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China’s sponge city construction: A discussion on technical approaches


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Since 2014, China has been implementing the Sponge City Construction initiative, which represents an enormous and unprecedented effort by any government in the world for achieving urban sustainability. According to preliminary estimates, the total investment on the Sponge City Plan is roughly 100 to 150 million Yuan (RMB) ($15 to $22.5 million) average per square kilometer or 10 Trillion Yuan (RMB) ($1.5 Trillion) for the 657 cities nationwide. The Sponge City Plan (SCP) calls for the use of natural processes such as soil and vegetation as part of the urban runoff control strategy, which is similar to that of low impact development (LID) and green infrastructure (GI) practices being promoted in many parts of the world. The SCP includes as its goals not only effective urban flood control, but also rainwater harvest, water quality improvement and ecological restoration. So far, the SCP implementation has encountered some barriers and challenges due to many factors. The present paper presents a review of those barriers and challenges, offers discussions and recommendations on several technical aspects such as control goals and objectives; planning/design and construction of LID/GI practices; performance evaluation. Several key recommendations are proposed on Sponge City implementation strategy, Site-specific regulatory framework and technical guidance, Product innovation and certification, LID/GI Project financing, LID/GI professional training and certification, public outreach and education. It is expected that the successful implementation of the SCP not only will bring about a sustainable, eco-friendly urbanization process in China, but also contribute enormously to the LID/GI research and development with the vast amount of relevant data and experiences generated from the Sponge City construction projects.Open image in new window
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Chinas Sponge City construction: A discussion on technical
Haifeng Jia ()
, Zheng Wang
, Xiaoyue Zhen
, Mike Clar
, Shaw L. Yu
1 School of Environment, Tsinghua University, Beijing 100084, China
2 Beijing Orient Tetra Tech Ecological Technology Ltd., Beijing 100051, China
3 Tetra Tech, Fairfax, VA 22030, USA
4 Department of Civil & Environmental Engineering, University of Virginia, Charlottesville, VA 22904, USA
1 Introduction
Over the past decade Chinas urban population has grown
to 52.4%in 2015 from 42.5%in 2005, and the build-up
areas have increased by 17,252 km
. This roughly equates
to an addition of 165 million people dwelling in urban
areas in a decade! This rapid urbanization process has led
to a worsening city syndromesituation such as urban
ooding, water pollution, heat-island effects and ecologic
deterioration, etc. [1].
To promote a sustainable urbanization strategy, the
Chinese government announced in late 2013 a Sponge
Corresponding author
Hot ColumnLow Impact Development and Sponge City (Respon-
sible Editors: Haifeng Jia & Shaw L.Yu)
Front. Environ. Sci. Eng. 2017, 11(4): 18
DOI 10.1007/s11783-017-0984-9
Barriers and challenges of Sponge City construc-
tion were presented.
Several key technical points on Sponge City
implementation were discussed.
Recommendations on Sponge City implementa-
tion strategy are proposed.
Article history:
Received 28 May 2017
Revised 29 June 2017
Accepted 9 July 2017
Available online 12 August 2017
Low impact development (LID)
Green infrastructure (GI)
Sponge City
Construction strategies
Since 2014, China has been implementing the Sponge City Construction initiative, which represents an
enormous and unprecedented effort by any government in the world for achieving urban sustainability.
According to preliminary estimates, the total investment on the Sponge City Planis roughly 100 to 150
million Yuan (RMB) ($15 to $22.5 million) average per square kilometer or 10 Trillion Yuan (RMB)
($1.5 Trillion) for the 657 cities nationwide. The Sponge City Plan (SCP) calls for the use of natural
processes such as soil and vegetation as part of the urban runoff control strategy, which is similar to
that of low impact development (LID) and green infrastructure (GI) practices being promoted in many
parts of the world. The SCP includes as its goals not only effective urban ood control, but also
rainwater harvest, water quality improvement and ecological restoration. So far, the SCP
implementation has encountered some barriers and challenges due to many factors. The present
paper presents a review of those barriers and challenges, offers discussions and recommendations on
several technical aspects such as control goals and objectives; planning/design and construction of
LID/GI practices; performance evaluation. Several key recommendations are proposed on Sponge City
implementation strategy, Site-specic regulatory framework and technical guidance, Product
innovation and certication, LID/GI Project nancing, LID/GI professional training and certication,
public outreach and education. It is expected that the successful implementation of the SCP not only
will bring about a sustainable, eco-friendly urbanization process in China, but also contribute
enormously to the LID/GI research and development with the vast amount of relevant data and
experiences generated from the Sponge City construction projects.
© Higher Education Press and SpringerVerlag Berlin Heidelberg 2017
Cityinitiative in building urban infrastructures. Deviating
from the traditional rapid-drainingapproach, the new
paradigm calls for the use of natural processes such as soil
and vegetation as part of the urban runoff control strategy.
The six-wordprinciple, which includes inltrate, detain,
store, cleanse, use and drain, forms the guidelines for urban
storm water management. These principles are similar to
those under the Low Impact Development (LID) paradigm
that has been promoted and implemented in many parts of
the world [2]. LID technology employs principles such as
preserving and recreating natural landscape features,
minimizing effective imperviousness to create functional
and appealing site drainage that treat storm water as a
resource rather than a waste product [3].
In October 2014 the China Ministry of Housing and
Urban-Rural Construction (MHURC) issued a draft
technical manual on Sponge City construction. In October
2015 the State Council of China announced a major
expansion of the Sponge City Initiative, which is being
implemented nationwide. Recognizing the limitation of
Low Impact Development (LID) / Green Infrastructure
(GI) facilities in controlling large or less frequent storm
events, the government mandates the integration of green
and gray infrastructure. The expanded Sponge City Plan
(SCP) includes as its goals not only effective urban ood
control, but also rainwater harvest, water quality improve-
ment and ecological restoration. The use of LID/GI
practices will be required for all new development and
retrot sites, science and commercial parks, green spaces,
non-mechanical vehicle roads, pedestrian walkways, etc.
