Overland flow works that require certification

In some cases, a water plan, water management protocol or code may require a landowner to provide a certified report when applying to reconfigure existing overland flow works or a new water licence to take overland flow.

Certification should be carried out by (or under the supervision of) a registered professional engineer of Queensland (RPEQ) on behalf of the applicant.

RPEQs are required to exercise professional judgement in determining any matters, and the basis for decisions should be explained in the certification. The applicant is responsible for securing the services of a RPEQ and paying any associated fees.

Certification by an RPEQ results in 2 documents:

• a registered certificate
• associated supporting details contained in a report that have been 'certified' (verified and signed) by the RPEQ.

Certified documents

The certification documents included with the water licence application will be used by the Department of Regional Development, Manufacturing and Water to make decisions about the proposal. The certified documents must be signed by the RPEQ and the person who currently takes, or intends to take, the overland flow water.

A certified report must provide specification on overland flow structures including:

• details of works
• dimensions of works
• capacity to take overland flow
• any attached design or survey plans.

Certification does not have to include the entire property. The report can refer to the relevant section of the property when only a small portion of the development requires certification. It is important to show the hydrological connection between that particular development and any other developments on the property, either via a schematic diagram or a property plan.

Information to include

The following information could be included in the certification documents:

• a completed storage data table. If unavailable, the top water level (RL), crest (RL), inlet pipe (RL) and outlet pipe (RL) may be excluded
• a statement of the calculation method used in determining the capacity of works
• a statement of the sources of water held in the storage (e.g. overland flow, river allocation, bore water)
• a statement on the management of inflows and outflows from the storage
• long-section of the crest and justification of selection of crest (RL) including year of construction, details on maintenance and history of filling to capacity
• a storage capacity curve or table showing storage volume in megalitres versus water depth (AHD).

You may also need to provide an A3 schematic site or property plan:

• showing the location of the storage on the farm
• illustrating the flow path of overland flow in the vicinity of the storage (including tailwater return from fields)
• clearly identifying any proposed changes to overland flow paths where necessary
• locating and detailing any benchmarks
• marking where the point of capture and control point will be (i.e. pump, channel)
• marking the general inflow and outflow points for overland flow
• for larger proposals, marking where the low points are (RL in metres)
• 0.5m contours and all data points used in generating the contours
• crest length and width
• inside toe length and width
• multiple survey points along the inside crest, outside crest and inside batter toe at a maximum spacing of 10m
• internal natural surface at all changes in grade
• internal borrow pits at all changes in grade and alignment
• significant features such as bywash location and level, inlet and outlet pipes, point of entry of uncontrolled overland flow
• any other features that affect the determination of storage volume, including linkages with others storages.

Applications for a new water licence for overland flow water

Applications accompanying certification documents must be made on the relevant forms and include the required fee. Any applications are required to be submitted as part of the assessment process when lodging the certified report. If the authorisation is granted, the type and its specifications will vary depending on the level of certification and the department's requirements.

For more information, contact your local business centre.