1. Green infrastructure and water engineering – a match made in heaven?
Professor David Butler
Director of the Centre for Water Systems, University of Exeter

2. Water in the City
Brown et al, Monash University

3. Water in the City...the Way Forward?
Low tech (natural)
Small scale ( decentralised)
Cyclical (joined up)
Resource water (recovery)
Bespoke water (fit for purpose)
Resilient (flexible)
Partners (stakeholders)
High tech (smart)
Large scale (centralised)
Linear (separate)
Wastewater (pollution)
Potable water (highest quality)
Robust (capacity)
Customers (bill payers)

4. Stormwater Management by ‘Sustainable Drainage (SuDS)’
Hard SuDS
Soft SuDS

5. Green Infrastructure - Water Engineering Considerations
Benefits:
Increases permeable area – groundwater recharge
Attenuates peak runoff flows – flood control
Improves runoff water quality – ecosystem protection
Reduces operational energy consumption – GHG emissions
Reduces costs?
Drawbacks:
Requires increased surface space – retrofit?
Lacks clarity of ownership – SuDS approving body (SAB)
Doubt over long-term performance – need for maintenance
Increases embedded carbon? – GHG emissions

6. Green Infrastructure - Added Value
Added benefits:
Improves local air quality
Enriches biodiversity
Improves habitat and connectivity
Benefits human (physical and mental) health
Provides amenity and recreation potential
Enhances quality of life

7. GI retrofit – US style
Green streets design solutions, USEPA

8. GI retrofit – UK style? After Before

9. Retrofit GI – making it happen
Barriers to retrofit GI
GI in practice
Lack of space, disruptions to the public.
Multifunctional GI.
Education, design for people first, opportunistic interventions.
Create adaptable infrastructure.
Lack of resources, high costs.
Numerous stakeholders.
Multifunctional GI, opportunistic interventions.
Work in partnerships.
Association of GI/SUDS to new developments.
Lack of experience.
Education, build awareness.
Pilot projects/ showcases.
Learn by doing.
Learn from successful experiences.
Education and awareness.

10. Conclusions
Water engineering is at a crossroads concerning water in the (future) city.
An important facet of the ‘water cycle’ city or the ‘water sensitive’ city will be ‘soft’ sustainable drainage systems or green infrastructure.
A pressing need is therefore to work our exactly how to retrofit systems into existing cities and how to overcome barriers.
Partnership working and realisation of multiple benefits are key to making this happen.
Water engineering & green infrastructure – truly a heavenly match!

11. Green infrastructure and water engineering – a match made in heaven?
Professor David Butler
Director of the Centre for Water Systems, University of Exeter