During 2015 and 2016, the China Ministry of Finance
(MOF), with support from MHURC and the Ministry of
Water Resources (MWR), selected 30 cities (Fig. 1),
among more than ve hundred applicants, as pilot sites
under the SCP. Each city is to receive 400 to 600 million
Yuan (RMB) (60 to 90 million US$) annually from the
central government for three years, with the total
investment estimated to be about 42.3 billion Yuan
(RMB) or 6.35 billion US$. Local matching is required
and public-private partnerships (PPP) are encouraged.
Cities will receive a 10%bonus from the central
government if the PPP contribution exceeds a certain
percentage of the overall budget. According to preliminary
estimates, the total investment on the SCP is roughly 100
to 150 million Yuan (RMB) ($15 to $22.5 million) average
per square kilometer or 10 trillion Yuan (RMB) ($1.5
Trillion) for the 657 cities nationwide [46].
Chinas SCP represents an enormous and unprecedented
Fig. 1 Locations of pilot Sponge Cities
2 Front. Environ. Sci. Eng. 2017, 11(4): 18
undertaking by the government for achieving urban
sustainability. MHURC ofcials recognize that the success
of the Sponge City construction will require a combined
and coordinated effort by many government agencies in
areas such as landscape/architectural planning, construc-
tion, municipal, water, transportation, nance, environ-
mental protection and input from other stakeholders. In
addition, to nance all the Sponge City projects is a real
challenge. The government has listed some innovative
strategies for fund-raising, which includes, in addition to
government grants and subsidies, local matching and
public-private partnerships. The government is also
encouraging participation by nancial institutions, and
will allow qualied entities to issue construction bonds to
nance the Sponge City projects.
2 Barriers and challenges for the Sponge
City construction
Since the initial implementation of LID practices in the
United States during the early 2000s, signicant barriers
and challenges have existed and hindered its progress. The
China Sponge City projects are now encountering similar
situations. The following is a list that is compiled from
experiences in both countries [1,7]:
(1) Resistance to change. Inertia of traditional
It is human nature to resist change, especially regarding
something that is unproven for its suitability and cost-
effectiveness. LID technology is relatively new and has not
be widely understood, especially at the local level. Many
misconceptions still exist, e.g. LID can solve all urban
ooding problems. Gradually people begin to realize LID
targets only smaller storm events and must be integrated
with traditional gray infrastructure approach for managing
larger runoff events. In China, e.g., the age-old notion of
man can conquer nature, yet the basic concept of the
Sponge City approach is living with nature and making use
of natures abilities. Although the Central Government has
mandated the Sponge City construction and has issued
technical guidelines, some provincial and local govern-
ment ofcials are slow to act due to inertia of traditions.
(2) Limited technical guidance on planning, design and
assessment of LID facilities
Even though LID practices have been widely used
beginning in early 2000s, revised or new technical manuals
and guidance books still are been issued in the United
States. Urban runoff characteristics are very site-specic
[8] and local environmental and social-economic condi-
tions vary from location to location. Therefore, local, or at
least regional, guides would be most helpful. A case in
point is the need for a list of native plants suitable for use in
bioretention cells. Currently, localized technical guidance
is still not available for many designated sponge cities in
(3) Lack of close coordination among agencies at the
local level
For example, design of the LID practice, bioretention
cell, needs input from both storm water and landscape
architect professionals. Such a coordinated effort has not
been the norm because storm water management and road
side vegetation management are responsibilities belonging
to different agencies. Currently, there is close coordination
among the key agencies responsible for implementing the
Sponge City Plan at the ministry level, i.e., MHURC, MOF
and MWR. However, at the local, or Sponge City level,
often many agencies are involved, such as the urban
planning, construction, water conservancy, and environ-
ment protection bureaus, etc. A smooth and efcient
Sponge City implementation requires a great effort and
time for inter-agency coordination. To facilitate such
efforts, some Sponge City pilot cities have created the
Sponge City Ofces,which include representation from
all bureaus related to urban water.
(4) Quantication of LID cost effectiveness
Currently, performance of an LID practice is usually
measured as percentage of runoff volumeor fraction of
pollutant loadremoved by the practice. However, how
this percentage of fractionis calculated is still been
discussed. Should this be based on a subjectively selected
design storm? Or it should be calculated on a continuous
basis for all storms occurred during a specic period of
time, say, a year? The other important factor is how the
success (or failure) of the LID/GI implementation be
incorporated into the performance evaluation of local
ofcials. If the promotional evaluation process could be
modied to include results of Sponge City implementation,
local ofcials would be much more committed to its
(5) Finance Sponge City project
Sponge City construction is a public endeavor and
would require public nancing. A number of nancing
schemes have been used in the US, e.g., storm water
utilities, federal government grants, state government cost-
sharing, etc. However, if the use of LID is a mandated
activity, a strong nancing plan should be provided to local
Public-private partnerships (PPP) are encouraged in
nancing Sponge City project. However, there are several
factors which inuence the invest interest of social capital,
such as the perceived high costs of design, construction
and maintenance; inadequate investment and return
estimates; no clear economic incentive for using LID.
(6) Education and training do not provide skills to design
and implement LID
To implement successfully an LID/GI practice construc-
tion project, knowledge from many disciplines is required.
Subjects of expertise needed are many. For example,
planning/design of LID facilities would need skills in
storm water management, urban hydrology and hydraulics
(scales from site to region to watershed), water quality
Haifeng Jia et al. Chinas Sponge City construction: A discussion on technical approaches 3
modeling, optimization techniques, etc. However, the
specic system education and training programs are still
lack in University and College.
The present paper is aimed at providing a discussion of
and recommendations for addressing a number of
challenges listed above, with emphasis on the technical
aspects of implementing LID/GI practices.
