Llanmaes Flood Alleviation Work

Llanmaes has suffered several recorded flood events dating back to the 1990’s and anecdotal evidence suggests the problems are even older than that.


A number of small civil engineering construction schemes have been undertaken in an attempt to alleviate the problems.




A Pre Feasibility Study was undertaken in 2004 which outlined some strategic scheme proposals. The issue had become so bad that the residents setup its own group and undertook their own flood appraisal study.


Following further flooding in 2007 the Vale of Glamorgan Council undertook a Project Appraisal Report (PAR) to examine the problems and provide a preferred option for design.


This option did not initially attract funding from the Welsh Government (WG) and so it was not progressed until the Vale of Glamorgan provided funds to develop the preferred option from the PAR.


Mott MacDonald (MM) were appointed to develop the preferred option in February 2012. They then undertook a number of surveys and ecological reports and developed the preferred option to a design stage. Funding for the preferred option was announced by WG in December 2012.


Following a review of the scheme hydraulic modelling the need for additional storage capacity in the scheme was identified, and a re-appraisal of potential options undertaken.  


A new preferred option has now been identified and re-design is underway. Funding for the revised scheme was announced by Welsh Government in January 2016, with construction planned for 2017/18.

Key facts:

Scheme is promoted by:

Vale of Glamorgan Council


Scheme is Financed by:

 - Vale of Glamorgan Council

 - Welsh Government


At risk of flooding:

49 Properties


Estimated Cost of scheme:



Anticipated timescale:

Design and development 2012 to 2017


Construction 2017 to 2018


Overall objective:

To significantly reduce the flood risk to the village of Llanmaes


Lead officer:

Clive Moon


The Vale of Glamorgan Council
The Alps