Hydrographic Surveys
A hydrographic survey measures water depths (bathymetry) and locates underwater features using sonar, GNSS positioning, and motion sensors. The result is an accurate 3D model of the bottom, tied to a known vertical datum (e.g., MLLW, NAVD88), with clear contours and spot depths for design and construction.
What we capture
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Depths & contours (bathymetry)
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Shorelines, structures & hazards: docks, piers, revetments, reef edges, submerged debris
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Channels & dredge limits with volumes (cut/fill)
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Tidal references and water-surface observations
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Optional: sub-bottom indicators (if specified), current profiles (ADCP), and sediment probes
How we do it (Hawaii Surveying)
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Single-beam and multi-beam echo sounders for small areas to high-density coverage
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GNSS/INS positioning with RTK/PPK for precise horizontal/vertical control
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Sound velocity and motion compensation for clean, corrected depths
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Tide control: RTK tides or tide gauge observations; datum transformations to MLLW/NAVD88
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Integrated topo + hydro using terrestrial LiDAR/drone mapping to stitch land–water edges
Typical deliverables
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Bathymetric surface (TIN/GRID) and contour maps (CAD/PDF)
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XYZ/point files, tracklines, and coverage maps
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Cross-sections & volume reports for dredging and as-builts
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QA/QC and control reports documenting datums and methods
When you need a hydrographic survey
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Dredging design & pay quantity verification
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Marine construction (piers, seawalls, outfalls, moorings)
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Harbor/reef channel condition assessments and maintenance planning
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Shoreline, erosion, and coastal engineering studies
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Environmental & habitat mapping and compliance documentation
Hawaii-specific notes
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Complex shorelines, reefs, and surge require careful tide/datum management
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Clear water + reef relief benefit from multi-beam density and topo–hydro integration
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Permits and vessel access windows may be needed; we coordinate with harbor authorities and contractors
Why choose Hawaii Surveying
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Faster, reliable results using GNSS/INS, calibrated sonar, and LiDAR/drone integration
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Clear, construction-ready deliverables for design, dredge, and as-built stages
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Island-wide mobilization: Oʻahu, Maui, Kauaʻi, Hawaiʻi Island, Lānaʻi, Molokaʻi
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Proud Operating Engineers Local 3 (OE3) member crews with marine jobsite experience
When would you need a Hydrographic Survey?
Common reasons to order a hydrographic (bathymetric) survey
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Dredging – Pre-design mapping, quantity estimates, and post-dredge pay verification
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Marine construction – Piers, docks, moorings, seawalls, breakwaters, intake/outfall pipes
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Navigation & safety – Check for shoaling, debris, reef edges, and channel conditions
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Permitting & compliance – Bathymetry and shoreline data requested by agencies for impact reviews
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Coastal engineering – Erosion studies, scour assessments, beach nourishment design
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Storm damage & maintenance – Post-event condition surveys and periodic harbor/marina monitoring
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Utilities & corridors – Subsea lines, cables, or pipelines route planning
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Design integration – Create seamless topo + hydro surfaces for engineers and contractors
Project timing
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Pre-design baseline (before concepts and permits)
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Pre-construction (to finalize grades/limits)
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During construction (progress checks, interim quantities)
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As-built/closeout (final verification for pay items and records)
Hawaii-specific cues
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Work near reefs, harbors, channels, or shorelines where tides and coastal processes matter
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Need data tied to MLLW/NAVD88 and coordinated with topographic surveys on land
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Access windows, vessel coordination, and clear-water planning are important—especially on Oʻahu, Maui, Kauaʻi, Hawaiʻi Island, Lānaʻi, and Molokaʻi
What you get from Hawaii Surveying
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Clean bathymetric contours/surfaces, cross-sections, and volume reports (CAD/PDF)
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GNSS/INS-corrected sonar data with QA/QC and control reports
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Integrated topo + hydro deliverables ready for design and construction
Hawaii Surveying combines calibrated sonar with GNSS/INS, terrestrial LiDAR, and drone mapping to deliver fast, accurate marine datasets.
Proud Operating Engineers Local 3 (OE3) member crews.
Ready to get started?
We're eager to learn about your project and get to work providing a fast, precise, and high-quality solution based on your needs.