RAIN GARDEN PROJECT – Water Sensitive Cambridge

Case Study: Water Sensitive Cambridge – Natural Cambridgeshire Rain Garden Project

June 2025

Water Sensitive Cambridge is a community-driven initiative to address drainage challenges in urban areas in Cambridge through innovative nature-based solutions. It is a Community Interest Company founded by local residents and managed by two volunteers.

Water pooling has become a particular problem in some areas of Cambridge. Where there has been run-off, the water becomes polluted and runs into the nearby rivers, reducing water quality. Water Sensitive Cambridge looks to solve this issue by creating rain gardens in built-up areas of the city. The rain gardens are wildlife-friendly spaces designed to soak up rainwater run-off from hard surfaces like roads and rooftops. They help reduce flooding as the water soaks into the soil which acts as a filter to prevent water pollution before it reaches the river. Urban biodiversity is also enhanced through the creation of habitat, while the addition of plants keep the air moist and cool in heightened summer temperatures.

Yair Perry from Water Sensitive Cambridge said: “The roots act like a sponge. They can actually hold a lot more moisture, and there’s a lot of life in them. Invertebrates, bacteria, microbes, and fungi that grow on these roots can hold onto some of the contaminants and actually clear them and break them down.”

Roadside rain gardens are created by digging out the soil up to 80cm deep and mixing it with compost. The level of the top of the soil will be a bit lower than the level of the road and slots are cut in the kerb to allow runoff into the garden, where the flowers and plants will benefit.

Water Sensitive Cambridge applied for the funding through the Cambridgeshire and Peterborough Fund for Nature to install rainwater verges and gardens in suitable public locations in north and east Cambridge. As well as the biodiversity benefit, their addition aims to engage the local community, educate them in actively maintaining these spaces as well as increasing their knowledge about urban ecology.

Water Sensitive Cambridge received £4,500 in grant funding from the Fund for Nature to support the design and construction of the rain gardens and raise their profile to encourage and increase community engagement. They are still in the early stages of the project but have so far identified flood-prone areas on Whitehill and Thorleye Roads in the Abbey area of the city, where they have worked with local contractor to cut curbs and create rain gardens in street verges.

Volunteers help to plant and maintain the gardens. For example, planters were installed in an apartment block at the end of February but for the entirety of March there was little to no rain, causing significant concern that the new plants and bugs were going to die. The local community stepped up, watering the rain gardens to ensure their survival.
“People really care for them” said Yair, who has been impressed with resident’s commitment since the planters were installed, “It’s even better than me organising a volunteering day”.

The team have also seen community spirit in action preventing flower beds being parked and driven on and dustbins being placed on them.

The project intends to host workshops with the local community to explain what they are doing and explain why it is important to have green spaces and let wildflowers grow. This will help prevent any pushback.

Longer term, they want to scale up project across wider areas of Cambridge, including working with schools, and build relationships and develop procedures with the county council to see the installation of rain gardens become more widespread.