3 Discussions on some technical
approaches for Sponge City Plan
3.1 Set clear management goals and objectives
(1) LID/GI practices are designed for controlling smaller
storm events.
LID practices are on-siteand distributedfacilities
and therefore are basically used to control smaller runoff
events. Also, a major consideration for targeting smaller,
more frequent runoff events is the rst-ashphenom-
enon observed in many urban areas [8]. For example, by
controlling the rst 0.5 inches (13 mm) of runoff, a
signicant amount (~80%) of pollutants carried by the
runoff can be removed. The rst LID design manual [9]
clearly identied the control target of LID facilities, as
shown in Fig. 2.
In Fig. 2, the amount of rainfall volumes (vertical axis)
are roughly divided into four control categories using
rainfall data for Prince Georges County, Maryland, USA.
At high frequencies, e.g. less than one year, the rainfall
volumes are small and control goal is to enhance
inltration for groundwater recharge and to remove
pollutants in the rst-ush of runoff for water quality
protection. For storms with 2-year frequency or less, the
goal is to control channel erosion and also water quality. A
10-year frequency is commonly used for peak ow
reduction for erosion and ood control. The regulations
usually require the use of a 100-year frequency for
detention facility emergency spillway design.
A more recent version of the control target illustration is
given in Fig. 3 [10]. It illustrates the overall strategy for
urban storm water runoff control. In the gure, Curve
represents the ows across all frequencies expected
after development (increase in imperviousness). The
ultimate goal of runoff control is to restore the site
hydrology (runoff peak and volume, time of concentration,
etc.) to the original regime or pre-development conditions
exited at the site, as depicted by Curve . The traditional
storm water management approach relies mainly on
detention processes (design frequency 10-100 years) that
moves Curve to Curve . With some modications (e.
g. extended detention) Curve could be achieved for
additional water quality benets. The current LID/GI
strategy is to optimize the control of smaller storms
(frequency 2 years or less) so that Curve can be reached
and water quality protection is further enhanced.
The nal selection of control targets should be made
considering local environmental, social and economic
situations. Of special interest, however, it should be noted
that if the control target is a frequency (e.g., 95%), it will
mean different design volumes for different locations. On
the other hand, if the target is a volume for control (e.g., 13
mm runoff), then it means different frequencies for
different locations, as shown in Fig. 4 for several typical
cities in United State [11].
An example of control targets and goals set by a locality
is given below [12]. In Town of Chapel Hill in North
Fig. 2 Storm water management basic control targets
4 Front. Environ. Sci. Eng. 2017, 11(4): 18
Carolina, USA, the control target of TSS is 85%removal
for rst 1 inch of precipitation; Volume leaving site post-
development shall not exceed volume pre-development for
the 2 year 24 h storm event (3.60 inches); Rate leaving site
post-development shall not exceed rate pre-development
for the 1, 2, 25 and 50 year storm are set as 3.00, 3.60, 6.41
and 7.21 inches respectively.
In China, the Guiding Opinions on Advancing the
Construction of Sponge Cities issued by the China State
Council sets a control goal of 70%annual runoff volume
for 20%of the built-up areas by 2020. To achieve such
goals, cities in different climate regions will need different
design criteria for their control practices, as in United State
illustrated in Fig. 4.
(2) Hydrograph generation and temporal distribution of
Hydrograph generation is needed for facility design and
detailed analysis of performance. The within storm rainfall
distribution, or temporal distribution of rainfall, enables the
determination of a hyetograph, which is needed for
hydrograph generation [13].
The most commonly used method in US for determining
the temporal distribution of a design storm is the SCS
rainfall distribution curves as shown in Figs. 5 [14].
Using rainfall charts shown in Figs. 5, one can generate
the appropriate design rainfall hyetograph and then the
design runoff hydrograph. An example of hydrograph
generation application is shown in Fig. 6 below [9].
In Fig. 6, Q is discharge ow; T is Time. Curve
represents the existing hydrograph at the site from a design
storm. Curve is the hydrograph from the same storm
under post-development conditions. Curve shows the
Fig. 3 Urban runoff control strategies
Fig. 4 Percentage runoff capture rate vs. Storage volume required
Haifeng Jia et al. Chinas Sponge City construction: A discussion on technical approaches 5
effect of LID plus additional detention facilities. The post-
development peak discharge is reduced to the pre-
development level and also signicantly, the ows during
the early time steps are removed or lowered, which helps
the removal of pollutants during the rst-ash time period.
3.2 Planning and design of LID/GI practices
The planning and design of LID/GI practices normally
include the following steps [15,16]:
(1) Site data, information collection and analysis;
(2) Low Impact Development Best Management
Practice (LID-BMPs) screening and selection; and
(3) LID-BMPs design and optimization
Local site (could be from block size to region and
watershed scale) data are important because runoff
characteristics are very site-specic. In the US, storm
water management guidelines and manuals have been
issued at the national [3], state (e.g. Maryland [17]) and
local (e.g. Chapel Hill, North Carolina [12]) levels. Some
of the local manuals provide very detailed information
such as a list of local plants suitable for use in green roofs,
bioretention cells, etc. In China, some LID-BMPs screen-
ing and optimization methodologies have been proposed
(e.g. [18,19].).
The design of a LID-BMP facility involvers many
Fig. 5 SCS Temporal Rainfall Charts
(a) Different type of SCS temporal rainfall; (b) Spatial distribution of different type of rainfall distribution
6 Front. Environ. Sci. Eng. 2017, 11(4): 18
factors such as the control area, design storm, pollutant
characteristics, the regulatory performance requirement,
etc. The design of a bioretention cell is used as an example
here. Features to be considered for best performance by a
bioretention are listed below [12]:
Ponding time and Depth
Planting Soil and In situ Soil
Underdrain System
Mulch Layer
Plant Material
Edge Protection
For certain purpose, the specic design and innovation is
required. For example, Fig. 7 illustrates a cross-section of a
bioretention cell, with its features derived from research
results. Earlier versions of bioretention cell design guides
mostly call for a gravel layer at the bottom with perforated
pipes for drainage. Recent research by Brown and Hunt
[12] suggested that by using a siphon pipe that creates a
water storage layer and thus enhances nitrogen removal.
