Gender of adverbs

[Hiperbólico]

¡Hola! I'm just going to use a quick example.

The water is shallow.
> El agua es poco profunda.
> El agua es poca profunda.

Now, agua is feminine and therefore profunda must be feminine. Now, I know the word poco/poca as an adjective changes gender. However, does the adverb poco also change depending on what it modifies? Or are adverbs generally "indifferent" to gender? (of course, in the case of modifying adjectives, not verbs)

Thanks in advance.