Client: Thames Water (on behalf of Solutions)
Location: Tottenham, London, United Kingdom
Service: Surface Water Drainage Culvert Survey, Inspection and Route Mapping
Project Overview
DJM Aerial Solutions was commissioned to carry out a confined space culvert inspection beneath a busy road in Central London using the Elios 3 drone system. The inspection was necessitated after two traditional inspection methods—CCTV crawler and amphibious vehicle—were unable to progress more than a few centimetres into the structure due to significant silt and debris accumulation.
Traditional methods would have required a jet vac clean prior to redeployment, a solution that would have involved prolonged road closures, costly traffic management, and widespread disruption within one of the capital’s most densely trafficked areas.
Instead, DJM Aerial Solutions delivered a full condition survey and georeferenced LiDAR route map of the culvert system in under two hours, without the need for prior cleaning or extended traffic management. The inspection was completed safely, efficiently, and with all deliverables submitted within one week.
This project once again demonstrated DJM Aerial Solutions’ unique ability to solve complex access challenges in confined urban infrastructure, solidifying our position as the industry leader in drone-based internal inspections.
Challenges of Traditional Inspection Methods
In an attempt to survey the culvert using standard techniques, the client engaged contractors to deploy both CCTV crawler systems and remote amphibious vehicles. However, both methods failed immediately due to silt and debris blocking the system at the point of entry.
The traditional alternative involved:
Option 1: Jet Vac Cleaning and CCTV Re-Entry
Disruption: Extensive cleaning operations requiring multiple vehicle setups and long-duration traffic management plans.
Cost: High operational costs due to labour, equipment mobilisation, and road closures in a high-traffic zone.
Time: Cleaning and preparation are estimated to take several days before any inspection could begin.
Option 2: Confined Space Entry (Manual)
Safety: High-risk confined space entry requiring gas testing, manned entry procedures, and rescue teams.
Delays: Risk of delay due to permit-to-work systems and compliance with urban safety protocols.
Both methods were deemed either unviable or too disruptive to proceed. A faster, safer, and more cost-effective solution was urgently required.
DJM Aerial Solutions’ Approach
DJM Aerial Solutions proposed a non-invasive drone-based inspection using the Elios 3 confined space drone, which is uniquely equipped for inaccessible environments.
Prior to deployment, traffic management measures were coordinated to allow for a short-term road closure after rush hour. This created a 2-hour window for the inspection team to enter the system via a manhole access point without causing significant disruption to city traffic.
Using the Elios 3, DJM Aerial Solutions completed the full scope of work within this limited timeframe, including:
Full internal condition survey using HD visual sensors
3D LiDAR scanning using the onboard SLAM-based LiDAR unit
Georeferencing of point cloud data using pre-established GPS control points outside the culvert
Overlay of culvert route onto a topographic survey, with accurate fall gradient analysis
Drone Inspection Findings
Despite the presence of extensive silt and debris, the Elios 3 successfully navigated the internal structure and captured key insights:
Obstruction Confirmation: Visual confirmation of heavy silt build-up that prevented crawler movement—validating the failure of traditional techniques.
Structural Integrity: No major defects or collapses were identified; the culvert was in structurally sound condition along the inspected route.
Route Verification: The internal path was successfully mapped to OSGB standards, confirming alignment with external utility records.
Gradient Analysis: The fall of the culvert was within expected tolerances, with data accuracy suitable for future design and intervention planning.
All findings were collated into a detailed report and supported by an annotated point cloud, visual imagery, and GIS-ready outputs.
Cost and Risk Comparison
| Method | Cost Estimate | Traffic Disruption | Safety Risk | Outcome |
|---|---|---|---|---|
| CCTV + Jet Vac (Traditional) | £25,000–£40,000+ | Several days | Medium (manholes, vehicles) | Still requires follow-up LiDAR survey |
| Manual Confined Space Entry | £30,000+ | Days to weeks | High (confined space entry) | Labour-intensive, high PPE and permits |
| DJM Aerial Solutions (Drone) | < £7,000 | 2 hours | Minimal | Full inspection + LiDAR + GIS overlay |
Client Deliverables
High-resolution condition video footage of the internal culvert system
Annotated LiDAR point cloud georeferenced to OSGB
Topographic overlay showing the culvert route and structure position
GIS-compatible outputs for integration with the client’s asset database
Full deliverables provided within 5 working days
Client Satisfaction and Ongoing Partnership
The client was highly satisfied with the speed, precision, and non-invasive nature of the inspection. DJM Aerial Solutions provided a level of data accuracy that exceeded the capabilities of traditional inspection workflows, all within a severely restricted access window.
By eliminating the need for pre-cleaning and avoiding extended traffic closures, we significantly reduced project cost, time, and risk, allowing the client to make informed asset management decisions immediately.
DJM Aerial Solutions continues to support critical infrastructure clients throughout the UK with innovative drone-based inspection services tailored to confined, hazardous, and inaccessible environments.
- Contact Us Today: Contact DJM Aerial Solutions for a consultation or to schedule your next Confined Space Drone Inspection.
- Request a Quote: Learn more about how our innovative drone technology can save costs and enhance safety for your industrial inspections.
Case Studies
Related Projects
Internal Inspection of Queen Mary 2 Scrubber Towers Reveals Critical Weld Failures
DJM Aerial Solutions conducted a confined space drone inspection of the scrubber tower assemblies aboard the Queen Mary 2. Using Elios drone technology, critical circumferential and longitudinal weld failures were identified within the exhaust gas cleaning system. Several months later,...
View Project Details
Stanlow Refinery Thermal Drone Inspection
DJM Aerial Solutions completed a thermal drone inspection of heat exchangers at Stanlow Refinery using radiometric UAV technology. The inspection identified thermal anomalies and potential insulation degradation while the refinery remained fully operational, eliminating the need for scaffolding, rope access,...
View Project Details
Inspecting Spring Hanger Systems Using the Elios 3 Drone
Spring hanger assemblies are critical components within industrial pipework systems, allowing pipework to expand and contract safely during temperature changes while maintaining correct load distribution. In this case study, DJM Aerial Solutions deployed the Flyability Elios 3 confined space drone...
View Project Details