Post-Construction Culvert Survey Near Morecambe
Pre- construction CCTV survey of approximately 60 metres of 1200mm concrete culvert to establish its existing condition before construction works commence, including the culvert barrel, inlet, outlet and associated headwall structures.
Location: Morecambe, Lancashire
Service: Pre-Construction drain survey
Overview
We were instructed to undertake a pre-construction CCTV survey of approximately 60 metres of 1200mm concrete culvert near Morecambe to establish its existing condition and general integrity before construction works commenced.
The inspection included the culvert barrel, inlet and outlet structures and associated headwalls, providing a baseline record of the existing condition and identifying any defects or obstructions present prior to the proposed works.
What we did
The survey was originally intended to be completed using a crawler CCTV camera. However, the culvert invert was approximately 50% full of turbid water at the time of inspection, preventing safe and effective use of the crawler system.
To obtain as much information as reasonably practicable, we adapted the survey methodology and used a CCTV camera supported by a flotation device to inspect the accessible length of the culvert. Encrusted deposits were identified around numerous joints throughout the surveyed section, indicating deterioration and potential water or mineral movement through the joint interfaces.
A fractured section of the concrete culvert was also identified, with root growth visible through the damaged area, confirming an existing structural defect. Approximately halfway through the culvert, a significant mass of reeds or vegetation was encountered. Due to the elevated and turbid water level, it was not possible to determine whether this vegetation was actively growing within the culvert or had become trapped as debris.
Large rocks were also detected around both the inlet and outlet mouths, suggesting that further debris may have been present along the submerged invert. Both headwalls were also inspected and found to be showing signs of deterioration. Of particular concern, the outlet gabion basket was failing, allowing aggregate and stone material to fall towards and into the culvert mouth.
The outcome
The survey established a clear pre-construction record of the accessible condition of the culvert and associated structures. A number of existing defects and maintenance issues were identified, including deteriorated joints, a fractured and root-affected section of culvert, accumulated vegetation and debris, deterioration to the headwalls and failure of the outlet gabion basket.
Due to the depth and turbidity of the water, visibility of the submerged invert and lower sections of the culvert was restricted. Cleansing and removal of accumulated debris, rocks and vegetation were therefore recommended, followed by a further CCTV inspection under improved flow conditions if a more complete assessment is required.
Structural repair of the fractured section was also recommended, together with assessment and repair of the deteriorating headwalls and failing outlet gabion.
The pre- construction survey provides a baseline condition record which can be referenced during and after the proposed construction works to distinguish pre-existing defects from any subsequent changes.
Location
The project was carried out near Morecambe.
We provide pre-construction CCTV culvert and drainage surveys for contractors, developers and infrastructure teams across the UK, helping establish the condition, integrity and accessibility of underground drainage and culvert assets before construction works commence.