Are tropical earthworks worth it?

My grandfather recently passed away, and we deciding to maintain his land as a food forest in his honor.

I see a lot of content on rainwater harvesting and earthworks for permaculture. And im really interested on trying it out. The thing is that most of this content is for dryland, my grandpa's land is a slanted humid tropical forest.

I imagine that water harvesting here would cause mold issue and too much water retention could cause landslides.

What should i do?

Im going next sunday to survey the area