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Intellistorm®- Rainwater Harvesting with Intelligent Attenuation

Sustainable Water for the Future

Urban drainage systems are often overloaded and continue to present a significant flood risk, especially in the case of new developments; the more buildings that are built, the more densely populated an area is, the higher the chance of overload and flooding. Current sustainable urban drainage recommendations set limits on the discharge of water from developments to help reduce the risk of flooding but the reality is that more action is needed, a much more intelligent approach. Enter Intellistorm Flood Resilience. The technology is currently in use at South Bank Place which you can read about here.

Intellistorm® has been designed and built from the ground up to increase flood resilience within urban areas and improve water efficiency through rainwater reuse. It uniquely combines a rainwater harvesting system, stormwater attenuation tanks and intelligent data gathering into one efficient solution. Where deployed, it can reduce site water consumption and stormwater discharge to drain by as much as 50%.

Intellistorm® can eliminate as much as £100,000 from the cost of integrating a rainwater harvesting system into a new build development where the attenuation of water already exists, ensuring maximum uptake of water reuse. Cost is not the only key factor; this system presents no additional equipment footprint or civil excavation associated with a second attenuation tank. This means that space is no longer as much of a barrier to integrating effective water reuse; a complete stormwater harvesting system.


Intellistorm Flood Resillience

Older Rainwater Attenuation Systems

Effective rainwater attenuation is a planning requirement for the majority of new developments. Developers have to make sure that the transition from ‘undeveloped’ to ‘developed’ land provides no impact on existing sustainable urban drainage infrastructure. This is because it’s such a critical factor in flood prevention and control strategies and therefore can’t be overlooked.

Historically, this was achieved by capturing rainwater that hit the roof of a building or other catchment area and storing it in rainwater attenuation tanks. The system then allowed the water to immediately discharge to sewers at a measured rate that would not impact the local drainage system. While this approach helped to alleviate flooding, it offered no benefit in reducing the volume and impact of water being discharged or indeed the overall water footprint of a building.

If a developer wanted their new building to reuse stormwater, this was achieved by integrating a separate rainwater harvesting system. This meant two separate systems were required for the attenuation of water and rainwater harvesting. This caused 2 crucial problems for developers:

  • Significantly increased costs
  • Inflated demand on space

At the time, these two barriers were insurmountable for the majority of developers and were therefore completely unrealistic without a good return on investment or significant benefit to the environment.

The [water recycling] team at Waterscan collaborated with a variety of major engineering consultancies who specified the new system requirements. This filtered right through to the end user who highlighted unique needs and challenges with rainwater harvesting and flood prevention. This process was critically important as they would be the people who actually approved and purchased the resulting stormwater harvesting system. This research and development resulted in delivering a unique, innovative solution to better manage stormwater, improve the adoption of water reuse and enhance flood resilience in new build developments.

The concept: Flood Resilience

flood from urban drainage system overload

So, Waterscan and the engineers understood there was a problem, analysed the key factors for success and identified a need for effective flood resilience and rainwater attenuation systems. Key factors such as criticality, security, simplicity, a need for low ongoing costs, a desire for custom system integration were identified. A reluctance to rely on third party cloud-based software also became apparent as this presented a great risk if those cloud systems went down.

A solution was then sought, incorporating these key factors, to achieve:

  • More effective stormwater management
  • Increase flood prevention and control
  • Improve rainwater reuse
  • A lower cost and smaller footprint

Intellistorm® enables a site to maximise water reuse and reduce discharge to drain by intelligently storing and using collected rainwater for non-potable applications such as toilet flushing, irrigation, vehicle washing and cooling systems.

Unlike traditional rainwater attenuation systems which temporarily attenuate stormwater and allow a continuous controlled discharge of any collected surface water – Intellistorm® actively empties attenuation tanks in accordance with weather forecast data, providing only sufficient space in the tanks to receive incoming rainwater and ensuring the maximum amount of water for reuse is continuously available. Furthermore, the water is released prior to rainfall occurring, hence at a time when the drainage systems aren’t stressed by stormwater events.

How these Rainwater Attenuation Systems Work:

Intellistorm® receives daily Met Office rainfall forecast data, detailing the amount of rainfall expected in mm/24 hours. It then calculates the amount of space required in the attenuation tank by multiplying site catchment area by mm of rainfall forecasted by the Met Office. The volume of water required to create this void is then released to the water course or sewer, prior to any rainfall occurring. This ensures the rainwater attenuation tank is ready to accept all forecasted rainfall and fully refill. The system then monitors and awaits the next weather forecast ready to release more rainwater in order to accommodate whatever rainfall is due.

Innovative Rainwater Attenuation:

The innovative concept was designed and crafted to mitigate the need for separate rainwater harvesting and attenuation systems where a new build development needed to consider both flood resilience and water consumption impact. By innovating to combine two systems and use intelligent data, significant construction cost savings are achieved and spatial restrictions to accommodate large water storage volumes are mitigated. Furthermore, end-users achieve ongoing cost savings through water reuse and the wider environment and society benefit from improved flood resilience.

Key innovations include:

  • Combining a rainwater harvesting system with attenuation and without the need to add additional storage or tank size. This results in massive cost and carbon reductions for a project. The same goals of flood resilience and water impact reduction can be achieved through use of approximately 40% less build materials and labour during construction over traditional systems.
  • High security and reliability through the eradication of cloud-based software giving clients full control. Rainwater attenuation system failure during rainfall could cause catastrophic damage, so failsafe operation is critical. All software is designed to be operated and held locally. The only offsite data is limited to the incoming weather forecast which can be sourced from a number of parties. Optional remote monitoring for offsite access and control available.
  • Competitor systems rely on cloud-based software with limited client customization and slow reaction to rainfall. These require complex interactions with the site system which in turn increases risk of failure.
  • Highly customisable water treatment – controls both the quality of water to surface water discharge and water for reuse, maximizing possible applications.

Benefiting the environment

Intellistorm® puts rainwater reuse well within the reach of every project where sustainable urban drainage is a planning requirement. The effect of this heavily benefits a building’s water supply and the large scale sewerage infrastructures in local communities. By reusing stormwater, not only is the impact on the local surface water network reduced, so is the demand for mains supplied water resulting in benefits across the board – a true win-win situation. A mixed use building’s water consumption can be reduced by as much as 50% through the use of harvested rainwater for irrigation, cooling systems and WC flushing.