Cohasset Harbor Maintenance Dredging, Cohasset, MA - US ARMY Corps of Engineers

For this contract IMT provided a number of survey related services including high resolution MBES, side scan sonar, RTK GPS, UAV aerial photogrammetry, above water line and shoreline LiDAR mapping, topographic mapping, and dredge disposal monitoring.

 In addition to the field data collection services introduced above, IMT also provided a number of data processing and deliverable development services for this project. IMT produced topographic and bathymetric mapping, volumetric estimates, hazards analysis mapping, dredge path, pre and post dredge surveys for pay confirmation, and construction documentation.

IMT utilized its state-of-the-art, fully dedicated, survey vessel for this project, the Atlas. The Atlas is permanently fitted with all of the required equipment to carry out a real-time, high resolution bathymetric survey. All of the positioning and survey systems on the vessel are maintained by IMT in a fully calibrated and ready to deploy state, allowing operators to negate lengthy mobilizations and calibrations prior to survey operations and significantly reduce data acquisition times, while improving overall data quality and turnaround times.

 

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Seawall Stabilization Project, Troy, NY – City of Troy, NY and FEMA

IMT performed a combined multi-beam side scanning sonar/LiDAR investigation to produce 3-D digital image of the vertical surface of the Troy seawall above and below the water surface. This continuous image produced a high resolution “picture” of the wall. To facilitate preliminary work with divers, an assumed vertical reference plane was used to measure the distance from it to the actual surface of the wall, such that it was possible to determine at any location if the wall surface was behind, or in front of, the vertical plane. Comparisons could then determine if the wall was tilted outward at the top indicative of rotation of the wall. Areas of depressions (cavities) of the wall surface were indicative of erosion of the concrete. Areas of “protrusions” of the wall surface could indicate a localized bulging failure of the wall. The results of the wall scanning were used to direct the extent and focus of the subsequent underwater diving inspection work to obtain more detailed information. The comparison/validation of results by the divers was considered to be very accurate in location and extent of deterioration.

IMT utilized its state-of-the-art, fully dedicated, survey vessel for this project, the Atlas. The Atlas is permanently fitted with all of the required equipment to carry out a real-time, high resolution bathymetric survey. All of the positioning and survey systems on the vessel are maintained by IMT in a fully calibrated and ready to deploy state, allowing operators to negate lengthy mobilizations and calibrations prior to survey operations and significantly reduce data acquisition times, while improving overall data quality and turnaround times.

Lock Boat Ramp & Site Renovations, Troy, NY – US Army Corps of Engineers

IMT provided construction management services for the project, coordinated all subcontractors, developed and implemented health and safety plans, met with on-site personnel and purchased equipment and supplies as necessary for the project.  

Work included new channel drains including the installation, concrete, all drain piping and appurtenances.  Also, modification to the existing concrete pads in addition to pouring a new reinforced concrete boat ramp with new pre-cast push ramps installed. 

Due to PCB contaminated river sediment, a temporary sediment drying area consisting of approximately 2500 square feet was constructed. 

IMT also provided all planning and surveying of existing conditions and final as-built drawings along with removal and grading of the entire area including the placement of 2900 square yards of asphalt.  Quality Control personnel were on site for the duration of the project with all quality assurance/quality control services being self-performed. The project was completed on time and on budget.

New York State Canal Corp FWOS - NYS Canal Corporation

IMT provided hydrographic and topographic survey services as part of the New York State Canal Corporation's (NYSCC) Flood Warning Operation System (FWOS). IMT utilized their combined MBES LiDAR vessel to collect data at 270 unique survey areas throughout the 525 mile long canal system. Stream cross section upstream and downstream of bridge/structure openings as well as coordinates of structures/features were delivered per FEMA appendix M guidelines for direct import into customized HECRAS hydrologic/hydraulic modeling software.

IMT utilized its state-of-the-art, fully dedicated, survey vessel for this project, the Atlas. The Atlas is permanently fitted with all of the required equipment to carry out a real-time, high resolution bathymetric survey. All of the positioning and survey systems on the vessel are maintained by IMT in a fully calibrated and ready to deploy state, allowing operators to negate lengthy mobilizations and calibrations prior to survey operations and significantly reduce data acquisition times, while improving overall data quality and turnaround times.

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Natural Trap Cave Survey, Bighorn Canyon National Recreation Area, Montana

The Natural Trap Cave is a national treasure containing over 30,000 fossil specimens of mostly extinct animals from as long as 25,000 years ago. IMT was tasked to scan the entrance and inner workings of the cave system to document the extents of the cave. The cave is characterized by a large 80 foot tall "great room" into which the majority of the animals that found their demise fell. It also has several offshoots that lead into a cave network that are yet unmapped with LiDAR.

The GeoSLAM ZEB-REVO was the perfect choice for the job because a scan of the great room could be gathered as the surveyor was dropped into the cave with repelling equipment. The tight spaces within the cave network were easily mapped with the ZEB-REVO where other bulkier scanners would have simply not gained access. The resulting scans were registered with existing control on the surface and in the cave. The complete model was used to document the progress of the archaeological dig, document the cave, and analyze for potential passageways to the surface or other cave systems.

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UAS Based Photogrammetric Mapping - South Carolina

IMT has completed dozens of UAS (unmanned aerial system) photogrammetric mapping projects for clients throughout the US, Central and South America. IMT was responsible for establishing ground control, collecting aerial photographs, and post processing aerial images into 3D point clouds, digital terrain models, and ortho rectified images.

Mapping areas for these projects ranged from 50 acres to over a 1,000 acres. For all projects aerial imagery was collected in under one day and in varying weather conditions (cloudy, windy, light rain) and the data subsequently processed and mapping developed within a day of imagery collection. Accuracies of the digital terrain model and orthoimagery where within +/- 3 inches of test points collected using RTK GPS techniques.

IMT was able to quickly mobilize, deploy, and obtain aerial imagery from the UAS under our client’s time critical scenarios. The quick data collection capabilities of the UAS technology combined with H2H’s state of the art data transmission and processing infrastructure allow for the delivery of valuable, realtime, and strategic geospatial information consisting of:

  • Orthorectified aerial imagery
  • Topographic contours
  • Planimetrics
  • Wetlands extents
  • Digital terrain models
  • Volumetric analysis
  • Economic analysis
  • Spatial change analysis
  • Extents of vegetation
  • Surface water elevations

Fish Creek Raw Water Tunnel Assessment Mapping, Rome, NY – City of Rome, NY

H2H performed ‘as-built’ tunnel mapping and post construction verification as part of the 1.1 mile long, 100 foot deep East Branch Fish Creek Raw Water Tunnel Rehabilitation Project. 

To verify shotcrete thickness on the walls and ceiling of the 5-6 feet diameter hand dug water tunnel, a full tunnel ‘pre-construction’ survey and several ‘mid-construction’ surveys were performed. The surveys were completed using a combination of RTK corrected GPS (Trimble R8), Total station (Trimble VX), and SLAM corrected mobile laser scanning (Geoslam-ZEB1). H2H utilized a thorough and accurate method of developing a tunnel model by establishing control at the site in a known coordinate system and vertical datum (NAD83 State Plane, NAVD88) and used high definition laser scanning equipment to characterize the tunnel areas.

The survey data collected was combined to generate models with accuracies of 3-5 cm and formed the basis of the 2D and 3D deliverables. H2H created 3-dimensional models of the pre and post construction tunnel surface as an AutoCAD Civil 3D surface file. Cross sections and volumetric assessments between the pre and post construction tunnel surfaces were generated.