The future of drainage – what the civil engineers think!
In our latest Spotlight post, we take a look at the thoughts and ideas of UK Civil Engineers and the key themes that emerged from our Future of Drainage debate.
The risk of flooding in urban areas and storm water management is an ever-growing issue in the UK with climate change, increased urbanisation and a push to build more housing placing greater pressure on existing drainage systems. As part of our Future of Drainage campaign this year we engaged with civil engineers at the Institution of Civil Engineering to start a debate on the issues and potential solutions for the future of drainage, stormwater and flood management in the UK.
Maintenance of existing drainage system
There was a feeling that problems with stormwater management were at least partly caused by a lack of investment in existing systems.“Issues of flooding and surface water management could potentially be solved with better maintenance and management of existing infrastructure.”
“Proper management of the existing system will alleviate a great deal of the issues I believe.”.
Sustainable Urban Drainage Systems
It was widely agreed that the use of sustainable urban drainage (SuDS) would be beneficial to managing stormwater by managing the water at source using a variety of methods including green roofs, tree planting and semi permeable paving amongst other things.
“What about blue roofs? How would this assist in spreading attenuation work further?”
“Separation, shared spaces, dealing with run-off at source, SUDS.”
Better use of SuDS and reducing urban creep by encouraging permeable and semi permeable solutions to paving and Tarmac of driveways etc.
Although the concept of SuDS as a method of managing rainfall seemed to be pretty much universally agreed, there is still some question marks over how these schemes could and should be implemented. Legislation and a ‘bigger picture’ approach were mentioned as possible answers.
“Sustainable drainage is a fantastic way of slowing the runoff, creating better environmental place and improving water quality but the legislation needs to give more teeth to the planners and Lead Local Flood Authorities to implement and enforce on developers undertaking these measures. The evidence base for the cumulative impact of SUDS (or no SUDS) at a catchment scale needs to be encouraged rather than focussing solely on the individual developments. There could be other solutions higher in the catchment such as Natural Flood Management which could help enable land which is currently at risk from flooding to be developable in the future”
The installation of SuDs is becoming more widespread in new developments, but our debate also highlighted the need for retrofitting of SuDS to ensure future resilience to flooding in existing urban areas.
“Retrofitting SUDS need to be an essential part of the conversation in urban regeneration not a sideline or a "nice-to-have"
“SuDS, new and retrofitted. See the Llanelli project by DCWW and also Greener Grangetown. Llanwern Village by Gallaghers designed by Jacobs will use a BMX park as a basin for extreme rainfall, this is the innovation required, not a huge expensive tunnel under a river!”
It seems likely that innovation could play a key role in the future of drainage. Intelligent drainage solutions that can detect, monitor and adapt to the volume of rainwater were suggested as a possible way of coping with the extreme weather events that are likely to accompany climate change. These intelligent systems could also be used for monitoring and maintenance of the systems.
“Smart drainage that can tell when it's being overloaded and shut off or redivert to avoid sewer backup”
“Drainage systems that are automated or computerised such that early warnings of potential floods can be sent and maintenance/repair requirements become known well before flood events occur.”
Stormwater harvesting and rainwater reuse
As water is such a valuable resource it makes sense that we find innovative ways to reuse rainwater not only helping to cope with large volumes of water but also providing greater resilience of the water supply. Stormwater harvesting and rainwater reuse were a key theme in our debate. Feeding rainwater back not buildings for use in various sanitary appliances including storing in header tanks and using for flushing of toilets was suggested as a way of reusing rainwater. It was also suggested retrofitting of such measure to existing buildings by councils could help to ease the impact of climate change.
“We need to move to more to grey water storage for cities - retrofit options for existing houses? Capture, storage and reuse of water on an industrial scale. The challenge is the climate change predictions, and economically designing systems to cope.”
“Increase storm water harvesting and reuse at local level, cutting down on the demands of potable supplies. Incentivise councils, industry and house builders to do so.”
We should stop thinking of drainage as a burden but as an opportunity.
An asset management approach
It was suggested that drainage could be looked at as part of an integrated and joined up approach to economic development.
“I think the future of drainage is seeing the water cycle as an asset with drainage a key part of it. Understanding how the balance of managing water quality over time (rain event and in terms of seasons and years) and wider economic development can be brought together. This means a review of drainage as a linear system and instead part of a wider asset management approach.”
Planning for increased capacity
As the population grows and the climate changes there is recognition that will be a growing need for adaptability in an approach to drainage. An interesting suggestion to adapting the network for growing capacity was made…
“When designing and dimensioning pipes for drainage and sewerage, why not design in parallel liners for the pipes that can be fitted more easily at a later date to reduce the friction and hence increase the capacity.”
There were lots of great suggestions from our participants on what the future of drainage could look like. As the stormwater management is such a large and critical issue, it is likely that the future of drainage will require a combination of approaches, innovation and a high level of co-operation between different organisations with the government taking a leading role in defining, leading and legislating for a successful strategy.
“The future of drainage is to continue to build on the foundations that have already been laid. It’s accepting the need to evolve and being able to educate the industry accordingly. It’s making sure developers understand its significance on a project and that it can no longer be perceived as an after thought. It's ensuring developers are encouraged away from a "why pay more?" and a "do the bare minimum" attitude by flipping their way of thinking. It’s understanding that the above is unlikely to happen without the implementation of an appropriate legal driver. It’s having early engagement with a developer to help them understand the constraints associated with their site and the opportunities that are available. It’s not allowing developers to cover an entire site with a new building just because the existing footprint did the same. It’s about allowing space for SuDS and improving the wider community via the reduction of impermeable area. Its moving away from engineers being appointed after the developer and the architect have schemed up a plan, whereby the entire site is covered in hard standing or building, giving the engineer little if not no chance to implement SuDS. The future of drainage is not just sticking crates in the ground, which is all to often accepted because it ticks the 'SuDS box' for the planners. It shouldn't be considered a tick box exercise, its about understand the actual benefits of the systems installed. It’s understanding that the above way of thinking is not sustainable, yes it allows water to be attenuated on site, but how can the carbon footprint associated with making the product, delivering the product, excavating for the product etc. ever be looked upon as being a sustainable design. The future of drainage is to understand how important a resource water is, its to inspire a generation as to how we can manage and reuse water and at the same time create biodiverse, sustainable environments and overall nicer places to live. It’s making the unseen seen. Its about engineering a better society. The future of drainage is to stop talking and start doing.”
“The future of drainage is about realising change. The combination of climate change and continued urban growth are creating significant pressures on our existing infrastructure, whilst new development is still failing to provide the drainage benefits it is capable of. There are many ways to improve our relationship with water - improving water capture, storage and distribution using smart technologies to sustain life, harnessing wave and tidal power to help meet our energy needs, improving our natural and built environment by giving land over to surface water flood storage, managed withdrawal from river and coastal areas to mitigate against extreme flood events. As a society, we are all responsible for delivering change, the challenge to deliver a relationship with water and drainage to meet the needs of the 21st century, is one we all need to understand and turn into a reality.”
What do you think about the future of drainage? Please share your comments with us below