Urban stormwater quality
Final draft October 2018 Implementation Guidance for Off-site Urban Stormwater Management
The final draft – October 2018 - Implementation Guidance for Off-site Urban Stormwater Management—State Planning Policy State Interest Water Quality 2017 Policy 5 (b)—Off-site stormwater quality management has been developed from initial consultation submissions to help achieve the outcomes of the State Planning Policy (SPP) State Interest: Water Quality 2017.
Final round consultation ended in November 2018.
Under the SPP State Interest: Water Quality, applicable development must meet post-construction stormwater management design objectives by managing stormwater, either on-site or off-site.
The aim of the implementation guidance is to provide local governments with information about how post-construction urban stormwater quality impacts from new development may be managed through off-site solutions.
Off-site management solutions (through a suitable alternative locally appropriate solution) provide flexible options for post-construction stormwater management design objectives.
For further information contact firstname.lastname@example.org.
Erosion and Sediment Control (ESC) capacity building workshops
A two million dollar Queensland Government program aims to help reduce the amount of sediment washing off building and construction sites and flowing into the Great Barrier Reef and Moreton Bay.
The Erosion Sediment Control (ESC) capacity building events are being developed by the department, Healthy Land and Water Ltd, the Local Government Association of Queensland, Master Builders Queensland and the Housing Industry Association (Qld).
The program includes:
- field days demonstrating best practice and emerging technologies such as high efficiency sediment basins
- training relating to the erosion and sediment control toolkit
- local information sharing workshops (Community of Practice)
- recent amendments to the State Planning Policy to improve erosion and sediment control measures during construction and through water sensitive urban design
- Information regarding graduated penalties for local government urban building site erosion and sediment control compliance programs.
Materials developed during the previous program – including online, mobile and App accessible ESC factsheets and iAuditor tool – aim to support the building industry to improve management practices and reduce sediment entering your local waterways, Moreton Bay and the iconic Great Barrier Reef. These resources are available on the Healthy Land & Water ESC Toolkit page.
The department has contracted Healthy Land and Water to coordinate delivery of the program in conjunction with industry and councils.
SPP Code: Water Quality
The State Planning Policy includes a SPP Code (Water Quality Appendix 2) that provides a Performance outcomes and acceptable outcomes to ensure development is planned, design constructed and operated to manage stormwater and wastewater in ways that support the protection of environmental values identified in the Environmental Protection (Water and Wetland Biodiversity) Policy 2019.
The SPP (Part E) contains interim development assessment (DA) requirements for some state interests including the State Interest-Water Quality. The interim development assessment requirements apply to the extent the SPP has not been identified in the planning scheme as being appropriately integrated in the planning scheme. ‘Part 2 State Planning provisions’ of the relevant local government planning scheme will identify if the Water Quality aspect of the SPP has been appropriately integrated into the planning scheme.
In making or amending planning schemes and designating land for community infrastructure, local governments must consider:
- the Principles in Part C of the SPP and
- all the plan making provisions outlined in Part D of the SPP ‘Making or amending a planning scheme or designating land for community infrastructure’.
The State Interest for Water Quality is that “The environmental values and quality of Queensland waters are protected and enhanced”. In order to achieve this Planning Schemes are to appropriately integrate the provisions in Part D of the SPP ‘Making or amending a planning scheme or designating land for community infrastructure relating to: Receiving water including urban stormwater management; development in water supply buffers areas in SEQ and Acid sulfate soils.
The SPP Code: Water Quality (Appendix 2) must be considered for interim development assessment for those triggered by the type of development (reconfiguring a lot, material change of use and operational works) and area of land to be developed (generally greater than 2500m2), until local planning schemes contain similar or equivalent provisions that ‘appropriately integrate’ the SPP Part D requirement including provisions reflecting the SPP Code: Water Quality.
Stormwater design objectives
A key element of the SPP Code: Water Quality are the ‘Design objectives’ for the construction phase and the post-construction phases of development, expressed in Table A and B respectively. Table A details the construction phase stormwater management design objectives.
