Generate terraces, keylining, and waterponds

I’m new to lands, but not so much with grasshopper.
I’m studying medium rise moutain farmland in France.
I am looking for the better way to :
1- generate terraces, following more or less the contour lines,
2 - generate ponds, with supporting wall,
3 - swales (small planted ditches nearly following the contour lines, but draining water thanks to a gentle slope (around 1%)
I haven’t tried hard allready, but I’m not succeeding to do this in a simple and parametric framework (understand with grasshopper)
Any help ?

Hi @DenisFRL,

I think you can do all of them using the _laTerrainAddCutAndFill command. You can use the Lands command in Rhino, but if you prefer to do it with Grasshopper, we have this command as component as well (“Terrain Cut and Fill” component):

Cut and fill.3dm (2.6 MB)
Cut and (2.6 KB)

Hello. I made a few tries.
1 - Yes, cut and fill works in my case to generate terraces along the contour lines
2 - I managed to “build” the pond bottom using several cut and fill functions, but “Cut and fill” doesn’t allow to build an earth ram with a determined profil, am I right ? I need a horizontal ram top, 3m large, and more or less 100% slope on one side, and the other.

3 - You might see on my model my try to create a trench in the terrain to drain water into the pond. It should be something like 0.5 to 1m deep, 0.5 to 1m large, and with a slope along the curve from 1% to 5%.

Thanks for your answers. And sorry for my very bas english.

See how does the section look like.

Hi @DenisFRL,

I think you can do it with “Cut and fill”. Is this what you need?
Cut and fill

Maybe you can do this with the _laTerrainAddPath command, also available in Grasshopper as the “Terrain Path” component.