Look for 'buildable terrain' or similar terms, there are least a couple.

My preferred terraforming mod is https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3225843229 It allows you to create or fill in various forms of marsh through water and has farming functionality.

It looks interesting I'll try this out!

Originally posted by Deadoon:

My preferred terraforming mod is https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3225843229 It allows you to create or fill in various forms of marsh through water and has farming functionality.

Something has trenches... can't remember what mod.
And I think you could use Dev Mode to make water.

Originally posted by Kalindigo:

Something has trenches... can't remember what mod.
And I think you could use Dev Mode to make water.

Vanilla furniture expanded has trenches which provide combat effects. Fertile fields(Which I posted above) has trenches which will flood with water if they connect to a water source.