Making space for waterIntegrated Urban Drainage pilots

River Aire Strategic StudiesPreliminary results

City of Bradford Metropolitan District Council

Leeds City Council

Yorkshire Water

Environment Agency

Pennine Water Group, Universities of Bradford and Sheffield

The challenge

To provide information to facilitate a sea change in behaviour

What if?

• The global carbon economy continues to expand unabated until constrained by the economies of scarcity?

• Densification of our urban areas continues at the same rate as it has done for the past 50 years?

• The management of our urban drainage systems continues as it has done for the past 50 years?

Pressures

• Up to 20% increase in rainfall depth by 2085!• Up to 20% increase in rainfall intensity by 2085!• Up to 20% increase in impermeable area by 2055 if we

don’t alter the way that we manage our urban landscape!

• Up to 30% more space occupied by buildings by 2055• Up to 20% reduction in infiltration to groundwater

overall by 2055 and up to 40% reduction when urban green space is excluded!

• Up to 40 increase in temperature of receiving waters in summer coupled with reduced base flows!

States• Ofwat and the Environment Agency will continue to

regulate inflexible nationally driven campaign based investment programmes with set deliverables identified on a five yearly basis. There will be little funding available for large scale upgrading of urban drainage systems

• Government refuses to legislate to define responsibilities such as the adoption of SuDS or to provide real guidance for brownfield development

• Local authorities will continue to be under-funded and under staffed in relevant disciplines and so will not be able to address the emerging problems

• As a result of this developments go ahead using conventional piped drainage systems with little concern for the management of excess flows

The study area

50 Km

KEIGHLEY HIGH LEVEL

KEIGHLEY LOW LEVELSUTTON IN CRAVEN

BINGLEY

HARDEN VALLEYSHIPLEY

EAST BRADFORD

THORNTON VALLEY

LITTLE HORTON

HORTON VALLEY

HEATON & FRIZINGHALL

CITY CENTRE/WTS

MANNINGHAM

MANCHESTER RD/BOWLING

Baildon

ECCLESHILL & GREENGATES

RAWDON

YEADON

RODLEY

PUDSEY

SMALEWELL

MORLEY

MIDDLETON

WORTLEY

HORSFORTH

WYKEBECK

MEANWOOD

GIPTON

50 Km

KEIGHLEY HIGH LEVEL

KEIGHLEY LOW LEVELSUTTON IN CRAVEN

BINGLEY

HARDEN VALLEYSHIPLEY

EAST BRADFORD

THORNTON VALLEY

LITTLE HORTON

HORTON VALLEY

HEATON & FRIZINGHALL

CITY CENTRE/WTS

MANNINGHAM

MANCHESTER RD/BOWLING

Baildon

ECCLESHILL & GREENGATES

RAWDON

YEADON

RODLEY

PUDSEY

SMALEWELL

MORLEY

MIDDLETON

WORTLEY

HORSFORTH

WYKEBECK

MEANWOOD

GIPTON

Urban impacts

Predicted percentage increase in runoff at a given location

0

20

40

60

80

100

120

140

160

180

2005 2025 2045 2065 2085

Year

Pe

rce

nta

ge

in

cre

as

e i

n

run

off

Climate change

Urbanisation

Predicted percentage increase in flood vulnerable areas

0102030405060708090

100

2005 2025 2045 2065 2085

Year

Pre

ce

nta

ge

in

cre

as

e i

n

nu

mb

er

of

flo

od

vu

lne

rab

le

are

as

Urbanisation

Climate change

Predicted percentage increase in urban surface flow

0

20

40

60

80

100

120

140

160

180

200

2005 2025 2045 2065 2085

Year

Pe

rce

nta

ge

in

cre

as

e i

n u

rba

n

su

rfa

ce

flo

w

Urbanisation

Climate change

• Potential doubling of the frequency of flooding due to climate change at a given location

• Potential doubling of the frequency of flooding due to urbanisation at a given location

• Potential quadrupling of the frequency of flooding due to combined impacts

River impacts

• Up to 15% increase in peak spill to receiving waters due to climate change during extreme wet weather, but unlikely to coincide with river peak

• Up to 80% increase in spill volume due to climate change at drainage area scale for twice yearly summer rainfall

• Up to 10% increase in flow to full treatment due to climate change during wet weather

Tales of the river bank

• Interaction between the river and the sewers

LegendManholePipeRoadsWaterFlood Depth (M)0.1 - 0.50.5 - 1.01.0 - 2.0Above 2.0

:0 15075

M

No flood defense

With flood defense and flap valves

With flood defense

10 year 120 minute rainfall with free outflow

LegendManholePipeRoadsWaterFlood Depth (M)0.1 - 0.50.5 - 1.01.0 - 2.0Above 2.0

:0 15075

M

No flood defense

With flood defense and flap valves

With flood defense

100 year river level with 10 year rainfall

120 minute 360 minute

LegendManholePipeRoadsWaterFlood Depth (M)0.1 - 0.50.5 - 1.01.0 - 2.0Above 2.0

:0 15075

M

No flood defense

With flood defense and flap valves

With flood defense

100 year river level with 30 year rainfall

120 minute 360 minute

The way forward

• The analysis is providing compelling evidence to change the way that things are done.

• Planners want to know where the predicted flooding is likely to occur so that they can either– Avoid specific areas– Develop suitable policy to allow development

• There are concerns over issues relating to blight of properties, so Defra needs to insist that the models and/or the results of the simulations are made available.

• The outputs indicate where more detailed modelling is required.

The AUDACIOUS approach (a framework for urban storm and surface

water management)

Urban flood risk management and the land and water planning frameworks – the storm

and surface water management plan and the land and water management plan

Water management Land Management management

Local development framework

Urban regeneration land management