On the evening of 9 October 1963 at 22.30, the side of Mount Toc, in the Dolomite Mountains of northern Italy, collapsed in the reservoir of the Grand Vajont, a hydropower dam some 268 metres high. The resulting wave cleared the top of the dam by over 100 metre, washed several towns away and killed over 2,000 people. Years later, during the International Year of Planet Earth, UNESCO would point to the Grand Vajont as a classic example of the consequences of the failure of engineers and geologists to understand the nature of the problem that they were trying to deal with.

Worldwide, hydropower currently represents 15% of power production and over 70% of all renewables. Rapid demand growth for electricity, a push to decarbonize economic growth and the need to harness the multiple benefits of river infrastructure are driving an unprecedented resurgence of hydropower across the world, particularly in developing countries. Most projections point to a doubling of installed capacity over the next 20-30 years. In other words, the world may end up building as much hydropower in the next two decades, as it has built over the last 100 years.

In particular, the African continent, whose hydropower potential is barely developed, will go through significant growth. Many African countries are in desperate need of power generating capacity to support their development. Demand for power is projected to grow at 6% per year, but supply has struggled to keep up. Rapid urbanization is one of the fundamental trends predicted for the continent, but many cities still experience intermittent supply of electricity. According to the African Development Bank Group’s Programme for Infrastructure Development in Africa, over the next 30 years, more than $40 billion per year in investment will be needed to close the gap in the power sector, and access to finance will be one of the key barriers to that development.

In this context, hydropower is a mature technology that offers a cheap, domestic source of power, associated with multiple water services – from storage to irrigation and water supply. Through the growth of regional interconnection systems, such as the multiple power pools developing on the African continent, hydropower can support the development of a portfolio of energy generating technologies, including other renewables. It is, however, capital intensive – one of the reasons its development on the continent has been slow.

But things are changing. Growth in hydropower is now being driven at least in part by the availability of Chinese and other middle-income countries’ capital and technical capacity. For example, in 2013, China’s Sinohydro Group was awarded a $1.65 billion contract by Uganda for construction of the country’s largest electrical plant on the Nile River. The Karuma hydropower project is a 600 MW installation, due for completion in 2018. Chinese contractors also have a keen interest in the development of the Inga site on the Congo River, in the Democratic Republic of Congo, with a total potential of over 40,000 MW – roughly double the output from China’s Three Gorges Dam. Many of these contracts come with significant access to finance from China’s development and Export-import banks.

Through years of dam building, a great deal of knowledge about how dams function has been accumulated. It is in the interest of countries seeking to develop their hydropower potential that they take advantage of this experience.

When it comes to sustainability, of all the lessons that have been learned from damming the world’s great rivers – from the Colorado River in the US to the Yangtze River in China – one lesson stands out: we cannot afford to keep thinking only at the scale of a single dam. Instead, we must strive to base our planning at the scale of whole systems; entire river basins from source to sea. Only by assessing decisions about dams at these scales can we produce more balanced outcomes that take into account the full range of benefits that rivers and river systems provide.

Doing so is leading countries like the US, whose hydropower has already largely been developed, to reconsider some of its choices. This is the case, for example, in the Penobscot River in Maine, where – by eliminating some dams and changing capacity and operations at others – the river has been reconfigured to produce the same amount of power, but with much greater river connectivity and significantly improved ecological outcomes.

Those who lead countries with significant hydropower development ahead of them must decide which path to take. One path leads to the unplanned development of dams, delivered as individual assets without broader planning or consideration for larger implications, such as the ability of rivers to produce fish for tens of millions of people. The other path leads to a more carefully planned development, where hydropower is considered in the context of an entire river system, and where the multiple services of a river are optimized.

Of course, under the intense pressure from electricity demand, choosing the second is more complicated, and risks being perceived as yet another obstacle that slows development. Lack of information makes it very difficult to execute what might be theoretically a very desirable optimization process. Good, real world information – including economic, social and environmental data – are needed to inform planning decisions, and those take time and effort to collect. Significant technical capacity is also required, but seldom available during the early stages of the development of a river, also contributing to making it the road hardest to travel.

An important practical tool to help countries guide them in the selection and planning of dams, and link individual projects to basin scale considerations, is the Hydropower Sustainability Assessment Protocol, published in 2010 by a multistakeholder forum under the sponsorship of the International Hydropower Association.

The protocol provides a framework for evaluating the sustainability of hydropower projects at different stages of development. It does not replace, but is a useful complement to more detailed and formal socio-environmental impact assessments. Critically, it is an objective framework that is independent of the values of any particular organization, and can be applied relatively quickly. The protocol can help developers and investors identify gaps and opportunities for improvement in a project or at a system level. If used from the early stages of project planning, it is a management tool that can provide a practical link between the individual project and the larger basin scale.

But the protocol is only the first step. Multilateral and national institutions operating in countries that are developing their hydropower potential should consider financing technical capacity for early stage planning. Doing so will more than pay for itself, as the cost of delivering information and capacity is likely to be much lower than the cost of building the wrong dams or making mistakes that can be easily prevented. And in the long term, planning hydropower within the context of an entire river system will pay off, as countries enjoy the benefits of more sustainable infrastructure asset base, greater resilience in the face of a changing climate, and more effective management of infrastructure costs and benefits.

Fifty years have passed since the Grand Vajont. We have experienced the results of hasty, unplanned development of hydropower. Today, we have the knowledge, and the opportunity, to make smart, enduring and sustainable decisions.  If we get it right – and we can – future generations will look back and salute our willingness to learn from the past and think big.

Giulio Boccaletti is Managing Director of Global Water at The Nature Conservancy, and a World Economic Forum Young Global Leader. He is participating in the World Economic Forum on Africa 2014 in Abuja, Nigeria. 

Image: A runner near the Katse Dam in Lesotho. REUTERS/Christa Cameron