Not to steal your thread...but I know how you feel.
Back in August, I took notice of a steady water trickle coming from under a bunch of terraced retaining walls in my front yard.
The parking area is up above all that.
First I thought it was rain runoff or maybe a bit of underground spring stuff...but then I realized it was in-line with my well.
I shut off the pump...the water stopped...and I new I was in for some digging to fix a main water line leak...which thanks to the terraced retaining walls, ran right under them (previous owner, not me).
I hand dug for days just trying to locate the fucker...couldn't use machinery so as not to destroy the retaining walls (I mean a LOT of walls, and lots of railroad ties underneath the dirt also).
It was some of the most painful digging I've ever done by hand...just shovel after shovel of broken shale rock after the first foot or so of topsoil. That's what they back-filled with in-between the retaining walls.
After 4 holes, 8' down...I found the pipe line....and in the end the leak traced out under my parking area, so at least when I got there, outside of the retaining walls, I was able to rent a small excavator, dig it up, cut out the cracked pipe, splice in a new piece, and then bury it.
Not to mention....some of the outer retaining wall ended up getting damaged...just no way to avoid that, but it was repairable.
The whole think lasted the entire month of September. Did it all myself. My hands and back still hurt.
Anyway...like I said, I know how you feel...though at least my headache was all outside.
Yours certainly looks like a much bigger headache!!! Fuck!
Good luck. I'm sure you'll be back to normal at some point. I mean, it is 100% repairable, right?