Have they ruled out agricultural use? In land reclamation we use a pit-and-mound system on slopes to capture more water, provide microsites for plants and shelter them from wind.

They are using them in Africa too https://www.youtube.com/watch?v=TU39jN0WEZg

This is a bit different than what land rec does but the principle is the same.

They also found maize and organic matter in the pits according to the article.