Harmonising habitats: Integrating water management strategies for biodiversity enhancement

Chris Adair, Product Innovation Manager, Marshalls explains why new and upcoming legislation gives housebuilders the opportunity to rethink their biodiversity strategies.

Described by the government as ‘one of the biggest changes to planning regulations for decades’, housebuilders have been anticipating the introduction of biodiversity net gain (BNG) for some time. Designed to ensure developments are contributing more positively to wildlife habitats than before building work began, the approach will force developers and their designers to consider the different ways they can make a more significant impact to nature’s recovery. 

However, there is also a second, similarly pertinent piece of legislation on the horizon which will require the housebuilding industry to think differently when it comes to drainage. Schedule 3 of the Flood and Water Management Act will soon be adopted in full, putting Sustainable Drainage Solutions (SUDs) central to the prevention of flooding from storm overflow discharges on new developments. 

This two-step shift provides an opportunity for housebuilders to reconsider their existing design principles, and instead opt for solutions which meet both requirements simultaneously. Thankfully, a new innovation in rain gardens offers the answer. 

Two-step change

Although they are two separate pieces of legislation, BNG and Schedule 3 overlap in terms of their impact on how housebuilders should approach their developments. 

Previously, it was up to each individual developer to decide how much of their developments would be dedicated to features that promote biodiversity. Now, it will be a legal requirement to achieve an at least 10% increase in BNG from the baseline for each site. That could be through the preservation of wildlife habitats, an increase in the number of green spaces or an improvement in water quality.

Similarly, while there’s been emphasis on the benefits of using SUDs in new housing developments for several years, it has always been at the developer’s discretion. Now, as urbanisation, population increase, and the impact of climate change have exposed towns and cities to increased risks of flooding and watercourse pollution, the introduction of Schedule 3 will dictate more of a developer’s drainage plans than before.

What’s key to ensuring housebuilders can navigate both of these crucial changes simply and efficiently, are solutions which offer the chance to both reduce the amount of water entering the sewer systems, while also adding natural beauty and biodiversity to a development. This is where a new modular rain garden kerb system, soon to be available from Marshalls, comes in.

A new innovation

Already widely used across public realm and housing developments to provide a flood management system that doubles up as an attractive, biodiverse feature, rain gardens have increased in popularity amongst housing developers in recent years. 

Rain gardens use plants and soil to retain and slow the flow of rainwater from surrounding hard surfaces. One way to use the rain garden method, is by combining with a kerb – where water flows into the garden through an inlet in the kerb, is slowed down by a diffuser flag, and is kept at surface level to be absorbed by the soil. This both supports plant life and prevents the water from immediately entering the sewer system.

Currently, housebuilders looking to use rain garden kerbs have to use bespoke solutions, taking up valuable resource in the design process and slowing down installation. However, Marshalls has developed an off-the-shelf system comprising three simple elements to make it easier than ever to add rain gardens to a new development. 

Combining a left hand inlet, right hand inlet and complementary diffuser flag available in a variety of sizes and finishes, it is a true ‘first of its kind’ system which will create both a time and cost saving on site when compared to cutting or repurposing standard kerbs. And due to its modular design, it will reduce the margin for error usually associated with bespoke and made to measure designs, increasing its effectiveness. 

Communities of the future

To understand its potential impact on housing developments of the future, Marshalls’ upcoming rain garden kerb has been trialled as part of a sustainable flood resilience plan in Mansfield, the largest project of its kind ever attempted in the country.

As part of the scheme, Mansfield District Council and Nottingham County Council have invested £76million on a range of nature-based solutions to protect communities from flooding. For context, just £15million has been invested into similar, previous projects spanning the whole of the UK. 

By the time the project completes in 2025, rain gardens, as well as several other innovative solutions, will have played a role in storing over 58 million litres of surface water run-off, reducing the flood risk for 90,000 people in the area. 

Intended to be the blueprint for how to manage flooding in the future, while also making the area a greener place to live, the project is a showcase of the major impact products like Marshalls’ rain garden kerb system will have on communities, as we battle to overcome the catastrophic consequences of biodiversity loss and climate change.

Futureproofing strategy

There’s no doubt that rain gardens will become one of the key features housebuilders come to rely on to realise the benefits of both BNG and Schedule 3 legislation, and the true beauty of EDENKERB™ is that it makes it easier than ever to help those working on new developments integrate rain gardens to their schemes. Today, swift action is required to make longstanding and widespread change to futureproof our communities. As such, there’s no better time for developers to begin utilising the solutions which cater for multiple mandatory requirements, while also making the world a better place to live.