Development of decision-support guidelines for groundwater related vulnerability assessments
Rantlhomela, Phaello Brigitte
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Climate change is major threat to our world particularly poor countries. Climate change is driven by changes in the atmospheric concentrations of Greenhouse Gases and aerosols. These gases affect the absorption, scattering and emission of radiation within the atmosphere and the earth’s surface thus resulting in changes in the energy balance (IPCC, 2007). Much strain will be placed on water resources especially in areas where water infrastructure does not exist, or where water delivery is difficult due to aridity (Pietersen, 2005). This dissertation examines the causes of climate change and explores the resulting effects on the environment, social and economic sectors. This study focuses its attention on South Africa as a whole. South Africa is viewed as a water‐stressed country with an average annual rainfall of 500 mm and any climatic change could have adverse impacts on water resources of the country. The potential impacts of climate change on water resources and hydrology for Africa and Southern Africa have received considerable attention from hydrologists during the last decade. Very little research has been conducted on the future impact of climate change on groundwater resources in South Africa. Climate change can affect groundwater levels, recharge and groundwater contribution to baseflow. The first step in the approach involves the creation of a climate change groundwater vulnerability profile. In analogy with the DRASTIC methodology the DART methodology was developed. The parameters considered in the DART methodology are as follows: D – Depth to water level change A – Aquifer type (storativity) R – Recharge T – Transmissivity The DART methodology focus more on typical parameters used in sustainability studies, but also indirectly accommodate the issue of quality due to the fact that the water quality is likely to deteriorate with a drop in water level over time as the salt load will concentrate. Two scenarios are considered; current and future. The current scenario is representative of the current precipitation patterns and the future scenario is representative of the predicted scenario based on the selected GCM. Vulnerability indices are developed to assess the impacts of global change at spatial scale to enhance the understanding of impacts on people, and develop the appropriate policies for adaptation. For the purpose of this study, a vulnerability index was developed to assess the impacts of climate change on groundwater resources of South Africa on rural communities. At first glance, the results indicate there is not a significant difference between the current and future average indices, which indicates that climate change impacts on groundwater have very little impact on communities and therefore few adaptation requirements are necessary for community impacts due to groundwater impacts based on climate change.