Llwynypia Wall Scour Remedial Project: Phase Two Delivered

Llwynypia Wall Scour Remedial Project: Phase Two Delivered

Project Overview

Client: Wales & West Utilities
Principal Contractor: Kaymac Marine & Civil Engineering Ltd.

The Llwynypia Phase 2 Wall Remedials project was a crucial initiative commissioned by Wales & West Utilities and executed by Kaymac Marine & Civil Engineering Ltd. This project focused on the scour repair of the Llwynypia Retaining Wall, a vital infrastructure component located in Tonypandy, Rhondda Cynon Taf.

Project Background

The Llwynypia Retaining Wall, measuring 35 meters in length and 3 meters in height, was constructed from engineering brick and classified as a gravity wall due to its structural characteristics. The wall supported a section of the Tonypandy Power Station and ran parallel to the Rhondda River and a Welsh Water asset. A nearby bridge, supporting the A4058, further underscored the wall’s strategic importance.

Previous works on this wall included:

  • Reprofiling the bank above the wall and removing soil and vegetation.
  • Repairing and repointing brickwork.
  • Adding coping to the wall’s top.
  • Installing a larger pipe to over-sail Welsh Water’s sewer.
  • Conducting a topographical survey.

Despite these efforts, localized scour remained an issue, necessitating the project.

Project Scope

The project involved comprehensive remediation works to address the scour and ensure the wall’s stability and longevity. Key activities included:

  • Mobilizing and setting up the site compound.
  • Implementing environmental protection measures.
  • Carrying out LP jetting to remove fines.
  • Erecting formwork and performing concrete repairs on designated bays.
  • Demobilizing and clearing the site post-completion.

Environmental and Safety Compliance

A detailed Construction & Environmental Management Plan (CEMP) was prepared to minimize environmental impacts and ensure compliance with statutory regulations. The CEMP outlined measures for pollution mitigation, waste management, ecological conservation, and adherence to health and safety regulations, including the Health & Safety at Work Act 1974 and The Environmental Protection Act 1990.

Key Measures and Practices

  • Pollution Mitigation: Utilizing biodegradable hydraulic oil for plant machinery, ensuring all refueling occurred away from watercourses, and maintaining spill kits on-site.
  • Waste Management: Daily inspections, segregated waste storage, and regular waste removal following regulatory guidelines.
  • Ecological Conservation: Training personnel to identify and protect local wildlife, implementing a ‘soft start’ protocol to avoid disturbing animals, and managing invasive species like Japanese Knotweed and Himalayan Balsam.
  • Health and Safety: Site inductions for all personnel, dynamic risk assessments, and adherence to PPE and manual handling regulations.

Project Challenges and Solutions

The project faced several challenges, including:

  • Access Constraints: Access to the site was limited and required careful planning to avoid environmental degradation. Solutions included the construction of scaffold platforms and access stairs.
  • Environmental Sensitivity: The proximity to the Rhondda River and local wildlife necessitated stringent pollution control and conservation measures.


The Llwynypia Phase 2 Wall Remedials project demonstrated a robust approach to infrastructure maintenance, combining technical expertise with comprehensive environmental and safety management. The successful execution of this project ensured the structural integrity of the retaining wall and contributed to the ecological health of the surrounding area.

This case study highlights the project’s scope, environmental and safety measures, and the collaborative efforts of Wales & West Utilities and Kaymac Marine & Civil Engineering Ltd. in successfully completing the remediation of the Llwynypia Retaining Wall.