Hydrographic Survey on the Rivers Tame and Trent

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Hydrographical Survey

River Trent

Revitalising Water Resources: A comprehensive bathymetric survey on the Rivers Tame and Trent

As part of an ongoing project that commenced in 2022, we have recently completed a bathymetric survey of eight weir locations and the adjoining channel of the River Trent for AECOM. The project, on behalf of Affinity Water, Severn Trent, and the Canal & River Trust for the development of a Strategic Resource Option (SRO) known as the Grand Union Canal Transfer, is part of the Water Resources National Framework to secure England’s long-term water needs.

The scheme plans to transfer 115 million litres of surplus water per day from a wastewater recycling centre in Birmingham in Severn Trent’s supply area, via 131-kilometres of canal network, to reach Affinity Water’s areas of deficit in the Southeast. The scheme will reuse and improve existing equipment along the canal network, as well as installing some new pipes and pumps where needed.

To assess the potential environmental impact of this scheme, the project’s ecologists required construction and simulation of hydraulic models of sections of the River Trent. Specifically, the hydraulic models were required to simulate and evaluate alterations in water depths and velocity at potential barriers to fish movement. To be constructed, these hydraulic models required detailed 3D terrain models of the River Trent’s riverbed and structures such as weirs and fish passes.

In 2022, AECOM initiated a tender for the surveying of several weir and riverbed locations along the River Tame and River Trent to provide the required terrain models, ultimately awarding us the contract. The success of this collaboration led to an invitation to revisit the project in 2023 for the latest stage of assessment, which

commenced on the River Trent in August 2023. Creating the detailed 3D terrain model of this stretch of the river involved topographical surveys to define the riverbanks and hydrographical surveys to model the riverbed.

Detailed data was obtained at one meter intervals at the weir locations and at five meter intervals along the channel. Echosounders mounted on boats were used to gather data along the channel. Due to the water volume and turbulence, surveying weirs is more challenging. Timing played an important role and when the water volume was low the weir locations were manually measured with poles.

Obtaining access to the riverbanks involved liaison with the Canals and River Trust as well as private landowners. We employed a combination of total stations for accessible banks and drones for areas with restricted access.

Delivering incremental 3D terrain models and CAD drawings as the project progressed enabled AECOM to construct their hydraulic models sequentially to ensure the project could be delivered to the tight regulatory programme.