Case Study:
Digley Reservoir Survey
Overview
The aim of the Digley Reservoir project was to establish a complete, measurable understanding of the site layout and critical assets, enabling accurate structural assessment, informed decision-making, and long-term maintenance planning.
To deliver this, Team UAV undertook the following scope:
A full LiDAR survey of the reservoir and dam structure, capturing both upstream and downstream environments to provide comprehensive terrain and structural coverage.
High-resolution inspection of the upstream dam wall face, achieving 0.2 cm spatial resolution to support detailed condition assessment and defect identification.
Targeted capture and assessment of overflow structures, bell tower, service shaft, and associated confined spaces, ensuring complete coverage of complex and previously difficult-to-access assets.
Integration of all captured datasets into a single, high-resolution 3D model, providing a unified spatial reference for engineering analysis, future condition monitoring, site induction, standard operating procedures, and emergency response planning.
Team UAV completed a detailed multi-sensor survey of Digley Reservoir for long-standing client Yorkshire Water, combining aerial, ground-based, and confined space inspections to capture a comprehensive, high-resolution dataset across the site.
The scope included detailed assessment of overflow structures, service shafts, and the reservoir dam wall, ensuring all critical assets were captured in sufficient detail to support safe, informed asset management and engineering decision-making.
By integrating photogrammetry and LiDAR datasets, the survey delivered consistent, high-accuracy spatial data across both exposed and complex environments, providing a reliable foundation for inspection, analysis, and future monitoring.
Project Objectives.
Approach.
The survey combined multiple capture techniques to ensure a complete and accurate representation of the site. Aerial and ground-based data were collected to map the reservoir and dam surfaces in high detail, while a specialised confined space drone was deployed to inspect internal areas of the bell tower and outflow structures.
Access to the outflow system was achieved from both the upstream and downstream extents, allowing data from separate internal flights to be accurately aligned and merged. This produced a continuous point cloud model of the internal structure, providing full spatial context across the entire system.
This approach removed the need for manual entry into hazardous confined spaces while still delivering a high level of visual and spatial detail suitable for inspection and assessment.
The combined use of LiDAR and photogrammetry enabled the creation of a fully integrated 3D model of the reservoir, dam, and internal systems, delivering consistent geometry and reliable spatial accuracy across both external and internal environments.
Data, Processing and Technical Detail.
Data capture comprised multiple LiDAR SLAM and photogrammetric surveys, all of which were processed within a common spatial reference framework. RTK GNSS was utilised on applicable platforms, with ground control points established across the dam structure to ensure all datasets were accurately aligned to OSGB36 (OSTN15).
Within GNSS-denied environments, including confined internal structures, a survey-grade LiDAR payload was deployed to maximise positional accuracy. Adequate overlap was deliberately captured between internal and external datasets, enabling robust registration from local coordinate frames into the georeferenced coordinate system.
Following alignment, the LiDAR data was further classified and processed, allowing Team UAV’s GIS specialists to establish a reliable baseline for ground terrain analysis and vegetation and foliage assessment, supporting both current condition assessment and future change detection.
The Results.
Several Output were created form the data captured.
Aerial LiDAR Point Cloud
The LiDAR data provided accurate 3D terrain data, understanding the slope and aspects of the ground across the site. This can be used to compare future surveys against the current condition as well as monitoring plant/tree health. These provide early warnings of any deterioration to the banks and surrounding environment, reducing the risk of a land slide or other significant event and ensure that ecosystems and biodiversity are sustainable and flourishing.
Inspection Grade 3D Mesh Model
The high-quality georeferenced inspection model can be used to inspect, markup and report both on location and severity of any damage. This allows organisations make decision on reparations and compare the findings against future surveys. This type of reporting better supports organisations than images alone, where personnel can change and knowledge of assets may not handled by a single individual.
Confined Space LiDAR Point Cloud
The confined space 4K video are located in 3D and can be marked up and reported on. This allows the client to review, annotate and locate areas of works that are required. The 3D point cloud of the confined space is fully measurable and would assist to plan any confined space activities and mitigations to carry our any reparations.
Combined Aerial & Confined Space LiDAR
An integrated geospatial 3D model of the site, including the confined space models can be used to update the original hand drawn plans and to create BIM models of the existing structure for future design and development of the asset.
The final output comprised a unified, high-resolution 3D model of Digley Reservoir and its associated structures. Integration of aerial, ground-based, and confined space datasets provided consistent spatial accuracy and detailed coverage across all survey elements, including both external and internal assets.
Achieving a 0.2 cm spatial resolution on the upstream dam wall face, the survey delivered a level of detail suitable for detailed condition assessment and structural review. The project demonstrated how advanced UAV and confined space inspection technologies can deliver safer, more efficient, and more comprehensive survey outputs when compared with traditional inspection approaches, particularly within complex or high-risk environments.
Are looking for a complete, measurable view of your assets without putting people into hazardous spaces? If so, get in touch with our team and book in a call with one of our experts.