Joda Olaekan Olatunde
Multi-criteria evaluation of urban water supply alternatives and sustainable water management for new megacities in developing countries- A case for portable water in Lagos, Nigeria
Safe drinking water is essential for all socio-economic development and survival of all life forms. Presently, the world population is expected to increase by 2.3 billion, passing from 7.0 billion in 2011 to 9.3 billion in 2050. Virtually all of the expected growth in the world population will be concentrated in the urban areas of the less developed regions (UN 2011). This phenomenal increase is already resulting in safe water shortages and as well exerting a great pressure on available water resources on our finite planet. This situation is not only critical in developed countries but also in less developed economies with multifaceted problems now visible in emerging megacities of developing countries where perennial shortages of safe water often forces people to evolve diverse and potentially harmful coping strategies many of which in-turn impacts negatively on many aspects of daily living and consequently undermine sustainable development in these locations. These complex problems associated with safe water are often poorly defined and partially understood owing to lack of adequate data or perhaps a simple disconnect between the researcher and the socio-economic context.
To deliver a sustainable solution, a wider definition of the problem boundary becomes essential (Fenner et al,2006) hence, this research examines the often very acute and complex problems associated with safe water shortages that ensue within emerging megacities in developing countries with a focus on Lagos, Nigeria. To unpack these “messy” complexities, a review of the water management framework, the involved actors, governance structure, available water resources, existing practices and as well current water demand and supply trends and characteristics were established to provide a sound understanding of the issues and problems peculiar to the Lagos Mega city context. Further, the spatial distribution of these safe water shortages was established and demonstrated to show how these might undermine the long term sustainable growth in Lagos. Further, a snapshot of nexus-thinking was introduced to as a way to better understand the interdependencies of water & energy within Lagos.
In selecting a preferred supply option, a multi-criteria analysis of the various water supply alternatives (i.e desalination schemes, rainwater harvesting, borehole schemes, protected dug wells) was tested against key sustainability criteria to combat the perennial drinking water shortages experienced in Lagos. This attempt at closing the demand gap yielded no easy answers as there appear not to be silver bullet solutions. However, key recommendations were made to guarantee the possibility of incremental progress towards closing the safe water shortages and as well to provide effective and holistic water management strategies that can deliver long term sustainability.