Abstract

The paper explores important concepts in the application of the SC initiative as a framework for improving urban drainage systems. Equally, the paper explores whether policymaking on the same can help improve the effect and impact of SCs in water conservation approaches. The research applies a mixed-method approach to examine various facts on the topic of discussion. The first method used to explore the topic of discussion is an analysis of existing documents. Existing literature on the construction of SCs and metrics involved will be used to gather important facts. The second method applied is a case-study approach that focuses on Jinan as one of the urban places in China that have embraced the SC initiative. The research will analyze collected facts and purpose to give a detailed conclusion on the topic of discussion. The construction of SCs should be applied as it promotes various sustainability practices in urban places.

1.0 Introduction

1.1 Introduction to Research Issue

The changing climatic conditions in most parts of the world have prompted many environmentalists to think of an alternative approach to combating the situation. It is important for every individual in society to contribute towards sustainability (Jiang, Zevenbergen & Ma, 2018). Environmental sustainability will ensure that future generations meet their obligations without compromise. It is vital to note that the Sponge City (SC) concept might be the solution to pluvial flooding that is experienced in urban places such as Jinan. Equally, the SC system will ensure water harvesting is made possible for storage and re-use in the town. The paper aims to examine the concept of SC construction and evaluate whether it is the most suitable strategy to handle drainage in urban places (Jiang, Zevenbergen & Ma, 2018). It is vital to evaluate the concept through a case study approach in a bid to get a deeper insight into the scope of SC construction. Problems with traditional urban drainage systems and pluvial flooding in cities prompted the Chinese to adopt the concept in specified towns, which has finally paid off. Understanding the concept of SC construction will help predict the implications of policies towards the initiative. Construction of SCs in urban place might be the framework for improved urban drainage systems.

It is important to examine whether overarching the policy on the construction of SCs can help improve conditions in many cities across the world. Different municipalities have varied approaches to handling of drainage systems. However, if legislation is put in place for all cities to follow suit, there is likelihood for improved drainage systems. Jinan presents a case of SCs that have improved urban drainage systems (Jiang, Zevenbergen & Ma, 2018). It is important to note that each city has its standards and the effectiveness of the systems depends on resources employed towards the same. It is the duty of law makers in respective countries to make it necessary for each city to improve urban drainage systems through the construction of sponge cities. Legislation can play a significant role in compelling urban places to improve their drainage systems by embracing what Jinan and has done.

1.2 Background Information

One of the approaches that developed countries use to address the issue of increased rainfall is the construction of sponge cities. The strategy ensures that water is absorbed from the ground and recycled for other uses (Wang, Sun & Song, 2017). It is an approach that can help transform and handle the problem of climate change. Construction of SCs is capital intensive and countries purposing to adopt the strategy must have a strong financial backing. China’s economy has grown tremendously in the last few decades, which has increased its urban population to a large extent. The increased level of population in the country has led to extreme weather conditions such as increased rainfall in cities (Shao et al., 2016). There is need to find a solution to the issue of drainage systems to avoid further social problems.

The research conducted aims to explore whether the construction of SCs can help control or combat extreme weather conditions such as increased rain fall (Zevenbergen, Fu & Pathirana, 2018). In essence, the study seeks to answer the question, “Can the construction of SCs be the framework for the development of sustainable urban drainage systems?” To answer the question, the research purposes to use a mixed method approach and gather the necessary data for a detailed conclusion (Jiang, Zevenbergen & Fu, 2017). In the event, China’s Jinan form a significant example of a town that can be used as a case study. As such, the research will explore the construction of SCs and whether they can be helpful in combating the changing climatic conditions in most parts of the world.

With construction of roads and buildings in cities, the permeability of water to the ground is challenged, which might result in flooding. The flooding worsens the conditions of living places in cities, which is why there is need to develop a sustainable urban drainage system. Poor drainage systems in cities can lead to spread of diseases and halt important operations within society (Zevenbergen, Fu & Pathirana, 2018). As such, it should be a priority for most city authorities to develop infrastructure as a way of enhancing sustainability. The research aims to address a significant problem that challenges the wellbeing of people in many urban places across the world. Construction of SCs might be the best strategy towards averting issues associated with extreme weather conditions.

