Hydropgraphic surveys of eight weir locations on the Rivers Tame & Trent.

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.

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.

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 metre intervals at the weir locations and at five metre intervals 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.

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. Carl Pelling, Technical Director – Water Resources commented, “Survey Solutions won the original tender based on their flexibility and ability to meet our timescales. I’ve been particularly impressed by their ability to adapt their surveying methodologies according to site conditions and requirements. The team are always very reliable and readily available to assist us when we need them. I wouldn’t hesitate to recommend them.”