Hoi An: History of sand loss repeats

Hue is one of Vietnam's main tourist attractions. It is on the Perfume River (Hương River) a slow moving river which is not much above sea level for about 30 kms inshore. It shares similar characteristics to the Mekong River with its delta of sand dunes layered with fertile sediment.

I bought a couple of interesting books while I was in Hanoi. One was a collection of academic papers collected at a UNESCO run symposium about Hue which is another world heritage urban site in Vietnam. One of the papers was about the city's geomorphology. It explored what had happened to the sea level over the past 4000 years. Turns out that Vietnam's leaders shared the same concerns as China's leaders did about the effect of traders on the attitude of local population. Which is why those leaders preferred and supported trading centres away from cities like Hanoi and Saigon. Hundreds of years ago when Hue was one of the most successful trading ports in South-East Asia it contained a Japanese city and a Chinese city. There were some Vietnamese locals, but the key Vietnamese role was to tax ships and their loads when they visited the Port.

Fishing was important to the locals as was rice growing, pepper, nutmeg and silk (Chinese nobles preferred Vietnamese silk to local silk). But the real economic purpose of the port at Hue was the collection of taxes shipping and goods that were imported or exported.

It appears this all changed very quickly about 200 years ago when something happened to the sea level and the navigability of the river and inshore water areas. The reasons for this are not particularly clear. What the paper says is that the sea rose by 3 to 4 metres, and because the sand flats which the city was built on were themselves only a few metres above sea level - they got flooded. The paper also reports that the bar, where the river entered the sea, closed off, so that sand washed downstream could not be cleared and so the harbour silted up. The upshot was that the harbour quite quickly became useless as a trading port.

Trade shifted elsewhere. But the city and its buildings remained pretty much untouched.

This map shows a bike trip we made from our hotel on that island (in the heart of Hue), to the coastal resort and its beaches. The route we took went through rice fields and small villages on cyclepaths, rather than along the main road (which turned out to be quite quiet - when we took it back). 'X' marks the spot of a very large bridge.

Here's the bridge. I guess it's 2 or 3 kms long, and must rise more than 100 metres above sea level. It's vast. Hardly carries any traffic. Part of a Vietnam growth plan.

We biked up it by mistake. Hot work that was.

Here's the view from the top - looking towards the coastal area you can see in the map - where the beaches are. The floating blobs are clumps of lilies that come and out with the tide (think the tidal movement was about 2 metres).

This is a telephoto shot from the same point.

And here we are at the beach. Beautiful white sand and coconut palms. Idyllic - and we could buy something to drink.

But right nearby this digger and the workers were filling jute sacks with sand and carefully laying them along the beach. Click the pic to see it more clearly. You couldn't easily walk over these sacks of sand to get to the sea....

About 100 metres along the beach this was the scene outside a resort. Deck chairs and sun-brollies lined up next to rows and rows of sand bags....

This picture was taken at a similar location about 2 years ago. And gives an idea of what the beach was like then. Google tells me that in less than a year a section of beach 1 kilometre long and 80 metres deep was taken by the sea. And we're not talking storms. Apparently it was normal sea action. The debate rages about the cause. Some say the sea level has increased by 30 cms (about a foot), whole others blame sand mining (there has been very extensive sand mining both in the estuarine areas and off shore). But so far as I can tell, nothing is being done fundamentally, just lots of sand bags....

The jute sand bags are probably an improvement on these plastic sand bags which I found another hundred metres along the beach. But I did wonder where all the sand came from that was used for the concrete to make that huge bridge....