suds kerrie ginns, andrew leadbetter & paul burrows environment agency july 2010
TRANSCRIPT
SuDS
Kerrie Ginns, Andrew Leadbetter & Paul BurrowsEnvironment Agency
July 2010
Green Infrastructure and SuDS
Green Infrastructure overview
Why Green Infrastructure is important to the Environment Agency
Green Infrastructure = SuDS
Local flood risk, current policy and future challenges
What is Green Infrastructure?
Green Infrastructure (GI) is a concept that describes a network of inter-connected, multifunctional green and blue spaces designed to meet the environmental, social and economic needs of a community.
Green Infrastructure assets
playing fields and allotments……
Green Infrastructure assets
towpaths and wildlife corridors………
Green Infrastructure assets
beaches…….
Green Infrastructure assets
watercourses…..
Green Infrastructure assets
wetlands and flood storage areas…..
Green Infrastructure assets
woodlands…..
Green Infrastructure assets
trees…..
Green Infrastructure assets
grasslands…..
Green Infrastructure assets
and green roofs and walls….
Why is Green Infrastructure important for the Environment Agency?
1. GI is essential for sustainable development and for the delivery of sustainable communities.
2. We support the enhancement and increased development of well planned and managed GI networks.
3. New developments should include sufficient GI to support community and environmental needs.
4. Where appropriate and feasible, GI should be retrofitted into existing developments.
5. For maximum effect, GI should be strategically planned and managed.
Why is Green Infrastructure important for the Environment Agency?
6. Partnership working is essential for successful GI planning, development and management.
7. GI is an important and useful concept for the Environment Agency.
8. We should encourage the enhancement of blue spaces within all new and existing developments and we should recommend safeguarding floodplains from development by highlighting their multifunctional and flood storage benefits.
9. The coast and surrounding coastal environments are valuable components of GI networks.
10. GI has an important to play in responding to play in responding to climate change.
Green Infrastructure = SuDS
Green Infrastructure = SuDS
Green Infrastructure = SuDS
Green Infrastructure = SuDSEssential for sustainable development
Can be retrofitted into existing developments
Plays an important role in responding to climate change
SuDSSustainable Drainage Systems (SuDS) are designed with three objectives in mind:
• to control the quantity and rate of run-off from a development;
• to improve the quality of the run-off;• to enhance the nature conservation, landscape and
amenity value of the site and its surroundings.
SuDS deal with run-off as close to its source as possible and balance all three objectives, rather than focussing only on flood prevention.
Benefits of individual SuDS techniquesSUDS
Technique Brief Description Water
Quantity Water
Quality Amenity/
Biodiversity Permeable
Pavings Infiltration through the surface into underlying layer
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Filter Drains Drain filled with permeable material with a perforated pipe along the base.
● ●
Infiltration Trenches
Similar to filter drains but allows infiltration through sides and base.
● ●
Soakaways Underground structure used for store and infiltration.
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Detention Basins
Dry depressions outside of storm periods, provides temporary attenuation, treatment and possibly infiltration
● ● ○
Retention Ponds
Designed to accommodate water at all times, provides attenuation, treatment and enhances site amenity value
● ● ●
Wetlands Similar to ponds, but are designed to provide continuous flow through vegetation.
● ● ●
Rainwater Harvesting
Capturing and reusing rainwater for domestic or irrigation uses.
● ○ ○
Green Roofs Layer of vegetation or gravel on roof areas providing absorption and storage
● ● ●
Economic benefits of SuDS
Experiences from UK, Europe and the US have shown that when properly planned and implemented, SuDS is no more expensive, if not cheaper than conventional drainage. For schemes where cost checks have been carried out, SuDS is nearly always cheaper to construct and maintain.
The savings accrued (both fiscal and social) are attributed to the following factors:
- Absence of conventional kerbs and gullies - Reduced need for pipes, surface water sewers, manholes etc and absence of deep trench excavations - Absence of storage tanks, leading to reduced excavations and
construction costs - Avoiding the need for pipe connections to distant outfalls - Avoiding the costs involved in routing pipes across land owned by
others - Simpler construction - Reducing the economic and social cost of flooding - Limiting the risk of sewage discharge during exceptional high
rainfall reduces risk to human health - Avoiding expensive connections to the local water authority. - Reducing maintenance costs
Local Flood Risk:current policy,
future challenges
Properties at risk of flooding in England & Wales
23.8m properties not susceptible to flooding
5.5m properties at risk of flooding
>1m properties at risk from river, coastal and surface
water flooding
>2.6m properties at risk of river and coastal
flooding
>3.9m properties at risk of surface water flooding
Flood and Water Management Act
Impact on surface waterSections 1-6:
LLFAs to manage local flood risk
Sections 7-12:
National and Local StrategiesSections 13-14:
Duty to cooperate & power to share informationSchedule 1:
Third party assets
FWMA and sustainable drainage
Schedule 3: Sustainable drainage Section 42: Automatic right to connect
Flood Risk Regulations - Timeline
Dec 2009
Flood Risk Regulations
2009 20092011 2013 2015
Preliminary Flood Risk Assessments
publishedDec 2011
Dec 2013
Flood Risk Areas - maps
Flood Risk Areas - Management Plan
2015
Dec 2011
Flood Risk Areas identified
Implementation
EA Strategic Overview objectives
Outcome: Flood risk from all sources is adequately assessed and managed using a strategic, risk-based approach
To be achieved by:continued delivery of flood risk management for main rivers and sea, and the oversight of reservoir safety
significantly improved flood risk management for surface water, groundwater and ordinary watercourses
Local Flood Risk RolesLead Local Flood Authority
• Lead delivery of local FRM
• Build partnerships
• SWMPs and SUDs
• Local Strategy
• Produce Flood Risk Regs assessment-map-plan
Environment Agency
• Set the national framework
• Support LLFAs
• Guidance, data and tools
• Flood warning
• Implement relevant SWMP actions
• Quality AssuranceRFCCs
• Role advising on quality and delivery
LA(District)
EA / RFCC
HighwaysAgency
Other localflood riskpartners
WaterCompany
IDB
LA(CC / UA)
Local floodrisk
partnership
Delivery
Surface Water Management Plans (SWMPs)
5 x SWMPs Defra funded (by March 2011)
Northampton, Ipswich, Norwich, Southend, Basildon/Wickford
1 x self funded Cambridgeshire (county wide – scoping only)
3 x successful early action bids Peterborough, Cambridge, Thurrock towns
Next steps
Commencement of the FWM Act
Establish and support Partnerships
Clarity on Funding sources
Delivery against Flood Risk Regulations
Pursue the Strategic Overview and Localism
Questions
Discussion
What progress is your Authority making in setting up partnerships, are planners linked into these?How well have the requirements of the Act and Regs been communicated within your Authority?What ideas have been discussed around implementation of your new roles in sustainable drainage?