Peter NicholsonARCADIS

Living with Water: The Sponge City Programme

A focus on the city of Wuhan, China

© Arcadis 2016

What is a “Sponge City”?

A Sponge City refers to sustainable urban development including flood control, water conservation, water quality improvement and natural eco-system protection.

It's not hundreds of projects but a nature based solution for urban planning and also a good way to facilitate the development of local policies and regulations.

© Arcadis 2016

Beijing Wuhan

Made in Nanjing

Chengdu

Made in Shanghai

Guangzhou

Changsha

Drivers for action in China

• Large scale urbanisation from

1980s

• Decrease of natural waterbodies

• Significant storm events

• Water scarcity events

• Aging infrastructure with higher

pressures

• Poor water quality

© Arcadis 2016

Reasons for Nationwide Issues

External factor: climate change

• Extreme rainfall events are getting more frequent, intense, and difficult for prediction.

• Wet areas get wetter, dry areas get drier

Internal factor: unsustainable urban planning

• Decrease of natural waterbodies: from 1960-2005,

Chinese lakes have shrunk in size and number. The total

area of Chinese lakes over that period shrank by 13% of

their original size, an area just a bit smaller than

Connecticut

• Urbanisation: urban population from 36.22% in 2000 to

54.77% in 2014

• Increase of concrete paved surface: China used more

concrete in 3 years than the US used in the entire 20th

Century

• With limited water retention capacity in urban areas: 70-

80% of storm water forms urban runoff once it falls,

which has to be transported by sewerage / drainage

systems or pumped out to rivers

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• Since 2010, extreme rainfall events are recorded as increasing in frequency, and a range of metropolises in China have suffered repeat flooding / water-logging events

• Pluvial problems are not a random event, but nationwide issue

Timeline

2010 2011 2012 2013 2014 2015 2016

• Jinan, Changchun, Nanjing and Guangzhou all had serious pluvial events;

• 137 cities and towns were flooded;

• Wuhan: 80 road sections were waterlogging in the June rainfall event ;

• The concept of Sponge City was firstly posed at April, 2012

• Beijing 21/7 Cloudburst: total economic loss was 11.64 billion RMB, and

• 79 lost their life.

• Shanghai 13/9 and 08/10 cloudburst events;

• More than 239 cities were affected by flooding;

• 12st December, 2013, the concept of ‘Sponge City was emphasised by President Xi.

• At October 2014, the sponge city national guidelines was published;

• At 31st December, the national government decided to start Sponge City pilot program

• 2nd April, 16 pilot cities were selected (including Wuhan)

• 27th April, 14more pilot cities were selected

Nationwide issues

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USACanadaLow Impact Development (LID)

AustraliaWater SensitiveUrban Design (WSUD)

United KingdomSustainableUrban Drainage Systems (SUDS)

The NetherlandsThe Climate Proof

City (2050) CPC 2050

ChinaSponge City(since 2014)

Sponge City – the inspiration

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PHILOSOPHY• Climate resilience

• Reduce flood risk

• Holistic approach

• Thinking about water, as an opportunity

• Urban natural water system

• An integrated and laddered water system

KEY WORDS• Water safety

• Water quantity

• Water quality & ecology

• Water reuse

A Sponge City is a city that acts as a sponge

with an urban environment planned and

constructed to soak up almost every raindrop

and capture that water for reuse.

China Sponge City

© Arcadis 2016

Data collection

and modelling

SUDS / LID

Traditional

storm water

system

Extreme

precipitation

storm water

system

Building and

community

Road

Green and

square

Water

Infiltration,

retention,

storage,

purification,

utilization,

drainage

Storage and

drainage

System type Applicable area Possible measures

• Using 3 different systems

(depending on the precipitation)

with 6 varied basic measures to

solve rainfall runoff problems.

China Sponge City principle

Problem with

Sponge City

compliance

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Sponge City Project - Technical Solutions

The advanced sponge

techniques was introduced in

this report.

基层

路面铺装

检查井

入水管

沉积井

出水管

土木格栅

雨水储存模

块

土木格栅

过滤材料

（土工布）

Underground rainwater storage system

Urban green roof

Rain barrels

Pervious

pavement

Bio retention facilityGrassed swale

beside the

sidewalk

Rainwater square

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Category No. Criteria

Water Ecology

1 Volume capture ratio of annual rainfall

2 Recovery of ecological shorelines

3 Groundwater level

4 Urban heat

Water Quality

5 Water quality

6 Urbana non-point pollution control

Water Resources

7 Wastewater recycling ratio

8 Stormwater recycling ratio

9 Pipes leakage ratio

Water Safety10 Water-logging prevention

11 Potable water safety

Institutional setup

and

implementation

12Regulation for managing the planning and

constructions

13 Define blue-green lines, and protection

14 Technical guidelines and standards setup

15 Investment and financial setup

16 Performance appraisal and rewarding

17 Industrialization

Display 18 Continuous effect

National Evaluation of a Sponge City

No Criteria Standard Range Remark

1

Use and

management of

funds

Funds were allocated in time, used and managed

securely, 15 credits; 70-90% of funds were allocated,

the use and management is okay and haven't

influenced the project 7 credits; less than 70% funds

have been allocated and the use and management was

not organized and have hindered the process of

project, 0 credits

0-15

credits

2

Collaboration

between

government and

social capital

The ratio: investments from PPP/total investment for

the project>70%, 10 credits; 70%-30%, 5 credits;

