Current improvement programmes

Notice of Regulation: Thames Water – Risk from Flooding

THE WATER SUPPLY (WATER QUALITY) REGULATIONS 2016 (AS AMENDED)

NOTICE UNDER REGULATION 28(4)

THAMES WATER UTILTIES LTD: Risk from Flooding

Site Names and references: see Annex 1

DWI Reference: TMS3892

THE SECRETARY OF STATE:

  1. has on 21 October 2017 received a report (the “Report”) from Thames Water Utilities Ltd (the “Company”) which states that there is or has been a significant risk of supplying water from the catchments and sites listed in Annex 1 that could constitute a potential danger to human health or could be unwholesome.
  2. GIVES NOTICE to the Company under regulation 28(4) of the Water Supply (Water Quality) Regulations 2016 (as amended) (“the Regulations”) that it must satisfy the following requirements:

For risks associated with:

  • Site contamination [risk from flooding]

Requirements

(a) to maintain the following measures for the period specified:

To ensure that wholesome water is supplied to consumers at all times, in accordance with the requirements of regulation 4, maintain existing operational measures which must include the following at all sites (catchments and their corresponding water treatment works as applicable)covered by this Notice:
Date: Ongoing for the duration of this Notice

  1. Operation of all processes within defined operating ranges with appropriate triggers, responses and contingency procedures with associated review programmes.
  2. Maintain continuous turbidity monitoring of water prior to disinfection with appropriate alarms and failsafe shutdowns where applicable. Respond to alarms from these monitors as per Company procedures.
  3. Ensure all water treatment works’ control and shutdown systems are operational and that monitors are calibrated at predefined frequencies.
  4. Continuous monitoring of raw and treated water with control systems, alarmed operating limits and automatic shutdown as appropriate.
  5. Ensure that turbidity monitoring equipment is maintained in-line with manufacturers’ instructions.
  6. Continuously review all critical control points and mitigation measures for the duration of this Notice with a view to updating the Notice with additional measures where required. Ensure that any new risk identified is assessed in accordance with the Company’s Drinking Water Safety Plan (DWSP) methodology.
  7. Water quality response procedures for: investigation of contraventions including process optimisation and reporting; customer complaints procedures; event response procedures for event actions and notification criteria.
  8. Up-to-date Site Operating Manual (SOM), defining normal operating ranges, triggers, response and contingency procedures, with controlled update and review programmes.
  9. The Company’s internal waiver process is followed where deviation from the Asset Standard is required. This must not affect compliance with the Regulations.
  10. Up-to-date and subject to continuous review, site specific disinfection policies, which identify clearly and unequivocally how disinfection is achieved at the water treatment works.
  11. Maintain contingency plans to protect human health in the event of a risk to human health associated with drinking water quality, which should include liaison with local authorities and Public Health England to agree any actions needed to protect human health and issuing of advice to consumers, where required.
  12. In accordance with the requirements of regulation 27(3), continuously review and revise as necessary the regulation 27 risk assessments for the sites and submit revised regulation 28 reports to the Inspectorate as necessary, in accordance with the published procedure.

(b) to review, revise or make operational the following measures, by the date specified below:

Measures for all sites listed in Annex 1

    • a) Review all catchments and water treatment works where screening indicates a potential risk from groundwater flooding.
      Date: 31 March 2019
    • b) Identify any measures required to address the findings of the review completed under measure (b)1.a) above.
      Date: 30 June 2019
    • c) Implement any required measures identified under (b)1.b) above.
      Date: 31 December 2023
    • a) Review all catchments and water treatment works where screening indicates a potential risk from fluvial or pluvial flooding.
      Date: 31 March 2019
    • b) Identify any measures required to address the findings of the review completed under measure (b)2.a) above.
      Date: 30 June 2019
    • c) Implement any required measures identified under (b)2.b) above.
      Date: 31 December 2023

Measures for Eton abstraction features and Datchet water treatment works

    • a) Complete a flood risk assessment for Eton abstraction features (including Eton pumping station).
      Date: Complete
    • b) Identify any measures required to address the findings of the flood risk assessment completed under measure (b)3.a) above.
      Date: Complete
    • c) Implement any required measures identified under (b)3.b) above.
      Date: 31 March 2020
    • a) Complete a flood risk assessment of the Datchet boreholes and Datchet water treatment works.
      Date: 31 March 2019
    • b) Identify any measures required to address the findings of the flood risk assessment completed under measure (b)4.a) above.
      Date: 31 March 2019
    • c) Implement any required measures identified under (b)4.b) above.
      Date: 31 March 2020

(c) to audit whether the measures have been effective by the following means:

  1. Define a strategy for auditing the effectiveness of the above measures.
    Date: 31 July 2019
  2. Implement the audit strategy outlined above.
    Date: Until revocation of this Notice.

