Gibbs Weir Fish Pass

An innovative headwall and flume system allowed the River Sirhowy to be diverted completely around the works, meaning all works could be carried out off-line and pollution risks to the sensitive river environment were eliminated.

Due to owning our own yard for the previous 30 years with 9000m² of storage we are able to store and reuse materials from numerous contracts. This was a particular benefit for Gibbs Weir where we sourced and fabricated a bespoke headwall in-house within our own workshop. This gave the benefit of programme certainty to the contract as a separate fabrication company was not required, along with the obvious cost savings.

McCarthys were able to use their in depth knowledge of South Wales to procure the rock required.

The Works

In recent years McCarthy's have constructed many fish pass schemes for the NRW including Brynmenyn Weir, Marcroft Weir, Railway Terrace. A notable job was Gibbs Weir near Pontllanfraith.

The work involved demolishing a weir that was preventing fish passage upstream. A rock ladder was constructed in its place for a distance of approximately 100m and associated cascades and weirs. The work was carried out by diverting the River Sirhowy through a flume.