Hydrographic Survey and Design Verification for the New Southern Barge Ramp

How QOffshore converted shallow-water and tidal constraints into decision-ready engineering
evidence for Tailored Spatial Solutions.

CLIENT

Tailored Spatial
Solutions

LOCATION

Chinaman Creek, Cairns,
QLD

FIELD SURVEY

30 August 2025

QOFFSHORE ROLE

Hydrographic survey

SERVICE

MBES survey and design verification

PRIMARY SYSTEM

NORBIT iWBMS Tx +
GNSS/INS

PROCESSING

Qinsy acquisition + Qimera QC

OUTPUTS

Surfaces, profiles, charts and volumes

The client issue

Tailored Spatial Solutions needed a reliable, high-resolution understanding of the seabed around the New Southern Barge Ramp and its approaches. The data had to support engineering assessment, operational planning and future maintenance, while allowing the existing seabed to be compared directly with the clientsupplied design surface.

The practical question

Had the required design levels been achieved, and were any local shallow areas still requiring attention?

The survey challenge

The nearshore zone was extremely shallow and the survey coincided with neap tides. The limited tidal range reduced the safe operating window for the survey vessel and made continuous water-to-land coverage difficult. A small residual gap in the shallowest zone had to be transparently documented rather than reached at the expense of vessel safety.

What QOffshore provided

QOffshore combined multibeam bathymetry with LiDAR referenced to a common datum, used a compact aluminium workboat and independently checked the survey control. The workflow produced a consistent seabed model that could be compared directly with the engineering design.

Mobilise and verify

Measure vessel offsets, complete position checks and confirm the survey control.

Acquire and calibrate

Run MBES survey lines, complete patch testing and monitor quality and coverage in real time.

Process and integrate

Clean and validate bathymetry, align LiDAR and generate a high-fidelity seabed model.

Compare and report

Create the difference grid, volume calculations, six longitudinal profiles and final charts.

What QOffshore provided

Mobilise and verify

Measure vessel offsets, complete position checks and confirm the survey control.

Acquire and calibrate

Run MBES survey lines, complete patch testing and monitor quality and coverage in real time.

Process and integrate

Clean and validate bathymetry, align LiDAR and generate a high-fidelity seabed model.

Compare and report

Create the difference grid, volume calculations, six longitudinal profiles and final charts.

The survey challenge

Measurable results

25,615 m²

Total surveyed area

16.5 million

Accepted soundings

0.134 m

Reported uncertainty

492.02 m²

Area below design

Design comparison footprint 493.13 m²
Area above the design surface 1.11 m²
Volume above the design reference 0.03 m³
Average difference 0.51 m below the design surface
Local exceptions Two isolated patches, up to approximately 0.13 m above design

Outcome and client value

The design comparison showed that almost the entire assessed footprint was at or below the engineering
design surface. Only two small, localised areas were shallower than design, allowing the project team to focus
attention precisely rather than relying on broad assumptions or repeat work across the full footprint.

THE SUCCESS STORY

QOffshore transformed a difficult shallow-water survey into clear, quantified evidence for
engineering review. The final outputs showed where the design had been achieved, identified the
limited exceptions and provided a reliable basis for next-stage planning.

Client testimonial

“QOffshore provided a practical and well-controlled hydrographic survey solution for the New Southern Barge Ramp. The team were professional, safety-focused and committed to quality, managing the shallow-water and tidal constraints effectively while delivering clear, reliable survey data for our engineering review and next-stage planning.”

Hydrographic Survey and Design Verification for the New Southern Barge Ramp