(d) not to supply water for regulation 4(1) purposes from sites listed in Annex 1, unless the conditions specified below are satisfied:

  1. n/a

(e) to provide the following information in the time and manner specified below to enable monitoring of progress towards the mitigation of the risk of supplying water that would constitute a potential danger to human health:

  1. Provide a progress report annually by 31 January each year after the final notice is served and against the following milestones:
    • a) Report outlining the findings of the review completed under (b)1.a) and (b)2.a) and the measures to be taken to address any deficiencies identified (as required under measure (b)1.b) and (b)2.b)) and their proposed timescales for delivery.
      Date: 31 July 2019
    • b) Confirmation of the completion of any measures required under measure (b)1.c) and (b)2.c).
      Date: 30 January 2024
    • c) Report outlining the findings of the flood risk assessment completed under (b)4.a) and the measures to be taken to address any deficiencies identified (as required under measure (b)4.b)) and their proposed timescales for delivery.
      Date: 30 April 2019
    • d) Confirmation of the completion of any measures required under measure (b)3(c) and (b)4.c)
      Date: 30 April 2020
  2. Review the risk assessment for the sites covered by this Notice and their associated supply systems as required by regulation 27(4) and subsequently submit revised regulation 28 reports accompanied by signed board level declarations.
    Date: From time to time and 2 months after the completion of all measures in section (b)
  3. Submit a satisfactory completion report.
    Date: 01 March 2025

Failure by the Company to comply with this Notice may result in enforcement proceedings under section 18 of the Act.


Signed by authority of the Secretary of State,
Laura Moss
Deputy Chief Inspector
08 July 2020
DWI reference: TMS3892
Version 2

Annex 1- Sites

Part I – Catchments and their corresponding water treatment works

Catchments identified by screening as being potentially at risk from flooding.

Catchment name

Catchment Ref.

Connected Water Treatment Works Name

Connected Water Treatment Works Ref.

Flooding

Risk

Type

Pluvial

Fluvial

Ground water

Addington Catchment

C01U.101

Addington

T01U.101

Ground water

Ashton Keynes Catchment

C07U.722

Ashton Keynes

T07U.722

Ground water

Bishops Green Catchment

C06U.615

Bishops Green

T06U.615

Ground water

Bradfield Valley Catchment

C06U.620

Bradfield

T06U.620

Ground water

Bradfield Windmill Catchment

C06U.670

Bradfield

T06U.620

Ground water

Brantwood Road Catchment

C01U.170

Brantwood

T01U.170

Ground water

Cleeve & Gatehampton (Gatehampton) Catchment

C06U.640

Cleeve

T06U.639

T06U.640

T06U.641

T06U.642

Ground water

Dapdune Catchment

C04U.406

Ladymead (Dapdune)

T04U.405

Ground water

Darenth Catchment

C01U.110

Darenth

T01U.110

Pluvial

Fluvial

Ground water

Dartford Catchment

C01U.114

Dartford

T01U.114

Pluvial

Fluvial

Datchet & Eton (Datchet) Catchment

C03U.310

Datchet/ Eton

T03U.310

Pluvial

Fluvial

Ground water

Datchet & Eton (Eton) Catchment

C03U.338

Datchet/ Eton

T03U.310

Pluvial

Fluvial

Deptford Catchment

C01U.115

Deptford

T01U.115

Pluvial

Fluvial

Ground water

Dorney & Taplow (Dorney) Catchment

C03U.318

Dorney/ Taplow

T03U.318

Pluvial

Fluvial

Ground water

Dorney & Taplow (Taplow) Catchment

C03U.319

Dorney/ Taplow

T03U.318

Ground Water

Enborne Grange Catchment

C06U.632

Enborne Grange

T06U.632

Pluvial

Fluvial

Ground water

Epsom (Nonsuch, Main & Rail) Catchment

C01U.119

Epsom

Epsom (New Stream)

