Ground investigation is vital in new channel design

Ground investigation can be critical in determining how to ensure water is retained within a new bypass channel. One of our recent projects demonstrates this and the importance of timely investigations.

Putting in the ground work

We were appointed by Antler Homes last year to produce a detailed design for a bypass channel on a branch of the River Loddon, east of Reading, to facilitate upstream fish migration past an existing sluice structure.

As part of the baseline and outline design process, we identified that there was no ground investigation information available for the proposed location of the bypass. Furthermore, on reviewing historical mapping for the area, we also found that the client’s proposed route of the bypass channel cut across a number of infilled, relic channels associated with the milling heritage of the site. The historical records provided by the client also indicated numerous registered landfills in the area.

We flagged the above risks to the client, who then commissioned us to develop a specification for intrusive site investigation, to develop a better understanding of the ground conditions of the site.

The results of this investigation revealed that the near surface geology of the site consisted of loose sands and gravel over thick clay, and confirmed the location of the relic mill channels, as made ground.

Moving forward

As we progress through the detailed design process, the results of the ground investigation will be critical in determining how we ensure water is retained within the bypass channel, particularly at low flows, determining whether it can continue to provide effective fish passage. It will identify how we minimise the risk of the creation of pathways between historical fill material and the river environment, and how we minimise the scale of the construction to manage costs.

Want to know more?

More information on fish passes can be found on our Catchment and River Restoration page. You can also find out more about this project from Jon Whitmore.

Our Catchment and River Restoration team will also be at the River Restoration conference on 4 – 5 April so please go along to meet them, and see the demonstration of the fantastic opportunity and benefit maps we have developed for the Environment Agency.

Leave a Reply