7.7 Survey Control Requirements
- 7.7.1 Overview
- 7.7.2 Vertical control (Australian height datum)
- 7.7.3 Horizontal control (map grid of Australia)
Overview
To enable Melbourne Water to undertake field audits during or after the construction period and to verify submitted information, the following survey information must be supplied on request:
- Source (Registered Permanent Survey Mark) Horizontal Control information that has been used to establish MGA94(z55) co-ordinate values of the constructed Works and surrounding title corners, if the subdivision has been duly co-ordinated.
- Any worksheets or fieldnotes that show internal Horizontal Control information, if the subdivision have been duly co-ordinated or the relationship of drainage assets to Title.
- Source (Registered Permanent Survey Mark) Vertical Control information that has been used to establish AHD values of the constructed Works and details of any temporary bench marks established.
- Include supply of "title information" used to establish the relationship of Drainage Assets to title boundaries.
Vertical control (Australian height datum)
The datum for all levels annotated on the original design plans must be Australian Height Datum (AHD). The adopted vertical control points and their values are to be annotated on the original design plans. Vertical Control information that has been used to establish AHD values of the constructed Works may be requested by Melbourne Water for auditing purposes. Refer to Survey Control Requirements for further details.
Accuracies
All 'as constructed' and existing surface levels must be quoted to two decimal places of a metre, with a relative accuracy tolerance of +/- 0.02m in respect to the adopted datum points. Discrepancies between the published Land Victoria values of control points used to establish the vertical control and that found by field survey must not exceed 0.04m.
Horizontal control (map grid of Australia)
Co-ordinates of as constructed works must be supplied and co-ordinate values are to be based on the Map Grid of Australia (MGA) Zone 55 projection, using the 1994 values for the geocentric datum (GDA94). MGA94(z55) co-ordinates of 'as constructed' works must be supplied. The datum points used for MGA94(z55) co-ordinates and their values are to be annotated on the original design plans.
If the subdivision has been duly co-ordinated, Horizontal Control information may be requested by Melbourne Water during the construction period for auditing purposes.
Accuracies
All co-ordinate values must be quoted to two decimal places of a metre, with an accuracy tolerance being set at +/- 0.10m in respect to adopted horizontal control points.
