This is a slightly changed copy of the wonderful "Landfill plus" mod by Prehistoric, see https://mods.factorio.com/mod/Landfill_plus
This version here is changed in a way, so that you can only apply landfill tiles on shallow water near coasts (not deep water) AND (and this is the actual change) you can apply landfill also on deep water that is closer than 5 tiles away from land tiles. That way, you can landfill annoying small water pieces in a cluttered shoreline while still not having the overpowered possibilities of landfilling anywhere.
Links
Part of https://mods.factorio.com/mod/schmitts-modpack
Discuss
Here or on discord https://discord.gg/jqq98wws