Rhondda Cynon Taf County Borough Council (RCT) as the Lead Local Flood Authority (LLFA) will be commencing a Flood Alleviation Scheme programed to start construction in August in the fields above Aberdare park and Park Lane. The proposed scheme will be part of an Upper catchment management plan which aims to alleviate flood risk to approximately 122 properties residential properties, 30 business and several highways.
The LLFA is acting in accordance with its Local Flood Risk Management Strategy (LFRMS) high level objective to ‘Reduce the Consequences of Flood Risk.’ The strategy was published in January 2013 in accordance with Clause 10 of the Flood and Water Management Act 2010. The LFRMS objective aligns with the four overreaching national objectives set out within the National Strategy for Flood and Coastal Erosion Risk Management Wales.
The area in which the works are proposed is Trecynon, which is within the Aberaman West/Llwydcoed Electoral Ward which is identified as being the 6th highest risk ward within RCT's Flood Risk Management Plan (FRMP). The proposed works fall within the Trecynon Community area, as identified by the Communities at Risk Register (CaRR), which is ranked 27th in Wales for surface water flood risk.
Description of Works
The proposed scheme outlines the opportunity to create an upper catchment attenuation wetland through the de-culverting of an ordinary watercourse culvert.
This work is based on the principal of Natural Flood Risk Management with a range of environmental improvements being explored to facilitate the development of a diverse ecological wetland with associated amenity use for the local community.
The Park Lane area of Aberdare has been subject to several flooding events in recent years, the most significant incident occurred on the 12th and 13th October 2018 following Storm Callum, where 5 internal classrooms were flooded and 2 properties internally flooded with a further 20 properties experiencing external flooding. This flooding event was the 2nd/3rd event following Storm Bronagh which occurred on the 20th and 21st September 2018 which identified the same level of internal flooding.
In response to these events, RCT have proposed to carry out land drainage improvement works on the ordinary watercourse and adjacent public open space of Aberdare Park which will enable the area to be re-profiled to attenuate peak surface water flows on the Unnamed watercourse at Trecynon. The works will involve the creation of a graded channel to provide greater storm water attenuation within the field area and de-culverting a section of the ordinary watercourse to install a wide span bridge structure on the existing footpath passing over the watercourse. The works will also involve creating a maintenance path around the attenuation basin which will double as an amenity path for local residents and park users.
The primary aim of the initial proposed works is to reduce the peak storm flows of water from the catchment thus reducing the risk of flooding within the Park Lane area of Aberdare by reducing the risk of overloading the urban drainage systems.
These initial proposed works will aim to provide a 50% reduction to the peak flows downstream watercourse reducing the overall flood risk to three downstream ordinary watercourse networks that are directly connected to the existing network.
In undertaking these works the scheme will aim to deliver on the following objectives within Council’s LFRMS.
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Reduce distress by decreasing the population exposed to flood risk.
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Reduce community disruption by reducing the amount of residential and commercial property exposed to flood risk.
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Reduce risk to life by reducing the number of people exposed to risk of flooding of significant depth and velocity.
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Reduce disruption to critical infrastructure or support the preparation of plans to allow their operation to be maintained.
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Improve or not detrimentally affect water quality
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Where possible, improve naturalness - reducing modifications to channels, water bodies and, where appropriate, create or enhance natural floodplain storage linked to nature conservation and landscape initiatives.
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Ensure projects are designed and constructed in a sustainable way.
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Maintain, or where possible, improve the status of Special Areas of Conservation (SACs), Sites of Special Scientific Interest (SSSIs), Sites of Importance for Nature and Conservation (SINC) sites and contribute to the RCT biodiversity action plan.
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Develop a better understanding of the risks of flooding from surface runoff, groundwater and ordinary watercourses and plan how best to communicate and share information with communities and businesses on all forms of flooding.
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Also undertaking these works the scheme aims to deliver multiple benefits as per the ‘Wales Future Generations Act Wales’.
- A Healthier Wales – The works will directly support the alleviation of flooding to approximately 122 properties (several of which have flooded twice during the 2018-19 storm season); which in turn will improve the mental well-being and health of the local community.
- A Resilient Wales – The proposed works aim to create an upper catchment attenuation wetland through the de-culverting of an ordinary watercourse culvert which enhances the existing ecology by reintroducing a natural and biodiverse environment for local fauna and flora. The works will further provide social resilience through enhance amenity use within the wetland area, providing interactive natural environment that is adaptive to the future impacts of climate change.
- A More Equal Wales – This work will be to the benefit of all parts of society, all will be allowed to fulfil their potential by reducing the likelihood of flooding and enabling long-term resilience for the local community, specifically the Park Lane Special School.
- A Wales of More Cohesive Communities – Connectivity is critical and this work will allow us to maintain community’s significantly important routes. As an organisation the safety of our communities is paramount and this work will also significantly reduce the risk for commuters, school users and local businesses.
- A Globally Responsible Wales – The project proposes the use of natural flood risk management techniques to mitigate existing flood risk whilst enhancing the local ecological and social environment.
Notice of Intention to Start Land Drainage Improvement Works
The proposed flood risk alleviation scheme is deemed permitted development under Part 14 (Development by Drainage Bodies) of the Town & Country Planning (General Permitted Development) Order 1995. As such the council is undertaking a consultation process under The Environmental Impact Assessment (Land Drainage Improvement Works) Regulations 1999 and 2006.
Project Commencement
The main phase of construction estimated to begin on the 10th August and is expected to take 12 weeks to complete. Construction will take place within the works area located at Park Lane, Aberdare and a general arrangement plan has been made available for viewing.