Elephants posed a mammoth problem to the PT&D project team in Botswana

Botswana is a landlocked country in Southern Africa bordered by its more illustrious neighbour, South Africa to the south, Namibia to the west and Zimbabwe to the northeast. Largely topographically flat, 70% of the country is the Kalahari Desert. Botswana is one of the world’s most sparsely populated countries with 10% of its population of just over 2.3 million people living in the capital city of Gaborone, that is also its largest. Formerly, one of the world’s poorest economies, Botswana has radically transformed itself into an upper middle-income country and is presently regarded as one of the world’s fastest growing economies and one of the highest in Africa.

This has spawned opportunities for infrastructure development riding on which our Power Transmission & Distribution business successfully executed the 400/220/132/33/11 kV Mawana Substation, a key power distribution hub, under Phase 1 of Botswana’s North West Transmission Grid Connection Project. PT&D constructed seven bays each of 400 kV, 220 kV & 132 kV and two bays each of 33 kV & 11 kV, a Control Building of 875 Sq. m, two transformers each of 125MVA & 60MVA and two reactors each of 60MVAr & 25MVAr.

Addressing an elephantine problem

Project Manager, Hari Krishana Panga (HKP), is a happy and satisfied man, having successfully delivered his project in December 2020, working through the rigours of the pandemic during the latter part of execution but in his estimate, while COVID-19 posed its unique brand of issues, what was a bigger safety issue for him and his team throughout the duration of the project was the threat of elephants, as the country has perhaps the highest concentration of
African elephants.

“The Mawana Substation is located 20 km south of Maun, an area frequented by elephants that could be seen from their large footprints left behind or when they vandalized our perimeter fence,” observes a worried looking HKP. Apart from the safety of his men, material, and machinery, this situation created an attendant problem for him as the movement of elephants created a path for other animals such as cows to walk on and accidentally wander onto the site. “This had cost implications for us as we would be forced to compensate the affected farmers in case their livestock fell into our excavation pits despite having danger nets and tapes.” Then there was the danger of elephants falling into the deep excavations pits that could attract national scrutiny from the Wildlife authorities to the project. Initially, a temporary orange net was used to patch up the damaged parts of the perimeter fence to prevent further encroachments especially by livestock but both HKP and his EHS In-charge, Patrick Galani Oleseng, realized that it was only a stopgap arrangement and that they had to evolve something more permanent and safer.

Fencing or floodlighting – that was the question

Aware of the pitfalls involved, they set about considering their options to keep the site and the animals safe. “Basically, we had two options,” shares Patrick, “to either put up electric fences around the site or install floodlights.” Fencing the project area involved using a single strand electrified fence that carried pulses of constant high voltages (>5kV) but low ampere electric current, of short duration passing through the wires every 1–2 seconds. If an animal standing on ground touched the wire, it received a non-lethal shock like a sharp sting to ward it away. The other option was to put up bright lights as had been adopted by similar projects in areas with high elephant presence around Botswana or light fires. The issue was that elephants quickly habituated themselves to fires and put them out by stamping or dousing with water.

Electric fences could be effective over a wide area and solar-powered ones free from power cuts though on the flip side, electric fences were costlier requiring more initial capital and the voltage required regular monitoring and maintenance across several kilometres at above 5 kV levels; anything less would not deter elephants. It required expensive equipment and expertise to detect the level of power supply. The batteries of solar-powered fences had to be periodically maintained and connections kept clean and dry. “Floodlights, on the other hand, had more going for them,” points out Patrick, “as they were easier and more economical to install, more reliable, consumed less power and were easier to maintain. But to be effective they had to be constantly bright enough to intimidate the animals.”

To take a final call, it was equally important for them to understand elephant behaviour. Normally, elephants move in search of food and water sources and are prone to destroy and trample down anything that comes in their way. Chances were high that a poorly maintained fence would soon be destroyed by an irritated and determined elephant while an annoyed one could resort to breaking the trees near the electric fence to destroy it. HKP adds that elephant movement was observed from the far southern part of the project to the eastern part and that their movement was usually in the evenings. “During the day, they were repelled by the movement of machinery at the site,” he adds.

“After weighing all the pros and cons we finally decided to go for IP65-make floodlights as our elephant deterrent system,” concludes Patrick, 200W x 2 floodlights on a 6 m gum pole that were placed around the perimeter fence, 100 m apart. In addition, the site offices had a 1.8 m high, single strand electric fence and 200W x 4 lights in the centre arena reflecting into the office premises. The lay down area was also fenced separately using galvanized iron sheets of approximately 2 m in height to deter elephants, while two security officers guarded each premise.

The efforts of HKP and Patrick proved extremely effective as the project has been completed and handed over without a single incident involving elephants. Also shows how intelligent those huge pachyderms are!