Table A: Construction phase—stormwater management design objectives
Table A deals with the three critical element of Erosion and sediment control (ESC) on construction sites including:
- Drainage control—providing for temporary drainage around and through the work site for a specified storm event. A local government may specify an alternative storm event in its Planning Scheme.
- Erosion control
- Sediment control, as well as:
- avoiding and controlling litter and other contaminants that can be generated from construction personnel and vehicle on site
- avoiding or minimising impacts on receiving water stream flow during construction activities for frequent small flows (1 year ARI events) and larger flood flows (100 year ARI events).
Further information on construction phase erosion and sediment control.
Table B: Post construction phase—stormwater management design objectives
Table B deals with the pollutants known to be generated from developed urban land uses1. Through Water Sensitive Urban Design (WSUD) (see below) and the use of a stormwater quality ‘treatment train’ consisting of devices such as rainwater tanks, grassed swales, bio-retention basins and/or constructed wetlands increased pollutant loads from fertilising lawns etc.
The effectiveness of the stormwater treatment device can be predicted through software such as MUSIC—Model for Urban Stormwater Improvement Conceptualisation. Table B specifies the minimum reduction in mean annual loads from unmitigated development expressed as a percentage required for several climatic regions across Queensland for 4 key pollutants:
- Total Suspended Solids (TSS)
- Total Phosphorus (TP)
- Total Nitrogen (TN)
- Gross Pollutants >5mm.
The SPP State Interest – Water Quality must also be considered by local governments and Queensland Government agencies when designating land for community infrastructure (as defined in Schedule 2 of the Planning Act 2016.
1 Australian Runoff Quality: A Guide to Water Sensitive Urban Design. Wong, THF (Ed). 2006 Engineers Australia.
Derivation of stormwater management design objectives
Background information on the derivation of stormwater management Design Objectives used in SEQ over the last decade.
The Technical note: Derivation of Design Objectives summarises the technical studies used to derive the statewide water sensitive urban design objectives presented in Chapter 2 of the Urban Stormwater Quality Planning Guidelines 2010. Further technical notes could be developed as modelling and monitoring data are received and analysed.
Water sensitive urban design supporting documents
A Business Case for Water Sensitive Urban Design by the South East Queensland Healthy Waterways Partnership (Water by Design 2009) addresses the costs and benefits of meeting urban stormwater design objectives for managing stormwater quality, frequent flows and waterways stability. The benefits are shown to significantly outweigh the costs.
The Water Sensitive Urban Design Deemed to Comply Solutions—Stormwater Quality by the South East Queensland Healthy Waterways Partnership (Water by Design 2010) outlines a series of off-the-shelf stormwater solutions for meeting water quality design objectives for small-scale development in South East Queensland.
The Concept Design Guidelines for Water Sensitive Urban Design assists urban design professionals to conceptualise and develop design solutions that integrate best-practice urban water management into urban development.
- Environmental values—Environmental Protection (Water and Wetland Biodiversity) Policy 2019
- Engineers Australia 2006, Australian Run-off Quality; Guide to Water Sensitive Urban Design
- International Erosion Control Association (Australasia) 2008, Best Practice Erosion and Sediment Control
- eWater CRC, MUSIC Modelling
- Water by Design, Bioretention Technical Design Guidelines (Version 1.1, October 2014) provides an updated bioretention design resource and supersedes all bio-retention references in the 2006 guideline.
- Water by Design, Guidelines for Water Sensitive Urban Design
- City of Gold Coast Council, 2016 Guidelines for Dewatering Management Plan
- Sunshine Coast Council 2008, Manual for Erosion & Sediment Control (v1.2)
Locally derived design objectives including:
- Townsville CityPlan Planning Scheme Schedule 6 Planning Scheme Policy—SC22.214.171.124 Water sensitive urban design guidelines.
- Department of Transport and Main Roads, Technical Specification—MRTS52 Erosion and Sediment Control (January 2018)
For further information please contact the Healthy Waters Policy and Strategy Team:
- by email at email@example.com
- by mail to the Healthy Waters Policy and Strategy Team at GPO Box 2454, Brisbane QLD 4001.