Synergy’s Building Surveying team were appointed by the Girls’ Learning Trust to deliver flood resilience measures at Whyteleafe School, Surrey. Located in a high flood risk area, the school has unfortunately experienced flooding multiple times between 2014 and 2019.
The most recent flood in 2019 was triggered by intense rainfall, which caused surface water to flow into the school grounds from Church Road and Whyteleafe Hill. Due to the school’s location in a natural dip and the presence of a drop kerb, the site is particularly vulnerable to intercepting the water’s path of travel.
A Sponge School
Many of the flood mitigation solutions at Whyteleafe School are passive in design, thoughtfully integrated to work in harmony with nature. Rather than obstructing the flow of water into the school site, these solutions guide water along safer, more sustainable pathways – ensuring that flood prevention on-site does not adversely affect neighbouring properties.
Whyteleafe is now proud to be known as a ‘sponge school’, a concept that utilises green infrastructure to soak up rain water and slow down surface run-off. Originally developed in China as an innovative urban planning model, the ‘sponge’ approach allows both nature and communities to flourish.
Adopting the sponge concept is particularly crucial in today’s world, as climate change is increasing the frequency and intensity of surface water flooding, only made worse in impermeable urban areas.
This has been achieved through the use of Sustainable Drainage Systems (SuDS), that replicate natural water management processes by capturing, filtering and slowly releasing rainwater. Whyteleafe School now has the capacity to store up to 233m² of water on-site.
Beyond flood resilience, SuDS offer a wide range of benefits: they improve water quality, enhance biodiversity, promote well-being, and even providing hands-on learning opportunities for students.
Whyteleafe’s SuDS Success
A huge number of SuDS planters (23 in total) have been integrated across the school site to intercept rain from the roofs before it reaches the drainage system. Made up of a series of layers, these innovative boxes not only store and filter water, but create an ideal environment for plants to grow in both wet and dry conditions.
Complementing the planters, four Rain Gardens have been created to capture rainfall from roofs and hard surfaces. Water is directed into natural aquifer blocks beneath the soil which stores the water temporarily and releases it into the drains when safe.
Small concrete bridges called Check Dams have been integrated into the rain gardens to help slow the flow of water. As one section fills, excess water gently overflows into the next section in a controlled cascade effect.
The largest of the rain gardens, located next to the school’s nursery doubles as a sensory garden for outdoor learning and well-being. Dotted around the garden are focused areas for mindfulness, habitats, natural play and various green rain management features that allow students to observe the flow of the water cycle. Smooth wide paths and a bridge connect parts of the garden together allowing equal access in all seasons. .
An overhead rill, or rainchain, has been installed to catch water from the roof, allowing it to cascade down the chain and soak into a stainless steel basket of cobbles to help dissipate and disperse water from the downpipe.
To help prevent flooding underneath the school building, anti-flood air bricks have been permanently fitted. Similar to SuDs, anti-flood air bricks offer passive flood resilience that don’t require human intervention during a flooding event. When water rises, the bricks will automatically shut off, inhibiting water ingress through the bricks.
A large attenuation tank has been installed in the playground to collect, store and release rainwater at a controlled rate. In a similar way to the planters and rain gardens, it will reduce surface water runoff, help to prevent the drainage systems from being overwhelmed, improve water quality and replenish groundwater supplies.
For additional flood protection in extreme circumstances, manual doorway barriers have been installed around the school building.
The works completed on site in June 2025 with a construction value of £725K.
The Impact
As well as reducing the risk of damage, cost and disruption to the school, Whyteleafe is now a haven for outdoor learning and biodiversity.
Children at Whyteleafe have a ‘free-flow’ system where they have the freedom to learn either inside or outside – rain or shine. Their ‘Forest School’ sessions give them the opportunity to explore muddy areas, climb trees, play games and take part in sensory activities.
This project has significantly expanded the school’s joyful outdoor spaces, fostering curiosity, creativity, and free play. Rather than installing overly manicured playgrounds, Whyteleafe has embraced natural landscaping, creating an inspiring environment where children can grow and connect with nature.
Students at Whyteleafe School have played an active role in shaping the SuDS features throughout the project. Each classroom is represented by an enthusiastic eco-warrior, who helps select plants and contribute ideas—creating a sense of ownership and environmental stewardship from an early age.
The SuDS installations will also attract pollinators and enrich the local ecosystem, turning the school grounds into a thriving habitat for wildlife.
With the sensory garden located next to the nursery, the school also hopes this inviting and nature-rich space will support the expansion of nursery places.
