The flagship This Land Ltd housing scheme for 540 homes at Soham has hit a major, and possibly defining moment, with an independent noise assessment that says modelling of noise previously “is grossly inadequate and cannot be relied upon”. Already stuck in a planning time warp, a fresh report casts doubt on previous noise assessment reports commissioned by This Land itself.
Mike Stigwood, lead consultant and acoustician for MAS Environmental Ltd, says the previous assessment “gives inadequate consideration of guidance in respect to the nature and character of the noise that will arise in this case and the appropriate indices used for assessment.
“The limited data provided indicates the noise is not benign in nature and warrants a more detailed analysis of its nature and character in terms of likely cause of awakening and / or sleep disturbance.”
He says in his report: “The modelling of noise provided is grossly inadequate and cannot be relied upon for a large number of reasons.
“Further, a crude comparative modelling exercise undertaken by me using the CadnaA (Computer Aided Noise Abatement) platform for the traffic data recorded for the Al42 indicates substantially higher sound energy levels than those predicted by SESL (This Land’s consultants).
“This arises even when exceptionally low traffic speeds are used, and excessively low traffic volumes adopted. Cross checking my basic modelling outcomes with data for the measurements at 140m from the road is in broad agreement. Both wholly contradict the SESL predicted levels. In any event their own analysis undermines their statement on the resulting levels.”
Mr Stigwood concludes: “Serious data inconsistencies are also presented in the very limited recordings provided, which serve to further underline their unreliability.
“The lack of any detail of modelling inputs and assumptions also serves to undermine them.
“They are in effect in disagreement with all expectations based on experience and basic model examples undertaken by me to compare outcomes.
“They are also wholly inconsistent with noise level checks by an independent acoustician who lives locally. In contrast my preliminary predicted levels align reasonably closely with levels measured by the third-party acoustician.”
He accuses the previous assessment of using “incorrect criteria and methods to assess internal noise levels….. and this needs to be visited anew”.
Mr Stigwood says his findings suggest “substantially greater excess noise” than that previously thought.
“Commercial use of adjacent land needs further consideration, if already approved, before this residential development,” he said.
“This is especially the case in terms of background sound levels and transport routes proposed.”
Mr Stigwood says: “It is important to realise that before giving conditional approval, the criteria to be met must be capable of readily being met. This must be through the use of controls that can practically be imposed.
“A condition that is unreasonable is unenforceable and if internal and external noise levels cannot be met then refusal is the only option.
“Furthermore, in this case, not only do we not know the noise exposure levels, other than being much higher than indicated by SESL, but the criteria to apply.
“There is insufficient data and analysis to determine the nature and character of the noise impact and therefore the downward shift of the criteria.
“What is clear is the irregularity of transport movements day and night produces a sound environment far from that described in the guidance relied upon. This is compounded by the variation in noise character that the roundabout will introduce.
“It is clear that the likely resulting noise levels are significantly higher than predicted by SESL. In turn this indicates likely far greater set back and physical mitigation such as screening is needed.
Mr Stigwood says his review of the application submissions, objections, and comments on noise aspects of the development is “provided independent of all other parties and looks objectively and impartially at the issues”.
He says previous reports were produced in 2017 and 2018 for development proposals on this site and an August 2023 report relates to the latest proposed development. The 2017 and 2018 reports should provide useful background noise data and may need to be considered.
Further reports were also issued by SESL 26th March 2020, April 2021, and May 2022.
“It is unclear whether the development proposal was formed, and the noise analysis fitted to it or whether noise analysis led to the development layout formulated,” says Mr Stigwood.
“The findings in this report indicate a fundamental review of the proposed development is needed as the noise levels predicted are not reliable. Furthermore, they appear to significantly understate the impact.”
He says the primary noise issue is from road traffic along the Al42. The proposal includes the insertion of a roundabout and whilst this slows traffic, arguably reducing average sound energy a little, it also introduces noise character in the form of slowing and accelerating vehicles which in turn introduces character into the noise that draws attention.
“Simply put it no longer easily fits within guidance for steady anonymous road traffic noise,” he says. “In summary it gives rise to adverse reaction at lower decibel levels.”
He adds: “Noise mitigation can be improved through building orientation, near source features such as screening but the extent to which this is necessary and the distance from the road will all depend on using a far more robust model that is transparent.
“Transparency is readily achieved. It will need to reflect the proposed built environment so that the effect of building is seen.”
PLANNING APPLICATION DETAILS
19/01600/ESO | Outline planning application for up to 540 dwellings, a medical centre (E(e) use class), and up to 1,600 sqm GIA of use classes: E (a)(b)(c)(e)(f)(g) sui generis (r) hot food takeaway, F1,and F2 and associated highways and infrastructure works, drainage, open space and landscaping, with all matters reserved save for Phase 1 and 3B including landscaping, drainage, infrastructure works and open space, and access (including highways and infrastructure works) via a new roundabout to the A142, and new access points to the NE boundary of Staploe Medical Centre, the former garden centre, and to the boundary of land between East Fen Common and Cornwell Close. | Land West Of A142 Between East Fen Common And Qua Fen Common, And East Of Brewhouse Lane Soham Cambridgeshire