Deep Impact

Dr Richard Coulton highlights the likely impact that new legislation will have on contractors undertaking dewatering operations

All contractors undertaking on-site dewatering will from now on have to pay a great deal more heed to the environmental impact of their operations, on account of a new licensing regime being introduced under the Water Resources Act 1991 (as amended by the Water Act 2003).

Under the changes, expected to come into force next summer, previously exempted activities such as the dewatering of engineering works, mines and quarries will need an Abstraction Licence from the Environment Agency. The change will cover all groundwater operations pumping in excess of 20m3/day. Navigation authorities, harbour authorities, Industrial Drainage Boards and trickle irrigators will also be affected. These licences are in addition to the existing mandatory discharge consents that have to be in place before water can be pumped off-site.

Those failing to comply with the new rules will face fines of up to £20,000 for each offence under the Act. Perhaps the biggest impact to the construction sector will derive from the Agency’s new powers to issue Enforcement Notices which could call an immediate halt to water abstraction if it is felt that an operation risks significant environmental damage. Such Notices could lead to the closure of some affected sites while issues are addressed.

Be prepared

The changes will move dewatering up the agenda when projects are being planned. Licences will have to be in place before abstraction starts, and the Agency will have the power to require reports in support of applications. For larger schemes this may require publication or even public consultation; contractors will therefore need to consult with the Agency and plan well ahead to avoid unnecessary delays.

To differentiate between the various durations and types of abstraction, three classes of licence are to be introduced in place of the current one. These are:

u Temporary Licence – for pumping operations lasting less than 28 days;

u Transfer Licence – for the pumping of groundwater from an excavation into the nearby receiving watercourse (this will also cover situations where groundwater is returned to the same aquifer but at a different point); and,

u Full Licence – where water is abstracted for potable or industrial use.

Most current applications through the Agency take about three months to process.

However, it is understood that the Agency is proposing a one-month fast-track route for Temporary Licences. These will cover most construction dewatering, as it tends to be of short duration and hence often poses least risk to the surrounding groundwater regime and adjacent abstractions. In contrast, Transfer Licences, for larger, long-term projects, will take around four months to process, or longer if the application is contentious.

Desk studies and investigations

The Agency is currently finalising the application requirements for the above licences, which they claim will be ‘risk-based and practical’. This will see the burden placed on contractors to provide information in proportion to the scale of the proposed dewatering and its potential for environmental impact. While a small project may require a relatively straightforward application, involving a desk study, large-scale works will need far more detailed investigations into the risks involved, such as the impact on the local water table.

While the methodology is still being finalised by the Agency experts, they are at pains to point out that the aim is to ensure contractors do not face an excessive burden when it comes to licence applications. Guidance will be published ahead of implementation.

At its simplest, an application will need to be supported up front by some sort of hydrogeological impact assessment (HIA) using basic mass-balance models to show that the impact of the proposed works is minimal. For most routine projects, the preparation of HIAs is not particularly difficult, given a basic understanding of construction dewatering. However, they are time-consuming and failure to get them right will cause unnecessary delays.

As a result, it is anticipated that many contractors will seek the support of experts to ensure the smooth, timely granting of necessary abstraction licences. It is envisaged that experienced water management specialists will be able to provide clients with a complete ‘one-stop shop’ by sorting out both abstraction and discharge licensing issues.

While much of the detail has yet to be agreed, one thing is clear: With the removal of exemptions under the Water Act 2003, contractors will have to pay far more attention to the environmental effects of their dewatering operations.

Dr Richard Coulton is the Managing Director of Siltbuster.

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