The nding has been incorporated into recent bioretention
design guides. Further research is continuing and will lead
to better designs and even product innovations.
LID-BMPs optimization is aimed at nding the most
cost-effective selection and placement of various LID-
BMPs facilities for a specic site. Such an analysis should
be carried out before a nal decision is made on facility
selection, design and placement [20,21]. Many optimiza-
tion tools are available. Figure 8 shows an example of
optimization of the LID-BMPs design scenarios in China
using the model SUSTAIN [19]. In the gure, the X axis
represents the cost of LID-BMPs implementation, the unit
is million YuanYuan (RMB). The Y axis represents the
total runoff volume reduction rate of LID-BMPs schemes.
We can nd the best solution of LID-BMPs design which is
the knee-of-curvepoint in the gure.
3.3 Evaluating LID/GI practice performances
Monitoring and assessment of LID/GI practices after their
implementation are required, not only for performance
evaluation but also for providing quantied proofs of the
benets of using such practices. The USEPA has issued
detailed guidelines for monitoring of LID-BMPs and
evaluating their performance [22]. The following methods
were recommended for assessing LID-BMPs performance:
Efciency ratio
Summation of loads
Regression of loads
Mean concentration
Efciency of individual storm loads
Inow vs outow probability curves
The most commonly used indicator of storm water
runoff pollution is the event mean concentration (EMC).
The term event mean concentration (EMC) is a statistical
parameter used to represent the ow-proportional average
concentration of a given parameter during a storm event. It
is dened as the total constituent mass divided by the total
runoff volume [22].
Many discussions are still being made regarding the
accuracy, reliability and preference of the various methods.
Fig. 6 Hydrograph generation: effect of LID on site hydrology
Fig. 7 Bioretention design features example
Haifeng Jia et al. Chinas Sponge City construction: A discussion on technical approaches 7
Theoretically, the summation of loads method, which is
based on a mass balance computation of pollutant loads
going into and out from the facility, is the most reliable if
the samples are taken over a wide range of ow conditions
[22]. Signicant advances have been made in the past
decades with respect to traditional BMP and LID-BMP
monitoring and evaluation [2325]. However, data are still
relatively scarce, especially in China [7]. It is expected that
the Sponge City projects will generate a vast amount of
data that would be very valuable to researchers and
practitioners in the eld.
Currently, most LID-BMP pollutant removal require-
ments are based on the performance basedapproach,
which sets subjectively the percentage of pollutant
removed, e.g., 40%removal of total phosphorus. However,
it might be more cost-effective to consider a water quality
basedapproach, which determines the percentage pollu-
tant removal needed for maintaining a specied water
quality for a water body [2628].
In addition, many methods and tools are used to evaluate
the environmental and economic performance of LID-
BMPs, such as life cycle assessment [29] and modeling
4 Looking ahead Recommendations for
Sponge City construction strategies
4.1 The Sponge City implementation strategy
The current Sponge City Plan scope has been expanded to
include not only dealing with the urban water runoff
problem, but also with the broader management of urban
water. For example, the integration of green and gray
infrastructures is required for ood control, water quality
improvement and ecological protection and restoration.
Local governments will need to adjust their land use
planning and storm water infrastructure construction
strategies to satisfy Sponge City requirements [31,32].
To effectively improve water quality, the government
could consider establishing regulations similar to the
National Pollution Discharge Elimination System
(NPDES) and the Total Maximum Daily Load (TMDL)
programs used successfully in the United States [3335].
Also, to provide a strong incentive for local government
ofcials, the success of Sponge City implementations
could be used as a performance evaluation factor for
promotion consideration for local ofcials.
4.2 Site-specic regulatory framework and technical
The China Sponge City implementation experience so far
has suggested that because the core principles of the
expanded version of the initiative are aimed at the
integrated management of urban storm water quantity
and quality, the legal status for Sponge City construction
should be enhanced. In essence, the construction of LID/GI
facilities should be planned as part of the urban overall
master planning at the beginning. Moreover, since the level
and scope of controlling storm water runoff depends
largely on local climate, rainfall, ecology and importantly
social and economic factors, it is suggested that localized
regulations should be considered under the states
Fig. 8 Optimization of LID-BMPs Design using SUSTAIN
8 Front. Environ. Sci. Eng. 2017, 11(4): 18
regulatory framework. An example of such an approach is
the federal government, state and local stormwater
regulations in the United States [27].
The rst technical guidance issued by MHURC in 2014
[6] has laid the foundation for the initial phase of Sponge
City construction nationwide in China. As the Sponge City
projects get underway, it has been recognized that detailed
technical guidance, including information such as local
climate, hydrologic, soil and even plants should all be
included in the guidance documents. Also, an operational
and maintenance instruction is needed, plus detailed
requirements for monitoring and analysis in order to
provide quantitative information on facility performance
and cost-effectiveness.
4.3 Product innovation and certication
Some of the control practices, such as an underground
storm water treatment system, are manufactured by private
companies. An evaluation and certication process would
be highly desirable before such products are used for
public projects. A sustainable development of Sponge City
requires a robust industrial base. The central government
should consider assisting related industries and establish-
ing a viable Sponge City industry chain. Under the current
economic climate of over-capacity reduction,the
Sponge City projects can offer good business opportunities
for manufacturers producing pervious concrete, permeable
bricks, inltration pipes, etc. A stable supply system will
help ensure the successes of the Sponge City projects. The
certication process in Unite States can be referenced for
us [36].
