Williams Gate to Quarry Hill Pipeline Project: A Comprehensive Water Management Solution

Naturally Compliant was brought on board to develop a comprehensive water management and pollution plan that would not only meet stringent regulatory requirements but also protect the surrounding environment, ensuring the project stayed on schedule and within budget.

The Williams Gate to Quarry Hill Pipeline Project is a prime example of the complexities involved in large-scale construction, especially when situated near environmentally sensitive areas. Tasked with installing 12 kilometres of water utilities infrastructure across Cumbria's countryside, the project faced significant environmental challenges.

The challenge: Navigating complex water management requirements

The Williams Gate to Quarry Hill Pipeline Project involved the installation of approximately 12 kilometres of water utilities infrastructure across Cumbria's countryside. With a 50-meter working area provided as part of the planning consent, topsoil was stripped and stored adjacent to the pipeline trench, resulting in a total working area of 480 square kilometres. The project route ran adjacent to the Lake District National Park, an area with an average annual rainfall of 652mm and 218.8 rain days per year. The route also crossed 11 watercourses, all of which represented significant pollution receptors.

The primary challenge was to develop a robust water management and pollution prevention plan. This plan needed to handle the expected rainfall and surface flow across the extensive working area and treat the water to acceptable environmental thresholds before discharging it into the 11 identified watercourses.

Client concerns and expectations

The client, aware of the environmental sensitivities and the scale of the project, was particularly concerned about the potential for delays due to strict environmental regulations. They needed assurance that water management risks would be effectively mitigated to avoid any disruptions to the project timeline or budget. Naturally Compliant’s approach offered the confidence they needed to proceed, knowing that all environmental risks were being proactively managed.

Pollutants and environmental concerns

The project posed several pollution risks, including:

Silt: The exposed subsoil represented the most significant risk, given the large working area.
Hydrocarbons and COSHH: Chemicals of concern in hazardous substances posed additional risks.
Concrete and elevated pH: The use of concrete presented challenges related to water quality.
Office and welfare wastewater: Wastewater management needed careful planning.

Key environmental concerns also included preventing pollution, maintaining compliance with Great Crested Newt (GCN) exclusion fencing, and adhering to permitting requirements.

The solution: A collaborative and data-driven approach

Understanding the critical importance of water management and pollution prevention, regardless of the projects size, Naturally Compliant approached the project with a focus on collaboration. By embedding our team within the principal contractor's delivery team, we ensured seamless communication with engineers, designers, and project management teams. This integration allowed us to influence the delivery process and align it with the required environmental outcomes.

We began by analysing pre-acquired topographical data to identify surface "catchments" along the route, essentially mapping areas from topographical high points to low points, which typically aligned with watercourses. Next, we studied the route's geology to determine soil types, infiltration rates, and particle sizes. This information, combined with pre-identified rainfall data, enabled us to calculate surface water peak flows for each catchment area.

Using these calculations, we modelled the necessary size of settlement lagoons to treat the peak flows effectively. The design isolated the working area from any offsite water flows, allowing us to implement gravity-based treatment systems, such as settlement ponds. In some instances, we identified areas where additional land beyond the site boundary was required to manage water treatment effectively.

One particularly challenging aspect of the project was maintaining the integrity of the Great Crested Newt exclusion fencing while draining the site. Our solution involved installing French drains, which allowed surface water to be discharged without compromising the fencing.

Additionally, we worked with the project management team to review fuel and COSHH storage, implementing measures such as storing fuel bowsers in impermeable, bunded areas and locking COSHH stores. A robust refuelling procedure further minimised environmental risks. Concreting activities, limited to road crossings, were managed through stringent washout procedures and controls to prevent pH issues in groundwater.

Key measures implemented

Collaboration: Close coordination with all project stakeholders ensured that environmental requirements were integrated into the project delivery.
Modelling: Accurate modelling of surface water flows and treatment needs informed our approach.
Site-specific solutions: Appropriately sized settlement ponds and drainage systems tailored to site conditions.
Proactive management: Ongoing water management and monitoring ensured the system's effectiveness throughout the construction phase.

The outcome: Successful project delivery with minimal environmental impact

The comprehensive design was accepted on schedule, allowing the project to proceed without delays. Throughout the 18-month construction phase, the water management system demonstrated exceptional performance, maintaining pollution levels within acceptable thresholds in the vast majority of cases. Out of the few incidents recorded, five occurred during in-stream works, and four during extreme rain events that surpassed the system's design capacity. The remaining two incidents were related to unexpected interactions with previously unidentified field drains.

Crucially, the robust monitoring system enabled us to demonstrate that, despite these breaches, the system allowed us to learn from each event and improve the treatment process accordingly. The project's success in managing pollution risk was recognised by regulators, providing assurance that the environmental safeguards were both robust and defensible.

“Naturally Compliant’s expertise and collaborative approach were critical https://www.naturallycompliant.com/post/risk-and-opportunities-in-water-management-during-constructionto the success of this project. Their thorough planning and proactive management of water risks ensured that we stayed on track while protecting the environment,” said Frank Hennity, Project Director.

Conclusion: Delivering on schedule, budget, and environmental stewardship

Naturally Compliant’s comprehensive water management strategy not only minimised environmental risks but also ensured the project was delivered on schedule and within budget. This case study underscores the importance of proactive planning and collaboration in achieving successful project outcomes in the construction sector.