How to reduce highway project maintenance costs with sustainable drainage solutions

Maintaining a highway against both general wear and tear and more substantial natural calamities—like severe storms—is an expensive business.

So expensive, in fact, that it is common for authorities that own highways to simply repair them on a ‘make do and mend’ basis, rather than a planned one, with the result that minor faults accumulate into major ones and become more costly once large-scale maintenance becomes unavoidable.

Those costs will become even higher if works carried out in the past were piecemeal, and used products that can longer be easily accessed or which no longer work well together. In these situations, maintenance can be unpredictable, expensive and disruptive with sections of highways closed for long periods.

The issue of surface water

Surface water is an issue for design engineers both because it can damage highway surfaces and sub-surfaces but also because pollutants on the road will be carried by stormwater runoff into nearby watercourses and sewers, carrying damaging toxins into the environment.

At a time of rising public concern about the environment this is something for which any highway owner will wish to avoid being blamed. Low-maintenance surface water management solutions are available both for new highways and for retrofitting to older ones.

These go by different names: Low Impact Development (LID) in the US, sustainable drainage systems (SuDS) in the UK, and water-sensitive urban design (WSUD) in the Middle East, Australia and New Zealand.

Whatever the name, such design approaches can incorporate technologies such as flow controls, storage blocks, stormwater separators and filters that are easy to install, and with few moving parts easy to maintain, are designed for simplicity of installation and maintenance.

Some of these go further by using modern ‘smart’ technology. While it will be self-evident when a flood occurs, it will not always obvious when maintenance is required. Products enhanced with smart monitoring capabilities can, for example, use sensors to collect real-time data and send an automated notification to the project owner when maintenance is required. 

Once equipped with this information the project owner can see trends in the data supplied and assess accurately what is going on and whether some intervention is needed, or whether whatever is happening does not require immediate attention. This means that in normal circumstances maintenance can be planned ahead rather than being reactive to sudden problems or based on regular callouts which may miss the problem.

Finding the right solution

The Hydro International Water Management Hub is where information can be found on the right product for each engineering situation, ones that are simple to install, need minimal maintenance and are tried and tested in many parts of the world.

One example is Downstream Defender®, which captures and retains sediment, oils and floatables from stormwater runoff in a small footprint. It is an advanced hydrodynamic vortex separator that is compact, low-maintenance and enables engineers to deliver effective pollutant removal at a single point in the drainage system.

First Defense® also captures and retains stormwater sediment, trash and floatables in a unit that saves site space and adapts to smaller or logistically difficult locations. First Defense® is a stormwater separator with the highest approved flow rates in the United States, enabling engineers and contractors to save space and costs by using the smallest possible footprint. It also works with single and multiple inlet pipes and inlet grates and is easily maintained from the surface by standard vacuum tanker.

Up-Flo® Filter can capture sediment, heavy metals, oil and nutrients from stormwater in an advanced treatment system that combines sedimentation and screening with filtration to deliver exceptional surface water pollution removal.

The Up-Flo® Filter was developed in collaboration with the US Environmental Protection Agency and has been verified to remove 80 per cent of total suspended solids, but with demonstrated removal rates up to 98 per cent.

Hydro-Logic® smart monitoring systems collect real-world data to provide notifications for inspection and early warning of flooding, automatically receiving data from remote Hydro-Logic data loggers. These enable managers to inspect data outputs, identify potential system blockages and flag up changes in environmental conditions that could indicate an imminent flood event.

These systems can also manage any automated alerts that have been configured, distributing them via email or SMS to designated recipients to provide early warning of risks. Hydro-Logic® Timeview is an online data processing, early warning and alarm platform able to store up to 12 months of data.

The ‘front end’ of such smart monitoring systems are the Hydro-Logic® data loggers, which provide both the real-time insight and long-term big data to inform better decisions.

They gather a range of hydrometric, environmental and climate data and transmit it wirelessly for visualisation, alerts or integration into systems, and are designed to operate remotely in difficult environments, and with battery lifetimes of up to seven years.

Working with a partner such as Hydro International will allow highway managers to keep storm water problems under control with advice and support and equipment that is simple and economical to install and maintain.