Embracing Sustainable Urban Drainage Systems

As cities continue to grow and urbanise, so does the need for efficient and sustainable solutions to manage stormwater and reduce the environmental impact of urban development. Sustainable Urban Drainage Systems (SUDS) offer a promising approach to address these challenges in an environmental and considered manner.

Here at renaissance, our civils work often utilises innovative sustainable drainage strategies that not only solve engineering challenges but enrich the biodiversity of the site we’re working on. At Castle Irwell for example, the verdant wetlands at the heart of the development provide green space for all whilst also forming an emergency water containment reservoir for extreme rainfall events.

In this article, we’ll delve into what SUDS are, their benefits, current implementation, and the exciting innovations shaping the future of these crucial elements of sustainable urban design.

What are SUDS?

Sustainable Urban Drainage Systems (SUDS) is a collection of water management practices designed to mimic the natural hydrological cycle within urban environments. These systems aim to manage rainfall and runoff, reduce flooding risks, and minimise pollution from stormwater while also enhancing the urban landscape and biodiversity through green spaces and habitat creation.

SUDS can be divided into three main categories: source control, conveyance, and storage/treatment. Source control methods focus on reducing the volume of runoff and improving water quality at the point of origin (such as green roofs, permeable pavements, and rainwater harvesting). Conveyance systems are designed to slow down and direct stormwater runoff (including swales, filter strips, and infiltration trenches), while storage and treatment solutions provide temporary storage and additional water quality improvement (e.g., ponds, wetlands, and detention basins).

The Benefits of SUDS

SUDS offer a myriad of benefits to communities, the environment, and the economy. Some of the most significant advantages include:

  1. Flood risk management and reduction: By slowing down and controlling stormwater runoff, SUDS help to reduce the risk of localised flooding and existing sewer overflows, protecting properties and infrastructure.
  2. Water quality improvement: SUDS naturally filter pollutants, such as sediment, toxic waste, and heavy metals from stormwater before it reaches waterways, improving the overall quality of our rivers, lakes, and oceans.
  3. Climate change resilience: By promoting groundwater recharge and reducing peak runoff, SUDS can help mitigate the impacts of climate change, including more frequent and intense rainfall events.
  4. Biodiversity enhancement: The green spaces created by SUDS provide valuable habitats for urban wildlife, supporting biodiversity and contributing to overall ecosystem health.
  5. Aesthetic and recreational value: SUDS features like ponds, wetlands, and green roofs can improve the visual appeal of urban areas and provide recreational spaces for the community to enjoy.

Current Implementation of SUDS

Many cities around the world have already embraced SUDS, integrating these systems into their urban planning and infrastructure. In the UK, the adoption of SUDS is becoming more widespread, with guidance provided by organizations such as the Environment Agency and CIRIA. Examples include grey to green in Sheffield, a large retrofit SUDs project, providing a continuous ‘Green Street’, providing regeneration and improved social value whilst managing surface water and providing water quality benefits globally. An international example can be found at the Sponge City initiative in China, which aims to increase urban resilience to flooding, and Philadelphia’s Green City, Clean Waters program, which focuses on managing stormwater through green infrastructure.

The Future of SUDS

As we look towards the future, several emerging technologies and innovations have the potential to revolutionise the way we implement and manage SUDS:

  1. Smart sensors and monitoring: The integration of IoT (Internet of Things) sensors into SUDS infrastructure can provide real-time data on water levels, flow rates, and water quality, allowing for better decision-making and more effective maintenance.
  2. Adaptive SUDS: Advancements in materials science have led to the development of responsive materials that can adapt to changing conditions, such as hydrophobic surfaces that become permeable when wet. These adaptive materials could enhance the performance and adaptability of SUDS in response to changing weather patterns and urbanisation.
  3. Nature-based solutions: Research into natural systems and biomimicry is driving the development of innovative nature-based SUDS solutions, such as engineered wetlands and biofiltration systems. These approaches harness the power of nature to manage stormwater, improve water quality, and support biodiversity.
  4. Urban planning and design: As cities continue to grow, the importance of integrating SUDS into urban planning and design becomes paramount. The future of SUDS will likely see a greater emphasis on holistic, catchment-wide approaches that incorporate green and blue infrastructure into the fabric of our urban landscapes.
  5. Community engagement and education: The success of SUDS depends on the support and understanding of local communities. Future SUDS initiatives will need to prioritise community engagement and education to ensure widespread adoption and long-term success.

Case Study:- The Blue-Green Infrastructure in Rotterdam

The Dutch city of Rotterdam is an excellent example of how innovative SUDS technologies are being implemented to address urban water management challenges. The city is actively working to become more resilient to climate change and has developed a comprehensive Blue-Green Infrastructure plan, which incorporates a range of SUDS features.

One such innovation is the “Water Square,” a public space designed to collect and store rainwater during heavy rainfall events. In dry periods, the square serves as a recreational space for the community, while during periods of heavy rainfall, it transforms into a temporary water storage area, helping to mitigate flood risk. This project demonstrates the potential of combining urban design, water management, and community engagement to create multifunctional SUDS that address environmental challenges while enhancing urban life.

Castel Irwell – a renaissance case study in sustainable drainage

Castle Irwell is an exciting new development in Salford’s Lower Broughton. Nestled alongside the River Irwell, the Salboy developed residential neighbourhood is situated on a plane liable to flood in extreme rainfall events.

The challenges of the site provided a great opportunity to put our knowledge of SUDS to work, finding strategies that not only protected the development from one-in-100-year flooding events with allowance for climate change but also enhanced the site’s sense of place and aesthetic desirability.

While we used many sustainable drainage solutions across the site (including permeable pavement systems and carefully placed run-off pipes), the primary solution took the form of a landscaped floodplain and wetlands.

Castle Irwell has ample community greenspace that can be enjoyed by the public year-round. This biodiverse and picturesque element doubles up as a sustainable urban drainage solution in the event of extreme rainfall as per the Rotterdam scheme. After developing design detailing exactly what was needed, we fed this data into semi-autonomous vehicles that excavated the ground profiles across the site that would hold water extreme events.

The bottom line

Sustainable Urban Drainage Systems (SUDS) are an increasingly important tool in our efforts to manage stormwater and mitigate the environmental impacts of urbanisation. As we move towards the future, the integration of emerging technologies and innovative design approaches will further enhance the effectiveness of SUDS in protecting our cities, communities, and environment. By embracing these developments and prioritising the adoption of SUDS, we can create resilient, sustainable, and thriving urban landscapes for generations to come.