4.4 LID/GI project nancing
The Sponge City construction represents an urbanization
process of an enormous scale that requires a major
nancial commitment from the government. Innovative
nancial options, such as appropriate PPP project
portfolio, credit support, loan guarantees, special construc-
tion funds and bond issuing should be considered and
promoted. The government should also simplify the
administrative approval process for reducing the upfront
costs of PPP projects. Decentralization of administrative
authority properly to local governments can help them
build a tailored and exible policy approach appropriate
for local social, environmental, economic and cultural
In the era of budgetary constraints and competing needs,
how to nance all the Sponge City projects is a real
challenge. The government has listed some innovative
strategies for fund-raising, which includes, in addition to
government grants and subsidies, local matching and
public-private partnerships. A major current issue is how to
develop a reliable, and tangible, estimate of returns on
investments in the Sponge City projects. For example, how
to quantify and appraise the benet of Sponge City
implementation is still an important question. Also, after
the completion of a Sponge City project, maintenance of
the LID/GI facilities will become a crucial factor affecting
project sustainability. The lack of information on main-
tenance requirements and costs would contribute to
uncertainties in Sponge City budget estimates.
In the US, with limited budgets, innovative approaches
are needed for nancing the green infrastructure projects.
One of the approaches is the Public-Private-Partnerships,
PPP or 3P. The following is an example from the Prince
Georges County, Maryland [37]:
The Private Partner is the general contractor and
program manager in partnership with the County through a
limited liability company (LLC) framework.
Program transparency is maintained through joint
program administration and decision making expressed in
the LLC operations.
The Private Partner will provide all or part of the initial
capital costs.
The County will pay back the Private Partner a
monthly fee that would include the debt service and cost
for operation and maintenance.
The Private Partners revenue is based on a negotiated
performance based fee.
The Private Partner doesnt get paid unless they meet
the performance goals.
This performance fee based approach ensures the Private
Partnersrst priority is to meet the Countys program /
performance goals; not the optimization of its prots.
Figure 9 illustrates the inter-relationships among various
partners in the PG Countys PPP Program [37]. The
County collects water quality (WQ) fees, which provide
the basic funding for the LID/GI projects. The County and
the selected private partner (LLC) form jointly the LLC
Company and implement the projects. Input and collabora-
tions are also solicited from relevant community associa-
tions, environmental groups, faith-based non-prot
organizations (NPOs), and industrial, commercial entities
during planning and design stages. The Private Partner will
be responsible for BMP maintenance and will be paid back
in accordance with a negotiated scheme as mentioned
4.5 LID/GI professional education/training and public
The design, construction and maintenance of LID/GI
systems require professionals with appropriate background
and training. Therefore, a consorted effort and time is
needed for research and development (R/D) in LID/GI
technology in order to achieve successes for the Sponge
City projects.
In the era of public awareness of the importance of
environmental protection, out task is to link the Sponge
City initiative to a sustainable urban development strategy
Haifeng Jia et al. Chinas Sponge City construction: A discussion on technical approaches 9
in a way that the public would clearly understand and fully
support. The use of the media, public hearing sessions,
comment periods for mandates, training sessions for
practitioners, etc. are all viable means of letting people
know and gaining their support and even participation.
Education at all levels, from kindergarten to college and to
adult education, is very important. For example, in the US,
some local community colleges offer course to adults on
plant selection for bioretention cells or rain gardens.
Working with environmental groups (such as the Sierra
Club in the US) and relevant non-government organiza-
tions (NGOs) would also be an effective way to raise
awareness and support.
Acknowledgements We gratefully acknowledge nancial support from the
Beijing Natural Science Foundation Project (No. 8161003), Natural Science
Foundation Project (No. 51278267), and the National Water Pollution
Control Special Project (No. 2011ZX07301-003). Several points and the
contents in the manuscript are discussed with many experts during 2016
International Low Impact Conference in Beijing.
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Haifeng Jia et al. Chinas Sponge City construction: A discussion on technical approaches 11
... to manage stormwater runoff and reduce surface runoff [5][6][7]. Common LID practices mainly include bioretention, green roofing, permeable pavement, bioswales, rain barrels, rain gardens, and so on [8], which manage stormwater through infiltration, detention, storage, and purification [9,10]. In particular, LID practices play a vital role in reducing rainfall runoff volumes and peaks [5,11]. ...
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An increasing focus has been given to stormwater management using low-impact development (LID), which is regarded as a “near-nature” concept and is utilized to manage and reduce surface runoff during the rainfall–runoff process. According to the hydrological monitoring data, we evaluated the retention and lag characteristics of rainfall–runoff in LID combination under three rainfall-intensity scenarios (light–moderate, heavy, and torrential rainfall) in Lingang New City in Shanghai. LID facilities have been constructed for three years in the target study area, including rain gardens, retention ponds, green parking, porous pavement, and grass swales. The average runoff retention was 10.6 mm, 21.3 mm, and 41.6 mm under light–moderate, heavy, and torrential rainfall scenarios, respectively, and the corresponding runoff retention rate was 72.9%, 64.7%, and 76.1% during the study period. By comparing rainfall, runoff retention, runoff retention rate, cumulative rainfall, and lag times, it becomes evident that the ability to retain runoff can be greatly improved in the LID combination. The average runoff retention was significantly enhanced by nearly two times and four times under the heavy and torrential rainfall scenarios compared to the conditions under the light–moderate rainfall scenario. Furthermore, the lag time from the end of rainfall to the end of runoff (t2) and the lag time between the centroid of rainfall and the centroid of runoff (t3) showed a significantly negative correlation with rainfall intensity. Meanwhile, t3 presented an incredibly positive correlation with rainfall duration. In this study, the LID combination demonstrated superior benefits in extending the duration of runoff in rainfall events with lower rainfall amounts, and demonstrated significant overall lag effects in rainfall events with longer durations and lower rainfall amounts. These results confirmed the vital role of the LID combination in stormwater management and the hydrologic impact of the LID combination on rainfall-induced runoff retention and lag effects. This work has provided valuable insights into utilizing LID facilities and can contribute to a better understanding of how runoff retention and lag characteristics respond to different rainfall intensity scenarios.
