Technology - trdoer50016

Technology

The UASV is a bottom-crawling

machine approximately 15 ft long, 8 ft

wide, and 6 ft tall. It can move for-

ward, backward, and sideways using

Archimedean screw propulsion technol-

ogy. The vehicle also incorporates re-

motely operated vehicle (ROV)

principles to assist in guidance, naviga-

tion, and control. It uses the Digital

Global Positioning System (DGPS) for

location and has imaging systems that

show where the dredge is at all times.

The dredging path is preprogrammed.

It has two dredging hoods, located at

each end of the dredge. The dredge

fluidizes the bottom material with a

low-pressure supply pump (80 gpm). This allows selective removal of

fine-grained sediments into an enclosed hood for slurry pipeline transport

to shore. The dredging hoods are designed to allow sand material (greater

than 120 microns) to fall back to the bottom and only fine-grained sedi-

ment is removed.

Current usage

The UASV has successfully worked at an Orange County Water Manage-

ment District (California) recharge reservoir. The system covered approxi-

mately 2 acres of bottom in an 8-hr work period, removing approximately

100 yd3/hr (in situ).

Potential application

The underwater Archimedean screw vehicle has potential application in

the following circumstances:

a. Contaminated sediment prospects where the contamination is con-

tained within the top layer of the project. The dredge can be used

to surgically remove the contaminated sediment. Conventional

dredging could then be applied to the remaining sediment.

b. Canals and lakes choked with fine-grained sediments (muck). The

USAV can work in confined areas, because it is relatively small

and does not need room to turn around. It dredges from either end

of the vessel and moves sideways for dredge cut setup. It removes

only the fine-grained sediment, leaving sand on the bottom, which

is often desirable in recreation areas.

c. Under-pier dredging. The UASV is small, can work in confined

areas, and is remote-controlled.