Simon Tilleard Archives

Getting the facts right on large hydro

by Simon Tilleard

How environmentally and socially sustainable are big dam projects? Simon Tilleard takes on the issue of large-scale hydro in his recent letter to the New Scientist.

What does “renewable power” mean to you?
Chances are, you’ll think of solar, wind and hydropower. But when it comes to large-scale hydropower, just how ‘renewable’ is this power?

I recently read an article in the New Scientist Rise of renewables starts climate-change fightback – (6 July, page 6-7) which brought home to me once again how common it is to see ‘the next generation’ of large hydropower dams held up as examples of environmentally conscious and sustainable sources of power.

In the article, authors Marshall and Aldhous indicate that large hydropower dams can help to fight back on climate change and produce ‘green power’ whilst sustainably managing environmental resources. They go on to state that a few large dams have erroneously given the sector a bad reputation and that the World Bank’s recent decision to return to funding large dams is proof of improved procedures for management.

My experience as a water resources engineer working in South East Asia brings me a different perspective. It’s abundantly clear that it’s misleading to suggest that merely a few of the older dam projects were ill-conceived and unsustainable. In reality, the negative environmental and social impacts of large dams often outweigh their economic benefits.

The 2000 independent World Commission on Dams, the most comprehensive study on dam impacts, concluded that big, complex schemes cost far more but produce less energy than expected. Examples of environmental and social impacts from large hydropower are plentiful, devastating fish losses from the Pak Mun Dam in Thailand or mass displacement caused by the Narmada Valley […]

River bank protection in the Mekong Delta

by Simon Tilleard

ICEM’s Simon Tilleard travels to the Mekong Delta with his father, visiting a unique project his father managed 13 years ago to prevent river erosion from destroying communities. This environmentally sensitive approach is proving effective and could provide a model for river bank protection today.

“It’s working!” my father exclaimed on a recent trip to the Mekong delta where 13 years ago he designed bank protection works for the My Thuan Bridge.

The bridge links the rice basket of the Mekong Delta to Ho Chi Minh, Vietnam’s largest city. At the time the bridge was Australia’s largest foreign aid investment ever.

The bank protection design was radical. The design aimed to stop erosion more than 500m upstream of the bridge. Rather than the standard concreting of the top segment of the bank where the erosion was obvious, the design instead incorporated a series of pile grovnes to slow the river flow velocity, encourage sedimentation and reduce the cause of the erosion from at the base of the bank and the bed of the channel. This was designed to treat the cause of the erosion – not the symptom.

Fifteen years ago my father sat drinking tea in the tropical heat with a man whose house was next in line for the river’s inevitable erosion. From a maximum rate of over 20m a year retreat during the 1960 and 70s the erosion had slowed to a still formidable six metres a year.

The man smiled and slyly joked “I have waited 20 years for a riverfront house, when the river destroys my house then I will just have to go to the back of the queue again”. But the old man is still grinning, drinking his tea and enjoying his river view.

Climate change is unlikely to affect the unique design […]