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Dewatering and groundwater control | Stuart Well Services Ltd

Regulatory Position


Dewatering operations by their very nature involves the abstraction of groundwater and in turn the discharge of this abstracted water. Since 2018 there have been changes regarding both abstraction and discharge regulatory arrangements.


In affect most construction dewatering operations and activities in the UK comes under the remit of national environmental regulations and require licencing. The policy is enabling a greater environmental management and control of groundwater resources.

Stuart Wells are adapt and proficient in undertaking or assisting in the licencing process as well as being proactive and imaginative in designing solutions, such as recharge wells. The advice is to contact us as soon as possible to discuss the project any regulatory implications.

There slightly differing regulatory positions regarding dewatering and groundwater in the UK, which depend on what part of the country the dewatering project is being undertaken. Links to more detail on specific regulatory policies are as follows:


England

Environmental Agency - Temporary dewatering from excavations to surface water
https://www.gov.uk/government/publications/temporary-dewatering-from-excavations-to-surface-water/temporary-dewatering-from-excavations-to-surface-water

Scotland

SEPA - Regulatory Method (WAT-RM-11) Licensing Groundwater Abstractions including Dewatering.
https://www.sepa.org.uk/media/151997/wat-rm-11.pdf

Wales

Natural Resources Wales - Water discharge and groundwater activity exemptions.
https://naturalresources.wales/permits-and-permissions/water-discharges-and-septic-tanks/discharges-to-surface-water-and-groundwater/water-discharge-and-groundwater-activity-exemptions/?lang=en

Northern Ireland

Department of Agriculture, Environment and Rural Affairs - Abstraction and impoundment licensing requirements.
https://www.daera-ni.gov.uk/articles/abstraction-and-impoundment-licensing-requirements

Guidance on requirements and exemptions for the Environmental Agency (England) are outlined below.


B). Groundwater Abstraction


Any Construction Dewatering operation that is deemed to be exempt from an abstraction licence requirement, needs to comply with all the following conditions.

  • a). Abstraction is temporary and undertaken within a period of less than 6 months.
  • b). Does not cause or is likely to cause damage to a conversation site, specific feature, and protected species.
  • and either:
  • c). A total abstraction rate of less than 100 m3/day (1.15 lts/sec) or:
  • d). Abstracted is immediately discharged to a soakaway or back to ground via recharge wells.

The reality is that the majority of construction dewatering projects fit within items a). & b) above, but items c) & d) create issues. In the fact that the exemption abstraction rate is this is low and below the steady-state abstraction rate of most Construction Dewatering projects in the UK. The ability to recharge abstracted groundwater back to ground is an option and may well prove to be a practical solution with the installation of a recharge trenches or recharge wells. However, feasibility is very much project specific and depends on required recharge rate, ground conditions, space on site, effect on the dewatering system and local hydrogeology.

Most Construction Dewatering operations are invariably either:

Planned - Where a groundwater issues is highlighted, and a dewatering scheme is proposed. In these cases, the task of obtaining an abstraction licence will need to form part of the planning process, unless the above conditions can be met.

Reactionary - Where groundwater issues are not foreseen, and a dewatering system needs to be installed promptly. Our understanding is that this would be considered an emergency, and subject to the objective of the dewatering system being to prevent immediate danger to engineering, building or other operations. Works can be undertaken provided notice is given to the EA within 5 days. Again, unless the operation is within the exemptions highlighted above, the process of obtaining an abstraction licence will need to be started.

Reactionary - Where groundwater issues are not foreseen, and a dewatering system needs to be installed promptly. Our understanding is that this would be considered an emergency, and subject to the objective of the dewatering system being to prevent immediate danger to engineering, building or other operations. Works can be undertaken provided notice is given to the EA within 5 days. Again, unless the operation is within the exemptions highlighted above, the process of obtaining an abstraction licence will need to be started.

Types of Abstraction Licences & Costs – There are two types of abstraction licences which depend on the discharge arrangement. Actual cost of abstraction charges is built up on a case-by-case basis and can be found at: https://www.gov.uk/government/publications/abstraction-charges-scheme.

  • a). Full Abstraction Licence – This would be the case where we are discharging to a utility sewer for more than 28 days, or as the EA would deem not back into their environmental resource network (i.e., removing water from their system). In these cases, there is an application fee for the licence and additional charges for the volume of water abstracted. We estimate basic application costs in the region of £135 with a separate formula establishing subsistence charges.
  • b). A Transfer Licence – This would be the case where we are discharging to a water course, or as the EA would deem transferring the water from one environmental resource (groundwater) back into another environmental resource (river etc..) without intervening use. In these cases, there is an application fee but no additional charges for the water abstracted. We estimate basic application costs in the region of £1,500.

If you are not currently abstracting, but planning a new abstraction, or planning to increase your current abstraction volumes, then you will need to have an abstraction licence in place before the abstraction can commence.

Please note the EA can take up to four months from the date they receive a valid application. However, although the EA are very helpful, we would strongly recommend that you submit your abstraction application as soon as possible to avoid issues.

Please go to https://www.gov.uk/guidance/water-management-apply-for-a-water-abstraction-or-impoundment-licence for more information.


B). Groundwater Discharge


This section details the regulatory position for groundwater discharge to an EA resource (i.e., river, stream) only and is not applicable if water is discharge to Utility Outfall (foul sewer etc).

A discharge licence is not required under current EA regulatory position statement, so long as you comply to certain conditions, summarised following: For more specific information on compliance requirements please go to: https://www.gov.uk/government/publications/temporary-dewatering-from-excavations-to-surface-water/temporary-dewatering-from-excavations-to-surface-water.


The discharge must:

  • Be clean water, not containing suspended solids (silty water).
  • Not last more than 3 consecutive months (the activity may stop and restart, but the clock does not restart).
  • Be made to surface water, such as a river, stream, or the sea.
  • Have a method statement that minimises the risk of pollution.

The discharge must not:

  • Pollute surface water.
  • Contain any chemical dosing agents, flocculants, or coagulants.
  • Be from a site which is contaminated by oil, metals, hydrocarbons, solvents or pesticides or other polluting substances and naturally elevated concentrations of substances which exceed environmental quality standards.
  • Result in the spread of non-native invasive species, parasites, or disease.
  • Cause flooding from surface water.
  • Cause erosion of the banks or bed of the receiving watercourse.
  • Contain concrete wash water even if it has been treated.
  • Contain site drainage from surface areas such as haul roads, storage or working areas.

The discharge must not be located within, or less than 500 metres upstream of:


Drinking Water Quality Standards

Please click to link for a table of our assessment and commenst (for information only) of current UK regulatory parameters and standards in accordance with the Water Supply (Water Quality Amendment) Regulations 2018. Some non-regulatory parameters are also included for information only. We can underatake water sampling
(PDF - UK Drinking Water Standards) and labratory analysis for DWQ standards, if required.

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