There are a number of ways to drain roads, but gullies are the most common. A gully is a large pot covered by a metal grid, usually found at the edge of a road or in pedestrian areas.
They are used to collect surface water from the road or pavement and drain it into a piped system (generally a 'surface water sewer' maintained by Anglian Water), an adjacent stream or river (referred to as a 'watercourse') or a roadside ditch. They can become blocked by a build up of silt or mud coming off the road, or washed off nearby land.
Read our quick guide to find out information and details on cyclic and reactive drainage.
Cyclic and reactive drainage quick guide (PDF 505,KB)
If you'd like to read other guides similar to this, on highways topics such as highway emergencies, visit our quick guides page.