Requires the library mod Collective.
This mod is part of The Vanilla Experience.
Conduits Prevent Drowned is a minimalistic configurable mod which disables drowned zombie spawns around the player when the conduit effect is active.
preventDrownedInRange (default = 200, min 0, max 200): The euclidian distance range around the drowned where a check for a player with the conduit effect is done. A value of 200 prevents the spawning of all drowned.
You'll be able to build your underwater city in peace, without having pickles all around: