Aqua Survey utilizes its vast array of geophysical instruments and our fleet of vessels to support the detection, characterization and precision mapping of cultural resources. Cultural resources studies are performed to locate and identify submerged artifacts, to investigate circumstances causing the resources to be submerged, to locate resources that need to be avoided during construction and to assist not-for-profit and for-profit marine archaeologists. The following services are provided to support these studies:
• Geophysical studies with side scan sonar, sub-bottom profiling, magnetometer studies, electromagnetic detection studies and bathymetric surveys
• Sediment vibracoring for C14 and grain size analysis
• Electromagnetic detection of buried metallic artifacts with benthic sled and diver maneuvered systems
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Jet probes are used for a variety of purposes and are normally deployed in conjunction with other data collection techniques such as hydrographic surveys, sub-bottom profiling, side scan sonar surveys and vibracoring. Jet probe surveys provide information by surveying the thickness and layering of sediment covers on land or underwater. A jet of water is used to penetrate the sand cover or unconsolidated sediment.
At Aqua Survey we have combined this standard tool with another standard; the Geonics’ EM-61 console. A new proprietary hybrid system combines Geonics’ EM-61 consoles with Aqua Survey-developed electromagnetic sensor tipped jet-probes. This combination allows divers as well as topside and terrestrial technicians to advance an EM probe by utilization of a water-jet at the tip of the probe while at the same time detecting both ferrous and non-ferrous buried metals. The probe can be attached to various length handles (2-40 feet). Operators are alerted both visually and audibly when metal objects are detected in advance of the probe. This system provides a safe, efficient and cost effective alternative for the probing of sediment or soils for metal objects. Probes can also be operated without water-jetting in unconsolidated sediments.
An EM-Tipped Jet-Probe™ will allow investigators to surgically and safely probe areas with:
- Sensitive Ecology
- Buried Utilities
- Buried Steel Drums
- Cultural Artifacts
- Munitions and Explosives of Concern.
Diver-Maneuvered EM Sled Pinpoints Buried Metal: Munitions, Treasure and Utilities
A new hybrid system combines Aqua Survey-modified EM-61 high-powered Tx/Rx coils, Aqua Survey underwater monitors and Geonics’ EM-61 consoles with precision positioning/tracking equipment. Combining new with proven equipment brings the detection force of state-of-the-art high-powered Geonics equipment to the seafloor. It provides the diver real-time target response data, the ability to follow monitor-displayed survey lanes and the ability to view completed survey lanes.
Precision positioning the EM Diver Sled™ in the shallows is accomplished with a mast-mounted GPS antenna. In deeper waters a submersible USBL system is utilized to precisely position the receiver coil. Survey lanes can also be established from the placement of underwater control point monuments and the use of guide lines.
Aqua Survey has extensive experience utilizing EM-61-based EM Diver Sled™ technology on both sand and mud bottoms. Aqua Survey will provide diver-training in the use of the system.
For more information download the EM Diver Tech Sheet listed above.
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Aqua Survey owns and operates more than ten heavy duty vibracoring systems. Vibracoring is considered to be the most cost effective technology to collect large numbers of sediment cores efficiently and with little distortion to the actual core. Three or four inch diameter cores can be collected continuously to a depth of about 40 feet. Sediment vibracores are used extensively for:
Barrel liners are typically flexible food-grade polyethylene for contaminant evaluations or rigid polycarbonate for geotechnical samples or high-resolution environmental cores. The flexible liners can be slit with a razor knife, allowing for easy processing in the field or in the lab. A standard 4-inch diameter sediment core yields about 0.5 gallons of sediment per foot of recovered core. A vessel-based field crew can typically collect 8-12 short cores (<8 feet), 6-10 medium cores (8-12 feet) or 4-8 long cores (>12 feet) a day, depending on sampling conditions. We can deploy multiple vibracoring field teams simultaneously.
Aqua Survey has a wide variety of sampling equipment such as: benthic grab samplers, kick-nets, gill-nets, seines, bongo-nets, plankton-nets, epibenthic sleds, fish traps, trawls, underwater video camera, underwater digital still cameras, lightweight ROVs and other monitoring equipment. Specimen samples are collected, sorted, taxonomically identified and enumerated by ASI professionals. Seagrass beds and coral reefs can be digitally imaged/recorded and this data processed to determine their relative health. Resulting data can be used to support:
Aqua Survey utilizes Sub-Bottom sonar echoes to detect and map targets and layering within the beds of lakes, streams, rivers, estuaries and oceans. The harder the target or strata, the harder and more resolute the sonar’s echo is to the transducer. Sub-Bottom can be used to three-dimensionally delineate contaminated sediment volumes. This technology can also be used to survey a riverbed for buried utilities prior to advancing drilling or vibracoring equipment into the sub-bottom, thus lowering the probability of making contact with or damaging a utility service. ASI uses sub-bottom profiling to support:
Aqua Survey provides board-certified
hydrographic/bathymetric surveying services worldwide. ASI has vast experience surveying in
estuaries, rivers, lakes, streams and ponds. Real-Time Kinematic Differential Global Positioning Systems (RTK-DGPS) can be used to provide centimeter-accurate vertical and horizontal control. Hypack Max™ is used for vessel control and tracking.
