Drainage - Help and advice
Good drainage is very important for the safety of road users.
Getting water away from the road surface is crucial, as flooded
roads can be dangerous, and even a thin layer of water in winter
may well freeze.
Water also causes maintenance problems, as it can soften the
ground under a road, which will allow it to flex and even break
up
Most of the larger roads in the County, and those in urban areas
have drainage systems, with road gullies catching the water and
pipes carrying the water away to watercourses or soakaways. On most
minor rural roads, there is little formal drainage, and the water
is allowed to run onto the verges, or sometimes into roadside
ditches, through channels (called “grips”).
Road gullies have a sump which traps the material washed into
them, so that the water flowing in the pipes is not obstructed by
accumulations of silt and other materials. This means that the road
gully sumps have to be cleared from time to time, to remove the
silt etc.
Most road gullies have fairly large sumps, which means that
emptying once or twice per year is sufficient to keep the system
operating efficiently. However, some old gullies (usually in the
old parts of towns and villages) require more frequent attention,
as the sumps are very small.
We sometimes need to do additional work following exceptional
weather when considerable quantities of soil can be washed into the
road gullies.
Flooding is a problem at certain locations, often where there is
no formal drainage system in place, although can occur when (for
example) gully gratings get blocked with rubbish such as plastic
bags. We use flood warning boards to draw the attention of drivers
to the presence of standing water on the road when the problem
cannot be cleared immediately.