As-built surveys

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

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.

Low Impact Development. A stormwater management strategy that seeks to mitigate the impacts of increased urban runoff and stormwater pollution by managing it as close to its source as possible. It comprises a set of site design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration and evapotranspiration, and rainwater harvesting.