SDS Weholite stormwater attenuation system protects new business park from flooding

Overview
Kestrel Park is a flagship business park development in Barnsley, designed to encourage economic growth, create employment opportunities for local residents, and support the wider regional economy. Delivered by Carnell Management Services and constructed by Manor Construction and BDB Design Build, the £12 million scheme comprises seven high-quality warehouse, industrial, and trade units with offices, ranging in size from 3,010 to 21,535 sq ft. The development meets BREEAM ‘Very Good’ standards and incorporates multiple sustainable features, including solar panels, EV charging points, cycle parking, LED lighting, and fully fitted offices and amenities.

As part of the scheme’s surface water management strategy, SDS was appointed to design and supply a below-ground attenuation system to manage runoff from the new buildings, access roads, and service areas. This infrastructure was essential to protect the development and surrounding areas from flooding, maintain pre-development discharge rates, and safeguard nearby ecological sites, including the Dearne Valley Wetlands Site of Special Scientific Interest (SSSI).

What They Did
SDS designed and installed a comprehensive Weholite® attenuation system to manage surface water across the 1.77 hectare site. The system features a tank constructed from 6 metre long Weholite HDPE pipes of varying diameters, joined together to create a structure extending over 100 metres in length. Four Weholite manholes provide access for inspection and maintenance, while an oversized Weholite Flow Control Chamber incorporating a Vortex Flow Control and HDPE penstock ensure discharge rates are carefully regulated. The system is integrated with upstream oil and grit separators to protect nearby conservation sites and maintain compliance with environmental and planning requirements. SDS coordinated closely with Manor Construction and BDB Design Build to deliver the system efficiently alongside the ongoing construction programme, ensuring minimal disruption to other site activities.

Results
The SDS Weholite® attenuation system now provides reliable, policy-compliant surface water management for the Kestrel Park business park. Surface water from the 1.77 hectare site is discharged at a controlled rate of up to 15 litres per second, maintaining pre-development runoff levels. The system effectively attenuates 100-year +40% climate change rainfall events using a combination of underground storage and surface management, while the removal of overland flows significantly reduces flood risk to buildings, roads, and parking areas. In addition, the system safeguards nearby ecological sites, including the Dearne Valley Wetlands SSSI, from pollution and contamination.

The successful installation demonstrates SDS’s ability to deliver high-performance, sustainable drainage solutions for complex commercial developments, combining resilience, environmental protection, and operational reliability in a single integrated system.

Testimonial

The attenuation scheme has addressed Natural England’s prior concerns that, without appropriate mitigation, the development would damage or potentially even destroy, through water and air pollution, key features for which Dearne Valley Wetlands has been designated a Site of Special Scientific Interest.

– Jason Cartwright, Key Account Manager, SDS

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