Technical Notes and Documentation
What a sewer design report and drawing set should record.
A design is only as good as what can be checked and built from it. The design report, the drawings and the calculation sheets together should let an independent reviewer reach the same conclusions.
Authorities typically require a design report, a long section and plan, calculation sheets, and confirmation against the current code and supplement. Getting the record right also supports asset handover.
Key design considerations
- Design basis: standards, authority documents, design flows, factors and assumptions.
- Calculations per reach, with the criteria applied and the result.
- Long section showing surface, invert, grade, cover and every structure.
- Drawing notes covering materials, bedding, testing and reinstatement.
- Hold points, inspection and test requirements, and who verifies them.
- As-constructed records and survey, which become the asset register data.
- Departures from the standard, and the approval that supports them.
Design checks
- Design report references current standard and authority revisions.
- Drawings and calculations agree on diameters, grades and levels.
- Departures documented and approved in writing.
Standards and authority references
- WSA 02 (current edition)
- Authority submission requirements
- Authority asset handover requirements
Confirm the current edition, amendment and any local supplement before applying any of the above.
Limitations and assumptions
- Submission formats vary; confirm the authority's current checklist.
This reference is general engineering information. Confirm requirements against WSA 02, the current Australian Standards and the local water authority's supplement before use in design, and obtain project-specific advice for the conditions at hand.