we are replacing a crumbling and sinking retaining wall. The wall and the earth behind it (parking for two cars) has been sinking for years. Yesterday the wall and 16 loads of material were removed. Now we have a 10’+ cut bank and an excavation about 4ft deep (down to hard pan) behind the house. It hasn’t rained for weeks, but the water in the hole is now at least 6″ deep. and scummy on top. more is coming in. the wall to be built is massive, with five foot wide footings, etc. but it looks like it will be always resting in the water, if the drains are done as specified by the engineer. (through the wall where it meets the footings)

can the wall be built on drain rock so the water escapes underneath it?
I have stacked block walls at the other end of the house that I built like this, on compacted drain rock, they are perfect after one year.

I should add the wall will be poured concrete, 10’+ high, footing 1’*5′,
creates after backfilling parking for three vehicles level with the lane behind the house.