Queensland Urban Drainage Manual 2017
WHO SHOULD READ THIS
- All those involved in urban stormwater management, including developers, engineers, planners and lawyers.
THINGS YOU NEED TO KNOW
- A new version of Queensland Urban Drainage Manual (QUDM) has been published. QUDM 2017 is responsive to the recommendations of the Queensland Floods Commission of Enquiring 2012, and also includes incremental changes for engineering best practice for urban stormwater management. Specifically, the lawful point of discharge test has been modified.
WHAT YOU NEED TO DO
- Developers, engineers and planners should familiarise themselves with the design methods and guidance on hydrological analysis set out in QUDM 2017.
New Lawful Point of Discharge ‘test’
The lawful point of discharge test has been modified to recognise that:
- minor changes to stormwater runoff are not necessarily required to discharge to a point under the control of a local government, and
- authority to discharge stormwater may involve dedication of a drainage reserve, an easement, written approval or statutory approvals.
QUDM has historically included a ‘lawful point of discharge test’ that has been used by Councils in development assessment. The former lawful point of discharge test required consideration of whether the stormwater is ultimately discharged to Council or State land in a way that does not cause a nuisance or damage to other property. This test helped Councils manage stormwater discharge from new development. However, the test caused some confusion in its application.
The new lawful point of discharge test is set out in section 3.9.1 of QUDM 2017. The due diligence assessment set out in section 3.5 of QUDM 2017 provides a process for addressing the full range of common legal issues associated with stormwater works. The lawful point of discharge test is one component of that due diligence assessment.
The lawful point of discharge test is a tool for minimising the risk of a complaint or claim of nuisance, through two means:
- confirming that there is not likely to be any substantial and unreasonable interference with stormwater, or
- obtaining informed consent from the landowners affected by the change in stormwater.
QUDM 2017 recasts the lawful point of discharge test to first explicitly require a consideration of the impacts arising from changes to the stormwater characteristics. Developers are responsible for ensuring their development is lawful and should:
- carry out a due diligence assessment of the land and local environment, and
- obtain expert advice from hydrologists and provide an assessment of the changes to stormwater including the diversion of stormwater, concentration of flows, changes in other flow characteristics and changes that may affect the future use of land.
This information may inform the discharge options, and whether land owner consent is required from the Council or a private property owner. Where a proposed development does not substantially or unreasonably impact on stormwater flows to other properties, it is not necessary to obtain a ‘lawful point of discharge’ from Council or a private property owner.
QUDM 2017 clarifies that stormwater may lawfully be discharged over private property if there is appropriate consent.
Importantly, it is the actual impact of the development, rather than the modelled stormwater outcome that is relevant to determining whether there is an actionable nuisance and assessing compliance with any easement or other consent.
The lawful point of discharge test in QUDM is merely a guide for engineers, developers and Councils. The specific provisions of any easements, reserves, consents and the applicable planning scheme provisions will override any general advice contained in QUDM.
New methods are provided for determining the time of concentration for urban waterways (rational method and stream velocity method), the initial sizing of detention basins and child safety around field (drop) inlets.
QUDM 2017 is supported by a new document ‘A Background to QUDM’ which is intended to provide explanatory information, science and theory to explain the design methods and guidance contained in the main QUDM document.
This publication covers legal and technical issues in a general way. It is not designed to express opinions on specific cases. It is intended for information purposes only and should not be regarded as legal advice. Further advice should be obtained before taking action on any issue dealt with in this publication.