Zandvlei Trust

ZIMP – Salinity

Opening the mouth of the Zandvlei estuary.

Zandvlei estuary mouth opened.

General notes.

• The vlei mouth is opened and closed mechanically at full moon and spring tides where the tide is in excess of 1,8 meters.This to get as much sea water into the estuary as possible. The rainfall in the catchment is monitored electronically and with telemetry notifies the responsible Managers.

• The Sand River Catchment Management Forum and Zandvlei Action Committee (City of Cape Town officials and other interested parties) regularly review in and out flows of Zandvlei, as there are a number of critical factors which have to be maintained. ie. water levels for the residents and waterbody user groups, also the salintity levels need to be maintained so that the estuary may function to an optimum.

• Martin Thompson has produced a pamphlet;
  Zandvlei - Factors concerning Water Level Management. This is available from the Roads and Stormwater Department –  Catchment, Stormwater and River Management Branch. 021 400 1205 or csrm.secretary@capetown.gov.za

• This pamphlet sets out the background in priority order for;
  Flooding
  Salinity
  Revetment stability (concrete walls around the vleis edge)
  Fish migration
  Recreation

This graph indicates the monthly average or mean salinity collected at 2 points in Zandvlei.
The readings are taken weekly.

• This information was collected and supplied by Timm Hoffman. It is only part of the information and should not be used to draw any conclusions or make deductions.

• The data may not indicate the current months readings but will be updated regularly.

• Royal Road bridge about 50 meters from the mouth of Zandvlei as it enters the sea, and

• Rutter Road about 2 kms away near the confluence of the Westlake and Keysers Rivers on the western side of the railway line. This water body is fresh, it is located out of the main river flow entering the main water body.