Old school asset condition assessment still has a place

No argument, technology has and continues to provide better and better tools for gathering information, interpreting it and applying that knowledge to our systems. But methods and methodology should be fit for purpose – one size does not fit all.

Small to medium-sized regional water service providers often have poor stored data, limited budgets and efficiencies of scale. They are often isolated and lack knowledge of what is out there or how to find out. But they know their networks well (part of our human resources); staff have a good “feel” for how things work and are resourceful, if not always highly skilled. But they work in a framework generally developed with/for larger organisations.

We all display an interest in the latest shiny thing. We are often an easy sell for salesmen of the latest tools, without necessarily doing our own research and – more importantly – analysis of how well it suits our needs. And that is a good thing in many ways. But something that has worked for many years does not become useless overnight. We can prolong the asset life of our asset management tools, just like we try to do with our operational assets.

Smoke testing

At Burdekin Shire Council (BSC), after relining our older gravity sewer network and regular inspection by CCTV, we learned we may have overestimated the asset lives of our new linings. And worryingly, the extra network capacity created was now filled by infiltration from private house drains.

SCADA shows we have a big problem with illegal inflows.

Figure 1: SCADA showing obvious signs of inflow from illegal plumbing or private assets in poor condition

In response, BSC has commenced a series of sewer inspection programs, including smoke testing of all gravity assets. This carries a considerable initial administrative overhead including quarterly Council resolutions, notification letters for customers and fire services, door knocks and considerable compliance follow-up letters and customer engagement. A skilled crew (3-person team) is essential, but equipment and material costs are minimal.

BSC has been successful in discovering illegal and non-compliant plumbing. At the same time, we inspect and install underlid seals for all manholes with warning signs about tampering with Council’s infrastructure.

This minimises stormwater inflows to the network via manhole lids in our flat delta catchments and is noticeable in pump station behaviours in rainfall events.

Figure 2: The smoking unit in operation over a manhole

Figure 3: Pool connected to network without plumbing to code

Figure 4: Badly damaged house drain identified by smoke flag

Leak detection

It is not unheard of to find up to 35% losses in regional networks. This can be largely accounted for by just a couple of serious leaks in the network; up to 85%.

These leaks can be discovered and located with minimal overheads and no dedicated staff resources. But consistent effort is required to maintain a low level of loss.

In just a couple of weeks at the commencement of BSC's program, in AC mains areas we had found: one moderate leak, one service leak, one illegal connection, and a service we did not know about. It has proved well worthwhile to continue with.

Figure 5: Example of software displaying leak data and suggesting possible problems

If you are a small or medium water service provider, I would encourage you to give these tried and true methods a try, rather than staring longingly at what bigger water service providers are doing and wishing you had the resources to imitate them.

You can achieve the same results in different ways.