... However, decision-makers can provide different criteria to be able to make a choice. A simple strategy could be to select a solution that satisfies all objectives the same way, i.e., the "knee of the curve" in the Pareto-front graphical representation (Jia et al. 2017). Another strategy could be to fix a value of performance for one of the objectives and select the solution in the Pareto-front that fit with that value (Lee et al. 2012). ...
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Nature-Based Solutions can be considered one of the best answers to the various consequences and problems caused by climate change, poor urbanisation and population growth. They are used not only as measures for the protection, sustainable management and restoration of natural and modified ecosystems but also as measures to mitigate certain natural disasters such as erosion, flooding, drought, storm surge and landslide. The benefit is for both biodiversity and human well-being. This paper reviews articles about optimising the selection and placement of Nature-Based Solutions. It presents several Operations Research approaches used in the context of climate adaptation. The analysis provided in this paper focuses on various case studies, state-of-the-art on Nature-Based Solutions, Operations Research algorithms, dissertations, and other papers dealing with infrastructure placement approaches in the context of climate adaptation.
... These strategies can also be differentiated into classic "grey" infrastructure and nature-based "green" solutions (Dong et al., 2017;Morris et al., 2018). One recent example of the latter approach is the Chinese Sponge City Program (SCP), a framework which refines established concepts like water-sensitive urban drainage (WSUD) and low-impact development (LID) (Jia et al., 2017;Qi et al., 2020;Sun et al., 2020;Li and Zhang, 2022). To address the predicament of increasing natural hazards in expanding urbanized areas, Sponge Cities make use of the natural hydrological cycle to effectively reduce urban flooding, harvest rainwater and improve water quality as well as restore ecological values (Köster, 2021;Jia et al., 2022). ...
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Urban flooding is a major challenge for many megacities in low-elevation coastal zones (LECZs), especially in Southeast Asia. In these regions, the effects of environmental stressors overlap with rapid urbanization, which significantly aggravates the hazard potential. Ho Chi Minh City (HCMC) in southern Vietnam is a prime example of this set of problems and therefore a suitable case study to apply the concept of low-regret disaster risk adaptation as defined by the Intergovernmental Panel on Climate Change (IPCC). In order to explore and evaluate potential options of hazard mitigation, a hydro-numerical model was employed to scrutinize the effectiveness of two adaptation strategies: (1) a classic flood protection scheme including a large-scale ring dike as currently constructed in HCMC and (2) the widespread installation of small-scale rainwater detention as envisioned in the framework of the Chinese Sponge City Program (SCP). A third adaptation scenario (3) assesses the combination of both approaches (1) and (2). From a hydrological point of view, the reduction in various flood intensity proxies that were computed within this study suggests that large-scale flood protection is comparable but slightly more effective than small-scale rainwater storage: for instance, the two adaptation options could reduce the normalized flood severity index (I NFS), which is a measure combining flood depth and duration, by 17.9 % and 17.7 %, respectively. The number of flood-prone manufacturing firms that would be protected after adaptation, in turn, is nearly 2 times higher for the ring dike than for the Sponge City approach. However, the numerical results also reveal that both response options can be implemented in parallel, not only without reducing their individual effectiveness but also complementarily with considerable added value. Additionally , from a governance perspective, decentralized rain-water storage conforms ideally to the low-regret paradigm: while the existing large-scale ring dike depends on a binary commitment (to build or not to build), decentralized small-and micro-scale solutions can be implemented gradually (for Published by Copernicus Publications on behalf of the European Geosciences Union. 2334 L. Scheiber et al.: Low-regret climate change adaptation in coastal megacities example through targeted subsidies) and add technical redundancy to the overall system. In the end, both strategies are highly complementary in their spatial and temporal reduction in flood intensity. Local decision-makers may hence specifically seek combined strategies, adding to singular approaches , and design multi-faceted adaptation pathways in order to successfully prepare for a deeply uncertain future.
... The concept uses natural methods to retain rainwater, thereby recharging groundwater, reducing flooding and water pollution problems, and gradually restoring the natural hydrology of the cities. The sponge cities pilot scheme started in 30 cities, and following the successes recorded, the concept is now being adopted at the national level [21,22]. ...
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Urban stormwater is known to cause a myriad of problems, ranging from flooding to water quality degradations. This paper provides an extensive review of analytical probabilistic model (APMs) used in the design of urban runoff control systems. APMs are closed-form mathematical expressions representing a long-term system’s output performance derived from the probability distribution of the system’s input variables. Once derived, the APMs are easy to handle, allow for sensitive analysis, and can be co-opted into optimization frameworks. The implementation of APM in the planning and design of runoff control systems will not only help address the runoff quantity and quality problems of urban stormwater, but will also go a long way in optimizing the benefits derived from the systems. This paper reviews studies that document the negative impacts of urbanization on runoff quantity and quality, and the best management practices (BMPs) used to mitigate the impacts. Three design methodologies used in urban stormwater control systems were reviewed. A detailed review of research on the development and use of APMs in urban stormwater management in various runoff control systems is presented, and recommendations are proffered.
... Nevertheless, there must be efforts in the integrated planning of hydrographic basins involving public agencies and private owners (MONTALTO et al., 2007). Public-private partnerships (PPP) are often cited in this context, as pointed out by various authors (JIA et al., 2017;LI et al., 2017;MONTALTO et al., 2007;WANG et al., 2017). ...
