Sewage line coming from the house.
Curving around to where it connects with the sewer underneath where the driveway will eventually sit.
Trench for the water line.
I didn't notice it until this evening until Jenny pointed it out but you can also see from that first photo above that the sidewalk that was poured earlier in the week has apparently been removed. It looked fine when I walked through with the project manager yesterday but something must have happened to cause it to be ripped up. I guess I'll ask him the next time he calls.