Kind of typical for this series when it comes to those OP spirits. And she even made him turn into minor spirit.
Just trees of the same kind with no undergrowth nor animals. As some people would say, that's not a forest; that's a plantation. But you need to start somewhere.
Spiral pattern really needs a pump. I'd say it's bad because it's less efficient than other ways of watering, but if you want a single line rather than a branching one, eh. And for a completely flat land like this you need a pump or magic to move the water anyway.
Why would you even ask that? It was obvious from the start what the answer would be. Or the warning of the answer.
Must be a very precisely engineered rock to hold out all water.
Yeah, I completely agree on the forest, but I wonder if it's just the artist. This would be better answered if there are novel raws. I don't know, I only read the manga, but I feel like there's definitely a LN/WN out there. But the artist definitely favors a more sparse artstyle. Though in chapter 13, they did do a forest with grass undergrowth lol. a few 'taller' plants, so I'm wondering if the undergrowth is just gonna edge in later. As for the animals part- The forest spirit did have him gather bugs! I suspect once the bugs get established, then they can start bringing in animals? Birds first once the bugs are established then get bigger and bigger.
The bigger issue I have with the forest is the mention of fruit trees- Most fruiting trees have to be carefully managed. Peach trees for example, if left to bloom naturally, will crack off their own branches from the weight of their fruit. Apple trees, if you don't prune the fruit almost excessively will only produce extremely tiny fruit. Crab apples basically. It's the same with most fruiting trees, such as cherry/persimmon/nectarine- Nut trees do much better unmanaged in comparison to fruit trees. I guess with magic, that can make a difference though.
For the water, since he wants it to water the land, I wonder if he built holes into the 'stream' like he did the square pond to water and soften the ground. I agree, 90 degree bend would need a pump- It would've been just a little better if instead of completely flat land he had Nomos raise the pond so it was on the top of a 'hill', and then the water could flow 'downstream'. Still not great at the bends, but at least then it'd make more sense. Though I'm not sure if Yuta (or the artist) is ready for branching paths lmao. Though you're right about the stone blocking the waterway. I do wonder if the land will become a 'wetland' once again as Yuuta restores it. It doesn't seem like it- a forested land instead. Maybe the wetland will be even closer to the sea?