Dig for victory
Better investment in sampling could make for safer water connections and save money in the long run. Environment Business reports
Maintaining the integrity of water supply systems has, for many years, been a cause for concern, particularly where pipelines have required replacement before the expiry of their design life. Permeation and accelerated deterioration of the pipe material can occur due to chemical reaction between pipes and contaminants in the ground. Such deterioration can also lead to permanent failures resulting in leakages and loss of water quality after ingress.
Recent large-scale re-development of brownfield sites, many containing contaminants, has rendered the problems potentially more significant. The government estimates there to be over 50,000 contaminated sites in the UK. It also believes that by 2021, 60% of new homes will be built on brownfield sites. While such development is vital to meet the our expected housing needs, the issues of ensuring safe, clean water supplies remains an issue high on the agenda of water companies, developers and customers alike.
Government guidelines have been issued for developers wishing to connect to the water supply. These include prohibiting the laying of unprotected water supply pipes through contaminated land, and guidelines on choosing suitable pipe materials. Such guidelines make it essential that accurate and comprehensive soil and ground water testing for contaminants is undertaken before work starts.
However, while the remediation of contaminated land for development is well governed, with reporting and monitoring required under planning regulations, the requirements for the surrounding land – through which pipes may run – are not currently part of this process.
Anyone wishing to make a connection has to gain approval from the local water supplier at design stage, presenting all details of the project, proposed materials, and information on contamination risks. As yet, though, a full sampling programme of conditions along the pipeline route outside of the development is not a statutory requirement – despite the possibility that the movement of contaminants through the soil might result in their presence in adjacent ground needing to be taken into account when making connections and selecting the correct pipe materials.
Rob Fuller, Laboratory Commercial Manager at Southern Water Scientific Services, frequently encounters developers who, while understanding the contamination issues on their site, have no knowledge of the status of the surrounding land. “New water supply pipes are typically laid at a minimum depth of 750mm, within the normal depth of investigation and remediation requirements under planning regulations for residential developers. However, developers and water suppliers must check that the results of normal site investigations, required as part of the planning process, are adequate indicators of contamination when designing water services.”
While the water industry has issued guidelines to the principles of material selection when laying water supply pipes, the recommendations are based upon the identification and classification of the contaminants on the site and through the pipeline route. “It’s all about transfer of risk,” says Dr Fuller. “If the developer does not provide accurate or full details of the land conditions of the pipeline, then should a problem occur at a later date, the water company would undoubtedly pursue the developer to resolve the matter.”
Speculation and accumulation
Of course, until planning permission is forthcoming, all money spent on sampling and consulting is pure risk from a developer’s point of view. “Sadly,” continues Dr Fuller, “cost is an overriding factor in the design stages and a wider sampling programme is not always top of the list.”
However if developers opt for a comprehensive sampling programme at the design stage, not only can they ascertain when non-standard materials are required for the pipe, but also when standard industry-approved materials could be used. Such a finding could well save them money.
Southern Water Scientific Services has worked with many developers to facilitate such savings. The company is in a unique position, being able to provide scientific services to the developer, while also being able to understand what the water suppliers will require.
“While the water supplier has no statutory duty to ensure the water remains wholesome after it has passed a property boundary, it will investigate and insist on remediation where a problem is found,” explains Dr Fuller.
“It is vital that developers understand the potential risks and work with the water suppliers to ensure the best results for all.”
For more information visit www.southernwater.co.uk