Tirfounder Road - Bro Deg Flood Alleviation Scheme

Scheme Summary
Strategic Flood Risk Area	Mid Cynon 1
Location	Tirfounder Road, Cwmbach
Properties benefiting	10 Residential Properties
Type of scheme	Culvert Network Rehabilitation
Status	Ongoing
Funding Source	Welsh Government Flood Coastal Erosion Risk Management Capital Grant

Scheme Background

Historical flooding issues associated with an unnamed ordinary watercourse conveying through Mountain Ash, as well as localised surface water flooding causing disruption along the highway at Victor Street, have impacted this area on several occasions.

The scheme is in response to flooding following the heavy rainfall experienced in early 2020; a significant amount of debris was carried downstream from the open watercourse which resulted in blockages to the network and localised flooding to residents and businesses.

The flooding that affected RCT on 15 and 16th of February 2020, was a result of an extreme rainfall event, designated by the Met Office as ‘Storm Dennis’. The impact of the event at Cwmbach resulted in internal flooding to a total of 34 properties, 18 of which were commercial properties

The primary cause of the flooding was debris blocking the watercourse channels and culvert inlets, leading to overflow. Additionally, several sections of the culvert network were found to be in poor condition, with structural defects contributing to the problem.

Cwmbach is noted as an area of high surface water and ordinary watercourse flood risk based on Natural Resources Wales’s Flood Risk Assessment Wales (FRAW) maps and is identified as the 122nd most at risk community for ordinary watercourse and surface water flooding in Wales according to the Communities at Risk Register (CaRR).

Proposed Scheme Objectives

• Reduce risk to life by reducing the number of people exposed to risk of flooding of significant depth and velocity.
• Reduce community disruption by reducing the amount of residential and commercial property exposed to flood risk.
• Result in no detriment to downstream receiving River/Watercourse
• Improve community resilience to flood events and climate change, promoting sustainability and wellbeing. Deliver a preferred option that works with natural processes and promotes green infrastructure.
• Enhance local biodiversity and support the resilience of ecosystem services.
• Improve the resilience of flood risk assets against climate change - Promoting accessibility and low maintenance requirements.
• Reduce the impact of climate change – mitigating the extent of the projects carbon footprint.
• Improve community wellbeing through the enhancement of local amenity.

Proposed Scheme Description

The proposed flood alleviation scheme aims to implement a Flood Alleviation Scheme (FAS) within the ordinary watercourse network to effectively manage the risks of blockage and hydraulic overload.

The project’s goal is to design a flood alleviation scheme that improves the resilience of the ordinary watercourse network, reducing the likelihood of blockage-related flooding incidents while improving the hydraulic capacity of the network. This scheme aims to reduce the potential for hydraulic and blockage-related flooding events within the ordinary watercourse that could affect the broader Cwmbach community.

The scheme consists of the installation of scour protection measures and/or debris control along a section of open watercourse upstream of the Cwmbach Industrial Estate drainage network. The scheme is in response to flooding following the heavy rainfall experienced in early 2020; a significant amount of debris was carried downstream from the open watercourse which resulted in blockages to the network and localised flooding to residents and businesses.

By installing the use of scour protection measurers and/or debris control it will reduce the rate of channel wall scour which in turn will decrease the volume of debris in the watercourse therefore reducing the risk of blockages and flooding within the watercourse.