Highways developers need to learn from the summer of drought, says ACO

After one of the driest summers on record, ACO Water Management is urging highways and civil engineers to use Nature-based Solutions and Sustainable Drainage Systems (SuDS) to conserve water, create resilient sites and support biodiversity.

England had its joint hottest summer on record according to the Met Office, and for the UK as a whole, summer 2022 has been the driest on record since 1995, averaging just 156mm rainfall. This saw eight areas of England officially declared as being in a drought in August.

However, even with the dry spells, the chances of extreme rainfall events are still increasingly likely. Thunderstorms and heavy downpours have battered the UK throughout September, and trends from the latest State of the UK Climate Report point towards a growth in frequency and intensity of rainfall across the UK.

With the UK’s weather patterns exhibiting drastic changes, Adam Cane, Sustainability Lead at ACO Water Management is calling on highways developers to create systems that better conserve water when droughts and storms hit. This includes using sustainable drainage systems and Nature-based Solutions to retain water as high up on site as possible and protecting sites by incorporating water cleansing solutions into highways and infrastructure projects.

Cane said: “The UK’s climate is changing rapidly and we’re seeing more regular cycles of extreme weather events. This is creating two challenges. Firstly, sites are starved of water and biodiversity suffers as a result. Secondly, flash floods and downpours mean large amounts of stormwater enter our systems and may bypass treatment, which can then mean harmful pollutants get washed into the surrounding ecological systems.

“This is something that needs to be considered early in the design by the construction industry and there are ways in which highways professionals can help protect our environment. The key to any new site development is to limit our intrusion into nature wherever possible and keep as much of the natural environment in place.”

Cane stresses that trees and green areas should form the backbone of new project design and be prioritised to help safeguard ecological site characteristics, connectivity and help lower carbon. These areas offer shade, amenity, natural air conditioning and refuge opportunities for wildlife.

Meanwhile, SuDS solutions, such as bioretention areas, rain gardens, swales and tree pits, can take runoff from hard surfacing and roads and store them at source to create resilience and slowly feed them back into the ground and waterways, rather than into sewers. Exposed water cools the surrounding environment and offers opportunities for amenity and biodiversity.

Cane said: “Crucially, for dealing with extreme events and where above ground space is restricted, SuDS features and Nature-based Solution can be coupled with underground geocellular storage tanks. creating resilience and allowing for long term infiltration.

“Space is often one of the key barriers when incorporating SuDS on sites especially when dealing with pollutants. Roads offer particular challenges due to the volume of pollutants. Here proprietary solutions, such as oil and heavy metal separators, are beneficial, as they can protect natural systems. Clean water is essential for nature.”

ACO Water Management’s range incorporates solutions from the full SuDS management train. This includes proprietary products that work to protect natural systems, such as its V-Septor and QuadraCeptor. These products help clean the water before it’s released into the soil or watercourse.

The V-Septor removes sediment-bound contaminants and helps to reduce sediment build-up in the downstream network, such as in attenuation tanks for example, decreasing how often the tank needs to be cleaned and maintained. Meanwhile, the QuadraCeptor is ideally suited to treating surface water run-off from highly trafficked areas. It is designed to remove heavy particles, silt, nutrients and dissolved materials like heavy metals from brake dust, in a four-stage process, hitting the same level of treatment as a wetland area.

Importantly, both ranges meet with the guidance from Design Manual for Roads and Bridges (DMRB) document, CD 528 Vortex separators for use with road drainage systems, and designers should refer to the CIRIA SuDS Manual (C753) when looking at SuDS schemes.

Cane added: “It’s vital that industry collaborates to understand the impacts of climate change and how it will affect the built environment. We’ve worked with engineering consultancies across the country and bringing in water management specialists at the start of a project can help ensure any new developments benefit the natural surroundings. For this reason, ACO offers free consultation and specification support to help designers connect SuDS to Nature-based Solutions.

“Alongside our support and consultation, we also have a complete range of systems to support the SuDS management train. From roofs, highways to industrial forecourts, through to car parks and distribution and warehouse loading areas, our channel drainage (collect), water treatment (clean), water storage (hold) and flow controls (release) products, coupled with our wildlife mitigation offerings where appropriate, can be designed into any project, delivering positive and measurable outcomes.”

For more information on ACO’s range, please visit