Sustainable Drainage Approval Body (SAB) Michelle Johnson - - PDF document

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Sustainable Drainage Approval Body (SAB)

Michelle Johnson Rhodri Powell

Highways House, Penmaen Ind Est, NP12 2DY

johnsm@caerphilly.gov.uk powelr4@caerphilly.gov.uk

Sustainable Drainage Approval Body (SAB)

• Schedule 3 of Flood and Water Management Act 2010
• What is a SAB application?
• What is the SAB?
• Why do we need SUDs in Wales
• Why the SUDs approach
• Welsh Statutory Standards
• Approval process
• Caerphilly’s SAB set up
• Pre-application example

Michelle Johnson johnsm@caerphilly.gov.uk

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Flood & Water Management Act 2010 Schedule 3: Sustainable Drainage Commencement Date: 7th January 2019

• All new developments of more than 1 dwelling or where the

construction area is => 100m2 require Sustainable Drainage Approval

• Design, built and maintained to Ministerial Standards
• Approved by the SuDs Approval Body (SAB), prior to

commencement

What is a SuDs Application?

• Demonstrates compliance to the Statutory SuDs Standards
• Submitted to the SAB
• Be in a form prescribed by the SAB

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So, what is a SAB? Suds directly deliver and contribute to our statutory functions

• Under Schedule 3 FWMA 2010 duty to approve SuDs

Flood & Water Management Act 2010

• Duty to Adopt in compliance with standards

Except single curtilage sites

• Act alongside Lead Local Flood Authority Functions

i.e Ordinary Watercourse Consent, Asset Register

What are SuDs? Why SuDs? Where does the rain go?

Video courtesy of SusDrain (www.susdrain.org)

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Why do we need SuDs?

SuDs are nothing new

• Surface Water is a serious problem

A major cause of flooding impacting citizens, communities and the economy.

• Flood risk is on the increase

Owing to climate change and urbanisation

• Increased Local Flooding due to overloading of constrained and

ageing drainage systems Limiting development opportunity

Source: Met office – Hazard Manager User Guide

The Approach? …… nothing new…been around for years

• Tradition drainage – pipe to tank.

Large volumes.. No additional benefits…adoption issues

• SuDs mimics natural drainage

Close to source…multiple additional benefits

• Management Train using series of components

Spreads the volumes…. Additional benefits

• Working with natural processes

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The Approach?……

• Improved water quality
• Easy to maintain
• Benefits:

Access to green space Improved air quality Biodiversity

• Support development resilience to climate change

Statutory Standards…

• Set of over-arching Principles
• Standards
• Guidance on delivery of Technical Standards
• You will have to demonstrate how you have complied with

these principles or provide detailed justification for any departure.

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Statutory Standards…

• Six Standards
• S1. Runoff Destination
• S2. Hydraulic Control
• S3. Water Quality
• S4. Amenity
• S5. Biodiversity
• S6. Construction, Operation & Maintenance

Statutory Standards…

• Six Standards
• S1. Runoff Destination

Priority 1: Surface Water (SW) is collected for use Priority 2: SW is infiltration to ground Priority 3: SW is discharged to watercourse Priority 4: SW is discharge to a SW Sewer, Highway Drain or another drainage system Priority 5: SW is discharged to a combined sewer Drainage across a site will have difference destinations. i.e not all to watercourse.

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Statutory Standards…

• Six Standards
• S2. Hydraulic Control

Manage SW Runoff from and on the site to protect; people property environment water quality morphological changes

Statutory Standards…

• Six Standards
• S3. Water Quality

Manage SW Runoff from and on the site to protect; people property environment water quality morphological changes

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Statutory Standards…

• Six Standards
• S4. Amenity

SuDs are visually better, provide education etc…. Enhance the provision of high quality, attractive public space which provides Health & Wellbeing Benefits.

Statutory Standards…

• Six Standards
• S5. Biodiversity

Create ecologically rich green/ blue corridors in development Enrich biodiversity value by linking network of habitats and ecosystems together

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Statutory Standards…

• Six Standards
• S6. Design for Construction, Operation &

Maintenance Design robust SW drainage systems which are: Easy/ safe to construct Easy/ safe to maintain East / safe to operate.

Approval Process

• A fundamental change
• All design information submitted up-front (Full App) to

make a determination – see design checklists

• All Wales Application Form
• Limited scope to use conditions.
• SAB Legal Agreement
• Secure Non-Performance Bond
• Maintenance Funding
• Inspection Regime
• Land Transfers etc
• Appeal & Enforcement Process

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Caerphilly Sustainable Drainage Approval Body

What's been done for implementation…….

• Application Forms – All Wales Standard

Guidance Pre-Application Full Discharge of Condition

Caerphilly SAB on WLGA Task & Finish Application Group

Caerphilly Sustainable Drainage Approval Body

What's been done for implementation…….

• Being part of various Welsh Government Advisory/ T&F Groups
• Purchased software
• Set up processes and procedures
• Regional working through SLA’s
• CCBC SAB website
• Online Application Forms
• Online Payments systems
• SuDs Training Courses
• SAB Legal Agreements
• SuDs Technical Standards – Design & Adoption
• Developer/consultant engagement workshops
• Internal Awareness Workshops
• Circia Presentation in London

Caerphilly is leading the way on SuDs implementation

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Next……. SuDs Pre-application Designing for compliant SuDs Example SuDs

Sustainable Drainage Approval Body (SAB)

Pre-Application Blue / Green Corridor Assessment Compliant SuDs

Email: powelr4@caerphilly.gov.uk Web: www.caerphilly.gov.uk/SAB

Rhodri Powell

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Pre-Application

• Key to successful multi-functional SuDS
• Compliant SuDs will influence

Development Layout

• Take account of:

Topography Flow paths Green/ blue corridors Ecology Constraints SuDs in a development

• SuDs should not be thought of as individual items, but an

interconnected system.

