Why pump? Grade drops 120 feet just to the west of the site a few feet. Gravity works all the time with no power needed.
I needed to trench to drain the water to be able to see to dig.
However, the main reason I'm trenching such a large trench is to create a tunnel to the ledge on the cliff. Should the house ever collapse when I'm in the basement I'll have an escape route. Think Texas tornados.
I believe we have decided to build the walls of "urbanite". The native stone coming out of the hole is too soft to build with and I can get busted concrete chunks delivered free.
The nearby town just tore down their FD and is digging up the old concrete slab. They will bring me 700 of 2000 cubic feet I'll need.
Here's a pic of an urbanite retaining wall. This will be what the basement interior walls will look like. The exterior will most likely have a coating applied.