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

21/05/2019 Sustainable Drainage Approval Body (SAB) Michelle Johnson johnsm@caerphilly.gov.uk Rhodri Powell powelr4@caerphilly.gov.uk Highways House, Penmaen Ind Est, NP12 2DY 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 1

21/05/2019 Flood & Water Management Act 2010 Schedule 3: Sustainable Drainage Commencement Date: 7 th January 2019  All new developments of more than 1 dwelling or where the construction area is => 100m 2 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 2

21/05/2019 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) 3

21/05/2019 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 4

21/05/2019 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. 5

21/05/2019 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. 6

21/05/2019 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 7

21/05/2019 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 8

21/05/2019 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 9

21/05/2019 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 10

21/05/2019 Next……. SuDs Pre-application Designing for compliant SuDs Example SuDs Sustainable Drainage Approval Body (SAB) Pre-Application Blue / Green Corridor Assessment Compliant SuDs Rhodri Powell Email: powelr4@caerphilly.gov.uk Web: www.caerphilly.gov.uk/SAB 11

21/05/2019 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…. 12

21/05/2019 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) Case Study - Former Ty Pontllanfraith, Blackwood Applying to Pre-application stage 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 13

21/05/2019 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) 14

21/05/2019  Existing drainage features, watercourses, ditches, drains etc Main River Ordinary watercourses - 8m easements  Existing Surface Water flow paths – Direct Rainfall Mapping 15

21/05/2019  Green corridors - Wooded areas Correspond to: Watercourse easements Blue Flow Path  Blue / Green Corridors 16

21/05/2019  Existing Flow Routes  Develop Design with Modified Flow Routes 17

21/05/2019 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) Source: http://www.bristol.gov.uk/page/environment/flood-risk-drainage-and-development Image courtesy of SusDrain (www.susdrain.org) 18

21/05/2019 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) Pecs, Hungary Image courtesy of SusDrain (www.susdrain.org) 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) 19