Book name? SF dystopian novel, set up in a metropolis with a great wall defending it against the rising ocean

[Jim]

copied from the introduction topic, msg #367

I'm Enrico.

I joined this group with the intent of asking for help because i am unable to find a book that i read years ago and to which i fell in love back then (can't remember author nor title). It was a sci-fi dystopian novel, set up in a metropolis with a great wall defending it against the rising ocean. The protagonist is a police, investigating the death of an important scientist. Other things that i can remember are the presence of a statue of quetzalcoatl and a woman with purple eyes. I know it's not much but if anyone ever read it i know he can recognize it.

[Jim]

It would help to have some more details.
When did you read it?
Do you have any idea when it might have been published?
Can you describe the cover?
What type of scientist?