So.. just a random question, what roles does an environmental engineer play in an aquatic envrionment?

[Maximilian]

So far ive got:

Sewage treatment
Water Monitoring (sewage, pipe system, rivers maybe etc)
Desalination plants operation

What else is there?? An aquatic environment being anything to do with water basically, and an environmental engineer being an engineer but skewed towards environmental concepts (not a tree hugger).