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Mokolo Crocodile Water Augmentation Project (MCWAP), South Africa

The project entails construction of two main bulk raw water transfer systems to meet the growing demand for power generation, mining activities and domestic use in the Lephalale area in South Africa.

Aurecon was engaged, along with four other consultants, in a joint venture as Mokolo Crocodile Consultants, to complete a wide range of engineering services for the first phase of the project, including:

  • Tender design and documentation
  • Detailed design
  • Construction supervision
  • Contract administration
  • Preparation of an environmental management plan, and 
  • Various risk and Hazard and Operability (HAZOP) components.

Phase 1 comprises a 4.5 MW pump station and 46 km (of up to 1 100 mm diameter) pipeline, delivering approximately 30 million cubic metres of water per annum, taken from the Mokolo Dam in the mountains south of Lephalale. This infrastructure was constructed parallel to, and tying in with, existing infrastructure supplying Exxaro's Grootegeluk Mine, Eskom's Matimba and Medupi Power Stations, and the Lephalale Local Municipality.

Phase 2 will include an abstraction weir in the Crocodile River, de-gritting channels with high and low lift pump stations, and approximately 160 km of pipeline with break pressure and balancing reservoirs.

Resources from five design companies, all contributing to a single project office and working in a common digital environment, were mobilised for Phase 1. The objective was to create an optimised and innovative environment for the duration of the project.

As a result, a noteworthy number of structural, process and product innovations were implemented and/or prototyped by the project. A selection of which are briefly described below:

3D modelling

The project was an early adopter of the 3D modelling and design applications in 2009. The design office was intentionally organised to function within an integrated digital design environment, resulting in a significant reduction in the cost-per-drawing metric for the project.

Controlled basting

A significant length of the MCWAP-1 pipeline was designed to be constructed adjacent to an existing pipeline of high importance, as it was the only pipeline feeding a power station, a mine and a municipality that could not be taken out of service. Constructing the new pipeline included blasting of in-situ rock formations without transferring the forces to, and potentially damaging, the adjacent pipeline. The project team developed a novel set of criteria for specifying and evaluating the design of blasting loads to mitigate this risk. It was successfully implemented without any structural damage or outages due to the blasting operations.

Excavation classification

The project specification for the excavation of trench material was significantly updated to include a predefined, project-specific classification of excavation effort, and how it will be determined on site.

This enabled numerous process innovations for on-site agreement of excavated material and maintaining measurements; reducing the time required by supervising personnel on non-quality driven activities.

Introduction of robotics

Various options to reduce construction duration, including using improved processes and robotic equipment, were investigated in conjunction with the contractor. A section of old pipeline was also inspected with a bespoke robotic crawler developed specifically for the project. The contractor subsequently improved on the beta version of the crawler and commercialised the design.

Novel welding technique

As part of the drive to innovate and improve construction methods, a welding technique that showed potential to significantly increase production rates was evaluated on site. However, due to compatibility issues and time constraints during the testing phase, the option was abandoned. The data and experience gathered will form the basis for further development and application of this technique on future pipeline projects.

Unique commissioning procedure

The project team developed an entirely new commissioning procedure to accommodate project and client specific constraints. The procedure borrowed concepts from existing procedures and then adapted those into a new procedure that still observed the contractual framework of the project, but was optimised for integrating, testing and commissioning the 52 sub-systems of the project.

Fully revised specification

The project team was tasked with developing a fully revised technical and performance specification for the project. It was also modularised to allow for easy application in different project environments and changed future circumstances.

The project duration presented an excellent opportunity for training and mentoring of project resources. Several of the junior engineers (including Client and Contractor) attained professional registrations, while others were mentored in more advanced management and contracts administration roles. This success also extends to the socio-economic development programme in which small contractors were empowered during the construction phase of the project. 

Phase 1 of the project was successfully commissioned in 2015.

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