Work to open the Silvermine and Zandvlei estuaries has recently been completed.The two estuaries have been opened for “very different reasons”, says Eddie Andrews, Mayco member (South)“As such, the management and the associated activities that they each support are also very different. The opening of Silvermine is really for the undercutting of the railway line and the opening of Zandvlei is for ecological reasons to assist the functioning of the estuary,” he explains.The Zandvlei estuary mouth has been opened on a regular basis over the spring high tide, explains Andrews.“This practice has been in place since early 2000 to regulate levels and salt water intrusion and to assist the exchange of estuarine fish. As a result of this, Zandvlei is functioning extremely well as an estuary, despite its urbanised nature,” he says.A secondary aim of opening the estuary is to ensure that the level of the estuary does not exceed a certain height, because this could result in the water flooding surrounding suburbs.“The mouth opening protocol has been refined with roleplayers over a number of years and has yielded good results in the improvement of the vlei’s fish stock over a number of years. This has been achieved by the flushing of Zandvlei’s waters with sea water at high tide, which also facilitates the movement of fish between the ocean and estuary,” he says.Work at Silvermine estuary was completed on Thursday 21 September, Andrews adds.“Some sand was excavated to realign the estuary outlets to be perpendicular to the coastline. The realignment of the outlet is intended to protect our infrastructure as well as the adjacent railway embankments from being eroded,” he explains.