Problem Addressed

This solution was sourced in response to UKGBC’s Innovation Challenge: “How can existing buildings be made more resilient to climate change, with as little disruption to their occupants as possible, by 2030?”

This solution aims to reduce downstream flooding, free up capacity within our surface and combined sewer network, and effectively treat water within medium and low risk areas.

Solution Overview

A modular, bioretention rain garden system, manufactured in the UK from 100% recycled material. The HydroPlanter was primarily designed to intercept water as close as source as possible, to decrease the volume of water from entering the sewer network. By diverting rain water from hard surfaces (roofs, roads, pavements etc) via the vegetated planter greatly reduces the peak flows during a storm event.

The HydroPlanter is a stormwater management solution that can be retrofitted into highways schemes and on new developments of any size. This is a ‘plug and play’ sustainable urban drainage solution that can attenuate and cleanse storm water and provide amenity and biodiversity to new and existing spaces. The modules will be filled with a particular soil specification and planted wildflowers and biodiverse grasses.

The concept is flexible, scalable and each unit stacks together. Installation is fast, simple and offers significant savings to alternative methods. The modular characteristics with pre-calculated hydrological performance statistics mean that specification and design is very simple for any given catchment area.

Features include:

  • 100% recycled materials
  • Slot-together modules
  • Optional exceedance flow drain point
  • Stack-able design for transport efficiency

The cost depends on the size of the roof, logistics and access. Retrofit green roofs cost between £100 and £200 per m2 to install and establish. The Milton Keynes Green Roof Project value is £80,000 which covers an area of 550m2. This includes a 6-month programme of ongoing maintenance and development and training for the end user.

By retrofitting green roofs it can result in multiple indirect benefits including reduced heating costs, extending the life span of the roof, health and wellbeing, food growing opportunities and biodiversity net gain, plus building internal capability for long-term stewardship of the roof.

Verification & Case Study

The effectiveness of a proprietary SuDS system can be simply verified by building the appropriate solution into a hydraulic modelling program such as MicroDrainage. There are also additional benefits which are not so easy to put a tangible number to such as the ecological and aesthetic benefits of a well-designed piece of Green Infrastructure.  Very few other elements within our public realm improve over time and bring exponential benefits to our communities.

Case study: The HydroPlanter was chosen as a solution in Grosvenor Yard Car Park in Newmarket to deal with an attenuation requirement of 33 cubic meters based on a 1:30 year event. Cheryl Froud from West Suffolk County Council, complemented the final look of the scheme and recommended for future use. Cheryl highlighted: “They have made the car park more appealing, broken up all the tarmac etc.”

Facts and Figures

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This page presents data, evidence, and solutions that are provided by our partners and members and should therefore not be attributed to UKGBC. While we showcase these solutions for inspiration, to build consensus, and create momentum for climate action, UKGBC does not offer commercial endorsement of individual solutions. If you would like to quote something from this page, or more information, please contact our Communications team at