Since it does, at least, stay properly wet, despite a very dry summer, there was lots of waterlogged (thus heavy) mud, which had to be carted away up sloping ground so it couldn't be washed straight back in once it did rain. This made for a slow job - along with the frequent need to dig at a shallow angle to try and avoid 'holing' the clay layer keeping the water in. It didn't help that the clay wasn't at a consistent depth.
Not much in the way of animal life here at this point in time, but our efforts were presided over by a couple of Southern Hawker dragonflies.
'Close-up- showing some of the excavation, and the liquid nature of the mud. Angled branch was put in to provide a dragonfly perching point.