@burcinc-- The American Institute of Hydrology does play a huge role in this, mainly through certification.
I have an uncle who works with AIH and I know firsthand that the Institute cares greatly about public interest and they want to make sure that all the practices of American hydrologists are by the book.
We can't make a generalization that hydrologists who have a certificate from the AIH are the only dependable ones. That's not true because hydrology jobs are flexible and give lots of opportunities for independent research, study and work.
But if an organization or institution is concerned about things like bias, which I don't think is that common an occurrence, they can opt to work with a hydrologist who has an AIH certification and plenty of experience in the field.