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The management of drainage and urban rainwater management in Brazil and in the world faces numerous challenges in order to be sustainable. When dealing with sustainability, it is important to relate the aspects: of social, environmental and economic, known as the sustainability tripod. Compensatory urban drainage techniques, through infiltration or detention and increasing the evapotranspiration rate, have the potential to reduce: the amount of rainwater runoff; flow peaks; vulnerability of urban areas to flooding; contamination of water courses. It is important that, even with all these benefits, such technologies are associated with such aspects. In this context, this systematic review article (SR) was developed, which aimed to identify trends in the use of sustainable drainage technologies adopted in Brazil and in the world, relating them to aspects of sustainability. For that, a systematic review (SR) was carried out in which the following were identified: trends in the adoption of technologies for sustainable drainage in the world and in Brazil; and the terms used and related to technologies for sustainable drainage. It was also observed, both in Brazil and in the world, that the approach to the theme begins with the technological aspect involving the implementation, life cycle and maintenance of sustainable technologies and, in sequence, the environmental, economic and social aspects unfold in this order, but which are not done in an integral way. It was possible to characterize an important knowledge gap.
Urban sprawl, also known as urban encroachment, is a low-density, intermittent advancement model that includes complicated multiple interactions of the social, ecological, economic, psychological, physical, structural, and engineering systems; it is highly complex and unpredictable in resilient city development. The disorderly growth of cities has irreversible environmental consequences. It is mostly represented in the expansion of the built environment and the encroachment of farmland, forestland, and grasslands.
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Climate change has aggravated the frequency and severity of extreme weather events, particularly in flood-related hazards. Cities nowadays face significant challenges in stormwater management from frequent heavy rainfalls. Traditional urban drainage systems can no longer cope with large amounts of surface runoff; cities are searching for new ways to deal with urban stormwater. Green roofs and other nature-based solutions have been widely used for stormwater management by combining water purification and retention functions but have not yet fully solved the flood problems. This article aims to (1) explore the different aspects of urban water management, particularly the urban stormwater topic, and (2) identify the existing solutions and discuss the potential and barriers to integrated solutions implementation. By introducing the concept of four domains and finding the overlapping area to investigate, we analyzed different solutions to reduce rainwater runoff from the roof and ground level, aiming at building and district scales. This paper proves that further research direction could constitute an integrated system to work together for urban stormwater management.
Bu çalışmada yağmur suyu yönetimi stratejisi seçimi için Çok Kriterli Karar Verme (ÇKKV) yöntemleri kullanılmaktadır. Bu bağlamda TOPSIS yöntemi Rize ilinden veriler kullanılarak sunulmaktadır. Resmi verilere göre Türkiye'nin en yağışlı ili olan Rize'de sel ve heyelan gibi afetlerde son 40 yılda yaklaşık 127 kişinin hayatını kaybetmesi ve son 10 yılda 500 milyon TL'nin üzerinde maddi zarar oluşması yağmur suyu yönetimini Rize için önemli kılmaktadır. Tez kapsamında en uygun yağmur suyu yönetimi uygulamalarının ÇKKV yöntemleri içinden konuya uygun yapıda olan TOPSIS yöntemi ile Rize sahil parkı ve Güneysu-Rize bağlantı yolu için belirlenmesi detaylı olarak sunulmaktadır. Bu kapsamda kentsel alan kullanımına uygun ve benzer alanlarda yaygın olarak kullanılan uygulamalar ele alınmıştır. Seçilen uygulamaların değerlendirilmesi için kullanılacak kriterler ve bu kriterlerin ağırlıkları, yağmur suyu yönetimi alanında dünyada önde gelen araştırmacıların uzman görüşüne başvurarak belirlenmiştir. Rize sahil parkı ve Güneysu-Rize bağlantı yolu için uygulamaların maliyetinde veya alanlara düşen yağmur miktarında değişim olması gibi farklı senaryolarda en uygun yağmur suyu yönetimi uygulamaları TOPSIS yöntemi ile tespit edilmiştir. SWMM programında yapılan yüzey akış simülasyonlarıyla TOPSIS çıktıları doğrulanmıştır. TOPSIS algoritmasının MATLAB programı ile oluşturulması sonrası strateji seçimi ve alternatif senaryo analizinin kolaylıkla yapılabildiğini gösteren bu çalışmanın farklı alanlarda yapılacak incelemelere kaynak oluşturması hedeflenmektedir.
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Worldwide, national governments and private organizations are increasingly investing in Nature-Based Solutions (NBS) to foster both human well-being and biodiversity while achieving climate and environmental targets. Yet, investments in NBS remain uncoordinated among planning levels, their co-benefits underestimated, and their effectiveness undermined. This study aims to provide a spatially explicit approach to optimize the budget allocation for NBS implementation across Italian urban areas while maximizing their effectiveness in terms of environmental health. We explored three different NBS implementation scenarios oriented to (i) maximize the Ecosystem Services supply of NBS (Scenario BP), (ii) minimize costs of NBS (Scenario LC), and (iii) maximize Ecosystem Services supply of NBS at the lowest cost (Scenario CP). Once selected, we prioritized their allocation through the territory following an environmental risk index for population, and we explored the relationship between costs and effectiveness for the three scenarios. The implementation of Scenario BP costs EUR 777 billion while showing 31 billion of effectiveness. Scenario LC costs 70% less than scenario BP (EUR 206 billion) while losing 70% of its effectiveness. Scenario CP costs 60% less than Scenario BP (EUR 301 billion), offering just 20% less effectiveness. Our results show that employing the risk index for NBS allocation would allow for reducing the surface of interventions by saving 67% of the budget in the three scenarios with a negligible loss in terms of return for human health. The here-proposed approach can guide the national funds’ allocation system, improving its cost-effectiveness and equitableness.
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Low impact development type of best management practices (LID-BMPs) aims to mitigate urban stormwater runoff and lessen pollutant loads in an economical and eco-friendly way and has become a global concern in modern urban stormwater management. A new methodology based on stormwater management model (SWMM) for block-scale LID-BMPs planning was developed. This method integrated LID-BMP chain layout optimization in site-scale parcels with scenario analysis in the entire block-scale urban area. Non-dominated sorting genetic algorithm (NSGA-II) was successfully coupled to SWMM through Python to complete the site-scale optimization process. Different LID scenarios of the research area were designed on the basis of the optimized LID-BMP chain layout. A multi-index evaluation that considered runoff quantity indices, pollutant loads, and construction costs simultaneously helped select the cost-effective scenario as the final planning scheme. A case study in Tianjin, China, was conducted to demonstrate the proposed methodology. Results showed that more than 75% control rate of total runoff volume, 22%–46% peak flow reduction efficiency, and more than 32% pollutant removal rate were achieved. The robustness analysis indicated that the selected final planning scheme was considerably robust with varied weight values. © 2017, Higher Education Press and Springer-Verlag Berlin Heidelberg.
