Incredible footage showing masses of water gushing down the Witpoortjie Falls in western Johannesburg caused quite the stir on social media over the weekend. This as Gauteng was pelted by heavy rains and flooding. Andrew Hankey, specialist horticulturist at the Walter Sisulu National Botanical Garden in Roodepoort, said he captured the incredible moment on camera at roughly 17.45 on Friday evening.The footage shows a brown mass of water billowing over the cliffs, cascading down at full force.Hankey's son can also be seen in the video - visibly drenched by the water and spray. He said the high-level flooding doesn't normally last very long."It subsided over a period of between 45 minutes to an hour," he told News24.The Botanical Gardens told News24 that water gushing from the waterfall is a common occurrence when there is heavy rain in the catchment over a short period of time."Although, this was a higher volume of water than usual," they said.Hankey, who has worked at the garden for more than 26 years, said this was not the highest volume of water he's spotted cascading over the cliffs."On one occasion, I couldn't even reach the lawn that leads up to the waterfall," he said."The paving at the waterfall and those wooden posts and rails were all washed away. All of it was gone," he said. He couldn't recall what year it was.The Witpoortjie Falls is a natural waterfall, fed by springs upstream. The falls have a 70m drop.While many social media users were in awe of the footage captured, some also expressed their concern for the garden's resident Black Eagle couple.Hankey said the female Black Eagle Makatsa actually moved their nest further away from the waterfall a few years ago, so they were never in any real danger."The nest is not anywhere near the waterfall anymore."He said Makatsa and Mahlori would probably start fixing their nest soon in preparation for the upcoming breeding season.