1.3 Purpose of the Research

Strategies to manage surface running water in cities are seen as appropriate methods to maintaining a sustainable urban drainage system. Some of the cities in the world go as far as storing the surface running water before it joins other water bodies (Jiang, Zevenbergen & Ma, 2018). SCs are the most strategic approach that cities should apply in managing and improving urban living conditions. There is need to build structures that can help harvest water to avoid flooding in such places. Increased levels of innovation and creativity can help advance sustainability measures in most populated cities across the world. One of the reasons why developing countries have cities with social problems is the lack of appropriate or sustainable urban drainage systems (Zevenbergen, Fu & Pathirana, 2018). The research purposes to examine whether construction of SCs can help manage urban drainage systems sustainably.

It is important to note that Jinan is a city in the world that has strategized to use SCs as a way of controlling urban drainage systems. The role of SCs is a strategy that can help promote water conservation in urban centers. Notably, the drainage systems employed ensure water harvesting and storage, which will help serve the population in urban places (Jiang, Zevenbergen & Fu, 2017). For instance, Jinan is one of the cities in China that has embraced construction of improved drainage systems. Poor water conservation strategies in urban centers can lead to serious problems for residents. With changing population in urban places, there is need to manage surface water as a way of ensuring sustainability. Construction of SCs will prove important towards enhancing improved urban drainage systems (Jiang, Zevenbergen & Ma, 2018). Extreme weather conditions due to changes in climate are affecting many places in the world, which is why the research is relevant.

The research purposes to examine the construction of SCs and evaluate whether the concept can be the framework to handling of water problems. Water problems in urban laces include flooding, shortage of water and other wastewater management strategies (Shao et al., 2016). The construction of SCs in cities might help reduce problems by absorbing the water, which can be stored and re-used later in the town. It is vital to put elaborate measures that can help promote the concept as a way of promoting water sustainability practices in urban places. Also, it is the role of the research to put clear whether further legislations on the concept of SC might help achieve set objectives.

1.4 Motivation for Research

The need to enhance sustainability in various cities is an important factor that should be prioritized by many (Shao et al., 2016). The aim is to examine whether SCs can help improve urban drainage systems. The motivation behind the research is the need to ensure that future generations meet their obligations without compromise. Climatic changes in the world are causing a problem to many people and there is need for strategic city planning to ensure that living conditions have improved. The research will use a qualitative analysis, which is one of the best approaches that can be used to gather information from existing documents and other sources (Shao et al., 2016). In essence, the idea of studying important aspects on SCs is important towards strategizing towards sustainable urban drainage systems. It is important to note that climate change is a global concern that threatens sustainability practices (Wang, Sun & Song, 2017). There is a need to conduct research and establish whether the construction of SCs can help reduce the impacts of climate change, especially in the event of increased rainfall. Equally, the need to improve and promote standards of living in cities is a significant reason why the research will study construction of sponge cities.

1.5 Aims and Objectives

It is vital to state the primary aim of the research and objectives that will act as a guide throughout the research process. The main aim of the study is to examine whether the construction of SCs can help maintain a sustainable urban drainage systems. People in urban places depend on the drainage systems established in a number of ways, which is why there is a need to ensure an improved urban city drainage infrastructure (Shao et al., 2016). It is important to note that China has made big strides and the research aims to use Jinan as a case study to ascertain the viability of the project in enhancing sustainability. It is also important to establish objectives that align with the primary aim of the study. Concise research objectives help one to know what they are exactly studying. Ambiguity in planning out the objectives might be detrimental to achievement of the set objectives. The main objectives are:

1. To examine construction of SCs to ascertain whether legislation can help improve conditions in most urban places.
2. To explore whether the construction of SCs promotes sustainability in urban drainage systems.
3. To conduct a rigorous study on the construction of sponge cities, challenges and their importance in promoting sustainability practices in Jinan.

