As-built surveys

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Throughout the construction process, it is sometimes necessary to deviate from the intended design of LID features and adapt the design to on-site conditions. The completion of a post-construction as-built survey is a standard operating procedure for engineering projects that captures any changes made to the feature’s design during construction. For an example of municipal standards for as-built surveys, refer to the City of Toronto's Engineering Survey Standards for Consultants[1]

Survey Steps:

  1. Use the same datum as the pre-engineering survey.
  2. If a pre-engineering survey is not available, use a reference feature as the datum.
  3. Identify the type, diameter, and material of exposed utilities.
  4. Include data on critical feature elevations and existing utilities, such as:
    • Inverts of newly installed pipe
    • Vertical and horizontal bends in pipes
    • Existing public utilities
    • Existing private utilities
    • New and existing structures (e.g., catchbasins, manholes, chambers, etc.)

Inspection Points:

  • Datum matches the pre-engineering survey or selected reference feature.
  • Data provided in as-built survey matches the as-built standards of the local municipality.