Kevin Winter

The management of greywater in the non-sewered areas of South Africa

The management of greywater in the non-sewered areas of South Africa has been identified as a key area of research owing to the fact that very little, if any, provision has been made for it. Without water-borne sanitation, the disposal of greywater becomes a problem that has the potential to create a host of environmental and health problems, and this is particularly evident in the high density informal settlements that surround the major South African cities. The main aim of this study was to understand the use and disposal of greywater in the non-sewered areas in South Africa, determine typical quantities and qualities, and develop a preliminary guide for its management, both in terms of reducing health and environmental risks as well as possibly providing benefits through controlled reuse.

Self Organizing Maps — Application to Census Data

In the previous chapter, Stan Openshaw provides a lucid overview of the classification of spatial data using neural-nets. In this chapter we follow with an example that uses one form of neural classification, namely the Kohonen Self Organizing Map (SOM). In this case, the SOM is used to organize demographic data gathered from census information in order to investigate population groupings and their spatial distribution. In other words, to perform an unsupervised classification, or a mapping of a ten dimensional input to a simple two dimensional surface, or in the full jargon, a nonlinear projection onto two dimensions of the probability density function. As this is an example of the techniques already discussed, we assume that we need not repeat the theory and practice of the preceding chapter.

Explaining declining agricultural total factor productivity in the Karoo districts of the Western Cape, 1952 to 2002

ABSTRACT Conradie et al. (2009a and 2009b) identified the Central Karoo as the worst performing area in the Western Cape, but left the reasons for the regions declining total factor productivity (TFP) unexplained. The current paper uses a combination of literature review and analysis of anecdotal evidence to evaluate a set of hypothetical reasons for the decline. The world wool price clearly affected farm-level profitability, putting up to 50% of sheep farms out of business in some parts of the Central Karoo. If census data were properly collected, this in itself should not have affected TFP. The evidence for overgrazing and increasingly ineffective predator control was less convincing. For example, there is no conclusive evidence yet on whether game and lifestyle farms exert any negative externalities on remaining sheep operations. The cost-price squeeze resulting from falling prices and rising input costs has led to an extension of production systems and poor maintenance which will no doubt lead to a further decline in productivity. We concluded that the rate at which the Central Karoo is shedding sheep farming, and the reasons for and effects of it, should be investigated further.

Towards a shared understanding of water security risks in the public and private sectors

Abstract This article investigates the knowledge and understanding of water risks, and how these are perceived in the private and public sectors. The article is based on a case-study catchment dominated by agricultural activity near Grabouw, in the Western Cape, South Africa. Starting with an overview of the hydrological context, the article follows with a discussion of the current water challenges and water-related risk perceptions of private- and public-sector actors. A conceptual framework is proposed, mapping the different water security risks. The article suggests that water management is improved when different actors acknowledge their shared water risks.

Effects of irrigation water quality on vegetables Part 1: Yield and aesthetical appeal

Research on the use of greywater for irrigation has focused attention largely on greywater quality and biomass of the crop, but not on the quality of edible vegetable crops, whereas aesthetical appeal of the vegetables determines the acceptance in fresh produce markets. Thus a field experiment was established at the Umtata Dam Research Station where combinations of cabbage and onion, spinach and beetroot, and carrot and lettuce were planted to coincide with four different planting seasons. Crops were irrigated with greywater generated from household activities such as bathing and dishwashing, diluted greywater (1:1 with potable water), and potable water from a tap stand. The yield and aesthetical appeal were measured. There were significantly higher yields and aesthetical appeal of cabbage from using diluted greywater. Onion yields were significantly higher when irrigated with greywater. Similarly, spinach had significantly higher yields but many leaves were infested with leaf-spot disease, which significantly lowered its marketability from greywater treatment. Beetroot yield was reduced by 47% (4.7 t ha-1) when irrigated with greywater compared to the control and external quality was not affected by any of the three water treatments. Carrot also did not show any significant difference in yield, but carrots that were irrigated with potable water were significantly more appealing. Lettuce irrigated with diluted greywater was significantly more appealing than other treatments. Crops that were irrigated with greywater resulted in higher yields, but compromised the quality of the crop to meet fresh produce market requirements.

Fieldwork and the International Geography Olympiad

Introduction Fieldwork forms a substantial part of the International Geography Olympiad (IGEO) both in terms of time and in the nature of the experience in which participants get a chance to explore the ‘real world’ of the host country. Fieldwork offers young geographers an excellent opportunity to explore the regional and local geography of the host nation thereby stimulating interest and developing skills in the context of unfamiliar environments. There is widespread recognition that fieldwork is essential to geography education (Fuller et al., 2000). Arguably its inclusion in IGEO is legitimate but assumptions about the value of and approach to fieldwork in IGEO have been poorly evaluated and lack critical appraisal. To illustrate this concern, this paper describes two different approaches to fieldwork that were adopted in South Africa in 2002 and Australia in 2006. Both accounts show that fieldwork was more than just about raising awareness or casually exploring a local environment of the host nations. The difference lies largely in the expectations of local organisers; the perceived purpose of IGEO; and the limitations of conducting fieldwork in the context of an IGEO.