• Water flows through a management train to:

 Store / re-use  Treat  Convey  Interact with….

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SuDs in a development

• Designers can use the management train to;

 Improve water quality  Reduce storage  Reduce maintenance and construction costs  Provide green/ blue corridors and links to;  Biodiversity  Improve amenity (education/ engagement)

Identify:

• Existing drainage features
• Flood Risk from all sources
• Watercourses i.e ditches, drains, passages through which water flows
• Existing Surface Water flow paths
• Details of sensitive environments
• Green corridors

Case Study - Former Ty Pontllanfraith, Blackwood

Applying to Pre-application stage

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Pre-Application – Where do I begin?

• Examine site topography and geology
• Spatial framework for SuDs
• Look for multi-functional spaces
• Integrate the street network with SuDs
• Cluster land uses to manage pollution

Pre-Application – Where do I begin?

• Pre-App is not need detailed design – Build an idea of

the concept SuDs – software is available.

Image courtesy of Innovyze (www.innovyze.com)

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• Existing drainage features, watercourses, ditches, drains etc

Main River Ordinary watercourses

• 8m easements
• Existing Surface Water flow paths – Direct Rainfall Mapping

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• Green corridors -

Wooded areas

Correspond to: Watercourse easements Blue Flow Path

• Blue / Green Corridors

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• Existing Flow Routes
• Develop Design with Modified Flow Routes

21/05/2019 18 What components could I use? A selection of examples

• Property Level SuDs

Rainwater harvesting – can be simple, sustainable development, SW control

Image courtesy of SusDrain (www.susdrain.org) CCBC SuDs Design Guide

What components could I use? A selection of examples

• Property Level SuDs

Green / blue roofs – Interception storage, biodiversity, amenity

Image courtesy of SusDrain (www.susdrain.org) Image courtesy of SusDrain (www.susdrain.org) Source: http://www.bristol.gov.uk/page/environment/flood-risk-drainage-and-development

21/05/2019 19 What components could I use? A selection of examples

• Property Level SuDs

Rain-garden –maximize use of space source control, amenity, biodiversity, SW control

Image courtesy of SusDrain (www.susdrain.org) Image courtesy of SusDrain (www.susdrain.org) Image courtesy of SusDrain (www.susdrain.org)

Pecs, Hungary

What components could I use? A selection of examples

• Property Level SuDs

Permeable surfacing – Water quality and SW management

Image courtesy of SusDrain (www.susdrain.org) Image courtesy of SusDrain (www.susdrain.org) St Davids Close, Rhymney, Caerphilly Former Junior School, Blackwood, Caerphilly Image courtesy of SusDrain (www.susdrain.org)

21/05/2019 20 What components could I use? A selection of examples

• Conveyance

Rills - You don’t need pipes – limited space, easy to maintain, amenity

Image courtesy of SusDrain (www.susdrain.org) Image courtesy of SusDrain (www.susdrain.org)

What components could I use? A selection of examples

• Conveyance

Swales - You don’t need pipes – limited space, easy to maintain, amenity

Image courtesy of SusDrain (www.susdrain.org) Image courtesy of SusDrain (www.susdrain.org) Pecs, Hungary

Not this!

21/05/2019 21 What components could I use? A selection of examples

• Conveyance

Pipes – still have their place….good for connecting suds features. Maintenance and operation is a key consideration

What components could I use? A selection of examples

• Site/ Regional SuDs

Pond & Wetlands….polishing for water quality….amenity…biodiversity

Image courtesy of SusDrain (www.susdrain.org) CCBC SuDs Design Guide

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• Develop Design – Type of solutions……

Ponds… polishing for improved water quality…..Amenity….. Habitat creation Create multi-functional spaces!

Image courtesy of SusDrain (www.susdrain.org)

• Highway SuDs

Many options….. Permeable Surface

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• Highway SuDs

Many options….. Rain Gardens – Greener Grangetown

Images courtesy of SusDrain (www.susdrain.org)

• Highway SuDs

Many options….. Tree pits / Vegetation units

Images courtesy of SusDrain (www.susdrain.org)

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• Highway SuDs

Opportunities Traffic Calming – wasted space….

• No one solutions fits all

Innovative SuDs…..

• Highway SuDs

Opportunities Verges / vision splays – wasted space…

21/05/2019 25 What components could I use?

• Management Train – All the above

SuDs components in series provide the management train

Image courtesy of SusDrain (www.susdrain.org)

When Traditional Drainage Fails! When SuDs operate!

Image courtesy of SusDrain (www.susdrain.org)

Source: Dwr Cymru Welsh Water

Highway Flooding Caerphilly CBC

21/05/2019 26 What resources are there? A starting point

• Caerphilly CBC SAB – www.caerphilly.gov.uk/sab
• Statutory National Standards for Sustainable Drianage Systems
• https://gov.wales/docs/desh/publications/181015-suds-statutory-standards-en.pdf
• CIRIA The SuDs Manual C753 - www.ciria.org
• Susdrain – www.susdrain.org
• SuDs Wales – www.sudswales.com

Sustainable Drainage Approval Body (SAB) Any questions?