Last updated: October 2021
Working with Cardiff local authorities, Dwr Cymru Welsh Water's (DCWW) upgraded Trelawney Avenue to its RainScape Sustainable Drainage System (SuDS) (Ref. 4) which alleviated risk to residents and nearby highway which were at a 2 in 10 year flood risk (highly-risky) (Ref. 3). Flooding commonly occurred due to rainwater run-off from the roofs and roads of upstream catchments that drained into a combined, overburdened sewer network. Traditional systems of increasing pipe-size and storage were not cost effective (Ref. 3). A sustainable solution was developed which combined road surface drainage (gullies and slotted grates) and provided water-butts (200 liter reservoirs for roof drains) to 101 properties in Trelawney Avenue and to 75 properties in the upstream catchment (Ref. 3). Additionally, a wall was built to protect properties from the potential effects from surface water run-off (Ref. 1).
Overview
Nature-based solution
- Grey infrastructure featuring greens
- Other
- Green areas for water management
- Sustainable urban drainage systems
Key challenges
- Climate action for adaptation, resilience and mitigation (SDG 13)
- Climate change adaptation
- Water management (SDG 6)
- Flood protection
- Stormwater and rainfall management and storage
Focus
Creation of semi-natural blue areas, Other
Project objectives
The achieved goals of the project were:
- Decreased flood risk to the residents of Trelawney Avenue, which were at a 2 in 10 year flood risk (Ref. 3), as well as reduce flooding of a nearby highway (Ref. 4).
- Rerouted water from the upstream catchment which overburdened the combined sewer system (Ref. 1; Ref. 3).
- Reduced flooding of a nearby highway through upstream solutions at Trelawney Avenue and an upstream catchment (Ref. 3).
- Implementation of sustainable, cost-effective solutions (RainScape SuSD) (Ref. 4) as a part of a larger citywide initiative (Ref. 6).
Implementation activities
The project’s main activities included installing water-butts to 75 residents upstream in order to divert the water runoff from their homes that was overwhelming the combined sewage system of downstream residents (Ref. 4). Also, to do the same for 101 residents in that downstream community, as well as building them a wall for flood prevention from rainwater runoff (Ref. 3). Finally, for road-water runoff, a network of gullies and slotted grates were installed to reduce runoff from the main sewer system of Trelawney Avenue (Ref. 3). This has provided a cost-effective, sustainable solution to reducing the risk of flooding. (Ref. 3)
Climate-focused activities
Climate change adaptation:
- Implement sustainable urban drainage infrastructure (e.g. to make space for water)
Main beneficiaries
- Local government/Municipality
- Private sector/Corporate/Company
- Citizens or community groups
- Other
Governance
Management set-up
- Led by non-government actors
Type of initiating organisation
- Private sector/corporate actor/company
Participatory approaches/ community involvement
- Dissemination of information and education
- Consultation (e.g. workshop, surveys, community meetings, town halls)
Details on the roles of the organisations involved in the project
Key project participants are Dŵr Cymru Welsh Water (client) 2. Arup (the design engineer and hydraulic modeller) and 3. Morgan Sindall (the contractor). Cardiff County Council was engaged in the scheme at an early stage (ref 3).
Project implemented in response to ...
... an EU policy or strategy?
Unknown
... a national policy or strategy?
Unknown
(The NBS )
... a local policy or strategy?
Unknown
Financing
Total cost
€100,000 - €500,000
Source(s) of funding
- Corporate investment
Type of funding
- Direct funding (grants, subsidies, or self-financed projects by private entities)
Non-financial contribution
Unknown
Impacts and Monitoring
Environmental impacts
- Climate change
- Strengthened capacity to address climate hazards/natural disasters
- Environmental quality
- Improved waste management
- Water management and blue areas
- Increased protection against flooding
- Improved stormwater management
- Enhanced protection and restoration of coastal and marine ecosystems
Economic impacts
- Unknown
- Other
Socio-cultural impacts
- Unknown
Type of reported impacts
Expected impacts
Presence of formal monitoring system
Unknown
Presence of indicators used in reporting
No evidence in public records
Presence of monitoring/ evaluation reports
No evidence in public records
Availability of a web-based monitoring tool
No evidence in public records
References
Ref. 1. Dŵr Cymru Cyf. (No Date). Other RainScape Projects. [online]. [Available at: Source link. [Accessed on: July 27, 2020].
Ref. 2. Gaines. M. (2013). Welsh Water to manage rainwater with RainScape project. WET News. [online]. [Available at: Source link. [Accessed on July 27, 2020].
Ref. 3. Ellis L. (2012). Trelawney Avenue Flood Alleviation Project. UK Water Projects 2012 - Virtual Edition. [No longer available online].
Ref. 4. Brockett. J. 2016. Interview: Tony Harrington, Director of Environment, Welsh Water. [Available at: Source link. [Accessed on July 27, 2020].
Ref. 5. Roberts, E., Flood and Coastal Erosion Risk Management in Wales, 2011–2014. [Available at: Source link. [Accessed on July 27, 2020].
Ref. 6. Water UK. (No Date). 21st-century-drainage Programme. [Not available online in 2020].
Ref. 2. Gaines. M. (2013). Welsh Water to manage rainwater with RainScape project. WET News. [online]. [Available at: Source link. [Accessed on July 27, 2020].
Ref. 3. Ellis L. (2012). Trelawney Avenue Flood Alleviation Project. UK Water Projects 2012 - Virtual Edition. [No longer available online].
Ref. 4. Brockett. J. 2016. Interview: Tony Harrington, Director of Environment, Welsh Water. [Available at: Source link. [Accessed on July 27, 2020].
Ref. 5. Roberts, E., Flood and Coastal Erosion Risk Management in Wales, 2011–2014. [Available at: Source link. [Accessed on July 27, 2020].
Ref. 6. Water UK. (No Date). 21st-century-drainage Programme. [Not available online in 2020].