Cong Canal Channel and Structure Survey

The SonarMite system is a portable hydrographic survey system so by definition the boat used will be either a light portable boat or a vessel of opportunity. The SonarMite transducer mounting is designed to fit on to a vertical pole although the actual fitting will vary with the different types of vessel. We can use this system with Survey grade GPS or using a Robotic total station to provide centimeter accuracy data on water depths.

It is currently mounted on our Newmatic safety boat .This is a very stable platform powered by a new 4 stroke 6Hp outboard and transported on a Snipe rollercoaster trailer that makes it easy to launch and recover even without having a slipway.

An example of a recent project we used this system on was to obtain accurate bed data for the Cong Canal for the South Mayo flood relief scheme. This is a fast-flowing river that has been cut through limestone with steep stone banks rising up over 3m on both banks. The water was too deep to wade and access from the banks was non-existent. There was also a heavy flow of water downstream. Although the nearest launch site was 2Km downstream 500m of river bed was successfully surveyed in a day. A particular challenge on this project was obtaining data around the sluice gates located in a remote area near lough Mask. The nearest access by Vehicle was 600m downstream and this was only on the left bank.

The data obtained from the sonar survey was combined with data from an aerial UAV survey and standard topographic survey to produce cross-sections for input into flood modeling software.

Orthomosaic image to ITM of the Sluice Gates Cong Canal

It was a challenging project because of the limited access and that it was not possible to navigate the boat through the sluice gates .
Using a UAV with ground control points we produced a 3D model of the canal both sides of the sluice gates.

3D Model of the Sluice Gates Cong Canal (1.67cm gsd)
The upstream sonar survey was carried out after being given permission to launch at Lough Mask house about 1.5Km away. One of the highlights of this project was on the morning of the upstream sonar survey a stag swam across the canal directly in front of the boat.