The Background

The Lancashire town of Earby has been prone to devastating flooding in recent years – most notably on Boxing Day 2015, when homes and properties suffered significant water damage. Since that date, the Environment Agency has worked in partnership with local authorities and Yorkshire Water to develop schemes to reduce the flood risk.

A significant contributor to the problem was the Victoria Clough Culvert, which carries water under the town. Part of the culvert, underneath a disused railway embankment, had collapsed.

In July 2018, a 13-week, £1million project began to replace the collapsed section and to re-line and replace a number of sections along the culvert to reduce the flood risk to 91 properties and 17 businesses. The scheme also included the installation of an improved trash screen at the inlet to the culvert, designed to be easier to clear and to reduce the likelihood of blockages.

The Environment Agency appointed JBA Bentley as contractors for the scheme. Selwood’s pumping solutions specialists were called upon by JBA Bentley to survey the overpumping of the culvert inlet while the trash screen was being upgraded.

The Challenge

While the trash screen works were being carried out, water needed to be overpumped away from the inlet and discharged into a manhole on a public street.

Selwood’s teams needed to move the water a distance of 450m, through woodland that needed to remain open to the public and through areas used by pedestrians, for the duration of the works.

Enabling pedestrians to safely cross the pipework and keeping access open at all times were challenges to be overcome.

The Selwood Solution

Because of the health and safety considerations and need for public access, the pumping setup needed to be as neat and tidy as possible. Two Selwood D150 Drainer pumps, connected together using a Y branch, were used to pump the water flow along the 450m distance.

One common line rather than two was used to minimise the amount of pipework involved, and at the point of discharge, the line was enlarged to reduce friction losses within the pipework. This was vital to ensuring the water could travel the distance required.

In the woodland areas, pedestrian bridges were used over the pipework to keep the footpath open. On the areas of public path, road ramps were used. These are wider than the bridges, with a more shallow ramp, helping the flow of pedestrians and providing an easier journey for those using wheelchairs or prams.

The Result

Selwood’s specialists were involved for seven of the 13 weeks of the project, successfully diverting the flow away from the culvert for the duration of the works without causing significant disruption to the public. The site manager reported satisfaction with the project and praised the expertise of Selwood’s team.

The project completed in late August 2019, with a new 40-metre length of culvert installed under the railway embankment and a further 60m relined. The project has been hailed as bringing significant flood risk benefits to homes and businesses in Earby.