We put in 67’ of 4” sewer line and one 4x3 wye. We tried to backfill and compact it, but the material was too wet. About 3’ down water was seeping in the walls, so we had to add rock to safe it up. We back filled it and added 4” of rock to the top. The road way was still wet and pumping, so we combed it up for the night to keep people from driving on it. Fueled up the well point pumps. Swept the roads. I took air monitor in the hole. The oxygen level was 20.9% and everything else was zero. The air monitor model is ventis mx4. The serial number is 170408N-68. 