Aquatic Solutions – A New Approach to Dredging
Aquatic Solutions uses a mechanical dredging technique that employs a self-propelled barge that has a
hydraulic excavator arm mounted on the front. For the excavation of sediment we use a 0.875 cubic yard
clamshell bucket mounted on the end of the boom. The dredge can remove material in 15 feet of water and
is able to reach out approximately 18 feet to work in hard to reach areas. The dredge can move effortlessly
around a lake, reaching down and removing a bucket of sediment from a lake bottom.
Once the material is excavated from a lake, it is placed in a hopper barge for transport to shore. Each
barge has a capacity equal to one tandem dump truck load (10 cubic yards). The barge is moved across
the lake by a small tug boat and can be made stationary in the water by the use of retractable spuds. This
allows a barge to be loaded by the dredge at the impacted area of the lake while another barge is
transported by the tug boat to the load-out site. With the third barge being unloaded. Additional barges can
be added to increase production, depending on the distance from the impacted area to the load-out site.
When a barge reaches shore a land-based excavator takes control of the barge and begins to unload the
material directly into a dump truck for transport to the spoil site. This keeps production cycles operating in
an efficient manner.
When loaded, the dump truck transports the material to a final spoil disposition site, in an appropriate
upland area. This is a key step in avoiding regulatory difficulties with wetland dredge and fill permitting.
Since the material is never allowed to touch the water, lake basin, or surrounding wetlands, section 404
permits are not required. In the instances where contaminated sediments are involved other permits are
required but the ability to transport the material on land offers flexibility that consultants are searching for.
Competitive Advantages
Aquatic Solutions methodology has several key advantages over other dredging methods currently being
used:
• No Loss of Lake Use- All equipment works on the water which eliminates the need to drain the lake.
• Mobilization- All of the equipment needed for the operation can be transported over land by truck.
Standard over width trip permits are needed for transporting the dredge and barges.
• Accessing the Job Site- The trailer used for hauling the equipment has a tilt bed and retractable rear
wheels which make launching into a lake quick and easy. Our methodology only requires one access point
on the lake. This access point can be used for launching equipment and loading trucks. This minimizes
disturbance to the lake shore and surrounding property.
• Maneuverability- The self-propelled dredge moves across the lake using hydraulic operated paddle
wheels located on each side of the unit. This allows the dredge to precisely align itself to remove sediment
from areas that were previously inaccessible with conventional equipment. Sediment can be removed
around sensitive shoreline areas, in and around boat docks, in front of storm water outflow pipes, and other
hard to reach areas.
• Verification of Quantities Removed- Our methodology makes contracting projects simple and
straight forward. Since each barge load is 10 cubic yards, projects can be contracted on a per unit basis
by simply counting barge loads or truck loads. Verifying quantities removed with other methodologies can
be difficult and sometimes impossible. The result is the client only pays for material actually removed from
the lake.
• Project Flexibility- Since all equipment is easily transported to the job site, large projects can be
done in a “maintenance” mode over an extended period of time. Dredging projects have historically been
done in an “all or none” mode. This limits large projects by requiring a large sum of money to be raised for
a single project. Our methodology gives lake owners flexibility to dredge their lake in more affordable
phases.
• Simple Project Design- Since there is not discharge of fill from the dredging operation and no spoil
ponds to design and build, projects which do not have contaminated sediments, can be accomplished
without special engineering services or regulatory permits. This advantage substantially lowers the overall
project cost.
• Innovative use of Spoil Material- When the clamshell dredge removes sediment from the lake, the
material is wet but has a relatively stable consistency. It can be hauled to different locations and used as
top soil, landfill cover material, or as additional fill for the back side of a dam. In rural areas the material can
be used as soil enrichment for agricultural or cilvicultural operations. In the case of Hamlet Lake in North
Carolina the lake has been contaminated with the toxic Carbon Black. This material us used in the printing
industry and its use is wide spread. Studies have identified that the safe disposal of this material is
spreading it on agricultural land where the effects of sunlight over time will render it harmless to the
environment.