What serves as the reference elevation for determining all other elevations across the site?

• A. Bench mark
• B. Datum point
• C. Elevation line
• D. Reference point

Answer: (A)

In site leveling, the reference elevation comes from a bench mark. A bench mark is a fixed, durable point with a precisely known elevation tied to a standard datum. By measuring vertical differences from this baseline, you determine the elevations of all other points on the site, ensuring consistency across grading, foundations, and drainage. The bench mark provides a concrete, on-site reference that remains constant over time, which is essential for accurate and repeatable elevations. A datum point is a general reference location, an elevation line is a map representation of constant height, and a reference point is too vague to ensure a precise, measured elevation on the ground.