<30%, 0 credit

0-10

credits

3 Cost guarantee

Set up the scheme of charging standards of different

categories of constructions, set up the cost guarantee

mechanism for maintenance, determine standards for

governmental subsidies, methods to evaluate the

operation conditions. yes 10 credits, o for no

0-10

credits

4 Quantity

All of the planed project area have been finished (or

even more) get 20 credits, 80-100% 10 credits, <80%,

fail

0-20

credits

Completeness of

planning

5 Quality

Refer to capture ratio, 10 credits go to the project

meets its objective, 5 go to project 90% of target

capture ratio or need 5mm to go. Others 0 credits

0-10

creditsCapture ratio

6Project

effectiveness

All the criteria(18) meet objectives, 25 credits; more

than the half criteria meet their objectives, 15 credits; 0

for the left

0-25

creditsAll the 18 criteria

7Technical

approach

Very systematic, scientific and meet requirements from

related technical standards and codes, 10 credits;

otherwise zero

0-10

credits

Setup of Sponge City Pilot Program Performance Assessment CriteriaSponge City Performance Appraisal and Evaluation

Criteria （Trail）

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Wuhan, Hubei

Short duration precipitation graph for Wuhan (1971-

2012)

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Wuhan Sponge City Project

• In March 2015, the Wuhan government published implementation plan for Wuhan

Sponge City project

• Qingshan and Sixin are the two pilot areas for Wuhan sponge city project

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Wuhan Sponge City Project - Qingshan

• Area targeted for redevelopment

• A main channel flows from northeast to south to supply

industry

• Suffers severe flooding and water quality problems

• The residents asked for more parking and activities space

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Wuhan Sponge City Project - Sixin

• New developed area

• Most channels connect to the surrounding lakes

• Water quality and flooding are the main issues

• Some new development have good existing landscape and

layout, only small retrofit needed.

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Sponge City Project - Examples in Wuhan

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• Technical services: giving

advice on SUDS / LID

measures selection, reviewing

feasibility study, control plan,

research subject, monitoring

plan, etc

• Policy and regulation: giving

introduction and case study on

EU's, Netherland's and

Australian water management

policies and rules, promoting

water assessment to WWA

• Program management: giving

advices on existing program

management system, focusing

on maintenance planning

• MOHURD evaluated our work

and gave positive feedback

Wuhan Sponge City Project – our scope

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• The Water Assessment is an instrument in

the preparation of spatial plans and

decisions.

• Ensures water has to be considered at every

stage of a plan.

Evaluation items:

• Safety (water quantity & erosion)

• Flooding (economic damage)

• Water supply / Dehydration

• Public health

• Surface subsidence

• Water quality

• Sewage (waste- and storm water)

• Groundwater

• Risks and costs

• Water and nature

• Sustainability

Water assessment - Guidance

Wuhan Sponge City Project - policy and regulation

© Arcadis 2016

The Sponge City criteria which

Wuhan should focus on was

identified in this report.

• Developing objectives and criteria for Wuhan

Wuhan Sponge City Project - objectives

Criterion Standard Sub-standard Requirement

Volume capture ratio of

annual rainfall70-75%

Pervious pave: account

for 35-50% of overall

pave

Depressed green to

green space >25%

Depressed green to

overall land use area

>3%

LID design scheme and

storm water route map

Waterlogging preventionP=20 (P=3 for pipe

and channel system)

Peak runoff coefficient

≤0.65

Hydraulic simulation

results

Point pollution controlEliminate point

pollution source

Investigation on point

pollution source and

sewerage system

Sewerage system

upgraded scheme

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• Some cities show 85% reduction of annual runoff, mitigating floods, conserving and recharging

groundwater

• Challenge - Geographical challenges and land scarcity

• Challenge - Funding and (new) PPP focus, local debt

• Challenge - Landowners permissions and stakeholder engagement

• Challenge - Maintenance / Ownership burden. Costs unknown

• Challenge - Lack of local government expertise, experience and local policy variances

• Challenge - Complex and irregular client and design arrangements

• Challenge - Data availability and sharing of lessons. Many agencies and boundaries

• Opportunity - Cost savings opportunities for maintenance and reduced new infrastructure need

• Opportunity - Improved design standards, legislations and regulation (MTRs)

• Opportunity - Improved quality of life!

Results, challenges, opportunities

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• During the urban planning and design stages an allowance must be made to

accommodate water management

• The building of Sponge City is not only a project but a program

• Cities should identify its own targets by analysing its own characteristics

• The strategy of building Sponge Cities should be unified and comprehensive

• The reliability of data or information collected, monitored or shared is the key

Wuhan Sponge City Project - Lessons learned & Recommendations

• Establish a centralised management mechanism.

• Co-operate with International companies or

organizations to learn the best practice experience

© Arcadis 2016

Arcadis.Improving quality of life.