Tilbury Fort protected London’s seaward approaches from the time it was built, between 1670 and 1685, until the Second World War. It has played a large part in the history of the river Thames, and is part of a nationally important landscape for wintering wetland birds.
Two concentric moats surround the star-shaped fort, which take in saline water from the tidal Thames and freshwater from the hinterland catchment. English Heritage wanted to determine how best to manage water levels in the twin moats, to preserve their historic appearance while exploring how the site’s biodiversity and ecological value might be enhanced. Such enhancement might include creating marginal wetlands areas for breeding and overwintering waterbirds.
ABPmer was appointed by English Heritage to develop a new moat management plan. We undertook a bathymetric survey and series of topographic surveys, as well as modelling studies to understand how the moat system functions, and how the water and salinity levels can be managed using the site’s complex, inter-connecting sluices.
To measure elevations across the site, we conducted a bathymetric survey of the inner moat using a Hydrone-RCV remotely controlled boat mobilised with a singlebeam system. Topographic data was acquired along the outer moats using high-precision Global Navigation Satellite System (GNSS) receivers.
We conducted aerial drone surveys, collecting photogrammetry data to provide additional, high-resolution topography of the site. This included photographic stills to build an orthomosaic (high quality map) image, and oblique images of the infrastructure to build a 3D site model.
The drone also collected aerial images, videos and 3-dimensional imagery of the fort infrastructure to help English Heritage promote the site as a tourist attraction.
The imagery, bathymetric data and modelling studies informed the moat management plan, which provided English Heritage with an improved understanding of how the moats operate and related management options.
ABPmer’s experienced surveyors support informed decisions in coastal development with a robust, reliable picture of assets, features and elevations. Learn more about our topographic survey capability.