Trust in manufacturer's data shouldn't be going down the drain

SuDS is becoming ever more complex. Government policies such as the Plan for Water and the anticipated introduction of Schedule 3 of the Flood and Water Management Act 2010 in England, suggest that SuDS designs must consider both water quantity and quality in parallel.

Where there are risks that surface water will carry pollutants, it must be treated. Where pollutant loads are low, natural vegetative SuDS may be sufficient, however where they are higher, some form of manufactured treatment device may also be required.


	Find out More - Schedule 3 of the Flood and Water Management Act 2010


	Find out More - The Plan for Water

	Recommended methodology The CIRIA SuDS Manual C753 details a risk-based approach for designing water quality in SuDS management trains. It also provides pollution Hazard Indices for different types of site, and for three forms of pollution: total suspended solids (TSS), metals and hydrocarbons. It also gives mitigation indices (MIs) for natural SuDS components. British Water's 2022 How to Guide, Applying The CIRIA SuDS Manual (C753) Simple Index Approach To Proprietary Manufactured Stormwater Treatment Devices, provides a method for calculating mitigation indices for TSS, metals and hydrocarbons. Most importantly, however, it allows manufacturers of treatment devices to publish their MIs to a recognised methodology. Designers can then specify the optimum combination of components, whose combined MIs meet or exceed the pollution Hazard Indices for the development, noting that 50% of the published MI value can be used for components downstream of the first treatment stage.
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The importance of trust

SuDS practitioners need to be confident that all the components of a SuDS system will perform as designed in relation to water quality as well as water quantity - and that they will continue to do so over the lifetime of the development. The manufacturer's MI data must therefore be robust and independently verified by experts.

Expert knowledge will also be required to scrutinise published MI data to ensure that it has been derived in a reliable way. Without such expertise there is a risk of poor decision-making and potential sub-optimal performance.

Our recent article in Drain Trader provides practical advice on creating a treatment train for different types of land use using a variety of SuDS components.

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	The importance of third-party verification When manufacturer's MI data is scrutinised, the methodology used to derive MIs needs to be determined and the process and results should be verified by a third-party expert. It is worth remembering that ADS StormTech is the first combined SuDS attenuation and water quality management system to have 3rd party verification, meeting the MIs for medium pollution hazards without the need for other SuDS treatment components.

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ADVANCED DRAINAGE SYSTEMS

StormTech is manufactured by ADS, America's largest manufacturer of thermoplastic corrugated drainage pipes and a specialist in water management systems. StormTech has a long and successful track record with over 50,000 system installations using in excess of 3 million units.

To book a CPD seminar or to contact ADS UK call
0203 442 0607 or click here