2.0 Literature Review

A background check on the topic of discussion can help gather important information on the construction of SC system. A rigorous background check must capture important aspects such as the historical development of the concept. For instance, examining weather conditions in both Jinan before and after the concept should help explain the city’s condition on advancements made (Wai et al., 2018). Also, a literature review should analyze various challenges that the SC concept has faced in the town of Jinan. There are numerous articles online that contain information on the construction of SCs as the framework that can help promote and improve urban drainage systems. For instance, the extreme rainfall condition experienced in the cities is a significant contributor to construction of SC concept. A literature review is a background check on what other authors have presented on the topic of discussion as a way of gaining a deeper insight into the topic of discussion. The notion of SCs has attracted attention in the media and academic world (Argent, Rolley & Walmsley, 2008). “Sponge City”(SC) is a new concept of urban rainwater management, which allows cities to be like sponges, with good “flexibility” in adapting to environmental changes and responding to natural disasters. It absorbs, stores, seeps and cleans water when it rains. Water, the stored water is “released” and used when needed (Bunster-Ossa, 2013). China has started the “SC” pilot in 2015. According to the government’s plan, by 2020, more than 20% of the built-up areas of Chinese cities will be naturally stored 70% in 2030, more than 80% of built-up areas in cities across the country will reach this target.

2.1 Background Information on SC Construction

Extreme rainfall condition in Jinan has resulted in losses of millions in the recent past as damages. In 2012, pluvial flooding in Jinan claimed lives of 79 people and made operations difficult for residents (Wai et al., 2018). The authorities of the city have since struggled to find a sustainable solution that can help control flooding in towns during heavy rainfall seasons. Equally, most cities in China have water shortage issues, which have challenged the quality of life in urban places. There was a need to establish a mechanism that can help conserve water in city for recycling during the shortage period. The SC concept framework can help manage flooding and ensure water issues in the cities have been handled (Argent, Rolley & Walmsley, 2008). The construction concept arose due to the need to solve water issues and promote the existing urban drainage system.

In the past decades, China has experienced an increasing trend of rural-urban migration. Individuals are shifting to urban cities in search of jobs that pay better wages. According to Yang (2013), China urbanization increased from 19.4 to 52.6% between 1980 and 2012. The trend is likely to increase because the population of the country is rapidly increasing. China’s rapid urbanization has also resulted in adverse impact on the hydrological processes within different cities in China. Furthermore, increased urbanization is associated with increased flooding in urban areas because of absence of good drainage system (Chen et al., 2015). The country is also characterized with high rate of rural to urban migration. According to Li and Song and Lin and Dixon and Zhang& Ye (2016), China has observed an increasing trend of rural-to-urban migration since 1990s. High population in the urban areas negatively impact drainage system of the highly populated areas. It happens because of unmanaged construction of infrastructures such as buildings that fail to consider proper drainage system. According to Nie, Lindholm & Braskerud (2009), urban areas experience increases climatic changes because of increased urbanization. Climatic changes in urban areas are a threat to the environment, leading to disturbance of drainage system. Using the concept of “SC” construction to develop a sustainable urban drainage system is a new, reasonable and effective method in China (Zhang et al, 2016). Figure 1 below is a map that shows annual precipitation level in China. The southern part of China has continually experienced high precipitation per annum as compared to other parts.

Figure 1: Annual Precipitation distribution in China (Li et al., 2017)

Increased rainfall in Chinese cities was a significant factor in the development of the SC concept in the country. It is important to note that high rainfall results in increased surface runoff water, which causes flooding and other water related problems in urban laces. High surface runoff water is unsafe a it destroys property and in some cases it claims the lives of people. It is important to examine the concept of SC and establish whether making legislations can help promote urban drainage systems (Argent, Rolley & Walmsley, 2008). Climate change in the area is the most significant reason for increased rainfall in urban places. For several years, Chinese cities have faced challenges as a result of increased water, causing waterlogging and displacement of people. The problem of water shortage in Chinese cities such as Jinan compelled authorities to seek solutions to curb flooding that claims millions of dollars as damages. In essence, the construction of SCs in China is a process that was triggered by climate changes resulting to extreme rainfall. Climate change is the major reason why most parts of the world are experiencing different conditions that have threatened sustainability measures (Ren et al., 2017). Rivers within the city become full due to surface runoff water, which results in breaking of banks. Increased rainfall in urban places and development projects contribute to low infiltration rate, which causes pluvial flooding in urban places.

