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This is a citizen scientist driven initiative to monitor the health of the estuary.

What do these values mean?

  • Seawater is at a value of 32 parts per thousand (ppt), and freshwater is at 0.
  • The readings are taken at the water surface or just below.
  • The ambient salinity levels is recommended to be at 5 to 10 ppt for maintenance of healthy pondweed population, which is needed for a nutrient management strategy (Harding 1999)
  • Seawater ingress is important not just for the flushing of the estuary, but also maintains low algal levels, and some invasives like water hyacinth cannot grow in salty water.
  • The readings are to be viewed over an annual season duration and then to determine the average reading for the cycle. Summer readings are high and winter readings low with the ingress of rain water via the catchment during the rainy season.
  • The readings will be lower towards the northern areas of the main water body where the sea water does not reach.

More information on the sampling points below.

Salnity pointSci Services WQ PtsSample location
1 In the outlet canal next to the parking lot at the “super slide”
2ZAV5Taken 40m upstream of Royal Road Bridge (ZAV5)
3ZAV4Take at the bend of the canal near a storm water input (ZAV4)
4 In the centre of the canal opposite the huts near Playwaters
5ZAV3Vlei body south (before narrows to form canal near Playwaters (ZAV3)
6 Taken in the centre vlei opposite park on western side.
7ZAV2Vlei body centre, opposite the Imperial Yacht Club (ZAV2)
8 Taken opposite Scouts Club, midway between ZAV1 & ZAV2
9ZAV1Vlei body north (between two inlet rivers) (ZAV1)
10WWLWestlake Wetland – down Rutter Road (WLW)
11ZAV6South entrance to Marina Da Gama (ZAV6)
12ZAV7North entrance to Marina Da Gama (ZAV7)
13ZAV8Marina Da Gama channel (The Anchorage) (ZAV8)
14ZAV9Marina Da Gama channel (Spearhead) (ZAV9)
15 Baleen Pond
16 T Wagon Bridge
17 Uitsig (new pt added April 04)