An assessment of the potential contribution of alternative water supply systems to urban water security for the Madina municipality of Accra-Ghana

Major cities, especially water sensitive ones, are battling with water security because of growing population and climate change unpredictability affecting precipitation. The study assessed the potential of alternative water supply systems; stormwater, wastewater and rainwater for the city of Madina in Accra-Ghana to contribute to meet both the current and future water supply deficit by the year 2030. The impact of climate change on rainfall amounts and the population growth on future water demand was investigated for 2030. Questionnaires, personal interviews, observations and review of literature were adopted to collect data for analysis. In this vein, water supply data for the period 2008 to 2018 was sourced from the Ghana water Company Limited and analysed for monthly and annual water supply trends and volumes. Assessment of the baseline water supply showed water supply deficits in both monthly and annual basis to meet water demand. The availability of the alternative water supply was able to fulfill the observed deficit over the period (2008-2018). The study showed that monthly rainwater and stormwater harvesting potential volumes are high in the rainy months of March, April, May, June and September and October for the period 2008 to 2018. The study also showed that since 2015, rainwater volumes have reduced until 2018. The study also showed that households’ prefer rainwater followed by wastewater and then stormwater. In terms of the volumetric contribution of these alternative water systems to meet the current and the projected 2030 water supply deficit, rainwater contributes the most, followed by wastewater and lastly stormwater. Households showed more willingness to adopt and implement rainwater, followed by wastewater and with the stormwater systems being the least. The study showed that the GWCL water supply system can only meet the current and future water supply deficits when combined with alternative water supply volumes. Implementing AWSs in combination with urban water demand management remain core strategies to achieve urban water supply security for the city of Madina now and by year 2030. The cost of infrastructure installation, land space for storage, negative cultural perception on the application of AWSs could prevent the contribution of AWSs to meet demand now and in 2030