Liu and Che (2005) argue that the urgency of managing storm water is necessitated with the rapid urbanization in China. Storm water management through SC is a proven technique that has been applied successfully in other regions such as Auckland city in New Zealand. Implementation of SCs initiative is beneficial because it promotes water security. Over decades, the increasing number of people migrating to urban areas in China has suffered because of water shortage. A successful implementation of SC program is beneficial because it promotes water security. In this context, controlled flooding water is stored and for other purposes including domestic use, irrigation and running manufacturing plants. Also, implementation of SC is beneficial to the environment because it promotes protection of environmental water (Ren et al., 2017). The traditional cities in China without the advanced drainage systems are characterized with increased unmanaged running water (Wang, et al., 2018). However, SC program is an effective approach to storm water management that also facilitates the easy of controlling the running water in the urban areas. Furthermore, sponge water plays an important role in restoration of water ecology. The SC initiative involves having adequate drainage system that necessitates the ease of controlling the amount of water released. As such, the initiative is also beneficial in addressing urgency climatic change and impacts destructive impact of running water. According to Li et al., (2016), the concept of flooding control through SC can be perceived from three major categories. These categories include discharge system for handling flooding inundation, urban drainage system to manage surcharge flooding and urban flooding resist system to address the challenge of urban flooding(Jiang, Zevenbergen & Fu, 2017; He et al., 2019).

In the year 2017, Bai and Yang committed to study linking aspects of extreme rainfall and heavy pluvial flooding in the Chinese cities. In the study, the authors have echoed the role of climate change in contributing to increased rainfall, which has become problematic (Ren et al., 2017). The traditional urban drainage system in towns such as Jinan is ineffective in combating the impact of extreme rainfall in Chinese cities. The authors assert that handling of pluvial flooding requires the input of spatial disparities that exist among cities in the country. According to the report, increased rainfall is a result of climate changes and urbanization. The construction of roads and buildings within urban places has changed the scope of operations in most places (Ren et al., 2017). It is vital to note that pluvial flooding in Chinese towns has been a significant problem for decades, and the emergence of the SC concept might be the framework to combat floods. The research is elaborate on extreme weather conditions and how they increase urban flooding. The article is informative and will help formulate a detailed argument on the concept of SC construction in China.

2.2 Traditional Urban Drainage Systems

It is important to examine the traditional system that was used in China to control urban flooding before the introduction of the SC concept. Traditional urban drainage systems in Chinese towns did not provide a sustainable solution to the problem of flooding and shortage of water (Jia, Yao and Shaw, 2013). Chinese towns continue to experience water shortages, which prompted them to seek a sustainable solution to the problem of water. The SC construction can help increase infiltration of water, harvesting, recycling and re-use of water harvested within the same city. It is argued that the focus on various constructions in urban areas is construction of buildings and other infrastructures such routes within the city. However, it is also established that that the construction fails to consider the inclusion underground drainage system (Jia, Yao and Shaw, 2013). The gap between the construction of drainage system and the increasing needs in the urban development is a significant factor leading to the challenging increase in urban drainage system. It is also argued that the traditional drainage systems are low, making it difficult for upgrading the systems to meet drainage needs. As such, it is difficult for the transformation process hence more cost may be required in the transformation process. Furthermore, the condition of the traditional drainage system in urban areas is contributed by weak flood prevention consciousness is weak. The unmonitored construction process is a leading factor that facilitates increased construction of drainage systems that fails to meet the drainage needs in the increased urban area.

