Flood Management – Conwy Valley
Levees
Description
Earth embankments of various sizes.
Can be natural or built. Usually
running parallel to the river course,
or set back from the river across low
lying land.
Function
Acting as a barrier to flood waters.,
controlling the spread of floodwater
across the floodplain. Situated
around priority areas such as Trefriw.
Other structural responses:
Riverside café on stilts
Structural response by local business owner to living on a
flood plain
Flood barriers near post office
Increasing the capacity of the Afon Bach and protecting
nearby properties
Household flood gates
Temporary defence protecting individual properties from
flood waters.
500m
Cost
£1million
When
Artificial Flood Culvert
Older levees 200.
New levees completed 2010
Description
720m long 1.8m wide overflow culvert.
Underground enclosed channel running under road,
fields, railway and main road. Water enters over
raised lip at culvert intake, only happens when Afon
Bach reaches level of lip.
Function
Transfer flood waters from the Afon Bach to the
Afon Conwy reducing flood risk in the town centre.
Culvert also acts as storage area. Still has to be
pumped out when Conwy is in flood.
Cost
£2 million
When
Completed 2009
Flood Plain Zonation
Description
Managed realignment of flood plain allowing
some areas of agricultural land to flood.
Planning restrictions on development.
Function
Allows large areas of flood plain to act as
flood water stores, thus reducing the
pressure on other high priority locations (ie
the town centre).
Cost
£500,000 (administration and one off
payments)
When
Ongoing
Dutch Dams
Description: Temporary slot in place flood barriers, stored in-situ below ground. Metal
flood barrier sections are secured onto a series of uprights creating a solid span of defence.
Behavioural Responses
Function:
Improved flood prediction
protecting houses near Pont Fawr as part of Llanrwst Flood Alleviation Scheme. The barriers
hold back flood water, preventing it entering areas where it would cause high levels of
damage or cause major disruption. These Dutchdams prevent flood water entering the
riverside residential and commercial area of Llanrwst.
Modified unitary development plans
Flood warning system (see EA pages in booklet)
Automatic voice messages
Cost:
£750,000
When: 2011