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Roath Brook Flood Scheme

Reducing flood risk in Cardiff


Penylan is a central suburb in Cardiff, through which runs Roath Brook. The Roath Brook burst its banks most recently during high river flows in 2007 and 2009 and during high tidal events in 2010 and 2012.Flood risk areas of Roath and Rhymney

Many homes and businesses in the area are at risk of flooding. This is from high river flows, high tides or a combination of both.

The likelihood of flooding will only increase over time, as a rise in sea levels and more frequent and intense heavy rainfall are predicted as a result of climate change.

Welsh Government has made a commitment to provide funding for flood management schemes across Wales, in order to minimise the risk and mitigate the impact of flood events. In light of the flood risk in Penylan, we’re delivering a Flood Risk Management Scheme (FRMS) for the area.

We have already undertaken works to increase the tidal flood protection at the River Rhymney in January 2015.

The Scheme

The Roath Brook Flood Scheme will increase the level of protection for the community up to a 1 in 75 chance flood event (1.3% chance of flooding in any given year) from high river flows and a 1 in 150 chance flood event (0.6% chance of flooding in any given year) of high tide levels. The scheme will reduce the flood risk to 360 homes and 45 businesses.

We will make improvements at several locations along the brook between Roath Brook Gardens and the River Rhymney at Newport Road (near to the Morrison’s supermarket). The main areas for improvement are:

  • Roath Brook Gardens
  • Roath Mill Gardens
  • Waterloo Gardens
  • Railway Gardens (The Sandies)

Overview plan

We are building flood walls and embankments in Roath Mill Gardens, Waterloo Gardens and Railway Gardens, but softening these hard features with urban landscaping. We are widening the river channel in Roath Brook Gardens and Roath Mill Gardens and replacing Waterloo Road bridge to increase the brook’s flow capacity.

Through continual consultation with local residents, businesses and stakeholders, we’ve listened to the local community who’ve helped us shape the final design, including minimising tree removal and reducing walls across the scheme.

Planning permission was granted for the scheme in April 2016 by Cardiff Council. The details for the planning submission can be viewed online.

We’re confident that this new scheme will really make a difference to people living and working in Roath who have lived with the threat of flooding for many years.

Construction updates

We are doing everything we can to minimise disruption to local residents and businesses while we undertake these works, and we appreciate the support, patience and cooperation of the local community.

We are keeping people informed of activities during the construction phase via this webpage and social media - Twitter: @natreswales, Facebook: NatResWales.

March 2020

We've completed our re-assessment of the flood risk in the Pen-y-lan area of Cardiff following our decision in January 2019 to consider the third and final phase of the scheme as a separate piece of work.

The re-assessment considered the work already completed downstream and the new footbridge built in Roath Brook Gardens by Cardiff Council. The footbridge was constructed after the original flood risk was assessed but formed part of the design for the works in Roath Brook Gardens as part of the wider scheme.

The initial result estimates the number of properties at flood risk during a 1.33% (1 in 75) chance flood event has reduced to 11. We remain committed to working with partners and the community to find a solution to manage the flood risk, and this risk will only increase due to climate change.

There may be a way to address this remaining risk as part of work that Cardiff Council is considering at Roath Park Lake, upstream of Pen-y-lan. We are discussing this with Cardiff Council and won’t consider further work in Roath Brook and Roath Mill Gardens until these discussions are finalised.

We will inform the local community once this work is complete and what options we have to address the remaining risk.

January 2019

On 24 January, NRW's Board approved our proposal to reassess the final phase of the Roath Brook Flood Scheme as a stand-alone project.

We’ve based this decision on advice from the Welsh Government, views provided by the campaign group from an independent consultant and no overwhelming support from the affected community.

We remain confident in our assessment of the flood risk in the area, but we are also committed to working with the community to reassess the options with a view to reapplying for Welsh Government funding at a later date. 

We’ve worked closely with the campaign group throughout the review so far and listened to their concerns, and we propose to continue with this approach. Working with the local community will be integral to finding a suitable solution to the flood risk.

August 2018

We have now completed all engineering works in the Park Gardens, such as the piled and concrete walls, and are now undertaking the hard landscaping. This month we will finish creating the paths through the gardens, placing coping stones, building the dais and pergola in Waterloo Gardens and laying the pennant stone paving for the viewing platform in Roath Mill Gardens. Once these engineering works are complete, the majority of the large construction machines will be leaving the Parks Gardens areas, with generally smaller machines / manual work used for the planting and final reinstatement.