China has observed an increasing trend of rural-to-urban migration since 1990s. High population in the urban areas negatively impact drainage system of the highly populated areas. It happens because of unmanaged construction of infrastructures such as buildings that fail to consider proper drainage system. According to Nie, Lindholm & Braskerud (2009), urban areas experience increases climatic changes because of increased urbanization. Climatic changes in urban areas are a threat to the environment, leading to disturbance of drainage system. The urban areas are at a higher risk of experiencing climate change because of increased industrialization. It is a factor that that increases precipitation rate leading higher chances of urban areas to experience high rainfalls. All these factors have led to water shortages, water pollution, urban waterlogging disasters, destruction of natural resources, and loss of habitat for wildlife parks. Therefore, it is necessary to develop a sustainable urban drainage system to solve these urban water problems. Using the concept of “SC” construction to develop a sustainable urban drainage system is a new, reasonable and effective method in China (Zhang et al, 2016).

The traditional drainage systems that were in place in China were overwhelmed by extreme rainfall, which has claimed lives and led to destruction of property in the recent past. The conventional approaches used could not harvest water or increase infiltration to the ground, which is why it was necessary to change tactic (Griffiths et al., 2020). Traditional approaches proved inconsequential in establishing culture that promotes sustainability practices. Economic losses attached to pluvial flooding in Chinese towns provides enough reason why they had to abandon the traditional model and adopt a new model. The traditional model of controlling urban drainage could nt improve infiltration of stormwater that can be dangerous if not well handled. The extreme rainfall as a result of climate change has changed weather conditions within town (Griffiths et al., 2020). As such, traditional urban drainage systems in China could not sustain the high population in urban places and changing climatic conditions. There is a distinct difference between the traditional system applied in China and the new concept of SC. For instance, traditional urban drainage systems did not have the capacity to increase the rate and quantity of infiltration (Griffiths et al., 2020). As such, the new system is a significant improvement from what was less useful to a more rigorous approach to water issues in urban places.

2.3 The SC Construction Concept

SC” refers to water absorption, storage, seepage, and water purification when it rains (Yu et al., 2015). The stored water is released and used when needed to realize the free migration of rainwater in the city. Starting from ecosystem services, building aquatic ecological infrastructure across scales and combining multiple types of specific technologies to build aquatic ecological infrastructure is the core of the SC (Dong & Han, 2011).

SCs initiative in China is a promising technique to alleviate the increased drainage challenge in urban areas in China. The initiative contributes to managing floods challenges by improving drainage system in urban areas. Unlike the traditional cities in China, implementation of SCs is preferable because it supports the natural water cycle. It is established that the construction of SCs in China serve an important role supporting management of urban runoff, protecting the environment and promoting good health for people in urban areas. Storm water management and urban hydrology is becoming an aspect of major concern because of increasing negative impact of increased urbanization. According to Che and Zhang (2019), it is established that there is urgent need to invest in practices that minimizes the negative impact of increased urbanization on the natural environment. It is also argued that the need control flooding in urban areas is more demanding in China urban areas. Despite the implementation of initiative such as Low Impact Development, the adoption of SC is more promising in controlling the impact of running water in the city (Liu, Jia& Niu, 2017; Ma, Jiang & Swallow, 2020). Figure 2 below shows a framework that summarizes the construction concept of the SCs and their significance.

Figure 2: SC construction Concept (Li, Xu and Yao, 2018)

The process of transitioning the China traditional cities to SCs is supported by advanced technology for constructing drainage system. Also, other major cities around the world like in Norway have successfully implemented the SC initiative. As such, the launching of SC in China can take advantage of benchmarking other cities. However, there are two major challenges that hamper effectiveness of implementing SC initiative and upscaling traditional cities. According to Zevenbergen, Fu and Pathirana (2018), successful construction of SCs requires a long-term planning horizon. A significant challenge in the implementation process in is difficulty in aligning SC initiative with the already existing urban infrastructures. The challenge arises because of the difference in infrastructure layout supported by the SC project. The transformation into a SC may necessitate demolish of some infrastructures that may result in disturbance of the ongoing economic activities. The second challenge associated with transformation process in high cost of completing the SC initiative projects. It is argued that SC initiative requires substantial investment. However, the projects lack reliable financing because they are bigger projects that highly depend on the Chinese Central Government. However, with increased sharing of funds to other sectors, the central government lacks sufficient funds to be invested in the SC initiatives. An estimate of construction cost ranges between 200 RMB/m2 to 1,200 RMB/m2. However, the cost challenge set in because the Chinese central government is focusing on transitioning at least 30 traditional cities to sponge cities. Having spent approximately 600 million annually from 2015 to 2018 in pilot projects, it can be deduced that the overall construction will require even more investment. The transitioning challenges may further be impacted by increasing urbanization in different urban areas. However, it can be effective for the government to encourage private developers to focus on observing SC infrastructures for all new constructions in urban areas. The figure shown below illustrates the concept of construction of SCs as the framework to promote urban drainage systems.

