Events

Technical Presentation

Implication of Urban Baseflow on Stormwater Management

A common characteristic of urban catchments within highly seasonal climatic regions, is the presence of a constant base flow within stormwater pipes and open drains. There can be multiple sources of this dry season flow however, natural groundwater seepage and excess irrigation within the catchment are key contributors. Our observations across Darwin and Townsville suggest that urban base flow is a significant risk which can lead to the failure of vegetated systems (in particular bioretention basins) due to over-saturation of soils and surface ponding. The goal of this investigation is to broaden our understanding of urban catchments in seasonal climates by deeply exploring what we observe and using this information to inform stormwater management responses.

Dylan Cain is a Registered Professional Engineer of Queensland with extensive experience in the areas of Urban and Environmental Civil Engineering. Positive outcomes are important to Dylan, and he has provided an outstanding level of service to a wide range of clients from masterplan phase through to detailed design and project supervision. He has a particularly strong base of technical design ability, to integrate innovative Water Sensitive Urban Design within Standardised Civil Engineering Documentation. Dylan is also very interested in emerging trends and technology and is a participant in the CRC for Water Sensitive Cities.

Free Pizza Boards and a Free Drink on Entry

For those who couldn’t make it to Cairns for the SQ conference late last year, we’re featuring some of the highly-rated presentations, including further updates and developments. Part one is on 19 February and will feature two presentations, followed by Part two on 19 March (mark that date in your calendar) with a further two highly-rated presentations (registrations will open in a week or so for part two).

Speakers and Topics

Ocean Plastic – the pressures and solutions that (almost) no one is talking about

Brad Dalrymple, Principal Environmental Engineer; and Jeremy Brown, Co-Founder, Ocean Protect

A recent survey of 1,000 Australians nationwide demonstrated that the highest concern of all Australians with regards to population growth is marine and waterway health – ahead of housing density and traffic. The survey also found that almost six in ten (57 per cent) of Australians are not satisfied with the health and cleanliness of their waterways such as creeks, rivers, ocean. The amount of plastic in our oceans and waterways is a key and growing public concern, and it is predicted that there will be more plastic in the oceans than fish by 2050.

Ocean plastic has devastating consequences to marine life. Many marine organisms cannot distinguish common plastic items from food. Animals who eat plastic often starve because they cannot digest the plastic and it fills their stomachs, preventing them from eating real food. For example, approximately 80 percent of seabird species have plastic in their stomach, A recent study of juvenile sea turtles from around the planet also found plastic in the bellies and digestive systems in all of the 100 turtles studied.

The survey, however, also identified that Australians do not know what the largest source of this plastic pollution, with ‘stormwater runoff’ (the source of approximately 80% of marine plastic) thought to be a minor source. Within Australia, stormwater is also the primary cause of degradation in our urban waterways.

The impact of stormwater runoff within Australia is due to a combination of factors: (i) high pollution generation rates in urban areas; (ii) the vast majority of urban areas have no stormwater treatment systems; (iii) where stormwater treatment systems are integrated, these assets receive minimal (and often zero) maintenance (e.g. to remove accumulated material).

To mitigate the impact of stormwater runoff within Australian waterways (and the ocean), study authors propose a range of actions, including:

• Increased community awareness and education in relation to the primary source of ocean plastic (i.e. stormwater)
• Transition away from single use plastics, supported by appropriate education.
• Enforcement of Government legislation requiring appropriate evaluation, monitoring and maintenance of stormwater control measures (and associated reporting)
• “Zero trash to ocean” targets established across Australia, requiring (as a minimum) full capture devices for all urban areas to capture all particles less than or equal to 5mm in diameter during a typical storm.
• appropriate funding to facilitate the aforementioned recommended actions via an appropriate ‘ocean protection levy’ (or similar).

