Aquasition was approached to provide a system to obtain video evidence of water ingress which was causing scour in four underground vaults. If left unresolved the scour could affect the structure supported by the vaults.
The challenge was that when and how the water ingress would occur was unknown so the system had to be designed to operate automatically 24/7 and 365 days of the year and record water ingress into any of the four vaults.
In order to understand when and how the water was entering the vaults it was critical that the onset and direction of the water ingress was detected. We proposed a combination of flow and level sensors installed at key locations to detect the onset and direction of the water. The system was configured so that the detection of flow or level at any one of five monitoring locations would trigger the camera system. The frequency of the measurements was also critical to catch as many readings and images as possible at the start of the event. As a result a measurement interval of 10 seconds was decided on.
The deployed system consisted of:
- Five video cameras and white light illuminators
- Two Doppler velocity sensors
- Six water depth sensors consisting off four hydrostatic pressure sensors and two upward looking ultrasonic sensors.
All sensors were connected back to a single data logger which provided the trigger for the camera system. Both the data logger and camera system were connected to 4G modems allowing images and data to be viewed in real time and also facilitate the downloading of data and images.
Installation was complicated by two of the vaults being classified as confined space due to the limited access and lack of natural ventilation.
The monitoring system has so far identified the main source of ingress into the vaults along with a secondary source of ingress.
