(Picture: Jonathan Britton of SANParks making sure the artificial breaching of the Swartvlei River-mouth has been successful)
As of 7am on Tuesday 27 November, the Swartvlei River-mouth was artificially breached by SANParks, and the lagoon level began dropping as the water flowed out.
Marine Ranger Jonathan Britton was at the mouth to oversee the process, whilst William Maralaza of Denron operated the excavator to remove the last bank of sand between lagoon and sea. Channels had been prepared well in advance so that the opening could happen without delay if the need arose.
“It went well,” said Britton, watching the water spill out as the tide turned, “Within 45 minutes it was all done.”
He explained that they had been closely monitoring the levels of the mouth since the heavy rains of 20 and 21 November, during which Ezigro in Karatara measured 95mm and Farleigh 84mm within a 24 hour period. Despite these unexpected downpours, Swartvlei had only risen to 1,90m above mean sea level – 10cm short of the 2 metre mark which is the norm for artificially breaching.
However, with more rains predicted for Tuesday and Wednesday and heavy mist hanging in the higher areas, the decision was taken at 4.30am on Tuesday morning to open the mouth.
“There were a few factors we had to take into consideration,” explained Britton, “Not only the predicted rain for this week, but the fact that the heavy rains of last week had already saturated the soil, and the badly burned state of the mountains meant runoff would be much faster than normal. The mechanical breaching of the Swartvlei is a tightrope walk of balance between maximising an ecological outcome, whilst still protecting infrastructure on low lying parts of Sedgefield. Swartvlei is the heartbeat of Sedgefield and we need to look after it. Breaching at the prescribed levels is important to ensure the ecological integrity, ecological infrastructure, social value and productivity of the estuary remain in good shape.”
Once the ‘go’ decision had been made, time was of the essence as the mouth needed to be breached soon after high tide. An outgoing tide will increase the ‘tidal pull’ and ensure deeper scouring occurs before the incoming tide starts pushing back in six hours’ time.
Britton fetched Maralaza, who was on standby, at 5am and work commenced as soon as they had reached the beach. Conditions weren’t the best with heavy swells and high seas making the operation quite challenging.
The opening will certainly be a relief to many Sedgefield residents – especially those living in the low-lying areas that have proven over the years to be susceptible to flooding. There are also those who believe that Sedgefield with the Swartvlei estuary open makes for a more attractive holiday destination, however, this is a frequently debated point.