Bathymetric Surveying

Underwater survey data and 3D modelling

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Accurate mapping of underwater floor depths and features

AAM’s bathymetric team helps you make better decisions

Specialist surveyors delivering data you can trust

AAM has built a reputation of providing accurate and informative data to engineers and scientists, helping them manage projects in and around bodies of water.

With customised solutions for delivery, training and capacity building, AAM gives you the fundamental data, skills and tools necessary to understand and use the acquired datasets efficiently and effectively. Our bathymetric survey is:

Safe

Unmanned shallow water vessels to measure submerged areas unsuitable for boats/dinghies

Accurate

Well-researched and well-planned project designs from experienced surveyors ensures there are no surprises

Efficient

Systems can be mobilised and launched quicky for fast data acquisition

Detailed

Merging bathymetric survey data with airborne Lidar data creates a seamless surface of exposed and submerged surfaces.

Need more information on AAM’s bathymetric surveying?

Bathymetric survey data for insightful decision making

When captured, processed and presented well, bathymetric survey data sets the foundation for your project’s success. The intelligence and insights gained from the data helps you make better, more informed decisions.

With an accurate understanding of the underwater environment, it’s easier to manage or minimise project risks. And while the survey data will meet your immediate needs, its true value lies in its long-term effectiveness for project management. Bathymetric data can be used for:

  • Tailings dams and mine site flooded areas
  • Accurate measurement for volumetric assessment and sediment monitoring
  • River cross sections
  • Remote site operations
  • Post-flood submerged hazard mapping
  • Completing mapping in urban areas
  • Jetty and harbour surveys

It’s not just the price – it’s how it’s presented

When you first start looking to commission a surveyor, your primary focus is finding a team capable of completing the work, on time and within budget.

But you need more than that.

You want a team that understands your overall project aims and what data you need delivered. Survey specialists who take the time to really understand your project – where it is today and how it will operate in the future.
So, engaging a survey team isn’t just about the data capture. It’s about how it’s processed, and importantly, how its presented to you.  Your data needs to help you make quick decisions, with confidence, to keep your project moving. And it needs to be useful for current needs and beyond.

Our land survey projects in action:

FAQs

Once the scope of works has been agreed and confirmed it’s within the capabilities of the equipment, your bathy team will prepare for the site works. This includes:

  • Mobilisation of equipment and surveyors.
    Dependent on the site, the equipment may be freighted first, or travel with survey team.
  • Site reconnaissance
    Scouting of the site includes identifying boat launch/retrieval pints, control marks and general site conditions. Safety documentation is amended as required.
  • Assemble, set-up and equipment test
    Ensure the equipment and technologies are working nicely together. Immediately before starting the survey, the water levels are measured using real-time kinematic (RTK) GPS.

For most projects the survey team will start by tracing around the outside of the water body to define the survey extents. They then capture the required extents at an interval suitable for the project, usually along parallel ‘flight lines’ set by the software e.g. 10m, 20m, 40m apart.

Once the survey is complete, the water levels are measured again, and the bathymetric data is checked in the software (Hypack). If it all looks as expected, the file is saved and the project closed.

The Hypack data is processed to produce the submarine surface XYZ values.

The data is then processed to produce the final survey output required. This may include surface TIN (triangulated irregular network), volumes or storage curves.

The submarine data can then be merged with data from other sources (LiDAR, UAV, TLS) for a combined surface dataset.

As each project is tailored to client specifications, project prices will vary. However, the following factors can influence the overall project price:

  • Size of the body of water to be surveyed
  • Remoteness of the water body
  • Site induction requirements e.g., mine sites needing medicals, inductions etc.
  • Pre-deployment, site specific works e.g., management plans, safety plans, SWMS etc
  • Systems to be used e.g., Z-Boat, Accura or dinghy. This will determine the number of staff required and mobilisation/demobilisation costs
  • Final output requirements

When assessing the start time for a project, we take into consideration

  • Current equipment availability and freight times to site
  • Induction requirements e.g., mine sites
  • Border closures
  • Site resource availability e.g., mine sites usually require an assistant/authorised driver and vehicle to work on site

Data accuracy is nominally 0.3m horizontal and 0.1m vertical.

Vertical accuracy is key with bathymetric surveying, so even if the horizontal accuracy drops out, loss of RTK GPS corrections, the methodology maintains a vertical accuracy independent of horizontal methodology.

Data delivery will depend on the final outputs and what other data sources are required (UAV, TLS, LiDAR). However, processing of bathymetric data alone is very quick. Several days data can be processed and delivered in less than a day.

The basic data delivery from Hypack is simple XYZ point data. This can then be used to compile a surface TIN or wireframe if needed. The points can be provided in any ascii format (.CSV, .TXT etc), while surfaces can be output in formats compatible with most software that produces TIN surfaces – 12da, .DWG/.DXF, .DGN etc.

If adding above surface data, the TIN can be expanded to produce 3D models.

It’s a big issue if the boat gets stuck, so we work very hard beforehand to make sure that doesn’t happen! These measures include:

  • Planning out the survey so the boat remains in radio range. However, it if loses radio signal, the boat has a default setting, so it moves in large circles until it either regains radio link or beaches downwind.
  • Testing of RC equipment (thrusters, steering, battery) on land before putting into the water, then testing again at the water’s edge immediately prior to launch.
  • Launching the boat under power from a beached position, not pushing it out into the water then applying power (in case you haven’t released the emergency power stop).
  • The initial survey is designed to capture an outline of the survey area while closely monitoring the water depth in real time via Hypack software. This creates a boundary for the planned flight lines so you know you can survey inside.
  • The boat speed is normally 6 – 6.5km/hr, so if an obstacle is encountered and stops/grounds the boat, it can usually be backed off the obstacle under greater or full power. The propwash can also scour out the softer materials.
  • If all else fails, someone needs to go get it.

Want to know more about how your survey data can be used for long-term benefits