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.

● ●

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?