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.

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More information on the sampling points below.


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