether a 4 year or 6 year amortization schedule is utilized. Therefore, the current total operating cost would be a maximum of approximately $0.676 per cubic yard.
The construction of the silt holding ponds is not included in any of the above costs and is a separate cost item. Currently, one silt holding pond is full to capacity and another older dredge silt disposal area is now being utilized from a former dredging operation.
The customer rates all A’s on this report card, as sediment from Lake Panorama continues to be removed to maintain the environmental integrity of the lake.
Reprinted from Lake Enhancement
