Highways and byways: Prevention is better than cure for gullies

A highway gully — sometimes spelt ‘gulley’ — is a drainage point typically covered by a metal grate at the side of the road. The gully is connected to the surface water sewer and its job is to take away excess water from the highway.

Gullies may discharge, ultimately, into drains, ditches, watercourses or sewers. Most, especially in urban areas, connect to the public sewers which carry both foul and surface water. Whilst responsibility for highway gullies usually rests with the local highway authority, the sewer itself comes under the remit of the incumbent water and sewerage company (WSC).

Dirty-DrainYou would not give them a second glance, most probably, but these roadside gullies play an important part in our everyday lives. Everyone knows that wet roads provide dangerous driving conditions, so it is obvious that if surface water is allowed to accumulate — a situation known in the trade as ‘ponding’ — driving would be hazardous to say the least. Good drainage improves stopping distances for vehicles, and keeps pathways and roads free of puddles making it safer for pedestrians to cross — and reducing the possibility of getting drenched by passing cars. On top of that, blocked gullies can produce unpleasant odours. Clearly it is in everyone’s interest to make sure they operate effectively. And that means the gully should be regularly emptied of silt and debris, checked and cleaned, to minimise the risks of water causing a hazard.

As a rule of thumb, most authorities clean each gully once a year — more in areas which are at high risk, whether that is for flooding generally, or of being more likely to collect detritus, for instance the presence of roadside trees or the repeated spreading of salt and grit in Winter. Of course, it is not always a blocked gully which causes ponding. Heavy bursts of rain or prolonged steady downfall can ‘fill’ the sewerage system so the water backs up in the gullies to cause the ponding or flooding. This may not mean that the gully is blocked, simply that the whole system is overloaded. As the waters subside, the gullies will resume normal operations. It’s worth noting too that standing water in gullies is part of the design, not a sign of it being blocked: the water trap is there to prevent foul odours venting back into the atmosphere.

Highway authorities have a duty of care to maintain roadside gullies — something best done using specialist technology which combines powerful vacuumation with high-pressure water jetting. Many highway authorities look to specialists like Lanes for Drains to carry out rolling maintenance programmes with its fleet of advanced super jet vac tanker units and teams of experienced technicians.

The contracts may be all year round and take in a full region, or simply cover specific areas and phases — like the most recent win for Lancashire County Council which will see Lanes service 2500 gullies in just under two months.

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