Figure 3: SCs and how they improve infiltration (Nguyen et al., 2019)

2.4 Challenges associated with the Construction of Sponge Cities

It is important to examine challenges that the concept of SC has faced in its implementation process in China. Establishment of a modern urban drainage system is a costly affair for both local and state governments in any country (Jia, Yao and Shaw, 2013). As such, it is vital to explore challenges from a financial perspective and other areas that are significant to changing the scope of life in urban places. Financial constraints include an imminent challenge that can cripple successful completion of a project. For instance, the Chinese government enacted a legislation that compels local governments and private businesses to finance a larger percentage of the construction budget. The national government of China finances around 20% of the total budget on the construction of SCs. In essence, financing of the SC construction requires a heavy financial background, which has challenged quality construction of infrastructure to improve urban drainage systems (Xu et al., 2018). Financing of the projects is a challenge for most cities, which is why legislation is necessary to promote and compel urban places to adopt the strategy for improved sustainability measures.

Rui and Jiang (2013) suggest that the challenges of drainage traditional drainage systems can be avoided in the future by focusing on an integrated planning. There is a need for the panning of a construction to include the planning to include underground drainage network in the construction process. For instance, Rui and Jiang (2013) suggest the need to consider greenbelts and surface infiltration to overcome disasters relating to drainage system in urban areas. The construction of SCs focuses on addressing the challenges of the transitional drainage system. The construction process focuses mainly on identifying the overall needs of the urban areas before initiating the process of constructing the drainage system. Consequently, the shortcomings of the traditional drainage system imply the need for all future constructions to be considerable of all drainage needs. Therefore, there is a need for a more reasonable way to build a sustainable urban drainage system, and SC construction is a more appropriate way to deal with the current situation.

Among them, the biggest problem is the uneven development of the drainage system. The North China region is significantly better than other regions. In terms of different cities, the evaluation value of most cities is between 0.90 and 1.00. The TOPSIS index value of some cities in the northeast, the southeast coast and most inland cities is greater than 0.94. The comprehensive evaluation value of water system facilities is high, which is reflected in the comprehensive level of urban drainage system. The evaluation value of some cities in the Yangtze River Delta and hinterland, Pearl River Delta and hinterland and northwestern regions is 0.90~0.94, reflecting the general level of urban drainage system, Daqing, Dalian and other cities in the Northeast, the Bohai Sea region and hinterland, and the northwest The comprehensive evaluation value of a few inland cities is less than 0.9, reflecting the high comprehensive level of urban drainage system.

2.5 Benefits Associated with the Construction of SCs

It is vital to examine how significant SCs could be towards handling and improving urban drainage strategies. The primary aim that prompted the instruction or adoption of the SC program is to reduce urban flooding and improve urban drainage systems (Jia, Yao and Shaw, 2013). Since its introduction, research indicates that there have been reduced cases of economic damages associated with increased rainfall. Several people have died in Chinese cities in the past due to pluvial flooding experienced in the urban places. The construction of SCs has led to reduced surface runoff, which was a significant contributor to pluvial flooding. Chinese cities such as Jinan have benefitted from the program as they have reduced deaths and displacement of people as a result of extreme rainfall. In essence, controlled pluvial flooding is a significant benefit that Chinese cities have accrued due to adoption of a modern urban drainage system (Xu et al., 2018). It is important to consider the idea that extreme rainfall in urban places is a constraint to economic progress as it causes flooding. Such flooding can be controlled with the adoption of the SC concept, which will ensure improved urban drainage conditions.

