A leading expert in water infrastructure provision has said that if UK flooding and water shortages are to be tackled it is time to stop waiting for legislation to be enforced. The UK needs a more holistic approach to water management - including more green infrastructure and the implementation of SuDS in both existing and new built environment.

In an Expert Focus article for Waterbriefing today, Matthew Jones, Regional Director, AECOM says a more holistic approach to water management is needed to tackle the fluctuating challenges of flooding and water shortages. On funding, he also flags up the strong business case for green infrastructure via a study showing that the benefits of green infrastructure interventions in Coventry were between three and seven times greater than the direct cost of the interventions over a 40 year period. 

Matthew Jones: Flooding has been almost constantly in the news this winter as hundreds of properties, thousands of hectares of farmland and transport infrastructure have been affected, prompting renewed focus on flood defence spending. While the flooding has taken place over an unusually long duration this year, it is part of an apparently increasing trend of events oscillating between periods of inundation and periods of water shortage in some parts of the country.

Significant steps forward have been made in the last few decades on the prediction of flooding and emergency response, as demonstrated by December’s east coast tidal surge, which had much less impact than a similar event in 1953 which killed more than 300 people. Much work has also been done to protect homes and businesses by constructing flood defence walls, embankments and pumping stations, though levels of spending on flood risk management continue to be hotly debated.

Water needs to be treated as a precious resource – not a national annoyance

While emergency response plans and flood defences are an important part of protecting life, infrastructure and farmland, it is clear that to manage flood risk effectively and to reduce water shortages in the summer, water needs to be treated less as a national annoyance and more as a precious resource. A more holistic approach is required where land practices contributing to flooding, such as deforestation, land drainage and urban creep, are gradually and proactively reversed.

The good news is that, by doing this, we do not have to return to pre-Industrial Revolution days and many more benefits will accrue than simply solving flooding. However, a much more imaginative and collaborative approach to project funding and stakeholder engagement is required than has been the norm for traditional flood alleviation schemes.

Planting different crops, trees and ponds for upstream water storage could help reduce flooding

In rural areas an integrated catchment management approach is increasingly gaining traction. Water companies and the environmental agencies in England, Wales, Scotland and Northern Ireland are working with landowners, the farming community and other stakeholders to modify farming and land management practices, reverting where possible to a more naturalised way of managing rainwater runoff.

 Initiatives include planting different crops, trees and introducing and maintaining more ponds providing upstream water storage. The benefits from this are not only a reduction in flooding, but also increases in biodiversity, recharge of groundwater resources, reduction in topsoil erosion, improvements in river water quality which help meet the requirements of the Water Framework Directive and benefits to the leisure and tourism industry.

A similar approach is also needed in our urban environments, with water’s interaction with the rest of the built environment becoming a key factor in urban planning rather than the afterthought that it has often been in the past.

SuDS should be implemented as soon as possible

Plans to begin implementing this approach for new-build developments in England, via the introduction of SuDS  Approval Bodies, have been delayed from April this year, with a new date yet to be confirmed by Defra. However, this should not be a reason to hold back the implementation of SuDS. Rather than enforcing developers and Lead Local Flood Authorities to adopt their use, engineers, architects and masterplanners should instead be persuading them that SuDS and green infrastructure are a cost effective and valuable way forward.

Key to achieving this is to convince the various stakeholders – councils, developers, water companies, environmental agencies in England, Wales, Scotland and Northern Ireland, businesses and the community – of the multiple benefits of taking a water sensitive urban design approach, both to new development and the regeneration of existing urban areas. This places water at the centre of place making, using it as a positive driver of community and environmental change. The use of raingardens, bio-retention tree pits, green roofs, permeable paving and open channels and ponds as alternatives or enhancements to piped drainage systems can improve the aesthetics of developments, adding a sense of playfulness or tranquillity, as well as attenuating peak stormwater runoff to prevent or reduce the impact of flooding.

