SAND RIVER CATCHMENT FORUM
Minutes of the meeting held on: Monday 24th November 2008 at 13h30 at the Alphen Council Chambers
Martin Thompson: (Chairman) :
CofCT Roads & Stormwater
Table Mountain National Park
1. WELCOME/ APOLOGIES & ATTENDANCE REGISTER
2. APPROVAL OF THE PREVIOUS MINUTES
3. ACTION ITEMS FROM LAST MINUTES
Action at foot of page 3 : Martin advised that if different clearing activities were required, himself or Talcott Persent should be advised and they would take the matter up internally to see if amendments need to be made to the guidelines. Joan Heming referred to the Ninham Shand report and suggested components of that be used for guidance.
Item 6 : Suretha advised that once the final product of the Rivers Brochure is available, the Institute of Landscape Architects will be contacted.
4. ADDITIONAL ITEMS TO BE PLACED ON AGENDA
11.4 Erf 3355 – added to agenda
5. WATER QUALITY : Presentation by Candice Haskins.
Die Oog – the condition of this water body appears to have improved over the last few years. Dredging was undertaken in 2004 to remove sediment that was nutrient enriched and which was food for the algae. The following year, fish were removed and with the good rains of the last 2 years, there has been good flushing. Recently a lot of duckweed (a small floating plant) was noted – this shades the water surface may have contributed to the decline in algae. It is possible that there is now competition between algae and other plants for nutrients. However, it is important to keep a watch for any change – there are still a lot of nutrients in the water and it is possible that algal dominance may recur. Faecal coliforms counts are fairly high probably due to droppings from resident birds and the heronry. It should be remembered that this waterbody is not used for human recreation but is a bird sanctuary.
Little Princessvlei – has relatively little algae although there are peaks during summer. Also has a lot of aquatic plants competing for nutrients. The southern portion appears to be more polluted than the northern portion and the two portions are considered separate hydrologically. Inorganic nitrogen shows strong seasonal cycles. Overall mesotrophic = moderate levels of productivity with a moderate nutrient level. Bacterial levels in Diep River increasing which is also reflected in the southern portion of LP where DR flows in. No data available for the northern section. John Green asked if the upward trend was significant to which Candice responded that there is always a seasonal peaks but there does also appear to be a long term increase.
Langevlei – Retreat – sample at inlet and southern outlet where it flows into an underground culvert. At the inflow there is high phosphorus. There are not many aquatic plants – but it is blue/green algae that is most dominant in this body. The whole system is considered eutrophic. John Green asked whether protective action should be taken, e.g. more plants introduced. Unfortunately the banks are very abrupt and the abundance of Egyptian geese adds to the nutrients. Sources of Phosphorus include faecal deposits, soap, detergents, fertilisers. Bacterial levels are quite high at inlet and slightly lower further into the water – but trending upwards.
Zandvlei - chlorophyll quite lower with cyclical peaks and troughs and also probably because of salt inflow from sea and regular flushing helps move nutrients. Inorganic nitrogen levels are seasonal
and assisted by the well managed mouth with flushing that disperses nutrients. Mesotrophic overall. There are a number of sewerage stations around with some faecal pollution in the Sand River
as opposed to the others which may only have occasional leaks. However to get better results, it is necessary to go out into the middle of the vlei which is not possible at the moment.
Westlake Wetlands – slightly higher chlorophyll levels than Zandvlei – probably because it is not affected quite so much by the saline inflow. Lot of marginal vegetation such as reeds and algae
and quite well balanced. Moderately nutrient enriched. A question was asked whether there water quality could be a reflection of the water from upstream – however there is only one sample
point at the moment.
Congratulations from all to Candice for an excellent presentation.
John Green asked if more sampling points could be set up as there is no longer one at Pollsmoor. Apparently it all depends on the budget.
It was suggested that in the Wetlands Forum consideration be given to plants being introduced for functionality rather than just decoration.
Joan Heming said that it should be illegal for people to empty their fish ponds or aquariums into water bodies. Nurseries and pet shops should be advised that it is not the right thing to do.
6. IMPACTS OF URBAN DEVELOPMENT
Dennis Davey asked if it was the policy of City to increase densification. Martin answered that that it was in certain areas. City would prefer vertical densification to horizontal in order to reduce impervious coverage. He added that the draft policies stem from the IDP and are to reduce the impact of flooding and to safeguard human health and natural aquatic systems.
Mandy asked about the attitude towards historical developments – Martin said there is provision for retro-fitting but it is difficult and expensive but it has been allowed for.
George asked if the models for best practice are from global sources. Martin said that they are – US and Australia had been looked at extensively and the Australian model was found to be particularly valuable as they have similar climates to our own.
Jean asked about fast flowing rivers and run off into aquifers below. Candice advised that in the policy storm water is controlled in terms of quantity, quality and that recharge of ground water where appropriate is encouraged.
On the point of aquifers, Cherry reminded the meeting that Joan had previously expressed concern about the number of boreholes and wells and wondered whether these are being recorded. She said we always look at what is happening on the surface and sometimes forget to consider what happens underground and there are so many more boreholes and well points.
George said that the Wetlands Forum have decided to have a ground water session next year to monitor this aspect.
7. WORKING FOR WETLANDS PROGRAMME
8. RIVER INSPECTIONS
8.1. REPORT BACK
8.2. POSSIBLE ACTIVITIES CO-ORDINATION
8.3. NEXT RIVER INSPECTION
9. SOURCE TO SEA
10. PAMPHLET - RIVERS IN OUR BACKYARDS
11.1 Dumping on Erf 3346
11.2 Wine Farms
11.3 Friends Groups
11.4 Erf 3355
James enquired about who making the rules and regulations if wetlands are privately owned. Suretha advised that there may be conditions imposed in any approval but they are difficult to enforce. The developer would have to adhere to any approved management plan.
Some history on the area – the old Div. Council had a dream of a continuous walkway along the rivers and the property was rezoned with the intention of later acquiring it. Div. Council
disappeared and now there is no money. Martin added that in terms of the new constitution, land is now acquired by the City in a different manner. It was agreed by all that each department in
City must view this development in its entirety – not narrowly – as it is such an important piece of land.
It would appear that the developer got a waiver from Province in regard to obtaining an environmental impact assessment
Liz wondered whether there are conditions for developments that relate to storm water run off into a river.
11.5 Gavin expressed his concern about the filing and retaining of the documents and presentations that have been created since the SRCF has been active again. He has some ideas and it
was suggested that this become an agenda item for the next meeting.
12. NEXT MEETING
Monday 23rd February 2009 at 13h30 at the Alphen Chambers