IWRA Proceedings

AbstractSubstantial changes to the South African climate are expected to occur over the next 30-50 years. South Africa is already water stressed and the predicted climate changes are likely to have dramatic impacts on the ability of local and national authorities to deliver water and sanitation services. In addition, this will make it increasingly difficult for authorities to abide by national policy that requires each household to be provided with 6 kl of free water per month. The research reported here draws on the lessons learned from a climate change vulnerability assessment of the eThekwini municipality, where the water sector is highly vulnerable to climate change. Local government needs decision-support tools that consider long time horizons, and which are simple to apply and not data intensive, in order to mainstream long-term planning for climate-change adaptation. Because the efficient and cost-effective provision of water and sanitation services is a critical challenge faced by all local authorities, a clear understanding of the costs of alternative options for service provision is essential. This study created a simple planning tool to evaluate the cost-effectiveness of a range of service provision options. The resulting model comprises a baseline scenario coupled with adaptation options for two types of development projects: 1) an ‘Urban Housing’ project (UH) and 2) a ‘Rural Housing’ project (RH). The UH project involves meeting increased demands for water in areas where water-supply and sanitation infrastructure already exist, while the RH project addresses remote areas where fully waterborne sewage is impractical and unaffordable, water is supplied by tank, and ventilated improved pit (VIP) toilets are used for sanitation. In the UH case two adaptation options were considered: the use of grey water (option 1.1) and rainwater harvesting (option 1.2). In the RH case, ‘urine diversion toilets’ (UDT) was the only adaptation option investigated. A non-linear micro-economic model was developed and used to estimate the present values of the total and volumetric costs of the development options available, over a period of 50 years. The economic model accounts for the capital costs of establishment, the recurrent costs of running and maintenance, the cost of water as an increasing non-linear function of time, and the amount of water used. The estimated present values for all options were converted to annual levelised values to make comparisons easier. The model results show that all adaptation options are more cost effective than the baseline choices. In the UH project, adaptation option 1.1 is not only more cost-effective than both the baseline and adaptation option 1.2, it also uses 40% less water. For the RH project, the adaptation option (UDT) is almost three times cheaper than the baseline (VIP) and has additional environmental co -benefits. The model was evaluated by potential users and was found to be an effective decision-support tool that could also be used to educate consumers on the benefits and costs of alternative technologies. Finally, possible barriers to the widespread implementation of adaptation options are identified and discussed in the paper, as well as possible ways of overcoming these obstacles.