Hundred years of sustainability

Published on: 21/04/2011

This is a relevant question to ask in the context of rural water supplies, where the quest for sustainability has been going on for as long as modern water supplies have been developed. As engineers, we have often talked in terms of life-spans of a water system. A piped water supply should have a life span of some twenty years. A hand pump would last 10 years. But few users would be happy to have a system for 10 years, and once it reaches the end of its life-span, to be left with nothing. Neither would engineers or planners expect to see such a situation. So, what happens when the 10 or 20 years have passed?

One option is for service providers collect enough money through tariffs from users over that life span to replace the assets, or even to expand them, and live happily ever after. However, the inclusion of the full replacement, or depreciation, costs in tariffs is often prohibitive – in most places, tariffs are barely high enough to cover operation and minor maintenance costs. In reality, in most places, some funder external to the community – for example a government agency, a donor or an NGO – turns up to cover the costs of replacing the assets, sometimes with matching funds with the service provider. However, such asset replacement is not frequently planned for in (local) government budgets, and done in an ad hoc manner, for example as part of a rehabilitation effort. In a certain percentage of cases, these agencies do not have the funds or capacity at the moment a system starts to break down, and the asset is not replaced, leading to the well-known graveyards of broken-down handpumps, or under-performing piped systems. And in many cases, the situation is even messier, as different components of a system have different life-spans – a borehole usually lasts longer than the handpump that stands on top of it – so different parts of a water system need to be changed at different moments in the life span of the system.

For us, sustainability is forever. Rural water supplies should last hundred years or more. Part of the assets may be replaced once their lifespan ends, but the service should last forever. This is an ideal that has proved elusive for all involved in the rural water sector: service providers and practitioners, policy makers and researchers, and above all users. Much is known about what is required to achieve sustainability of rural water supplies: the whole set of activities that are needed to ensure preventive maintenance, so that life spans of systems components take as long as possible; it involves doing proper asset replacement once the end of a life span is reached; but it also requires service providers and government agencies to join hands to finance that. Putting all these elements in practice at the same time is harder, though many good practices exist all across the globe.

This blog aims to regularly report experiences, stories and questions on rural water supply. It will ask questions and provoke debate on how sustainability of water systems can be improved. It seeks to provide examples and learn from failures. It does not aim to provide ready-made answers; if those would exist, they would win the Nobel Prize for Water, or, more likely, the Silver Bullet Award. We invite you to contribute your thoughts and stories, to provoke and to question, and to share these debates more widely.