Wild vegetables (WV) are an important source of food in the maize based subsistence farming sector of rural South Africa. Their main role is as relish as they are used as an accompaniment for staple cereal based diets. They are generally reported to be rich in micronutrients. Although they may be consumed in small quantities, they influence the intake of cereal staples, manage hunger and play a central role in household food security for the poorer rural groups. Mixing several WV species in one meal contributes to dietary diversity in terms of more vegetable types as well as in terms of choice of relish. For some very poor families WV are substitutes for some food crops. The seasonal occurrence of these vegetables leaves many families without a food source during the off-season. Wild vegetables increase agro-biodiversity at the household level. This agrobiodiversity helps in buffering against the accumulation and multiplication of pests and diseases and provides important cover for the soil. Further research on agronomic, social and economic dimensions is required to understand the roles of WV in subsistence farming systems in South Africa.

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11Wetlands are conservation priorities worldwide, due to their high biodiversity and productivity, but are 12 under threat from agricultural and climate change stresses. To improve the water management practices 13 and resource allocation in these complex systems, a modelling approach has been developed to estimate 14 potential recharge for data poor catchments using rainfall data and basic assumptions regarding soil and 15 aquifer properties. The Verlorenvlei estuarine lake (RAMSAR #525) on the west coast of South Africa 16 is a data poor catchment where rainfall records have been supplemented with farmer's rainfall records. 17The catchment has multiple competing users. To determine the ecological reserve for the wetlands, the 18 spatial and temporal distribution of recharge had to be well constrained using the J2000 rainfall/runoff 19 model. The majority of rainfall occurs in the mountains (±650 mm/yr) and considerably less in the 20 valley (±280 mm/yr). Percolation was modelled as ~3.6% of rainfall in the driest parts of the catchment, 21 ~10% of rainfall in the moderately wet parts of the catchment and ~8.4% but up to 28.9% of rainfall in 22 the wettest parts of the catchment. The model results are representative of rainfall and water level 23 measurements in the catchment, and compare well with water table fluctuation technique, although 24 30 31 4 groundwater level. This approach can also be called actual recharge, as it determines the amount of 59 water that reaches the groundwater table (Rushton, 1997), but in doing so it neglects any processes that 60 occur in the unsaturated zone, thereby reducing its spatial and temporal extent. However, for numerical 61 modelling of recharge, it is not possible to neglect what is happening in the unsaturated zone, as most 62 models require information on the physical and chemical pathways of recharge. Therefore, this type of 63 approach is rather defined as potential recharge, which is constrained by the amount of water that has 64 percolated through the unsaturated zone, contributing to the saturated zone (Rushton, 1997), and hence 65 requires knowledge of the percolation rate. 66Within numerical modelling, the percolation rate (Scanlon et al., 2002) can be modelled either by 67 looking at variably saturated flow or rainfall/runoff partitioning. Both these methods use a water-68 balance to determine the percolation volume using input data, such as climate (rainfall, temperature), 69 vegetation (interception) and biosphere (soil texture) to partition water into runoff, infiltration, 70 evaporation and recharge. These two methods differ in their ability to simulate soil moisture. Variably 71 saturated flow models can simulate vertical distributions of soil moisture and estimate recharge by 72 routing water through the soil column using soil hydraulic conductivities. Many rainfall/runoff models 73 partition infiltrated water into storages based on soil type parameters (J2000: Krause, 2001; and ACRU: 74 Schulze, 1995) . This makes variably saturated flow more favoura...

Abstract.A major task of the newly established "Southern African Science Service Centre for Climate Change and Adaptive Land Management" (SASSCAL; www.sasscal.org) and its partners is to provide science-based environmental information and knowledge which includes the provision of consistent and reliable climate data for Southern Africa. Hence, SASSCAL, in close cooperation with the national weather authorities of Angola, Botswana, Germany and Zambia as well as partner institutions in Namibia and South Africa, supports the extension of the regional meteorological observation network and the improvement of the climate archives at national level. With the ongoing rehabilitation of existing weather stations and the new installation of fully automated weather stations (AWS), altogether 105 AWS currently provide a set of climate variables at 15, 30 and 60 min intervals respectively. These records are made available through the SASSCAL WeatherNet, an online platform providing near-real time data as well as various statistics and graphics, all in open access. This effort is complemented by the harmonization and improvement of climate data management concepts at the national weather authorities, capacity building activities and an extension of the data bases with historical climate data which are still available from different sources. These activities are performed through cooperation between regional and German institutions and will provide important information for climate service related activities.

