Chesnut Lodge Specialist School: Flood Resilience Scheme
Client: Department for Education / Chesnut Lodge Specialist School
Industry: Education
Location: Widnes, Cheshire
Case Study at a Glance
Chesnut Lodge Specialist School supports approximately 85 pupils with complex physical and medical needs. Following a significant flooding incident in 2021, Watertight International was commissioned to design and deliver a comprehensive Property Flood Resilience (PFR) scheme.
The solution addressed multiple flood pathways, combining resistance, resilience and drainage measures to reduce flood risk and improve the usability of the school’s buildings and outdoor spaces that would become water logged during spells of wet weather.
The Challenge
In September 2021, the school experienced significant flooding after heavy rainfall overwhelmed nearby highway drainage.
Surface water flowed down the sloping car park and entered the building through the main entrance, impacting classrooms and specialist learning areas. The event caused extensive disruption and resulted in approximately £175,000 of damage.
The project presented several key challenges:
- Surface water runoff from adjacent highway drainage and sloping site levels
- Multiple vulnerable access points into the building
- Risk of sewer backflow flooding through the drainage network
- Delivering works within a live specialist school environment.
All resilience measures needed to be safe, accessible and suitable for pupils with complex needs, while ensuring minimal disruption to day-to-day school operations.
The Solution
Following a detailed flood risk assessment, drainage investigation and site survey, Watertight developed a tailored, multi-layered flood resilience strategy.
Building PFR Measures
- StormMeister flood door installed at the main entrance (tested to PAS1188 standards up to 600mm flood depth)
- Flood gate for secondary entry points
- Four demountable flood barriers installed across vulnerable openings.
Internal Water Management
- Eight puddle pumps installed to remove water in the event of ingress
- One sump pump system providing active drainage management.
Drainage Adaptations
- Installation of multiple non-return valves across the drainage network to prevent sewer backflow flooding.
The project was delivered within a live specialist school environment, requiring careful planning and coordination throughout.
Detailed method statements and risk assessments were developed, with works scheduled around the school day to minimise disruption. Close collaboration with school leadership ensured safeguarding requirements were fully met and that the needs of pupils and staff were prioritised at every stage.
The Results
The completed scheme provides integrated flood resilience across the site, delivering:
- Greater resilience relating to surface water entering the building
- Prevention of sewer backflow flooding
- Rapid internal water removal capability
- Improved resilience to extreme rainfall events.
In addition to reducing flood risk, the scheme has delivered wider benefits across the site. Areas that previously experienced pooling are now effectively drained, and outdoor spaces, including a woodland used for forest school activities, are now more accessible even following periods of wet weather.
Client Testimonial
John Thompson, Headteacher at Chesnut Lodge Specialist School said:
“Watertight really understand how schools operate, always showing pragmatism and considering the impact on the school. Joel is a superstar – and that reflects the wider team. Coordination surrounding the programme of flood resilience works was top class and they made sure they were able to install what was needed, with minimal impact on our schooling day.
It would have been easy for Watertight to expect us to work around their way of doing things, but they didn’t – they were flexible and always put the needs of the school first. The level of support, both during and after the project, has been brilliant. The aftercare support has been second to none, including support with the Resilico app, where they provided tutoring and training, as well as helping with things beyond the original scope when needed.
Now the measures are in place we feel super confident - we really do, particularly having seen some of the worst rainfall in a short space of time. Where water would previously pool, now there’s none - it just soaks away. And our woodland, which was previously difficult to access, is now usable again for our forest school activities, including for wheelchair users.
Interestingly, we’ve also seen a real benefit in our orchard. We had a bumper crop last year - tonnes of apples, pears and cherries – and whether that’s a coincidence or not, it’s been a lovely outcome for the school.
I’ve worked with contractors over the years, and for what was a significant project, there were no difficulties whatsoever. The team worked incredibly cleanly; it was like they’d never been afterwards.
The work has been excellent - completely faultless. I would recommend Watertight without hesitation.”
