CST Level 1 Land Surveyor Certification Practice

Which location would be the best for a Temporary Bench Mark (TBM)?

1. Middle of the sidewalk

2. Top of a fire hydrant

3. Edge of asphalt

4. Top of anchor bolt

The correct answer is: Top of a fire hydrant

A Temporary Bench Mark (TBM) should be placed in a location that is stable, easily identifiable, and unlikely to be disturbed. The top of a fire hydrant is an ideal choice for a TBM because it is a permanent structure that is typically found in consistent locations. Fire hydrants are constructed with recognizable features, making them convenient reference points for surveyors. Additionally, a fire hydrant is often set at a known elevation, which can facilitate the establishment of precise level references. While the other potential locations could seem viable, they have limitations. The middle of the sidewalk might not be the best choice due to possible interference from pedestrian traffic or temporary blockages like furniture or plants. The edge of asphalt can also be subject to wear or damage, especially from vehicles, making it a less stable reference point. Similarly, the top of an anchor bolt might not be reliably visible or familiar to different crews or survey teams, which diminishes its effectiveness as a consistent TBM. Hence, the top of a fire hydrant stands out as the most suitable choice due to its durability, visibility, and recognized elevation.