Client:
Eswatini Government, Ministry of Natural Resources and Energy

Location:
Eswatini

GIBB’s Responsibilities:
The Maguga Dam and hydroelectric power station is part of the Komati Basin Study performed in north-west Swaziland.

The study was carried out in two parts and included: feasibility studies for the 105 m high Maguga Dam (configured as a clay cored rockfill dam); a concrete faced rockfill dam, a roller compacted concrete dam; feasibility studies for a 15 MW capacity hydroelectric power station located at the foot of the dam; studies to identify land suitable for irrigated agriculture.  Additionally, agronomic, economic and financial studies were carried out to identify how best to utilise water supply from the dams.  Legal studies relating to the international agreement between Swaziland and South Africa were also performed.

Client:
North South Power Company

Location:
Nigeria

GIBB’s Responsibilities:
GIBB was appointed for the detailed condition assessment of the 600 MW hydropower plant which includes a 115 m high concrete faced rockfill dam with a crest length of 700 m.

Client:
Government of Botswana’s Department of Water Affairs

Location:
Botswana

GIBB’s Responsibilities:
In a Joint Venture, ACE GIBB were appointed for the 1 600 m long, 35 m earth embankment dam. The project included project management, civil engineering, waterworks and pipeline design, foundation engineering, dam engineering, cost estimation, scheme documentation, construction supervision and administration.

Client:
Copperbelt Energy Corporation

Location:
Zambia/DRC

GIBB’s Responsibilities:
Owner Engineer for the Master Plan of the potential 900 MW total capacity which includes five dam structures ranging in height from 20 m to 70 m along the Luapula River.

Client:
Department of Water Affairs

Location:
Limpopo, South Africa

GIBB’s Responsibilities:
The De Hoop Dam is a gravity dam on the Steelpoort River near Bugersfort, Limpopo as part of the Olifants Water Management Area and catchment.

The resultant dam design was a 81 m high roller compacted concrete dam, 1 015 m in length, with a storage capacity of 347.6 million m³ and a surface area of 16.9 km². The project also included project management, construction supervision, contract administration and cost control of all the works.

Location:
Gauteng, South Africa

GIBB’s Responsibilities:
GIBB was appointed for the Gauteng Rapid Rail Link Tunnel which serves part of Gauteng with a rapid transport service, providing a safe, efficient and reliable service to commuters.  It is also linked to the OR Tambo International Airport.

GIBB’s tasks included: design review and specifications; provision of a construction supervision team for 15 km of soft and hard rock tunnelling, including three underground stations; earthworks; bridges; viaducts; stations; the EM and M depot; signals; telecoms; safety; security, and noise and vibration.

Client:
Copperbelt Energy Corporation

Location:
Zambia

GIBB’s Responsibilities:
The Kabompo Gorge Hydroelectric Project is a reservoir scheme to provide power to the Zambian grid (40 MW installed capacity). GIBB was appointed as lead consultant in a 3-way Joint Venture.

Main components included underground waterways and caverns, a roller compacted concrete dam (54 m in height) and 4 km of waterway tunnels. Main components included feasibility studies, tender design, evaluation and appointment as Owner’s Engineer.

Specific tasks included: project management; civil engineering; underground and foundation engineering; dam engineering; electrical and mechanical engineering; environmental services; cost estimation; scheme documentation; contract and tender document preparation and adjudication; contract negotiations, and Owner’s Engineer.

Client:
Metolong Authority

Location:
Metolong, Lesotho

GIBB’s Responsibilities:
The Metolong Dam Project is an 83 m high straight Roller Compacted Concrete (RCC) gravity dam with a storage capacity of 63.7 million m³. The downstream face is stepped to suit the RCC construction method and has a slope of 0.8:1 (H:V).

The project included a multi-level intake tower and a raw water pumping station with a capacity of 1.2 m³/s, with provision made for the capacity to be increased to 2.4 m³/s. The project formed part of the water supply programme that was identified as the next long term solution to meet increasing water demands in the Lesotho Lowland.

GIBB as the consultant covered the tender and detail design of the dam, intake tower and pumping station, and provided supervision of construction.

Client:
Metolong Authority

Location:
Lesotho

GIBB’s Responsibilities:
GIBB, as lead partner in a Joint Venture, was appointed for the construction supervision of the downstream conveyance system, which forms a portion of the overall Metolong Dam and Water Supply Programme.

The downstream conveyance system consists of a system of pipelines totalling approximately 132 km, as well as associated appurtenances and pump stations. Included were storage reservoirs for conveyance of potable water to several communities of Maseru.

Tasks were split into three contracts; Contract 1 included the primary line from near the command reservoir at the water treatment works (WTW) and the Mpilo Reservoir in Maseru, and the Metolong Connector. Contract 2 included secondary lines with pump station, tanks and all appurtenances.

Contract 3 included a secondary line from the command reservoir near the WTW to the Teyateyaneng community, including tanks, pump station and appurtenances.

Location:
Near Butha-Buthe, Lesotho

GIBB Responsibilities:
GIBB, in a Joint Venture with EDF, URS, Royal HaskoningDHV and Knight Piésold and supported by local firm GWC, was appointed to undertake a pre-feasibility study of the Monontsa Pumped Storage Scheme.

