Wetlands and retarding basins

Land development reference 7.19

​The 'as constructed' information for all pipelines/structures and channels relating to retarding basins and wetlands, or retarding basin walls (levee banks), must be provided.

For assets such as lakes, earthen mounds, wetlands and retarding basins and general landscaping within these assets, 'as constructed' information should be provided as a feature survey plan.

If the Works have been constructed generally in accordance with design, then spot levels annotated on the design plan will suffice. If the works aren't in accordance to design or the 'as constructed' information can't be legibly annotated onto the design plan, then new addendum sheets must be submitted depicting spot levels taken and showing generated contours from the spot levels and specific features delineated, including all pipes, channels and manholes/structures.

In addition, the 'as constructed' Normal Top Water Level (NTWL) is to be shown on the feature survey plan.


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