A detailed water balance and conceptual flow model was calculated and developed for the Sandspruit catchment for the period 1990 to 2010 on a winter rainfall water-year (1 April -31 March) basis. The Sandspruit catchment (quaternary catchment G10J) is located in the Western Cape Province of South Africa and is a tributary of the Berg River. It contributes significantly to the salinisation of the mid-to lower-reaches of the Berg River and thus the hydrological drivers need to be quantified and conceptualised in order to develop salinity management strategies. Various components of the water balance, i.e. precipitation, evaporation, streamflow, recharge, etc., were monitored and quantified. In addition, stable environmental isotopes and water balance modelling were used to perform hydrograph separation as well as to quantify components of the water balance. Annual streamflow in the catchment during the period of observation was variable, ranging between 0.026 mm•a . On average, 6.5% of rainfall was converted to streamflow during the period of observation. Evapotranspiration was found to be the dominant component of the water balance, as it comprises, on average, 94% of precipitation in the catchment. Groundwater recharge was calculated to average at 29 mm•a -1. The water balance model (J2000) performed well during the simulation period with all measures of performance exhibiting acceptable values. Simulation results indicate that streamflow is driven by interflow from the soil horizon (94.68% of streamflow), followed by overland flow (4.92% of streamflow). These results, together with the physiographic conditions evident in the catchment, were used to develop a conceptual flow model. Streamflow is interpreted to be driven by quickflow, i.e. overland flow and interflow, with minimal contribution from groundwater, and is also more dependent on the rainfall distribution in time rather than on the annual volume. The correlation between average annual streamflow and average rainfall was observed to be poor, suggesting that alternative factors, e.g. the spatial distribution of winter wheat, the temporal distribution of rainfall, climatic variables (temperature), etc., exert a greater influence on streamflow. The water balance and conceptual flow model will form the basis for the application of distributed hydrological modelling in the Sandspruit catchment and the development of salinity management strategies. Results from this investigation, e.g. ET estimates, methods to quantify groundwater recharge, hydrograph separation, etc., could potentially be extrapolated to other semi-arid areas.

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Water is a critical resource necessary to support social and economic development. Economic growth and, in particular, the growth of urban and peri-urban areas, however results in declining water quality which threatens water-dependent industries. In developing countries this is a particular concern due to the rapid rate of urbanisation and the limited financial resources and technical capabilities to adequately maintain and upgrade wastewater treatment works. This is particularly relevant in catchments with a high dependence on export-orientated agriculture. This study considered water quality risks in the Breede River catchment as an area which experiences significant urban and peri-urban growth, focusing on economic risks associated with declining water quality, estimates of the costs needed to rehabilitate existing wastewater treatment works, and alternative strategies such as the use of artificial wetlands, the rehabilitation and protection of natural wetlands, as well as the clearing of invasive alien plants. A major conclusion is that the financial risk associated with a declining economy and social instability outweighs the costs that will be needed for rehabilitation of existing treatment plants. Together with more pronounced fluctuations in precipitation anticipated with climate change, these risks due to declining water quality are likely to increase in future with continued urban and peri-urban growth.

Abstract:The purpose of the study is to assess whether Corporate Social Responsibility regarding water is considered relevant for sustainability in companies related to agriculture in South Africa, considering that their impact directly influences public access to water. To accomplish this purpose, a qualitative approach was developed through the study of the 22 existing companies from the agriculture sector, food and beverages, forest and paper production, and Tobacco, which published their last integrated report within the Global Reporting Initiative framework. A thematic content analysis was carried out, involving the analysis of the written sustainability reports. For data analyses, ATLAS.ti 7.1 software was used to match the main aspects related to water management. Pragmatic advice for practitioners derives from the research results, considering that Corporate Social Responsibility in general-and sustainable water management in particular-represents an opportunity for companies to get competitive advantages in the market. The study also determines the best practices in the field in South Africa with benchmarking purposes.