A Quick Introduction To Blue-Green Infrastructure

As the impact of climate change and global warming is felt more keenly as time goes on, it’s important that those involved in the planning and management of our towns and cities consider how increased risks of flooding and drought will affect our buildings, roads, waterways and so on.

The first-ever National Infrastructure Assessment for the UK was published in July 2018, detailing how the needs and priorities where infrastructure is concerned should be addressed. This included advice for the government to put in place a long-term strategy to tackle floods and deliver a national standard of flood resilience by the year 2050, with funding for flood risk management set to increase significantly over the next few decades.

Floods and drought are more likely to become issues in the future because climate change will see increases in extreme weather events – so decisive policy action is required in order to mitigate the risks of these events. Approximately five million properties around the country are now at risk of flooding and protection from floods in the past has been reactive, instead of proactive.

Plans for flood protection should evaluate the full range of options available, including green infrastructure (be it sustainable drainage systems or natural flood management), spatial planning, individual property measures and traditional flood defences.

The National Infrastructure Commission recommends that by the end of this year, the government should have a rolling six-year funding programme in place, in line with the funding profile as detailed by the Commission. This would mean that efficient planning can take place, as well as delivery of projects and the addressing of risks from all sources of flooding.

The Commission has also recommended that planning authorities and the Ministry of Housing, Communities and Local Government should make sure that from this year all new developments are flood-resilient, with an annual likelihood of 0.5 per cent over its lifetime while not increasing risks elsewhere.


How can blue-green infrastructure help?

The Environment Agency has been working alongside the Construction Industry Research and Information Association (CIRIA) to keep the Benefits Estimation Tool (B£ST) updated to ensure that it continues to provide a structured approach to help identify and quantify the social, environmental and financial benefits of sustainable drainage systems and natural flood management measures.

These are known collectively as blue-green infrastructure, with the newly updated tool from the Agency and CIRIA able to be used to support the cost-benefit assessments required to secure investment in this kind of infrastructure. It can also help risk management bodies, landscape architects, planners and drainage engineers to understand the benefits of such infrastructure in rural, semi-urban and urban environments.

Blue-green cities aim to recreate naturally oriented water cycles while bringing water management and green infrastructure together to benefit the city as a whole. This is achieved by combining the hydrological and ecological values of an urban setting while also providing adaptive and resilient measures to tackle flood events head on.

Sustainable urban drainage systems (SUDS) are especially important where a blue-green approach is concerned, systems that contribute to sustainable development and improve where we live and work by balancing the challenges and opportunities that have an impact on urban design and how communities develop.

As explained by SusDrain, SuDS are environmentally beneficial because they cause minimal or no long-term damage, designed to efficiently drain surface water in a sustainable way by minimising pollution and managing the impact that local water bodies have on water quality.


How do SuDS work?

SuDS are a sustainable option because they’re able to reduce the impact of urbanisation on flooding by managing runoff volumes and flow rates from hard surfaces. They’re also able to protect or improve water quality by reducing pollution from runoff, can help to encourage natural groundwater recharge and provide habitats for wildlife in urban watercourses.

More traditional approaches to surface water drainage see it taken away from urban areas as quickly as possible in order to minimise the risks posed from flooding and poor sanitation, with little consideration given to the likes of biodiversity and water quality.

SuDS, meanwhile, have been designed to replicate the natural drainage from a site as closely as possible prior to development, while delivering the most benefits for biodiversity and water quality and quantity.


Flood risks & the UK

Recent research published in the journal Science Advances, reported on by the BBC, suggests that coastal parts of the UK and Northern Europe will see a rise in compound flooding over the next few decades, with storm surges and heavy rainfall combining and becoming more common as a result of rising global temperatures.

The Bristol channel, Cornwall and Devon were identified as potential hotspots for compound flooding, with events being seen more than once every six years – resulting in significant losses to both people and property.

Computer models were used to assess the current climate, showing that about three per cent of coastal areas see compound flooding events more than once every six years, predominantly in the Mediterranean, Algeria, the Gulf of Lyon in France, southern Turkey and around the Gulf of Valencia in Spain.

The report also noted that the parts of coastlines predicted to see return periods of lower than six years are expected to rise from the present three per cent to 11 per cent by the end of the century.

For help with marine structure repairs and other civil engineering work, get in touch with the team here at Freyssinet today.