T01U.119

T01U.120

Ground Water

Eynsford Catchment

C01U.124

Eynsford

T01U.124

Pluvial

Fluvial

Greys Road Henley Catchment

C06U.626

Greys Road

T06U.626

Pluvial

Fluvial

Hambleden (Medmenham) Catchment

C03U.333

Hambleden

T03U.333

Ground Water

Hampden Bottom Catchment

C05U.504

Hampden Bottom

T05U.504

Pluvial

Fluvial

Hawridge Catchment

C05U.505

Hawridge

T05U.505

Ground Water

Hoddesdon (Essex Road) Catchment

C02U.366

Chingford South

Coppermills

Hornsey

T02S.004

T02S.001

T02S.002

Ground Water

Horton Kirby Catchment

C01U.129

Horton Kirby

T01U.129

Pluvial

Fluvial

Ground water

Kangley Bridge (Bell Green) Catchment

C01U.111

Kangley Bridge

T01U.111

Ground Water

Ladymead Catchment

C04U.405

Ladymead (Dapdune)

T04U.405

Pluvial

Fluvial

Ground water

Langley Vale Catchment

C01U.132

Langley Vale

T01U.132

Pluvial

Fluvial

Latton & Meysey Hampton (Latton) Catchment

C07U.709

Latton (M. Hampton)

T07U.709

Ground Water

Latton & Meysey Hampton (Meysey Hampton) Catchment

C07U.710

Latton (M. Hampton)

T07U.709

Ground Water

Lea Bridge Catchment

C02U.331

Coppermills

T02S.001

Pluvial

Fluvial

Leckhampstead Catchment

C06U.633

Leckhampstead

T06U.633

Pluvial

Fluvial

Ground Water

Merton Abbey Catchment

C01U.135

Merton Abbey

T01U.135

Ground Water

Middlefield Road Catchment

C02U.367

Chingford South

Coppermills

Hornsey

T02S.004

T02S.001

T02S.002

Ground Water

Millmead Catchment

C04U.404

Millmead

T04U.404

Pluvial

Fluvial

Ground water

Netley Mill & Albury (Brook, Albury) Catchment

C04U.401

Netley Mill/ Albury

T04U.401

Ground Water

Netley Mill & Albury (Netley Mill) Catchment

C04U.472

Netley Mill/ Albury

T04U.401

Ground Water

Pann Mill Catchment

C03U.325

Pann Mill

T03U.325

Ground Water

Radnage Catchment

C03U.322

Radnage

T03U.322

Pluvial

Fluvial

Ground water

Sheeplands Catchment

C06U.643

Sheeplands

T06U.643

T06U.638

Ground Water

Shortlands Catchment

C01U.153

Shortlands

T01U.153

Pluvial

Fluvial

Southfleet Catchment

C01U.156

Southfleet

T01U.156

Pluvial

Fluvial

Speen Catchment

C06U.613

Speen

T06U.613

Ground Water

Streatham Catchment

C01U.158

Streatham

T01U.158

Ground Water

Sundridge Catchment

C01U.160

Sundridge

T01U.160

Pluvial

Fluvial

Swell (Upper) Catchment

C07U.702

Upper Swell

T07U.702

Pluvial

Fluvial

Ufton Nervet Catchment

C06U.621

Ufton Nervet

T06U.621

Ground Water

Waddon Catchment

C01U.169

Waddon

T01U.169

Ground Water

Waltham Abbey (Waltham Abbey & Rammey Marsh) Catchment

C02U.236

Waltham Abbey

T02U.236

Pluvial

Fluvial

Wansunt Catchment

C01U.173

Wansunt

T01U.173

Ground Water

Wantage (Manor Road) Catchment

C06U.601

Wantage Manor Road

T06U.601

Ground Water

Watlington Catchment

C05U.509

Watlington

T05U.509

Ground Water

West Wickham Catchment

C01U.179

West Wickham

T01U.179

Ground Water

Wilmington Catchment

C01U.181

Wilmington

T01U.181

Ground Water

Part II – Water Treatment Works

Water treatment works identified by screening as being potentially at risk from flooding.

Catchment name

Catchment Ref.

Flooding 

Risk 

Type

Pluvial

Fluvial

Groundwater

Coppermills WTW

T02S.001

Pluvial

Fluvial

Hornsey WTW

T02S.002

Pluvial

Fluvial

Shalford WTW

T04S.002

T04S.003

T04S.004

T04S.005

Pluvial

Fluvial

END OF ANNEX 1