Adaptive Asset Management – a pathway to better stormwater management

Ben Penhallurick, Environmental Scientist, Renew Solutions

In Australia, governments and utilities own and manage infrastructure assets to provide services to their customers (i.e. the public). This includes assets whose management is simple and predictable like footpaths and roads. It also includes assets whose performance, outcomes, and management requirements are complex, highly variable, and not yet fully understood.

An example of a complex asset can be found in bioretention systems. The management of these assets has and continues to be a challenge for governments around Australia. In particular, governments have struggled to keep up with the maintenance required to ensure assets are kept in a good and working condition. It appears that this has been driven by the following.

1. The large amounts of assets handed over to government ownership as part of urban development projects.
2. The often unpredictable performance, outcomes, and management requirements of assets.

It also appears that, by and large, governments don’t undertake long-term monitoring on their assets to understand what’s required to manage them to ensure they’re performing as per design expectations and achieving desired outcomes. That is, management doesn’t appear to be evidence-based and guided by an understand of what’s happening with assets in the real world. This lack of evidence-based management may be at least partly responsible for the difficulties in maintaining assets as well as their high failure rates in the real world.

This presentation will introduce the adaptive asset management framework as a potential solution to the above. Adaptive asset management is a framework to support the evidence-based management of complex assets. It is a hybrid framework combining the core principles and processes of infrastructure asset management, used ubiquitously by governments across Australia, and adaptive management, historically used in ecosystem management for conservation purposes. The framework has been conceptualised to overcome some of the issues affecting the management of complex assets like bioretention systems including the following.

1. A lack of evidence-based management owing to the absence of long-term monitoring to evaluate performance, outcomes, and management requirements in the real world.
2. A lack of technology to support evidence-based management.

The presentation will provide an overview of how the adaptive asset management framework could be applied by governments in the context of bioretention systems and other complex stormwater assets. It will then present plans for a case study in South East Queensland before concluding with a discussion on the significance of the framework for the stormwater management industry.

SQ Conference – Brisbane Roadshow Part 2

For those who couldn’t make it to Cairns for the SQ conference late last year, we’re featuring some of the highly-rated presentations, including further updates and developments.

Event Sponsor – Hydrorock 

“Keep the water where you need it the most.” That is the mission of Hydrorock Australia.

Learn More – Hydrorock Australia Brochure

Speakers and Topics

Assessing the Impact of Urban Development on On-site Stormwater Detention on Regional Hydrology

Dr Rodney Ronalds, Principal Engineer, Michael Bale & Associates

Urban development is a contributor to increased peak runoff and adverse hydrologic effects in regional catchments. On-Site Stormwater Detention (OSD) is a common way to mitigate these problems, however it is well known that OSD can have the opposite effect when it is installed at inappropriate locations. Parameter uncertainty and the need for a probabilistic approach to hydrograph generation are also factors that add to concerns regarding our reliance on OSD for the protection of regional hydrology. This study contributes to awareness of these issues and a practical solution to the problem. A hydrologic model for Monte Carlo simulation of regional catchment hydrographs has been developed using interrelated modules based on previous studies. A sample of ten regional catchments has been modelled with three simulation scenarios: i) status quo, ii) a land parcel of varying sizes is urbanised at varying locations within the regional catchment, and iii) the urbanised land parcel includes OSD. The focus on the results has been the identification and analysis of two key parameters that influence the regional catchments’ peak runoff, being the size and location of the urbanised land parcel. A regression analysis of the model results has revealed recurring patterns that have been used to develop new equations for predicting the mean impact of urbanisation and OSD on regional catchment peak runoff. The study highlights the significance of rainfall pattern uncertainty and the importance of considering land parcel location in considering the need for OSD as part of urban land development projects.

