Developments must provide adequate drainage for surface water.
Norfolk County Council will resist any development which involves surface water flowing onto the public highway from private accesses or non-highway areas.
Standing water must be drained away or it can pose a hazard and carry debris etc onto the highway to the detriment of highway safety.
Disposal of surface water from public highway
Disposal of surface water run-off from new highways within residential or commercial developments must be through a sustainable drainage system, which incorporates adequate anti-pollution measures where possible.
Usually run-off water is drained from highways directly to a watercourse, such as a river, through a network of pipes. This means that the water enters the watercourse very quickly. In an urbanised area with a lot of run-off this can lead to flood conditions when a lot of water enters the watercourse at once.
Urban drainage is changing to balance the impact of drainage on flooding.
Norfolk County Council seek to reduce the rate of surface water run-off through the use of Sustainable Urban Drainage Systems (SUDS), which may incorporate filter strips and swales, filter drains, permeable surfaces, infiltration devices and basins or ponds.
These systems are more sustainable than conventional drainage methods as they:
- Manage run-off flow rates, reducing the impact of urbanisation on flooding
- Protect or enhance water quality
- Are sympathetic to the environmental setting and the needs of the local community
- Provide a habitat for wildlife in urban watercourses
- Encourage natural groundwater recharge (where appropriate)
They do this by dealing with run-off close to where the rain falls, managing potential pollution at the source, and protecting water resources from point pollution (such as accidental spills).
SUDS should be approved by the adopting authority and where necessary also accord with the specifications of Norfolk County Council, as Local Highway Authority.
A commuted sum for future maintenance may be required.
The design and installation of private soakaways used to drain surface water from properties or private hard-standings must take account of the needs of the Highway Authority.
They must be positioned to not interfere with the stability or use of the public highway.
Drainage apparatus – distance from buildings/structures
In order to maintain the drainage infrastructure, Norfolk County Council requires a five metre-wide easement strip free from any obstructions along the line of all pipes or drains and around all drainage apparatus.
Exceptions will be considered on a case by case basis where the form of development proposed makes achieving this impractical, eg a high density urban development.
In these cases special measures may need to be agreed to protect the apparatus and allow future maintenance.