Understanding site viability for development

Brownfield land is often seen as the solution to solving the housing crisis. While Authority planners will give preference to brownfield redevelopment, builders will be rightly concerned that the land could come with a financial as well as physical health warning.

Understanding site viability for development is the important first step

Exact past site use and potential contaminants can be unknown. Toxic pollution from waste materials, industrial processes and chemical or fuel storage can leave residues for many years in both the underlying soils and groundwater.

Contaminants can migrate from the site and pollute underlying groundwater, neighbouring rivers, and local environmentally sensitive areas. Substances may also be corrosive, and potentially explosive, threatening the local ecology, animals and humans. Aside from the nuisance risks, there are substantial punitive costs for the disposal of contaminated soils, if not identified and managed from an early stage.

A developer must ensure the site is suitable and safe for the purpose for which it is intended. They must have a clear understanding of the risks and liabilities associated with the site, to ensure the scheme is viable and that profit margins are safeguarded.

The first step in land risk assessment is a detailed contaminated land study. By identifying the underlying ground conditions and understanding the proposed use and size of development, initial potential risks are uncovered and show the overall viability. From this, a more detailed appraisal can be made of the likely remediation programme, and therefore the costs that need to be built into the project.

Compliant flood and drainage assessment

New builds reduce the land’s capability to absorb rainfall through the introduction of hard, impermeable surfaces. This results in greater runoff as less water seeps into the ground, increasing the speed, and volume, of flooding.

Sustainable Drainage Systems (SuDS) are now a key consideration for new-builds. The April 2015 revision to Building Regulations Document H on Drainage Systems clarifies a “drainage hierarchy” which favours sustainable drainage as the first priority. Planning consents also favour this approach where it is suitable to do so. If it is not suited, then traditional mains drainage applies. Developers must understand this in the context of their site and provide planning authorities with an effective statement to show compliance.

Our SuDSmart report range is designed to explore suitable SuDS options for new build sites and outline a site’s infiltration suitability.

The National Planning Policy Framework (NPPF) also requires that new developments in areas at risk of flooding should give priority to the use of SuDS and demonstrate that the proposed development does not increase flood risk downstream to third parties.

The ability to drain surface water within the site is key but so is an appreciation of the wider flood risks. Authorities and the Environment Agency have clearly defined zones based on likelihood to flood and this has determined land use zoning within the NPPF. A detailed flood risk assessment will show where existing risks from surface, groundwater and river flooding occurs.

Get the complete view of the site

There is a wealth of support available to developers to deliver a full understanding site viability for development. It is always cost effective to do this with one suite of reports as part of initial site due diligence. This will lead to more compliant planning applications and a clearer identification of risks required by regulators, clients and lenders.

GeoSmart is currently offering two or more reports purchased in a bundle at a special discount of up to 15%. Call us on 01743 298 100 or email enquiries@geosmartinfo.co.uk to claim this special offer today!