would be nice to be able to multiply the cost of adding water to make it more costly and a big investment for hard mode playthroughs. i.e making the player really consider if it is worth making that moat for defence or waterway for boats. thus making the cost of change worse when combined with more costs for landfill, thus making terraforming a costly endeavour.

Are you talking about a simple setting for the amount of explosives to make Waterfill? Currently it's just 1 explosive, so I could easily add a setting to use a specific amount

Yep. That would be good.

Done. I'm not experienced at modding but it seems to work, let me know if there are any issues.

Also, this really is a great idea, I think I'm going to start using this setting set to like 10 or something at least. 1 explosive really is too cheap

Thanks :)

id suggest playing around yourself and when you find a price value you think is reasonable setting that as the new default as now anyone can tweak it. Also you can double the cost for expensive recipes. Heres an example from one of my mods

Just make expensive either your default or the custom variable in the settings and times it by 2 ( or maybe more if you think 2x isn't hard enough for expensive mode )

https://github.com/zanven42/FactorioMod-Wood-Walls/blob/master/prototypes/recipe.lua