Hydrographic sonar equipment emits sounds that travel to the bottom (depth of the water) and then bounce back to the sounder at the surface. The delay
in the sound’s return to the surface is translated into water depth. Bathymetric surveys provide clients with
an accurate relief map of a pondbed, lakebed,
riverbed or other area of interest.
Historically, bathymetric surveying was
performed to chart the physical features of water bodies to allow vessels to navigate safely. We perform hydrographic surveying services today to support:
Aqua Survey utilizes electromagnetic (EM) detection systems to detect and map submerged metal targets. EM detectors are well known for their ability to detect unexploded ordnance (UXO) and treasure. ASI’s EM systems are high powered to maximize their detection range. EM systems can be towed behind survey vessels on floating platforms or submerged benthic sleds, to survey up to 6-meter swaths, towed by a diver (1-meter swath) or included within the nosecone of a vibracoring barrel (4-inch diameter). Submersible electromagnetic detectors are used to support:
To support benthic investigations Aqua Survey can deploy a Smith-Macintyre grab sampler to collect sediment and benthic macroinvertebrate samples. Once the macroinveretebrate samples are onboard the samples can be prepared with a sieving station to process the samples making them ready for the laboratory to sort and identify. A drop camera may also be deployed to assist with characterizing what is happening at the water-sediment interface. Specimen samples that are collected can be sorted, taxonomically identified and enumerated by ASI professionals. Resulting data can be used to support:
The use of markout services to protect utilities buried on land can never eliminate the possibility of a utility being damaged. However a properly executed markout can greatly reduce the probability of equipment making contact with or damaging a utility. Urban waterways are riddled with submerged and buried utilities. Available markout services rarely flag utilities past the banks of a waterway. “As built” plans for the most part do not exist for the older submerged utility runs in the U.S. Complicating things further and adding an unacceptable level of uncertainty, pipeline routes have been known to shift from their original placement due to heavy storm surges and other natural forces.
Engineers and project managers should take full advantage of Aqua Survey’s on-water markout services prior to penetrating an estuary bed, riverbed, lakebed or pond bottom.
Typical tools for on-water markout may include:
•Electromagnetic time domain detection systems (towed benthic sled, diver maneuvered system, float system and Smart-core vibracoring system).
• Sub-bottom sonar survey
• Magnetometer and gradiometer survey
• Side scan sonar survey
Side scan sonar can produce remarkable real-time images. Aqua Survey operates single/dual-frequency side scan sonars. Side scan uses transducer-produced pulses of sound emitted from a towfish. The sound waves are emitted at an angle to “illuminate” the bottom. These sound waves bounce off the relief of the bottom and return to the transducer as a sound reflection. Images of the bottom’s relief (e.g., sunken vessel) can be viewed real-time on the survey vessel and are recorded digitally for post-survey viewing, processing and mapping. Side scan surveys are used to support:
Aqua Survey can deploy a CME-55LC track-mounted drill (or equivalent), a Diedrich D-25 skid-mounted drill, or a portable Winkie drill on several of our vessels. Unconsolidated or moderately consolidated sub-bottom samples can often be collected by vibracoring. Harder bottoms frequently require the use of percussive (hammer) or rotary drilling techniques. During standard drilling, a casing is either hammered or rotated into the bottom to sampling depth. To collect samples at prescribed depths, a split spoon is pushed into the casing and immediately removed and containerized. Unlike a split spoon, a Shelby tube is inserted and then pushed into the casing pipe. Then the sample is allowed to swell in the tube for up to 30 minutes to prevent loss during extraction. After removal, the sample tube is capped and wax-sealed for offsite geotechnical testing. Rotary drilling techniques are utilized to collect consolidated sediment and rock cores.
Vessel-based services include:
Aqua Survey owns and operates a fleet of over 20 research / survey vessels that have been customized to support markout, environmental and geotechnical field services. The vessels range in size from a 12-foot amphibious vehicle to our 100-ton, 70-foot long flagship, the R/V Robert E. Hayes. All vessels are capable of operating in shallow-draft areas. Our vessels are operated by scientists who are United States Coast Guard licensed captains. All crew members are OSHA HAZWOPER 40-hour trained. Our vessels are also used by the motion picture industry as filming platforms.
The following Aqua Survey vessel types are available:
• Class 80-foot Liftboats
• Commercial grade catamaran self-propelled pontoon vessels
• Mono-hulled survey vessels
• Commercial grade pontoon platforms
• Inflatable self-propelled pontoons (Excellent choice for working in remote areas)
• Mono-hulled open support vessels
• Amphibious vehicles
Aqua Survey utilizes depth sounders and side scan sonar to rapidly characterize the sediment grain size characteristics to economically map surficial grain size of expansive areas. Grain size can be used to accurately predict the potential for contaminant loading. Hypack Max™ software is used for vessel control and tracking. RTK-DGPS or DGPS precision can be achieved for accurate mapping. This technology can classify: Bedrock, Cobble, Gravel, Sand, Silt and Clay.
Aqua Survey collects proposed dredged material, processes the sediment samples, and preserves them for analyses. Our scientists regularly perform geotechnical, chemical and biological analyses in support of water quality and disposal alternatives studies. Aqua Survey will help clients prepare a sampling and analysis plan to submit for regulatory approval. The following are examples of in-house procedures: