Issue link: https://geospatial.trimble.com/en/resources/i/1480702
Case Study Customer: PDS Surveys Project: Limited access survey with multiple challenges Solution: Trimble SX10 and senseFly eBee x help of a bat ecologist was enlisted. If bats were present, the bat ecologist would take the lead and advise as required. The first step was the CCTV survey. With no access allowed, Lee's solution was to create a raft base for the camera which could be hauled through the tunnel using the existing rails and rope. On completion, the CCTV survey revealed that, although the tunnel appeared to be safe, one of the UK's rarest mammals, a horseshoe bat, was hibernating in a central section. The ecology expert, along with the client, reviewed PDS's Method Statement & Risk Assessments for the second survey and requested that Lee carried out the work following a strict 'No Entry' into the tunnel policy to avoid compromising the sleeping bat. For Lee Husk, Director of Caerphilly based survey company PDS Ltd, a combination of over ten years laser scanning experience, a reputation for loving a challenge and the unique functionality of Trimble's SX10 Scanning Total Station provided the answer. Located in a steep valley in the Pembrokeshire countryside between the coast at St Brides Bay on one side and the River Solva on the other, the Solva Water Treatment Works has no access routes apart from an unused 170m tramway tunnel linking it to the town's harbour. The only alternative is a demanding twenty minute uphill walk that makes the transportation of equipment to the works particularly arduous. In order to find the best way to provide access, it was decided that a full condition survey of the tunnel would be undertaken starting with a CCTV survey to determine its safety. This would be followed by an aerial survey of the works and the surrounding countryside to complete a feasibility survey for alternative access solutions such as a new haulage road. Contracted to undertake the work was Lee Husk, Director of PDS Ltd, who is known for his early investment in 3D Laser Scanning technology and experience in confined space work. For Lee, the aerial survey looked a large, but straightforward job that he planned to complete with his senseFly eBee X fixed wing drone. However, the tunnel survey looked more complex. Bat activity The client was already aware of signs of potential bat activity at one end of the tunnel. Therefore, prior to the ground- based survey works being carried out, the Let sleeping bats lie! How do you produce an accurate point cloud of a 170m tunnel, with no human access permitted, that's also home to one of Britain's rarest bats hibernating over winter? "This demanding survey has showcased every aspect of our SX10's unique functionality ." Lee Husk, PDS Surveys Project highlights: n Consistency of the SX10's performance and finding its unique range of functionality a perfect fit for the project's unusual demands n Ability to confirm the quality of the scan data on site n Capturing a vast area with just five flights, all to survey accuracies n Letting sleeping bats lie! The hibernating horseshoe bat