Vetiver System - bridge protection/flood mitigation- 1

Eroding Bridge abutment (Truong)

Bridge abutment approach 18 months after vetiver treatment (Truong)

The weakest part of any bridge in the world, including the “developed’ world, is the abutment.  Bridge abutments often do not get the compaction they need to withstand the force of a flood. Whirlpools and eroding eddies caused by high pressure flood water being held back from going under the bridge can wipe out an embankment if not protected by vetiver hedges  Once the abutment has been washed away, communications are severely disrupted, roads to markets can be cut for days or weeks, villages can be isolated, while the bridge can be standing in the middle of the river, isolated and useless, until it is joined to the road again, usually at great expense.

A strong flood can leave many bridges in the catchment area cut off to the public, totally impinging the communication network.  In some countries, water, power and telecommunications are carried over the river, under a bridge. Once the abutment is washed out, these can be cut and take a long time to replace.

Paul has shown, with his work in Queensland that strategically placed vetiver hedges can protect bridge abutments from washouts, this is a very important use of the vetiver system that should be emphasised more. I think at the next conference on vetiver in Lucknow, Paul Truong should broach this subject as he has some very good slides of the work he did in Queensland protecting bridges.

John Greenfield