Due to the ongoing dry weather the soft landscaping work, involving turfing, seeding and planting, has been delayed, as we are unable to undertake this. Unfortunately we cannot predict when this work will be completed, as we need some decent rain first.

We will be re-opening sections of the Park Gardens and key access routes as soon as we can. The new footbridge between Newminster Road and Waterloo Gardens will be open in the next few weeks. Likewise, the new path and boundary gate to the shops in Roath Mill Gardens will open this month. We are looking at how we can open other paths also, with suitable fencing, in advance of completing the soft landscaping work.

We wish to thank you for your patience during these works and apologise for the ongoing delays. We need to ensure the new grass in the parks is well established before opening them fully, so the desired standard of reinstatement is achieved.

As previously communicated, we have agreed to pause tree felling and construction in Roath Brook Gardens and Roath Mill Gardens (Phase 3 of the Roath Flood Scheme) after listening to the views of the community and the concerns of the Roath Brook Trees campaign group.

This pause allows the campaign group time to further scrutinise our modelling (the hydrology and hydraulic model used to predict the flood risk) and the options appraisal that selected the current design. We have committed to consider any new evidence prior to making a decision on how to progress.

Local Businesses

All of the businesses on Waterloo Gardens remain open as usual during the construction of the scheme.


We have undertaken a range of consultation with the community and stakeholders to inform the scheme. This has included:

  • Door knocking and meetings to raise flood awareness and produce Community Flood Plan: from 2012 to 2014
  • Public drop-in sessions: May 2014, October 2014, July 2015, January 2017, April 2017, November 2017
  • Stand at Waterloo Gardens Fete: August 2014, July 2015, July 2016
  • Walkover of site with local residents: September 2015
  • Press adverts, site notices and consultation letters to properties that border the gardens
  • Regular updates via newsletters, posters, the Roath Flood Scheme webpage and social media
  • Series of seven workshops in January 2018 to discuss the flood scheme with residents

Before and After Images

 waterloo pergola before waterloo pergola after


A series of photo montages have been prepared to show how the scheme will look before and after the works, once the trees have established, at particular locations along the route and within the Roath gardens.

Public Art

As part of NRW’s commitment to meeting the goals of the ‘Well-being of Future Generations (Wales) Act’, the integration of public art into Roath has been identified to support these goals. The aims of the public art commission, to be installed in Roath Mill Gardens, are to:

  • Recognise and interpret Roath Mill Gardens’ historic and environmental interest
  • Contribute to a sense of identity for Roath Mill Gardens
  • Promote an attractive, safe and well-connected community
  • Advocate local culture and heritage through encouraging people to participate

Our artist, Rubin Eynon, has been working on a piece of art to be integrated into Roath Mill Gardens. Informed by community consultation and Rubin’s dedicated Facebook page, the chosen design is a bronze model of the old Roath Mill, as shown in the images below. This will be approximately 50cm by 50cm wide on a 100cm high plinth, and will be located on a widening of the footpath upstream of Waterloo Road bridge, near where Roath Mill was located. A time capsule will be placed beside the artwork, compiled by local school children.

Art figures standing around an art displayClose up view on an art display

Tree Removal and Planting

To achieve the required flood protection and construct the new flood walls, embankments and channel widening, unfortunately the removal of some trees along the banks of Roath Brook is required.

For details on tree removal and planting, please email

We understand the concern the community has for the trees in the area, so we have focused the design efforts to minimise these impacts. For example, by avoiding removing trees around the edge of the park boundaries and replanting higher value trees.

We cannot save every tree within the gardens, but have tried to get the correct balance of protecting the conservation area and the heritage features of the park, whilst still being able to construct the scheme and meet the required standard of flood protection.

Community Tree Bank

As NRW, our objective is to maintain a positive contribution to the community. We have planted additional trees Roath Park Recreation Ground and have offered tree saplings to school children for home planting.

Key dates

October 2015              Planning application submitted

April 2016                   Planning permission granted

January 2017              Contractor (Dawnus) appointed

March 2017                 Construction started

Summer 2018             Construction to finish

Note works at Roath Brook Gardens and upstream Roath Mill Gardens will now be separate to the above.

Contact information

If you have any questions about the scheme, please email

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