This is a fantastic story that has a variety of angles - you could start by highlighting that it ties in with the rise of China, because China's demand for cement is driving the demand for the sand from the Mekong river's banks.

However, the real interest in the story is about how to protect increasingly rare riverbank sand, and how the market is operating to encourage the use of alternatives like desert sand in the creation of alternative building materials. You might start by thinking about how property rights could play role in resolving the issue.

The banks of the Mekong River are collapsing & half a million people are at risk of losing their homes due to the world's insatiable demand for sand. 50 billion tonnes of sand are dredged globally every year - the largest extractive industry on the planet