Topographical Surveys on the River Sulby and River Dhoo


JBA Topographical Surveys on the River Sulby and River Dhoo
Topographical Surveys on the River Sulby and River Dhoo

We recently carried out topographical surveys for river models on the River Sulby, Isle of Man for Manx Utilities. The project required two distinctive phases, a cross section survey of the main river and also a bathymetric survey within the Ramsey harbour area, where the River Sulby meets the sea.

Manx Utilities also required an additional survey of the River Dhoo so that a Flood Risk Assessment for the proposed new Waste Water Treatment Works (WWTW) at Crosby could be carried out. A quick turnaround was important to the client to inform the design and Flood Risk Assessment.

Wishing to improve their understanding of the flood risks associated with the River Sulby, Manx Utilities wanted to inform a maintenance regime in the area. To support the hydraulic model development, they wished to carry out topographic surveys including a channel cross sectional survey and bank level survey at a number of locations along the river banks. A bathymetric survey to recalibrate the forecasting services was also required.

As the models were to be used for flood risk management purposes, and may also be used to evaluate possible flood alleviation options in the future, they needed to be accurate and reliable.


JBA Topographical Surveys on the River Sulby and River Dhoo
Topographical Surveys on the River Sulby and River Dhoo

We were able to carry out the survey in an efficient and safe manner by using cutting edge technology such as:

  • Global Navigation Satellite Systems (GNSS)
  • High precision auto-tracking total station
    survey instrumentation
  • Remote control survey boat equipped with a
    lightweight echo sounder
  • Specialist GeoRiver processing software.

Deliverables for the channel survey were provided in various hydraulic software ready formats, providing the modeller with survey data ready for direct input into their models.

The bathymetric survey of the harbour area was undertaken using a remote-control survey boat, totally eliminating the risk of anyone working on water. We also worked collaboratively with the client to integrate the additional River Dhoo survey into the overall River Sulby survey programme.


The surveyor is often the only eyes that actually walk the entire length of the watercourse that is being modelled, and therefore their observations and understanding of the modelling requirements was critical in ensuring that no important hydraulic feature was missed.

Combining the technical knowledge of our in-house survey team and the local knowledge of our Isle of Man office, the survey’s for both the River Sulby and the River Dhoo were delivered smoothly, safely and successfully.

Want to know more?

Email Greg Parkinson, Chartered Senior Engineer, for more information on this project or visit our engineering web pages.

Learn more about our work on the Isle of Man.

Visit our Knowledge Hub

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