Developers of the new technology are urging industry stakeholders to recognise the nationally-important strategic contribution that new smart stormwater systems could make, not only to reducing mains water demand but also to lowering surface water flood risk and preventing sewer overflow pollution.

The National Infrastructure Commission has called for a water supply and demand reduction of 4,000 megalitres per day to avoid severe drought risk by 2050 (published in its 2021 Annual Monitoring Report). Meanwhile, as part of a groundbreaking study into rainwater reuse, commissioned by the water efficiency NGO Waterwise, implementing a combination of effective policies and incentives for water reuse was said to have the largest impact of any water efficiency measure on reducing demand, with the potential to reduce the Environment Agency's predicted 3,500 megalitres water deficit by 630 megalitres a day by 2050.

Richard Averley, Sales and Marketing Director for SDS, a leading company involved in the development of combined water reuse and flood storage systems, believes smart rainwater management technologies can play an important role.

"Installing smart rainwater systems in homes and larger commercial or public buildings not only reduces demand for treated mains water, but also delivers attenuation to shield against surface water flooding at a district or catchment level. By holding back surface water from entering the drainage network, smart rainwater systems also help to prevent sewer overload and CSO spills, therefore providing important pollution protection often in environmentally sensitive locations.

"Intelligent rainwater systems work by processing weather forecast data to manage the amount of rainwater collected and stored in combined flood storage and water reuse tanks. The autonomous digital controls enable rainwater to be collected for toilet flushing and garden watering, while the same storage capacity provides measurable protection against surface water flooding at peak times. The levels of water in the tank are lowered in a controlled way whenever heavy rain is predicted, creating sufficient void space in the system to provide effective flood mitigation.

Decentralised Protection

"This smart Internet of Things concept is scalable from smart water butts at an individual property level right up to large reuse and attenuation tanks in multi-use commercial or public buildings, so Water Companies and flood risk authorities could work together to plan a measured amount of protection at a distributed, decentralised level.

"These systems can therefore be purpose-designed not only to ease demand in water-stressed areas, but to target stormwater discharges in hotspots where sewer flooding and CSO spills are a frequent headache for water companies. This can be especially helpful in areas where other options for retrofitting stormwater management measures have already been exhausted.

"Autonomous rainwater attenuation technologies can also be combined with grey water recycling schemes, for example in hotels, office blocks or leisure centres, to contribute further to water efficiency with the added bonus of reduced costs for the building operators. By reducing the need to use heavily treated mains water, water reuse systems could also make a vital contribution to meeting the water industry's 2030 net zero carbon emissions targets.

Proven Successes Already

"In the few areas of the UK where stricter personal mains water usage limits of 110 litres per day are enforced through planning conditions, particularly in central London, well-proven smart rainwater management systems are being completed or are currently underway in new developments. For example, at Southbank Place, the SDS Intellistorm® smart rainwater management system is already operational. Elsewhere several pilot schemes are monitoring how effective lower-budget smart rainwater reuse systems, deployed in a cluster of domestic properties, can combine to deliver district level flood risk and CSO pollution reductions.

"Because smart rainwater management technologies span the remits of so many agencies involved in demand reduction, flood risk management and pollution control, it will be vital to recognise their potential at the national strategic level to mitigate against all these severe impacts of climate change.

Strategic Water Planning

"So, we urge policymakers like the National Infrastructure Commission, as well as Water Company stakeholders involved in water infrastructure and demand management strategy, to appraise themselves of these upcoming technologies. Just like the emerging technology for electric cars, we should plan for their potential to contribute significantly to national targets in the long term.

"A whole raft of regulations and incentives are being mooted and debated to make the country more resilient to drought and flooding in the face of climate change and population growth. Some, like compulsory water metering, or nationwide 110 litres p/p/d water use limits are essential. Water efficiency measures, including water reuse, also need to be part of incentives for greener homes, such as the widely proposed Property Resilience Certificate, or by the extension of a Green Homes Grant to include water efficiency measures.

"Above all, recognising the benefits of autonomous attenuation technologies on a national scale would be a significant driver for change. It makes no sense at all to use expensively treated mains water when rainwater is free and can be recycled close to where it falls."

SDS will be pleased to provide a briefing on the latest developments in smart rainwater reuse and management technologies to any interested stakeholders.

www.sdslimited.com