Basement Impact Assessment
Land values remain very high in central London and also in many of the desirable suburbs. Development space is limited with pressure to ensure that all development maximise the potential opportunity. Utilisation of basement opportunities for new and refurbished developments is increasingly more common.
Basement development has been recognised as having an impact on local flooding, groundwater flow and quality and ground movements. All these issues could impact on immediate neighbouring properties and possibly combined developments on larger geographical areas.
The London Borough of Camden adopted CPG4 in April 2011, a five stage process in support of planning guidance to use in the consideration of planning applications involving basements in the Borough. This important planning guidance is a formal and structured approach to identifying any potential risks to the actual development and the locality. CPG4 covers the screening of the applicant and actions up to the review and decision of the planning office.
The BIA is a process of incorporating a combination of surface and groundwater conditions, with geotechnical analysis into a comprehensive review. The objective is to establish ground movements arising from the basement development and any impact on adjoining or neighbouring properties.
Our Consultancy has seen a steady increase since 2010 in requests for BIA and have completed many assessments particularly in Camden, Tower Hamlets, Westminster and
Kensington & Chelsea. We believe that other London Boroughs will also be requesting BIA as part of the planning approval process.
Chelmer has been working within the Thames basin for over 15 years and has developed working relationships with many of the local authorities and the Environment Agency as a regulator. This experience ensures that reports are best placed to gain approval quickly and efficiently.
Chelmer’s senior Expert Witness, Keith Gabriel has also acted for insurance companies when projects have not followed best practice.