The Monontsa Pumped Storage Scheme is located in 38km North East of the town Butha-Buthe in Lesotho. The upper reservoir is located on the Tsehlanyane River (which drains southwards as part of the headwaters of the Katse Dam) and the lower reservoir on the North flowing Pitseng River. The distance between the upper and lower reservoirs is approximately 5.2 km and the elevation difference approximately 695 m.

The capacity of the scheme installed was 1200 MW with a continuous generating period of  21 hours. The underground powerhouse complex consists of a machine hall, a transformer hall, access and construction tunnels.

The pump/turbines are connected to the upper reservoir by a concrete lined headrace tunnel and pressure tunnel that is partially steel lined in the immediate vicinity of the power house. A concrete lined extended draft tube and tailrace tunnel connect the pump/turbines to the lower reservoir.

Client:
Lesotho Highlands Development Authority (LHDA)

Location:
Lesotho

GIBB’s Responsibilities:
The Lesotho Highlands Water Project (LHWP) is a multi-billion Maloti/Rand bi-national project which was established by the treaty of 1986 between the governments of the Kingdom of Lesotho and the Republic of South Africa.

The LHWP includes large scale civil engineering, socio-economic and environmental components. The LHWP harnesses the water resources of the highlands of Lesotho through the construction of a series of dams and tunnels for the mutual benefit of Lesotho and South Africa.

Phase II of the project has commenced. GIBB’s tasks on Phase II of the project include a 163.5 m concrete-faced rockfill dam at Polihali, downstream of the confluence of the Khubelu and Senqu (Orange) Rivers, and a gravity tunnel that connects Polihali Reservoir to the Katse Reservoir.  This is currently underway.

Client:
Lesotho Highlands Development Authority (LHDA)

Location:
Lesotho

GIBB’s Responsibilities:
This project was awarded to GIBB with the objective of identifying additional hydropower in Lesotho.  GIBB’s services included: project management; contract administration; quality management; risk management; progress monitoring and reporting, and assistance to the client.

The specific scope of work includes: conventional hydropower feasibility review; screening study of viable conventional hydropower options (both within and out of the Lesotho Highlands Water Project, LHWP); review of the existing and projected Lesotho electrical system; generation capacity and power demand; analysis of viable small or medium hydropower options within the existing LHWP system; review of the existing and planned expansion of the Lesotho transmission and distribution network; review of options for the expansion of Muela hydropower station;  conduct of pre-feasibility screening study of other viable hydropower options in Lesotho (outside the LHWP);  conduct of economic assessment of hydropower options and comparison with alternative energy sources (e.g. wind power).

GIBB also conducted final engineering studies, including: revised cost estimate; project development programme; due diligence review of the relevant Lesotho legal and regulatory framework; assessment of financing requirements; geotechnical site investigation; environmental & social studies and various project development options.

Location:
Mahe Island, Seychelles

GIBB’s Responsibilities:
The La Gogue Dam was a homogeneous earth fill dam with a maximum height of 35 m from the excavated foundation level and a length of 152 m at the crest. The La Gouge Dam is one of the main water supply reservoirs for north east Mahe.

GIBB maximised the storage capacity of the reservoir by identifying and comparing the cost, technical engineering analysis, resources availability (including transfers) and the availability of construction material. The latter made a priority of maximising the storage capacity of the reservoir.

Client:
ZINWA & DTI South Africa

Location:
Harare, Zimbabwe

GIBB’s Responsibilities:
Kunzvi Dam is located on the upper reaches of the Nyagui River and its dam site is located approximately 4 km upstream of the confluence of Nyagui River and the Nora River. The main purpose of the reservoir is to supply water to Harare, which is 55 km away.

The water supply scheme project consists of Kunzvi Dam on the Nyagui River, Nora Weir on the Nora River and a channel diverting water from the Nora River to Kunzvi Dam. Tasks included raw water conveyance from Kunzvi Dam to the treatment plant, a water treatment plant, water transmission pipeline and reservoirs, and water distribution pipe network with 3 trunk pipelines.

The total storage capacity of the reservoir is 158.4 million m³, a live storage capacity is 146.9 million m³ and the dead storage is 1.6 million m³. The design capacity of the water treatment plant and water transmission pipeline is 235 000 m³/day. GIBB was appointed as Owner’s Engineer and did the design review, EPC Contract Negotiation and construction supervision.

Client:
Eskom Uganda Limited

Location:
Jinja, Uganda

GIBB’s Responsibilities:
GIBB’s involvement was to design and supervise the refurbishment of the main dam at Nalubaale Power Station. The scope of the task consisted of refurbishment of the main dam.

Design and implementation of the grouting (the action to reduce or stop leakage through the dam body) required designing the grouting works, reviewing the technical specifications of the contract for the works, and where relevant, proposing modifications.

Further responsibilities were crack repair works of the main dam to improve the structural and functional integrity of the dam structure. GIBB was responsible for design, quality, time and cost control over the life of the project and supervision of the grouting works.