DSpace Collection:

Hydrogeochemical characterisation and evaluation of groundwater resources and review of groundwater management schemes in Kamiesberg, Northern Cape

Sun, 01 Jan 2012 00:00:00 GMT

Title: Hydrogeochemical characterisation and evaluation of groundwater resources and review of groundwater management schemes in Kamiesberg, Northern Cape Authors: Van Wyk, I; Roychoudhury, AN; Maherry, A; Genthe, B Abstract: Kamiesberg, located in the semi-arid regions of South Africa, depends primarily on subsurface water resources for domestic, agricultural and industrial use. In order to assess geochemical evolution of groundwater and to identify salinization, a constant threat, regular monitoring is required. Here we evaluate decadal hydrogeochemical data collected by water management schemes applied in Kamiesberg to improve our understanding of the success of groundwater supply and management schemes in sustainable use of groundwater resources. IC and ICP-MS results proved a distinct Na-Cl character of the groundwater as well as elevated salinity of 100-350 mS/m towards the interior, along the Kamiesberg Mountains, and 730-1165 mS/m towards the west coast. Several towns are subjected to microbial contamination as well as fluoride concentrations above the allowable drinking water limit. Municipal water chlorination may be a contributing factor to increased chloride levels (>400mg/L). Potable water quality at towns served with treated (desalinated) water complies with the national drinking water standard for major element composition, emphasising necessity for wider distribution of desalinated and disinfected potable water. Soils analysed for U mainly indicated concentrations higher than the world mean value of 0.7-9mg/L, however, no correlation between U levels in groundwater and host rock was established. Description: Water Institute of Southern Africa (WISA) Biennial Conference and Exhibition, Cape Town International Convention Centre, 6-10 May 2012

Comparison of water-use by alien invasive pine trees growing in riparian and non-riparian zones in the Western Cape Province, South Africa

Mon, 01 Apr 2013 00:00:00 GMT

Title: Comparison of water-use by alien invasive pine trees growing in riparian and non-riparian zones in the Western Cape Province, South Africa Authors: Dzikiti, S; Schachtschneider, K; Naiken, V; Gush, M; Le Maitre, D Abstract: Self-established stands of alien invasive pine trees are common in many parts of South Africa and elsewhere. They mainly invade non-riparian settings but sometimes invade riparian habitats. There are clear visual differences in the physical attributes of trees that occupy riparian and non-riparian zones. We have little information whether the differences between trees growing in these contrasting habitats reflect their water-use. The goal of this study was to establish the water-use of alien invasive pines growing adjacent to and away from a perennial stream, and to determine the driving factors behind the variations. The study was conducted in a self-established 20-year old mixed pine forest occupied by roughly equal proportions of Pinus pinaster and Pinus halepensis. Individual tree transpiration rates were measured using the heat pulse velocity (HPV) sap flow method. Evapotranspiration (ET) from entire stands was determined from the surface energy balance equation using sensible heat flux data collected using a boundary layer scintillometer and measurements of the available energy (net radiation – soil heat flux). A simple two-layer model in which the stand ET was calculated as the algebraic sum of the outputs from transpiration (E) and soil evaporation sub-models was evaluated at the two contrasting sites. Annual transpiration and ET rates were higher in the riparian zone at 980 and 1417 mm compared to 753 and 1190 mm, respectively in the non-riparian area. The model predicted stand transpiration fairly accurately for both sites (average R2 44 > 0.75), but was less accurate for evapotranspiration (average R2 45 < 0.70) due to the difficulties in simulating soil evaporation. No significant differences in sap velocities were found between trees at the two sites so the greater water-use of trees in the riparian zone was due to the larger basal area per stem. Based on the measured transpiration data we conclude that self-sown pine stands growing in riparian zones use at least 36% more water than those occurring in non-riparian settings justifying the high priority given to clearing invasive trees in riparian zones. Description: Copyright: 2013 Elsevier. This is the Pre/post print version of the work. The definitive version is published in Forest Ecology and Management, vol. 293, pp 92-102

Nanotechnology for potable water and general consumption in developing countries

Wed, 01 Aug 2012 00:00:00 GMT

Title: Nanotechnology for potable water and general consumption in developing countries Authors: Hillie, T; Hlophe, M Abstract: This chapter discusses water and its sources; the main focus is put on surface water and ground water. Factors such as water pollution and sewage are also discussed in areas of mining and agriculture. Furthermore the global water challenges that affect people in developing and developed countries. The challenges outlined are; poor governance, water scarcity, sanitation and climate change. Nanotechnology is sufficiently advanced to help provide potable water and water for general assumption in developing countries. The technology to be implemented will depend on the available infrastructure, and in most remote areas in developing countries where potable water is required, these include such rudimentary basics as electricity and accessibility. Water is vital to sustain life in every organism, including human beings. As a basic need for rich and poor alike, water takes on primary importance among public resources, one that we need to better understand and sustain. Description: Copyright: Taylor & Francis, New York, USA.

Scenarios for the South African water sector in 2025; Paper

Tue, 01 Jan 2013 00:00:00 GMT

Title: Scenarios for the South African water sector in 2025; Paper Authors: Claassen, M; Funke, N; Nienaber, S Abstract: In 2008 the Water Research Commission initiated a project to develop ‘Water Sector Institutional Landscape in 2025 Scenarios’. The aim was to build knowledge about key drivers and uncertainties related to the future of the South African water sector. A diverse group of stakeholders contributed to the development of the drivers, which translated into different scenarios and associated stories that have potential implications for social and economic development, as well as for the management of water resources and water services. The four scenarios were derived from a matrix with two axes that represent the ability of the decision-making paradigm of water institutions to deal with complexity, and the reconciliation of environmental, social and economic demands of present and future generations (sustainability). The Wise Tortoise scenario describes a sector which deals with complexity and is sensitive to sustainability issues, whereas the Ignorant Ostrich scenario describes the opposite conditions. The Greedy Jackal and Busy Bee scenarios describe the other combinations of the key drivers. The scenarios provide stakeholders and policy-makers in South Africa’s water sector with insights to strengthen decision-making and to counter undesirable trajectories of change. The knowledge will empower role players in the water sector to engage in participative governance by equipping them with insights into potential futures that the South African water sector may face. This paper reports on the process to develop these scenarios for the South African water sector institutional landscape in 2025, presents the key forces, introduces the stories, and reflects on the use of scenarios in the water sector. Description: Copyright: 2013 SA Water Research Commission. This is an ABSTRACT ONLY. The definitive version is published in Water SA, vol. 39(1), pp 143-149