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Dam Inspection
Client: GZA Geoenvironmental, The Metropolitan District Commission

SeaVision completed an internal investigation two dams on the Nepaug Reservoir in Connecticut. Working with divers from Halcrow and engineering staff from GZA Geoenvironmental, SeaVision performed the internal investigation of the gate houses, intake shafts, and intake tunnels remotely by using its Seabotix LBV150SE remotely operated vehicle (ROV). Access into the intake shafts measured 24” x 36”, and operating depths were near 60 feet and penetrations near 200 feet. The use of the ROV prevented the need for a confined access dive team and/or cost and safety risks associated with deployment of divers, while minimizing the amount of time required to shut-down the dam for the internal investigation. Deliverables included a letter report documenting conditions in each of the dams and video DVDs for each dam on the reservoir.

Sub-Bottom Profiling
Client: TEC Incorporated, U.S. Navy

SeaVision assembled all of the available historic geologic borings and bathymetry for a site at Naval Station Mayport to develop a basemap of the project area, from which we developed a survey plan that could characterize the project. We mobilized our equipment (including our survey vessel) and personnel from Connecticut to Mayport, Florida, and then performed the shallow marine geophysical survey of the project area using two separate acoustic sub-bottom profilers. All data was geographically referenced using a survey-grade differential GPS receiver, and post-processed in order to highlight subsurface features within 15 to 20 feet of the seafloor. By integrating all available data (bathymetry, geologic borings, and sub-bottom profiles), SeaVision developed interpreted cross-sections of the subsurface, top-of-sand and top-of-clay elevation maps, sediment isopach maps, and volume estimates to describe the quantity of beach suitable sand that can be further investigated for beneficial use.

Hydrographic Survey and Sidescan Sonar Investigation
Client: Hardesty and Hanover LLP, MTA Bridges and Tunnels

SeaVision completed an integrated hydrographic survey, sidescan sonar investigation, and ROV investigation at the Cross Bay Bridge in Jamaica Bay, New York for Hardesty and Hanover LLP and the MTA Bridges and Tunnels. Prior to a proposed rehabilitation of the bridge, the clients desired to investigate whether any remnants of an old bridge (circa 1939) remained in place in the waters of Jamaica Bay. SeaVision provided a complete investigation solution that consisted of a single-beam echosounder hydrographic survey of the entire area of interest, a sidescan sonar investigation of the bottom, and an ROV investigation of potential targets of interest. Deliverables, in both electronic and hardcopy format, consisted of a both processed and fully-interpreted data with recommendations regarding the significance (or lack thereof) of targets observed on the bottom.

Flooded Tunnel Investigation
Client: Nuytco Research Limited

After an accidental rock-fall flooded a mine in northern Saskatchewan in Fall 2006, the mine operator reached out to Nuytco Research Limited for a solution to perform an underwater investigation of the mine. Though the mine was 1500 feet below ground level, the water flooded to within 60 feet of the ground surface. Nuytco contracted with SeaView Systems and SeaVision Marine Services to provide a unique, world-class solution for performing a tunnel investigation in the flooded mine. SeaView Systems deployed a SeaEye Falcon remotely operated vehicle (ROV) into the mine in order to investigate a reportedly open bulkhead door in the mine. Anticipating visibility less than 3 feet, SeaVision configured and calibrated an inertial navigation system for the ROV that allowed us to track the location of the ROV in real-time. SeaVision also developed a 3-D model of the tunnel based on as-built drawings that we were able to use in order to monitor progress during the investigation. At depths of near 1500 feet and with a total penetration distance of approximately 1850 feet, we completed two successful inspection runs to the bulkhead door.