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Over the past decade China’s urban population has grown to 52.4 percent in 2015 from 42.5 percent in 2005, and the build-up areas have increased by 17,252 km2. This roughly equates to an addition of 165 million people dwelling in urban areas in a decade, which is extraordinary! This rapid urbanization process, sometimes lacking adequate planning and design, has led to a worsening “city syndrome” situation such as urban flooding, water pollution, heat-island effects and ecologic deterioration, etc.
A cost-combined life-cycle assessment was conducted to estimate the environmental and economic burdens of a low impact development best management practice (LID-BMP) treatment train system in China. Results showed that climate change, human toxicity, terrestrial ecotoxicity, freshwater ecotoxicity, marine ecotoxicity and fossil depletion dominantly contributed to the overall environmental effect. Infiltration pit exhibited the highest environmental effects because of high consumption of PVC and non-woven fabrics, whereas grassed swale and buffer strip had the lowest environmental impacts. The operation phase showed great environmental benefits because a LID-BMP treatment train system can significantly reduce the emissions of heavy metals, suspended solids, total nitrogen, and total phosphorus to water. From an economic perspective, constructed wetland exhibited the highest economic burdens where the costs of graded gravel and bedding plants had a significant function, whereas grassed swale had the lowest economic burdens because of low consumption of raw materials. Optimizing the efficiency of PVC, non-woven fabric consumption, and road transport is an effective way to improve the potential environmental performance of LID-BMP construction phase.
Storm runoff is considered one of important water resources for urban areas. Over a geologictime, streams and lakes are periodically refreshed with flood water and continually shaped with the flood flows. Urban development always results in increases of runoff peak rates, volumes, and frequency of higher flows. As a result, flood mitigation has become a major task in urban developments. Before 1970’s, storm water drainage systems in an urban area were designed to remove flood water from streets as quickly as possible. From 1970 to 1980, the US EPA conducted a nationwide stormwater data collection and reached a conclusion that stream stability is more related to frequent, small storm events rather than the extreme, large events. Since man-made stormwater systems were designed to pass extreme events, the large inlets and outlets release frequent events without any detention effect. As a result, urban pollutant and sediment solids are transported and deposited in the receiving water bodies. Under a US Congress mandate starting in 1980’s, a nationwide stormwater best-management-practices (BMPs) program was developed and implanted in major metropolitan areas. The tasks in BMPs include: (1) retrofitting the existing drainage facilities to achieve a full-spectrum control on peak flows, and (2) applications of Low-Impact -Development (LID) designs to reduce runoff volumes under the post-development condition. With the latest observations in climate change, the uncertainty in the design floodhas imposed unprecedented challenges in flood mitigation designs. The flexibility in freeboards and easements need to be refined in order to accommodate the changes in extreme rainfall events. This paper presents a summary of the Green approach in stormwater management and LID designs as the engineering measures to preserve the watershed regime.
In 1978, the U. S. Environmental Protection Agency established the Nationwide Urban Runoff Program. The five-year effort, intended to help resolve the uncertainties surrounding the contributions of urban runoff to water quality problems, had as its objectives the determination of: The nature of urban runoff problems where significant effects had been identified; The causes of these problems (e. g. , sources, transport modes, impacts); The severity of these problems, based on consideration of beneficial uses and water quality standards; and Opportunities for controlling urban runoff problems, including descriptions of control measures, their effectiveness, costs, and strategies for broad-scale implementation. A very large data base, collected in 28 major metropolitan areas, has been set up in computerized form, and some analysis and interpretation have been done. This paper will present the conclusions reached by the program based on data analyzed to date.
An environmental capacity management (ECM) system was developed to help practically implement a Total Maximum Daily Load (TMDL) for a key bay in a highly eutrophic lake in China. The ECM system consists of a simulation platform for pollutant load calculation and a pollutant load hierarchical allocation (PLHA) system. The simulation platform was developed by linking the Environmental Fluid Dynamics Code (EFDC) and Water Quality Analysis Simulation Program (WASP). In the PLHA, pollutant loads were allocated top-down in several levels based on characteristics of the pollutant sources. Different allocation methods could be used for the different levels with the advantages of each method combined over the entire allocation. Zhushan Bay of Taihu Lake, one of the most eutrophic lakes in China, was selected as a case study. The allowable loads of total nitrogen, total phosphorus, ammonia, and chemical oxygen demand were found to be 2122.2, 94.9, 1230.4, and 5260.0t·yr(-1), respectively. The PLHA for the case study consists of 5 levels. At level 0, loads are allocated to those from the lakeshore direct drainage, atmospheric deposition, internal release, and tributary inflows. At level 1 the loads allocated to tributary inflows are allocated to the 3 tributaries. At level 2, the loads allocated to one inflow tributary are allocated to upstream areas and local sources along the tributary. At level 3, the loads allocated to local sources are allocated to the point and non-point sources from different towns. At level 4, the loads allocated to non-point sources in each town are allocated to different villages. Compared with traditional forms of pollutant load allocation methods, PLHA can combine the advantages of different methods which put different priority weights on equity and efficiency, and the PLHA is easy to understand for stakeholders and more flexible to adjust when applied in practical cases. Copyright © 2015 Elsevier B.V. All rights reserved.
An overview of the management of the hydrology of urban runoff is presented. Topics discussed are as follows: effects of urbanization on runoff; causes of hydrologic change; effect of detention storage on control of runoff; and capture of stormwater runoff.