Flood response - highways

Flooding and road drains (gullies)

Heavy or prolonged rainfall can sometimes overwhelm road drains (known as gullies), causing surface water flooding. If the water drains away once the rain stops, it usually means the drainage system is working as intended but could not cope with the quantity of rainfall.

Staying safe during flooding

If you encounter floodwater:

• Avoid walking or driving through it. It may be deeper or faster moving than it looks
• Do not lift manhole covers or attempt to access drains unless authorised. This can be extremely dangerous and may make flooding worse.
• Call 999 in an emergency
• The Environment Agency warnings and alerts (opens in a new window) website provides information on your flood risk and how to stay safe during a flood event.

How road drainage works

Keeping roads clear of surface water is one of our main objectives. Gullies are designed to carry away rainwater, but extreme rainfall can cause gullies to be overwhelmed. In addition, leaves, litter, and debris can block gullies and reduce their effectiveness. This can lead to surface water flooding.

Water from gullies flows into public sewer systems or local watercourses like ditches, streams, or rivers. These usually carry water away as intended but problems can occur when water levels rise. High water levels downstream can limit flow out of the system. This back up of water can lead to surface water flooding.

You can find more information and report issues on our gullies and drainage page.

What happens after a flood

We will assess any damage caused to the highway network after flood and adverse weather events. Our recovery work can range from whole scale reconstruction of parts of the highways, to more minor damage repairs and clear up operations (additional gully emptying, jetting and road sweeping etc).

Improving drainage for the future

We regularly review and improve drainage systems as part of our long-term planning. Each year, we deliver targeted upgrades to help make roads more resilient to future weather events.

Highway drainage improvements are prioritised through our asset management approach, with planned schemes delivered annually.