Zandvlei Trust

The Economic relevance of Zandvlei Estuary.
 
Prepared for the Zandvlei Estuary Management Forum by J. Fowkes.

CAPE Estuaries Programme: Implementation of the Estuary Management Plan (EMP) for the Zandvlei Estuary, Muizenberg, Cape Town.


On page 33 of their August 2007 report “Development of a Conservation Plan for Temperate South Africa Estuaries on the basis of Biodiversity Importance, Ecosystem Health and Economic Cost and Benefits’ the lead authors, Jane Turpie and Barry Clark (Turpie/Clark) identify five key components in estuarine ecosystem goods and services.

These are:

  • Consumptive use value (e.g. harvesting)

  • Non consumptive use value (e.g. tourism)

  • Indirect use value (ecosystem functions)

  • Option value

  • Existence value.

These five components are linked through “Use Value” and “Non-use Value” to give a Total Economic Value. See Figure 1 below. - not alvailable.

Applying these five components to the Zandvlei the following emerges.

1. CONSUMPTIVE USE VALUE

The Zandvlei Estuary is used by both recreational and subsistence fishermen. The subsistence fishermen, particularly, make use of the fish caught either for direct food for their families or to raise cash by selling them. The sand banks of the vlei are also harvested for prawns.
The very nature of the activity makes it impossible to place a value on the fish catch.But the fact that the waters are fished every day, even in inclement weather, suggests that the value of the catch makes the effort and discomfort worthwhile i.e. it is a contributor to the economic well-being of, at least, the subsistencefishermen. The fish of the estuary also migrate into the ocean where they are caught (see below under Indirect Use Value).

2. NON CONSUMPTIVE USE VALUE

Non Consumptive Use Value is the use of the estuary which does not take away anything of value from the site. The Zandvlei Estuary is a major recreational and sport activity area. These activities includecanoeing, sailing, fishing, and wind-surfing on the water and picnicking, braaing and informal games on the banks. 
There are a Canoe Club, a Yacht Club, a Sea Cadet base and a Sea Scout base that have their buildings on the banks of the vlei and use its waters for their various activities. Other non-consumptive uses include walking, bird watching, plant studies, kite flying etc. There is also an Environmental Education Centre which is regularly used by schools in the area as part of their teaching programme.
The importance of this recreational function is indicated by the presence of 14 x 60 seater buses being seen beside the recreational grasslands on the west bank on one summer Sunday.
All the recreational tourist activities contribute to the health and well-being of the users. They also contribute to the economy of the area in terms of the transport, equipment and consumables that are bought to enable these activities to be carried out.
The recreational activities also have a cost in terms of policing and litter removal. But these, too, provide jobs and contribute to the economy of the area.

3. INDIRECT USE VALUE (ECOSYSTEM FUNCTIONS)

3.1. G. Prince of the Cape Piscatorial Society comments on the importance of Zandvlei as a nursery for juvenile marine fish species. He writes;
The Zandvlei Estuary is an important recreational resource in the Western Cape. It serves as a nursery for juvenile marine fish species in False Bay especially for Garrick (Leervis), Cape Stumpnose , Flat Head Mullet and White Steenbras to name a few. Some of these species are currently endangered and Zandvlei is the only functioning estuary in False Bay capable of supporting them. Other estuaries in False Bay have limited recruitment of these species. These fish spawn at sea and the juveniles then recruit into the estuary during spring and summer. Steenbras in particular require the sandy environment of the vlei for their wellbeing. The breeding stock of White Steenbras has declined dramatically (90% est.) over the past 20 years due to overfishing and habitat degradation due to water quality issues caused by sewage spills and urban runoff from the catchment. More than 20 species are reliant on the estuary for their continued existence.
The fish of recreational value to anglers in Zandvlei and False Bay are all marine migrants. To enhance the nursery role of the estuary, it is necessary to make the estuary more accessible for the juveniles of these fish during spring and summer. Shallow areas with pondweed must be maintained to provide food and shelter from predation for juveniles. Salinity must not be allowed to fall too low as this will kill marine species. Pondweed harvesting and the opening and closing of the sandbar at the mouth must be carefully managed to ensure that the estuary functions properly.

3.2. Bird life. The Zandvlei Estuary is an important feeding and breeding ground for a large number of birds.

3.3 Western Leopard Toad. The wetlands to the west of the Zandvlei are a major breeding site for the endemic and endangered Western Leopard Toad.

4. OPTION OR FUTURE VALUE

Turpie and Clarke write: Option value is the future value of resources and services offered by ecosystems such as possible medicinal, leisure, agricultural or industrial uses. Option value is particularly important when there is still uncertainty regarding the potential use and value of the ecosystem later on (Nhuan et al. 2003; Perman et al. 1996, Barbier 1993). Even though an estuary may be underutilised at present, it may possibly be valuable for scientific research, education, tourism and other commercial enterprises which would increase its economic value in the future (Barbier 1993)”.

In this context the Zandvlei has been used as a training centre for foreign rowing teams. This generates income in surrounding hotels and guest houses. The opportunity exists for this utilisation to be upgraded.

Turpie / Clark continue “A quasi-option value is the value obtained from not undertaking irreversible activities in order to retain options for future use of the ecosystem (Perman et al. 1996). “Ecosystem functions may either generate outputs that form inputs into production processes elsewhere (in other words the benefits are realised off-site)”. This function is best exemplified by the role the Zandvlei plays as a nursery for marine fish.

Turpie/Clark continue “or they result in engineering costsavings by performing functions that would otherwise require costly infrastructure or manmadeprocesses. The provision of ecosystem services is generally positively related to thelevel of health or integrity of ecosystems.” 
The Zandvlei provides a large flood surge pond for the City, absorbing the waters that flood down the Westlake, Keyser's and Sand Rivers.
Recent experiences of an algal bloom at the Zandvlei have indicated the costs incurred by the City of Cape Town as the result of an ecosystem that went out of balance.

5. EXISTENCE VALUE.

Work by Bin and Polesky in the United States (quoted by Turpie/Clark p36) found that proximity to coastal wetlands has a positive association withthe nearby property value. Reducing the distance to the nearest coastal wetland by 1000 feet raised the property priceby $US1010 at the initial distance of one mile. The Zandvlei has domestic residences on both the east and west sides. The Marina da Gama is a clear indication of the value of the existence of the Zandvlei Estuary and the property values associated with it. Should the health of the Zandvlei system diminish, leading to pollution and unpleasant smells the property values of the surrounding residences could be reduced changing from a desirable to an undesirable location to have a home.

Turpie / Clark (p 50) write: Respondents claimed that scenic beauty and biodiversity were the main factors contributingto the existence value of a particular estuary. The economicand subsistence contribution was considered slightly more important, suggesting that theyvalued estuaries for the contribution to society as well as to biodiversity”.

CONCLUSION.

A study on the value and condition of Temperate South African Estuaries used five indicators for the assessment of the economic relevance of an estuary. In all five categories of the evaluation the Zandvlei is represented and can be shown to make a positive economic contribution.
It is not possible to place an accurate figure on many of the intangibles that contribute to this economic contribution. What is clear is that the loss of the estuary and its use would have severe negative consequences in terms of marine fishing, property values and its recreational facility.

                                                                                                                                                  

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