Ezemvelo KZN Wildlife and the eThekwini Municipality has allayed residents’ fears after the estuary mouth of the uMhlanga Lagoon moved last month. Residents and beachgoers expressed their concern as the mouth had affected the sandbanks near the uMhlanga Lagoon Nature Reserve with some questioning if developments up river had effected the change.
Santosh Bachoo, a coastal ecologist with Ezemvelo KZN Wildlife said it was natural for estuary mouths to move.
“Estuary mouths do move naturally. Estuary mouths are in a very dynamic area of the coastal zone and their position/behaviour is often a result of interplay of a variety of factors, such as sand movement (transported by wind and/or water), wave climate, sea condition, geology, water abstraction and river/estuary flow modification. While we have not recorded this configuration in my time at least, its current position falls within a predicted envelope of movement i.e. it is not unexpected to see this happen,” he explained.
The lagoon seaward of the M4 is part of an Ezemvelo Protected Area, the Umhlanga Lagoon Nature Reserve and Bachoo explained that Ezemvelo conducts monitoring of the lagoon seaward of the highway. He also cautioned residents approaching the new channel.
“Currently, there is no concern but it will have to be monitored. Beachgoers are encouraged to exercise caution when approaching the channel as it can be very deep especially when closed, much like what had happened at Margate main beach a few years ago. It can also have a strong current if there is an outflow of water through the mouth. The lagoon, being at the tail-end of a larger catchment, is unfortunately the recipient of impacts of upstream activities e.g. pollution (sewage spills from wastewater treatment works, plastics etc.). Caution must therefore also be exercised when it comes to contact with the water,” he said.
