Asset Mapping & Performance Evaluation

A detailed sweep by Glanville’s CCTV department highlighted some deviations from asset records, this necessitated a follow up completed by our Geospatial department, using GPR (Ground Penetrating Radar) and EML (Electromagnetic Location) techniques. This phase found a number of redundant and undocumented lines and successfully answered the questions highlighted from phase 1 CCTV. Once all the data was integrated and reviewed holistically, it was possible to determine the redundant state of the undocumented assets.

With the shore based part of the investigation complete, attention then turned to the mapping and performance evaluation of the outfall, located 100m offshore.

The first task was to map the outfall pipe – this has been completed up to the low water mark using GPR and EML but confirmation of its extract route, depth and discharge point remained. This task was especially challenging given the tidal nature of the area and the fact that the outfall pipe could be partially submerged in the sea bed: It was time to deploy Glanville Geospatial’s Hydrographic Survey experience.

The survey would be split into a number of phases: Having already confirmed the condition of the pipework using CCTV up to the point of tidal influence, the plan was to first survey the section of pipework above the seabed using Multibeam Echo Sounding (MBES), this would provide a highly accurate point cloud that would determine the extent and condition of the outfall pipe, where visible on the sea bed. Next, a sub-bottom profiler would be deployed on the same vessel to accurately position the outfall pipe should it become submerged. Given the metallic make-up of the pipe, the sub-bottom profiling work was independently verified using a magnetometer, adding redundancy to the methodology.

Once all on and offshore components of the network had been mapped, the performance and precise location of the discharge point remained to be confirmed. Glanville’s Cleansing department would seek to pump 1000s of litres of dyed seawater into an upstream MH on the outfalls shoreward side. Meanwhile, the Geospatial department would simultaneously fly an RTK (Real Time Kinematic) drone over the suspected outfall location, enabling a centimetre grade location to be captured at the exact moment of discharge, precisely locating the point of discharge.

The investigations went extremely well and the customer was happy that we could confirm the condition, performance and location of one of their critical assets whilst successfully adding a number of redundant assets to their database. We believe that the seamless integration of several usually unrelated techniques, unified as one product/service, is both novel and innovative and demonstrates the initiative and depth of skills within Glanville Environmental.

The success of the project can largely be attributed to the integration of different departments within Glanville Environmental, all focused on providing the highest possible standards in deliverables and customer service. Of course, delivering great workmanship is one thing but also completing the work over an extended period, hitting key milestones and mitigating unexpected costs is central customer satisfaction. Thankfully, due to realistic advice, great communication and hard work, both cost and time estimates were met, ensuring complete value for the client.

Local residents and members of the public were other key stakeholders than needed to be effectively and considerately communicated with at all stages. Every effort was made to share information on the methodologies/reasons for the investigations and all means were explored to mitigate impact on third parties, incorporating their concerns wherever possible.