Barrier to Flood Water: Is it Effective?

[coolul007]

This has been bothering me for a year. I saw a news report outlining the potential of a flood coming down a street. The street was lined with plastic barricades filled with water to keep the flood waters from getting to the buildings on the street. It seemed to me that since the specific gravity of the barricade was only slightly greater than water, they would merely become part of the flood debris and stop nothing. Am I missing something?

 

[gmax137]

I think these barriers are only "good" for flood level up to some specified fraction of the barrier's height. If the flood height reached the barrier height, the barrier would indeed lift off the ground surface and float away.

EDIT
Google: water filled flood barriers

 

[coolul007]

I think these barriers are only "good" for flood level up to some specified fraction of the barrier's height. If the flood height reached the barrier height, the barrier would indeed lift off the ground surface and float away.

EDIT
Google: water filled flood barriers

I did not know whether the flood happened or not. Thank you for pointing out that it could help to a point.