Environmental Services

Conserving Endangered Species on Construction Sites – challenges and opportunities

Conserving Endangered Species on Construction Sites – challenges and opportunities

Transmission lines are integral for getting the energy produced around the country to the grid, however linear projects such as power lines and pipelines have a whole suite of environmental impacts which need to be mitigated by the project team. On this particular project the impact on an eagle species, more specifically the Martial Eagle, was a new challenge.


The Gappa-Kappa B 765kV transmission line follows an existing 400kV line across the Great Karoo, to the Gamma substation, located South of Victoria West in the Cape. This line passes through the Laingsburg Local Municipality, the Prince Albert Local Municipality and the Beaufort West Municipality of the Western Cape and into the Northern Cape where it passes through the Moordenaars Karoo and the Karoo Highland Local Municipality. The line passes through many large sheep farms, onion seed farms and game farms. It also happens to be a chosen spot by Martial Eagles to nest and breed.

Martial Eagles (Polemaetus bellicosus) are the largest eagles in Africa, with a length of 96cm and a wingspan of up to 2.6m. Weighing in at up to 6.2kgs, they are also the fifth heaviest eagle in the world on average. Most importantly, they are considered an Endangered Species which must be carefully protected. They mate for life and return to the same breeding location annually. As apex predators they have extremely keen eyesight and prey on dassies and other small animals and have, on occasion, been known to hunt small buck like Klipspringer or Steenbok. Nests are circular in shape and their size can be up to 3m x 3m. Bones and the remains of small animals can determine the activity of a nest, as well as the preferred diet.

The Construction Impact

Nests were noted on the 400kV line whilst constructing the 765kV line, resulting in the contractor having to stop works to identify the presence of other nests and potential breeding sites in the construction footprint. There was little information available to the team from avifaunal specialists in the EIA and specialist report, so EWT was asked to offer advice on the way forward to reduce the environmental impact on these birds. Mitigation measures such as the education of construction teams on how to identify martial (and other) eagles as well as the correct reporting lines. All is well that ends well and the project saw the successful breeding and fledging of one chick.

Lessons learned:

A large part of the problem lay with outdated information provided in the EIA causing delays in the commencement of the project. A further delay in the project would have led to a more significant impact on the birds, as it would have meant construction in the middle of the breeding season of the eagles (from May to November). The time it took to identify breeding sites on the existing line was time consuming, and ideally should have been done in the pre-construction assessment of the project.


Although the project team does involve Environmental Managers, they are often not involved in the project early enough to identify and mitigate risks before these risks become reason for stopping works. This often results in the Environmental Team seen as a hindrance more than a help. Realistically though, the risks need to be mitigated and so the involvement of an Environmental Manager from the beginning is integral to reduce risks and stoppage time, and for the project to be successfully completed in an Environmentally conscious manner. 

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