Looking Forward: considering climate change and variability in managing the Great Barrier Reef

Lisa Walpole, Water Resources Engineer, Alluvium Consulting

It is widely acknowledged that climate change is one of the greatest threat to the Great Barrier Reef (GBR). In response, the primary focus of plans, strategies and actions to date has been to increase system resilience to shocks and pressures that may be exacerbated by climate change, such as improving water quality and managing invasive species. But is this enough? Following recent, unprecedented coral bleaching and extreme runoff events, the need for action which considers the future climatic state, rather than managing the system as a static state, has become apparent and the management response is beginning to reflect this need with a new sense of urgency. This presentation explores the outcomes of an evaluation of the current GBR management response at the strategic and operational level, and opportunities for targeted management responses which better reflect the future climate state and the multiple dimensions through which climate events threaten the condition of the reef. It will also reflect on outcomes of the Great Barrier Reef Foundation investment pathways prioritisation process, and the QWMN review of how climate change and climate variability is being represented in water models across Queensland to support decision making which considers a range of future climate states.

If you are not currently a Stormwater Queensland member, you might like to consider joining SQ and attend this and all other events at the discounted member rates, along with enjoying additional value as a member – apply online now at http://stormwaterqueensland.asn.au/about/membership/ and then attend this event at the Member rate.

Topic:  Looking Forward:  considering climate change and variability in managing the Great Barrier Reef

Presenter: Lisa Walpole, Water Resources Engineer, Alluvium Consulting

Date:  Thursday 23 April 2020

Time:  2.00pm – 2.45pm

Presentation Summary:  It is widely acknowledged that climate change is one of the greatest threat to the Great Barrier Reef (GBR). In response, the primary focus of plans, strategies and actions to date has been to increase system resilience to shocks and pressures that may be exacerbated by climate change, such as improving water quality and managing invasive species. But is this enough? Following recent, unprecedented coral bleaching and extreme runoff events, the need for action which considers the future climatic state, rather than managing the system as a static state, has become apparent and the management response is beginning to reflect this need with a new sense of urgency.  This presentation explores the outcomes of an evaluation of the current GBR management response at the strategic and operational level, and opportunities for targeted management responses which better reflect the future climate state and the multiple dimensions through which climate events threaten the condition of the reef. It will also reflect on outcomes of the Great Barrier Reef Foundation investment pathways prioritisation process, and the QWMN review of how climate change and climate variability is being represented in water models across Queensland to support decision making which considers a range of future climate states.

Registration:  This webinar is free of charge to all.  To access the Webinar, open up this link (when the meeting is ‘open’) .. https://teams.microsoft.com/l/meetup-join/19%3ameeting_MWY2ODk4ZGUtNjViYi00ZjkwLWJlZTEtMDYxODEyOThlNTk5%40thread.v2/0?context=%7b%22Tid%22%3a%2286f6a188-653f-4171-8a75-b35ab0f3509f%22%2c%22Oid%22%3a%229a302fe2-748d-4c98-8197-f39cfcdde7f9%22%7d

Topic: (Im)probable Maximum Flood

Presenter: Rick Dennis, Principal Engineer, Allan & Dennis.  Rick specialises in hydrology, hydraulics, water quality, flood management and stormwater infrastructure

Date:  Tuesday 26 May 2020

Time:  1.00pm – 1.45pm

Presentation Summary: Flood design approaches have recently changed from standards-based (ie Defined Flood Level) to risk-based (probability and consequence).  This has resulted in the requirement of rare flood consideration up to the Probable Maximum Flood (PMF) for most applications.  Whilst the PMF appears a simple enough concept, in practice its consistent estimation is difficult.

Furthermore, a PMF cannot be assigned a specific probability (as it is a function of catchment area), and therefore not strictly appropriate to a consistent risk-based approach.  Moreover, with the recent Australian Rainfall & Runoff (ARR) 2019 update, there is an even greater disconnect between design event and PMF methodologies.  The concept of ‘reasonableness’ with respect to PMF is advocated in ARR2019.  However, as engineers are generally conservative, the adoption of the PMF for design approaches are becoming more common.

