Highway Drainage

Concrete Channel Drainage, Fildrain Type 10 - A1 Leeming to Barton Scheme, North Yorkshire, UK

Client Highways England

Carillion – Morgan Sindall JV

Consultant AECOM / Grontmij

Fildrain – Highway Edge Drains


7,000 lin metres


– High strength, keying effect
– Excellent flexibility
– Bespoke dimensions
– BBA Approved

Project Description

The A1 Leeming to Barton upgrade has replaced the existing 12 mile stretch of dual carriageway with a new three lane motorway. It will also include the provision of a new local access road alongside the new motorway, improving safety for local traffic from the surrounding communities. Access to the strategic road network is via a new grade separated junction at Catterick and an improved junction at Scotch Corner.

Award Winning Project

The A1 Leeming to Barton Upgrades won the Highway Awards category for Environmental Sustainability in October 2017. The judges commented “Really impressive saving with 100,000 m³ of existing pavement and 97% of waste diverted form landfill”. The assessment criteria for this award includes carbon footprint reduction, local environmental benefits, sustainable material use and reduction of CO2. ABG Fildrains made a major contribution to all these criteria.

The Challenge

Highway drainage has two objectives: safety of the road user and longevity of the pavement. Trapezoidal channels are the preferred choice to remove surface water and provision of effective sub-surface drainage will maximise longevity for the pavement, avoiding softening of the road sub-layers. The consultant chose the Fin and Narrow sub-drainage system detailed in the standard Highways Construction Details (HCD) F Series. This uses a shallow V channel to drain surface water and a Type 10 findrain (HCD F21) combined with a Type 6 findrain (HCD F18) to drain sub-surface water. The challenge for the contractor was to find the required BBA approved, cost effective, combined solution which gave additional benefits to the client, minimising potential maintenance in the future and maximising the long-term asset value.

The Solution

The ABG Fildrain Type 10, a BBA certified system, was selected due to its optimised design, which met and exceeded all the criteria specified by the consultant. Additional benefits include the strong but flexible HDPE cuspated core, creating a regulated surface which includes a keying effect to the concrete to aid slip forming. The well bonded geotextile and dimpled surface gave a high friction surface to the underside. The ABG Fildrain Type 10 is compatible with the ABG Fildrain Type 6 edge drain on one side of the channel and allows the choice of the two alternative corner details as illustrated in HCD F21, as shown below.

ABG Fildrain Type 10 and ABG Fildrain Type 6 integrated under channel drainage

The ABG Service

ABG provided technical and practical support from all stages of design to managing the logistics of supply. The ABG Fildrain Type 10 was manufactured in site specific widths at our factory in West Yorkshire which saved installation time on site.

Contact ABG today to ask for specification clauses in line with SHW Clause 514 and other project specific requirements.

This scheme is an example of implementing an idea from the Highways England “Managing Down Costs” Toolkit.

Additional information