Welsh Water (DCWW) approach to Surface Water Management Scotland s Flood Risk Management Conference 2014
Dwr Cymru / Welsh Water (DCWW) approach to Surface Water Management
Scotland’s Flood Risk Management Conference 2014 Jeremy Jones – DCWW Lead Advisor...
Dwr Cymru / Welsh Water (DCWW) approach to Surface Water Management
Scotland’s Flood Risk Management Conference 2014 Jeremy Jones – DCWW Lead Advisor, Surface Water Management and SuDS
Dŵr Cymru Welsh Water ➜
DCWW - Not for profit company
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Only water company of this type
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Customers not shareholders are our priority
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All financial profits reinvested into the company
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We are midway through a £1.5 billion investment programme to help protect customers water, their local community and the environment
Brief introduction to RainScape ➜
If we take steps to prevent surface water from entering our assets then the effects are mitigated
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There are additional benefits in the form of:– Reduced carbon use – Lower energy costs – The influent to our Advanced Digestion plants become stronger improving their efficiency.
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Customer Benefit from societal value
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Dŵr Cymru’s Strategy for Surface Water Management is called RainScape
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Provide infrastructure headroom for communities to plan new homes and commercial enterprises
RainScape GlawLif
Brief introduction to RainScape Why is surface water runoff so important? ➜ “…The principle
that …sewerage systems should accommodate future flows is unsustainable in the long-term context of climate change.” - Ofwat Climate Change Policy
➜ DCWW
– Flow reduction strategy
Building resilience through surface water management ➜ ➜ ➜ ➜
Climate change has many potential impacts on our assets and operations. Many measures have been put in place to prepare for the impacts. Risk assessment shows that our wastewater assets are the most vulnerable. A key approach we are taking to build resilience for our wastewater networks and assets is using our Surface Water Management Approach
Surface Water – where does it come from? ➜ ➜ ➜
Paved area and highway runoff Roof water drainage Groundwater infiltration
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Land drainage inflows Overland flow from permeable land River intrusion
Surface Water – Causes and Impacts? Problems
Unwanted inflows
Consequences
Surface water in sewers
Influences from overseas
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Portland
Influences from overseas
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Malmo
Influences from overseas
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Malmo
The following slides show SuDS used to improve Asset Resilience in a: ➜ Local
Approaches ➜ Catchment Approaches ➜ National Approaches
Caldicot – A local solution Caldicot Castle Lea
RainScape proposals for Llanelli – A Catchment approach
What’s the answer? ➜
Over the next 3 years, we will be installing RainScape solutions across Llanelli.
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These include:
Basins (example):
What’s the answer? Planters (example)
Drainage kerbs (example)
Before and after examples – Alban Rd Small planters around trees to capture more rainwater
Before and after examples – Glevering Street Extended basin, allowing more rainwater to be captured
Grass channels – e.g. to the rear of properties on Glevering Street
Proposed along back lanes to help absorb rainwater
Before and after - Stepney Place
Reconfigured planters with a range of plants
Queen Mary’s Walk Swale captures and slows down rainwater
Stebonheath Primary School → Developed with the school children →Includes areas to increase biodiversity
Why should Dŵr Cymru be involved in the scheme? ➜ Particularly
as:
➜ There are no regulatory sewer flooding issues ➜ There are no regulatory quality problems ➜ Sewer improvements for development growth
not required in Grangetown
are
BUT...Greener Grangetown is a unique opportunity ➜
Taff is no longer tidal because of Barrage and water levels are stable
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Create new system which embraces modern engineering techniques – and don’t impact underground services
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Topography of area allows flow by gravity into the Taff
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Bio retention areas incorporated into the urban fabric to cleanse surface water run off
Feasibility Study area ➜ Study
area ➜ River Taff to east and Corporation Rd to the west ➜ A number of distinct street ‘types’
The Feasibility Options ➜ Options: ➜ Narrow Street
Before
After
The Feasibility Options ➜ Options: ➜ Wide
Before
Street After
The Feasibility Options ➜ Options: ➜ Wide
Before
Street, alternative proposal After
The Feasibility Options ➜ Options: ➜ Embankment
Before
After
Benefits of Greener Grangetown ➜ Wider benefits: ➜ Reduce overflows into
rivers ➜ Reduction in ponding surface water ➜ Improve water efficiency ➜ Increase in green and blue corridors in urban areas ➜ Improve the environmental and recreational connectivity between Cardiff City Centre and the Bay ➜ Enhance the living experience of residents ➜ Legacy for generations to come - multicultural; multi-stakeholder; customer orientated; resident friendly
→ Ensure the 12 principles are embedded in all schemes →Developing approach to evidence considerations → Maximise socio-economic and environmental benefits in a considered way
Cooperation & Collaboration Welsh Government has devolved powers ➜ ➜ ➜
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A consistent policy underpinned by National Strategies One tier of Local Government Doesn’t make it easy but it helps that our customers (shareholders) are the same public that the politicians serve DCWW has developed a unique team in this field that spans many disciplines DCWW has a determination “to do what is right for the customer” and to work around unwieldy legislation
Summary ➜ Climate
Change makes a big impact to our Waste water assets ➜ Our Rainscape Strategy is an example of how we are adapting our operations to mitigate that impact ➜ SuDS are an important part of that Strategy ➜ We derive additional “non-tangible” customer benefits ➜ Cooperation and Collaboration with all stakeholders is of paramount importance ➜ Rainscape improves the overall resilience of our asset base.