This is resulting in disproportionate costs and significant restrictions in development and that would otherwise be appropriate to the flood risk.  A short introductory presentation will summarise current best practice methodology, recent implications, and other design standards in order to provide a basis for an interactive and robust discussion with all attendees.

Registration:  This webinar is FREE of charge to all & will be recorded and made available after the session.  To access the Webinar, simply open this link at 1pm on May 26:

Topic: How stormwater can deliver cooler greener cities

Presenters: Kim Markwell – Associate Environmental Scientist of E2Designlab, Chris Tanner – Regional Manager of the CRC for Water Sensitive Cities & Luke McPhail – Integrated Water Management Specialist of Water Technology.

Date:  Thursday 11 June 2020

Time:  1.00pm – 1.45pm

Presentation Summary: A growing body of research is demonstrating the linkages between human health and wellbeing and creating cooler urban environments by retaining water in the landscape. This is where stormwater can play a major role in designing liveable cities.

In this webinar Kim Markwell (from E2Designlab) will investigate the drivers to consider urban cooling and demonstrate the multiple benefits which can be achieved through adopting principals of water sensitive cities. Kim will also introduce “Designing for a cool city: Guidelines for passively irrigated landscape”, the newly released national guidelines which looks at considerations for design, construction and maintenance of these systems.

Chris Tanner (from the CRC for water Sensitive Cities) will use a current case study at Norman Ck, Brisbane to showcase the use of CRCWSC tools for economic frameworks, infill development typologies, urban heat and water cycle investigations using a timeline of “Now, New and Next”.

Luke McPhail (from Watertech) will present a demonstration of the newly released Scenario Tool which brings together a range of data sets including climate, demographics and landform in an online GIS platform. Various planning scenarios can be assessed through metrics including Water Balance, Land Surface Temperature and Thermal Comfort.

Registration:  This webinar is FREE of charge to all. Follow the link below to register:

Topic: Challenges in transitioning to Sustainable Stormwater Practices: Insights from the Investigation of Stormwater Control Measures Maintenance in Melbourne

Presenters: Andrew Thomas – Vice President, Stormwater NSW

Date:  Thursday 25 June 2020

Time:  1.00pm – 2:00pm

Presentation Summary: The expansion of urban development across the globe has brought with it significant environmental impacts. Prominent amongst these impacts is the degradation of marine and freshwater environments caused by conventional approaches to stormwater management infrastructure that facilitate the rapid conveyance of untreated stormwater to waterways. Stormwater control measures (SCMs) are a sustainability innovation developed to redress these environmental impacts. However, there are growing concerns that SCMs are not receiving sufficient maintenance and that, consequently, their long-term performance may be compromised.

This study sought to gauge the veracity of these concerns and ascertain the barriers and challenges to the maintenance of SCMs. Nine local councils in Melbourne, Australia were engaged to provide condition data for their SCMs and access to their professional staff to collect perspectives on the barriers and challenges to SCM maintenance. 55 inter-dependent barriers and challenges were identified across nine sociotechnical categories, confirming SCM maintenance as a complex multi-causal sociotechnical problem, and one potentially symptomatic of a loss of momentum towards mainstream adoption. Termed Failure to Thrive, this loss of momentum is considered a function of three over-arching issues: An under-developed stormwater industry, government policy inertia and, importantly, the invisibility of SCMs in the community.

Three ‘intervention pathways’ are postulated to redress shortcomings in the maintenance of SCMs by Victorian local government and, likewise, address the Failure to Thrive scenario. An alternative transition pathway for Sustainability Transitions is proposed that accounts for the complex path-dependencies involved in the transition of sustainable innovations like SCMs and the need for pro-active institutional work accordingly to minimise the risk of partial or total failed transitions.

