How do I block shallow water?

[DiamondDuty]

I have my colony built around a river, with walls encompassing it. Problem is, during raids, they circumvent my funnel and go around the walls via shallow water. How can I block this route?

Thanks in advance. :)

[Baked.Bread]

Gotta build a bridge then put a wall on it. Dunno if it's in vanilla. There are bridge mods.

[Astasia]

In vanilla you can make bridges and build wood walls on them (only wood walls, any other material is too heavy).

If it's normal shallow water you can also use moisture pumps to convert it to gravel, but moisture pumps do not work on moving water like that found in rivers.

[The Yeen Queen]

I THINK wooden walls will be enough to encourage most raiders to go for the killbox funnel, though.