Stormwater management

IDENTIFYING THE POINT OF CRITICALITY

WHILE UNKNOWNS ARE A PRODUCT OF A CHANGING CLIMATE, SUNSHINE COAST COUNCIL IS TAKING STEPS TO BETTER INSPECT ITS ASSETS IMMEDIATELY BEFORE, DURING AND AFTER A MAJOR STORM OR CYCLONE.

It is clear that knowledge of the past is no longer a valid basis for making projections about the future,” writes a 2010 research paper on incorporating climate change into asset management by the London School of Economics and Political Science.

Although the world has changed a great deal since then, the report highlights that while the science on man-made climate change in near unequivocal, the capacity to project the trajectory of local climate for a given mitigation framework is limited.

Faced with these challenges, engineers and asset managers must make effective use of limited capacity to accurately project environmental conditions over the lifetime of their assets.

Navigating these challenges also means undertaking an appropriate risk management strategy accessible to all asset owners, a process explored by Sunshine Coast Council through the development of a critical assets database. “

In early 2012, after a period of significant rainfall events, Sunshine Coast Council identified a need to undertake a study of the region where stormwater assets would be impacted by major storms..

Andrew Priest, Asset Management Engineer at Sunshine Coast Council, explains widespread flooding of the region saw multiple roads blocked.

“We spoke to a couple of external stakeholders within council and emergency crews and what we got back is that there was a lot of overland flood areas with reinforced box culverts,” Mr. Priest says.

As the region continued to experience flooding over the years, in early 2017, Sunshine Coast Council decided to undertake a study of stormwater assets.

The council wanted to know where stormwater assets may be significantly impacted by a major storm event. A critical asset was defined as an asset likely to result in a more significant financial, environmental and social cost and affect

Sunshine Coast Council wanted to know which stormwater assets may be impacted by a major storm event.

organisational objectives.

Importantly, the council hoped to be in a position to inspect its assets immediately before, during and after a major storm or cyclone to be able to deal with potential flow impediments and minimise flooding.

Its key criterion comprised maintaining the safety and wellbeing of the community, financial risk, service delivery and engaging key stakeholders.

Critical to the assets were council-owned stormwater infrastructure consisting of pipes, pit, culverts, open drains, water quality and drainage easements and miscellaneous, valued collectively at $1.5 billion.

Mr. Priest says it was important the culverts were in a good condition and at a serviceable point. Additionally, the council wanted to know how many culverts it had and the areas it was drained. .

The initial development included undertaking desktop surveys of the council’s ArcGIS system to identify catchments that may have a more significant effect on local communities.

During the initial consultation phase, it became clear there was a need to expand the database to include other critical assets such as hospitals and community centres. Telecommunications facilities such as major switchboards, pump stations and water treatment plants were also prominent considerations. It was also clear from the early stages of the survey that a more detailed investigation was needed.

As such, a cross collaborative team of internal stakeholders was engaged to ascertain key assets and the units responsible for maintaining them. This comprised construction and maintenance services, the stormwater planning and policy unit and the Sunshine Coast Council Disaster Management Team.

Mr. Priest says one of the biggest challenges

is managing older networks that were not fit for urbanisation. For example, some of the older culverts proved to withstand tough conditions compared to newer ones.

“The big issue is we’re trying to keep pace with development, we’ve got these older networks that are legacy assets,” Mr. Priest says.

Part of the initial development was also to identify key assets, relevant asset owners and their respective responsibilities. This meant understanding the interchange of responsibility between asset owners.

“QLD Department of Transport and Main Roads have a lot of roads in our area with culverts but have our stormwater going through them, so it was also going back to Main Roads and noting that it may affect their roads if a culvert collapses,” Mr. Priest says.

Mr. Priest says it’s important to ascertain the age of the asset, which is why council takes samples of these. Additionally, weather factors such as the council’s coastal location plays a role in asset lifespan.

A gap analysis helped to inform which areas needed more resources. The Australian Road Research Board also supported a review of the culverts.

A contractor was engaged to undertake a comprehensive review of existing assets to facilities and road networks to access these facilities, in addition to an assessment of stormwater assets. External stakeholders such as State Emergency Services and Queensland Police Services were included as part of the scope of works.

Some of the key objectives in the development of the database were to ensure a defined level of service and implement a lifecycle approach.

Additionally, it was important to develop cost-effective management strategies for the long term, manage the risks associated with asset failures and ensure a sustainable use of physical resources.

All trunk collector roads were included in the assessment.

Once the contractor had received the information, a register was developed listing all possible affected facilities and assessed against Sunshine Coast Council’s flood modelling system.

Stormwater assets were assessed only if they were negatively affected by at least one flood model.

Digitally accessible local maps were compiled to identify stormwater assets onsite and present the flood modal affecting the critical facility or road. The register included details of stormwater assets located on and directly downstream of the facility property. It is now available to all council employees and has been introduced as a vital source of information for Council Disaster Management team.

In terms of next steps, the assets register continues to be worked through with a set criteria based on general criticality conditioning. In the meantime, the council has a robust model allowing for critical assets to be easily surveyed and paid attention to during large storm events.

“The take home message is you’re not going to get it fixed overnight.

“Don’t try to solve it in one hit or throw unrealistic objectives at your executives or leadership team and contractors. It’s an ongoing process so knocking out those little milestones can be a positive way to go,” Mr. Priest says.

Built Australian. Built tough

Humma is the only Australian made and owned pick & carry crane. Manufacturing since 1996 the flagship model is the high capacity Humma 55.25. With 55 tonne capacity and the patented self levelling suspension, Humma 55 is both the highest capacity articulated pick & carry crane and safest in the world. Manufactured – Perth, W.A.