Hyack Hyack:
Y'all ever hear of a place in Louisiana called New Orleans.....

...... great place to build a city folks, great planning.....
![Drink up [B-o]](./images/smilies/drinkup.gif)
The problem is that many of the world's major cities were built long before knowledge of such things was readily available. Everything now is just trying to compensate for our ancestor's lack of foresight.
Frankly, I would think any city built on the coast at or close to sea level would consider something like this vital to its survival, and build it ASAP, instead of looking for reasons not to build it.