Strong business case for green infrastructure

There are numerous papers available by the likes of Forestry Research, the US Environmental Protection Agency, Natural England and the Royal Town Planning Institute extolling the wide ranging benefits of green infrastructure. These include improving air quality, reducing the urban heat island effect, improving mental and physical health of the community, reducing crime and vandalism levels and increasing house prices, all in addition to the water-related benefits of managing flooding, improving water quality and recharging groundwater resources.

Photo: The Ripple Effect: daylighting the River Sherbourne would provide a pleasant and attractive public space which is adaptable to make space for higher water levels during heavy rainfall.

The recent ’Ripple Effect’ research carried out for the Technology Strategy Board and Defra by AECOM and Severn Trent Water, in collaboration with Birmingham City Council and Coventry City Council, found that the benefits of green infrastructure interventions in Coventry were between three and seven times greater than the direct cost of the interventions over a 40 year period. Daylighting the currently culverted River Sherbourne as part of a regeneration of the Burges site, for example, would cost £3.3m but would alleviate flooding, improve water quality and biodiversity, increase achievable property rentals and drive up footfall to the retail centre. By quantifying these multiple benefits a business case can be more readily made for leveraging multiple sources of project funding.

In the future even more imaginative benefits may accrue. AECOM’s recent Urban Food Jungle initiative advocates a water management approach that also produces cost effective food for cities while reducing energy use. Our concept is that surface water from roofs and pavements could be channelled into covered attenuation ponds adjacent to large public buildings.

Fish could be farmed in the ponds, providing a local source of food (aquaculture), which would be cheaper and less energy intensive than meat and would require less fuel for transportation to consumers. The nutrient-rich water could be recycled using solar-powered pumps to irrigate and feed edible plants grown on green walls (hydroponics), which would also look attractive and help manage temperature. The resulting ‘aquaponics’ solution is a neat way of managing surface water flooding while also tackling several other issues.

UK evidence base for retrofitting SuDS now being developed

 This may still be blue-sky thinking, but a number of more conventional green infrastructure retrofits are currently being trialled in the UK. These include the Environment Agency’s South East SuDS Retrofit Project, Greener Grangetown in Cardiff, RainScape Llanelli and the Greenstreets@Counters Creek scheme in London, which AECOM is working on with Thames Water, the London Borough of Hammersmith and Fulham and the Royal Borough of Kensington and Chelsea.

Photo: Greenstreets@Counters Creek: visualisation of a proposed raingarden

These schemes are providing an evidence base that retrofitting SuDS can be achieved with growing support from the public and a realisation that current urban water management practices have to change. Over the course of the Greenstreets@Counters Creek project, for example, a programme of engagement events, including the use of community champions, workshops, drop-ins, mail-outs and home visits, has helped to educate local communities about the benefits of SuDS. Public attitudes towards the pilot scheme have changed from an initial engagement level of 10% to positive support of between 30% and 63% across the three trial streets. This is an encouraging shift, although it shows that the implementation of retrofit SuDS will be a long term programme that will need to be developed alongside conventional drainage solutions for many years to come.

UK must act now – not wait for legislation to be enforced

Such pilot schemes now need to be translated into a broader acceptance and support of green infrastructure and water sensitive urban design as a business-as-usual approach. Planning authorities, developers, water companies, architects and engineers need to be discussing future programmes of work at an early stage and looking for opportunities where regeneration schemes can access funding from several stakeholders to deliver the multiple benefits of water sensitive urban design. More work also needs to be done on engaging the public to accept responsibility for the way they manage their own properties, for example by educating homeowners about the impact of paving over gardens on increasing urban flood risk.

By piggy-backing on existing opportunities for regeneration, the water sensitive urban design approach can be cost effective and mutually beneficial for all stakeholders. The positive aspect of this year’s flooding is that it has further raised the profile and reinforced the importance of water management, providing a good foundation for action. If flooding and water shortages are to be tackled it is time to stop waiting for legislation to be enforced and to set up proactive local stakeholder groups with the holistic and imaginative vision to make this happen.