You have a required elevation at “A” of 107.85. The benchmark elevation is 106.35 A back site reading of 4.65 is taken. A front site at the grade you are checking (location “A”) has a reading of 2.40. What needs to be done?

You have a required elevation at “A” of 107.85. The benchmark elevation is 106.35 A back site reading of 4.65 is taken. A front site at the grade you are checking (location “A”) has a reading of 2.40. What needs to be done?