What does a benchmark provide in a survey?

A benchmark in surveying primarily serves as a reference point that indicates elevation. It is a permanent marker that is set at a known height above a designated datum, often sea level. Engineers and surveyors use benchmarks to ensure that all measurements are consistent and to provide a reliable point of reference for determining elevation changes across the surveyed land. This is crucial in various applications, including construction, road design, and land development, where accurate elevation data is necessary to establish proper drainage, soil stability, and overall design integrity.

While benchmarks can play a role in land ownership by helping determine property lines and legal descriptions, those functions are secondary to their primary purpose of elevation measurement. Legal descriptions are more related to boundary markers and surveys that outline property limits based on geographic coordinates rather than elevation data.