I might add we've discarded the top 6" of soil with the liverwort more than once. It comes back.

I can do that - cover the area with mulch. I have a mountain of wood chip mulch I use in the garden. But, how does that improve the drainage?

Sorry, that was confusing. Liverwort thrives in poorly drained soil. Drainage in the area must be improved to make it less inviting.

Mulch does nothing to improve drainage. Mulching is supposed to kill it but does not address the underlying issue of poor drainage.

Not to beat a dead horse, but can drainage be improved without taking out the entire area several feet down, adding sand, then refilling? I do appreciate your help because I am completely stumped. Yes, it is horrible stuff!

Why is your drainage so poor? Do you have clay soil, water pooling in that area because of improper grading, runoff from buildings....? Is this a garden bed?

There is no need to excavate. Just add.

Generally to improve drainage organic material such as compost or leaf mold is added to the soil. Coarse grit and stone is sometimes added too. No sand - coarse grit.

I am asking these questions because I want to find the best permanent solution for you. Others will likely chime in as well. I really do empathize.

My soil is hard packed rocky clay soil. No water pooling. In fact, it is a little built up in the center of the approximately square bed next to the house on one side, porch on the other with the rest bordered by lawn.

I can certainly add organic material including coarse grit to the soil.

I am so grateful to you for taking the time.

Happy if I have been able to help. You can incorporate some of your wood chips too. It will not be a quick fix for heavy clay but if you add more organic material every year your soil will continue to improve.

Since no one else responded here I would like you to have the input of others experienced with your type of clay. There is a Soil Forum at this LINK