Guernsey Water has a long-running and successful scheme for surveying and relining old drains before they collapse, which saves money and reduces disruption.
This relies on historic data and regular checks. There is limited information of the drains around Clifton and Constitution Steps, but that has been changing.
Guernsey Water staff have been undertaking checks in the area this week.
Capital delivery manager Carl Falla said it was important to fully understand the drains.
‘We do have some information, but not a full picture,’ he said.
‘And we need to have a full picture to know what we are working with. We know where most of the drains are, but part of this work is to identify the ones we don’t know about.’
It is believed the drains were built about the mid-1800s. It is not that unusual to not have detailed information on drains in Guernsey.
‘We don’t have a huge number of records,’ Mr Falla.
The drains are made of a mixture of old brick and clay pipes, but exactly what is going where is less clear.
Normally the Guernsey Water team take a van to a manhole cover, and then run the CCTV robotic units into the hole on an umbilical cable, where it can be remotely driven and images transmitted back to the vehicle.
But that is not possible around Clifton and Constitution steps. Instead the kit has to be carried down to the nearest access point.
‘It is quite a challenging area,’ Mr Falla said.
So far the checks have found the drains to be in a reasonable condition. But if work was needed, access would be difficult, so it is helpful to be prepared.
There is a variety of sizes of pipes around Town, up to 800mm in diameter. But the drains around Clifton are some of the smallest ones, ranging in size to 150mm to 225mm.
Work was due to take place last week, but heavy rain meant it had to called off. Within Town the surface and sewage drains are often combined, and if workers had tried to survey last week, the large amount of moving water would have obscured the view.
Surveys will be going on at Clifton Steps, Constitution Steps and Arcade Steps.