Registration:  This webinar is FREE of charge to all. Follow the link below to register:

Topic: A Blueprint for Improving Waterway Management

Presenter: Glenn Browning – Civil Engineer at Healthy Land and Water

Date:  Thursday 9th July 2020

Time:  1.00pm – 1.45pm

Description: Glenn’s presentation will be on the recently released SPP Review – A Blueprint for Improving Waterway Management. This is an informal document, whose purpose is to prompt discussion and interest regarding future recommended improvements to the State Planning Policy (SPP) – Water Quality State Interest. While SPP amendments are just part of the solution, complimentary recommendations have also been made to improve waterway management more broadly.
The Blueprint for Improving Waterway Management is based on foundational research by Alluvium as well as interviews with many key stakeholders in the stormwater industry. The document proposes 12 strategies across three themes: Protect, Maintain and Enhance. This paper was sponsored by the Department of Environment and Science and is for discussion purposes only. You can directly download the document here.

Topic: Why we should change what the guidelines, codes and specifications say about Manning’s n in the design of grass-lined and rock-lined channels

Presenters: Martin Jacobs – Principal Hydraulics Engineer at Pitt&Sherry

Date:  Thursday 23rd July 2020

Time:  1.00pm – 1:45pm

Description: Most guidelines, codes and specifications include tables of fixed Manning’s n values for different types of channels. A few include references to vegetal retardance types, but these are rarely used in practice. It is rarely recognised that Manning’s n varies with depth and that the values used for shallow flow should be much higher than deep flow. This often results in the adoption of inappropriate, low values in the design of shallow grass-lined and rock-lined channels such that the resulting channels could be one third, one quarter or one fifth the size required to convey the design flow. The dynamics of design-and-construct procurement of infrastructure pressure designers into adopting the most favourable, lowest possible value of Manning’s n, which are justified by placing onerous maintenance burdens (mowing) on asset owners.

There are established techniques to estimate the values of Manning’s n for grass-lined and rock-lined channels, based on the underlying theory and empirical experiments. Although they are tedious to work out manually, they can be completed computationally and Martin has developed a program.

By re-writing the codes, guidelines and specifications to recognise the depth-varying nature of Manning’s n, not only will there be better outcomes for design, but also asset owners can balance the competing demands of capital costs and maintenance and continuity can be achieved with water sensitive urban design, which favours the use of grass-lined channels with low velocities.

Registration:  This webinar is FREE of charge to all. Follow the link below to register:

Hosted by Stormwater Queensland and Stormwater Victoria, and sponsored by Wave Maintenance.

Topic: WSUD audit, maintenance and rectification insights for assets 5-15 years old.

Presenters: Ralf Pfleiderer – Director at Wave Maintenance

Date:  Thursday 17 September 2020

Time:  12.30pm – 1:30pm

Description: This seminar will cover a range of design and construction suggestions gleaned from years of observation and auditing systems, and more recently of maintaining and rectifying raingardens, tree pits and biofilters as part of stormwater harvesting  systems. Over the last two years, as director of the new WSUD maintenance company, Wave Maintenance based in Melbourne, Ralf Pfleiderer has been getting up close and personal with mainly assets, doing monthly and quarterly cleaning. This gives you a great insight into how quickly inlets block and sediment accumulates. Over the last two months Wave Maintenance have also rectified over 60 assets ranging in design styles, ages, catchments types and maintenance regimes. The seminar will present aspects that make maintenance easy (and therefore the assets perform well), what designs reduce failure and blockages and what not to do again in the future.

Registration:  This webinar is FREE of charge to all.

About The Presenter: Ralf Pfleiderer is a well-respected leader in stormwater across Australia, with over 20 years’ experience in the industry, across public and private enterprise. Ralf is an Environmental Engineer applying his engineering skills within a landscape, green infrastructure and open space context. Ralf has been involved in delivering all stages of WSUD assets from policy to design, undertaking or managing the construction and maintenance to monitoring and auditing a range of large and small WSUD assets for local governments, Melbourne Water and developers. Ralf runs his own consulting practice as well as being a hands-on director at Wave Maintenance.