ZIMP
Zandvlei Inventory and Monitoring Programme (ZIMP)
Buy a rain gauge and start
recording the daily figures.
If you measure rainfall data in
the area, please let us have your records.
Rainfall data
The annual
total rainfall, averaged from the
measured sites = 784.3mm
General Notes.
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Rainfall data are measured daily using a standard funnel shaped rain gauge that can be purchased at any hardware store in Cape Town.
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The approximately 35cm long funnel is 12.8cm wide at the top and is graduated in 1mm units for the first 20mm, in units of 2mm up to 50mm and in units of 5mm thereafter to 100mm.
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The data may not indicate the current months rainfall but will be updated regularly and as close to the information being made available.
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Prof Timm Hoffman at the Spring Festival 2005, ZIMP – 5 year Reportback, highlighted that with the known rainfall data, a 50% accuracy figure can be calculated of the salinity levels in the Zandvlei estuary water body. This re-emphasises why it is so important to collect this data.
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As of Sept 2005 new graphs illustrating trends and emerging rainfall patterns will help to present clearer information we now have at our finger tips.
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Daily rainfall measurements are taken at 6 sites around the Zandvlei main water body at present.
1.
Mountain side (west)
of the main body of the vlei. From May 1999 to July 2002 this was at
19 Barbourne Rd,
Zandvlei and thereafter at Craig Road, Lakeside (a few hundred metres
north).
The data are collected by Timm Hoffman.
Jan Feb March April May June July Aug Sept Oct Nov Dec
2. Marina da Gama side (east) of the main body of the vlei. These data have been collected by
Peter Gray since April 1999
at Park Island Way, Marina da Gama.
Jan Feb March April May June July Aug Sept Oct Nov Dec
Annual Rainfall for Park Island
3. Marina da Gama side (south east) of the main body of the vlei. These data have been collected by
Roger and
Carol Lamb since April 2001, at Eastlake Island Way, Marina da Gama and thereafter at
Battleridge
Road, Marina da Gama.
(a few hundred meters south).
4. Marina da
Gama side (north east) of the main body of the vlei. These data
have been collected by
Lucia Rodrigues, Texel Close, Marina da Gama since January 2006.
5. Muizenberg East
(south east) of the main body of the vlei. These data have been
collected by
Anita and
Warren Flockhart, Bournemouth Road, Muizenberg East since August 2006.
Jan Feb March April May June July Aug Sept Oct Nov Dec
6. Marina da Gama side
(north east) of the main body of the vlei. These data have been
collected by
Gerrard Wigram, Michel Way, Marina da Gama since May 2003.
Jan Feb March April May June July Aug Sept Oct Nov Dec
End of October 2008 – This is the
combined rainfall of all the measured sites, with the
monthly
average and the annual average.
End of December 2007 –Annual accumulated total rainfall from the measured sites = 870.3mm.
End of December 2007 – This is the
combined rainfall of all the measured sites, with the mean monthly
average and the mean annual average measured.
End of December 2006 – This is the combined rainfall of all the measured sites, with the mean monthly average and the mean annual average measured.
End of December 2005 – This is the combined rainfall of all the measured sites, with the mean monthly average (yellow) and the mean annual average (pale blue) measured
This graph illustrates the averaged west and east of the Zandvlei rainfall readings, established by Timm Hoffman and Peter Gray over this time scale.
This is one of the challenging pieces of information, from the "5 year report back" presentation by Timm Hoffman at the Zandvlei Trust – Spring Festival in Sept 2005.
Historical Rainfall Data
General rainfall measured from 1841 at
Observatory in Cape Town.
The red line through the graph is the – 10 year running average.
This graph indicates recent droughts in the 1990's and severe one in the 1930's during the Great Depression. The graph is from SA Weather Service, and an article in the City of Cape Towns – Contact Newsletter – No 18 April 2005.