SCs have been instrumental in managing stormwater in towns that have embraced the concept. Most of Chinese cities have been plagued by the problem of water yet stormwater causes destruction of property and loss of lives. The SC concept ensures harvesting of surface water, which is treated and stored for re-use by residents in the same city. In the event, the government has controlled important aspects including flooding and water shortages. The construction of SCs is a beginning of a new era that aims to improve water management strategies. Water is an important raw material for both industries and domestic use. As such, it is the interest of authorities to ensure that the high population in urban places has enough water for use. Failure to administer appropriate water management strategies might prove consequential to improved living standards in urban places (Xu et al., 2018). The SC project has benefitted towns that have adopted it in the sense that the project has reduced the problem of water.

3.0 Methodology

3.1 Research Purpose and Design

A methodology in research outlines the processes and techniques applied in gathering important information on the topic of discussion. Failure to capture a practical procedure for a research might be detrimental to achievement of various milestones as expected (Myers, Well & Lorch, 2010). For instance, the research will employ a mixed method approach in examining the issue of construction of SCs and their contribution to sustainability in cities. The mixed method approach will use a case study analysis and a collection of secondary sources available in a bid to, ascertain various facts. The methodology chapter should capture aims and objectives of the study and possible research questions as established (Myers, Well & Lorch, 2010). The first approach that will be employed by the study in gathering information is use of secondary approaches. Article journals and other online books might prove helpful in gathering important facts. Content analysis is an approach widely applied by researchers to gather important information from texts. The aim of the work is to gather information necessary for an informed decision on whether the construction of sponge cites can be the framework to handling of urban drainage systems. The case of Jinan will provide important information on construction matrices and other useful aspects.

The main objectives of the study include:

1. To recognize the benefits of building a sustainable urban drainage system to solve water issues under the concept of SC and use it to alleviate water shortages, maintain urban water and soil, and improve humanities and natural landscape of the city.
2. To use document analysis and Secondary data combined with Case study technique to analyze the development status and achievements of the typical “SC” drainage system in Jinan, and at the same time recognize the deficiencies and challenges, and improve them.
3. To explore the essence of legislation towards improving water conservation practices in urban centers.

3.2 Research Questions

It is important to state precisely the research questions, which will act as a guide to achievement of the set objectives. The research aims to examine whether the construction of SCs is a strategic approach towards handling water issues in urban centers. The main research question is, “Can the construction of SCs be the framework for the development of sustainable urban drainage systems?” Other sub-questions that might prove helpful in the study include:

1. What are some of the benefits that accrue to the construction of SCs as a strategy to sustainable urban drainage systems?
2. What are some of the views that exist on the current development status and achievements that the China has made under the policy system concept of sponge cities?
3. Can legislation help advance the concept if SCs in most parts of the world?
4. How has Jinan benefitted from the construction of sponge cities?

3.3 Research Strategy

The research applies a secondary approach to gather and analyze important information on the topic of discussion. It is vital to note that a qualitative strategy can help gather the necessary information for a formidable conclusion (Badke, 2017). The integration of different approaches towards gathering of information is an important factor, which improves the possibility of achieving reliable results. The study purposes to use a qualitative approach, which allows for analysis of various themes on the topic of discussion. The first method that will be integrated in the study is the use of a descriptive approach in examining various aspects that revolve around the construction of SCs across the world (Foss, 2009). The case study is based on Jinan in Shandong Province, China, as a city in the world that has embraced the SC strategy (Badke, 2017). Using different research strategies will help the study establish valid and reliable claims on the construction of SCs and sustainable urban drainage systems.

Document analysis is the most appropriate approach that can help review various materials that exist. It is also vital to echo the role of the internet in conducting reliable research on the construction of SCs (Badke, 2017). The internet provides an opportunity to access a large pool of information that might prove helpful in arriving at a conclusion. For instance, Google scholar is an online resource center that has numerous article journals and books for review. Notably, there is a need for an inclusion and exclusion criteria, which should help in determining the most relevant materials for the study (Jiang, Zevenbergen and Fu, 2017). Failure to use the right materials will compromise the quality of results expected. Content analysis captures themes in various texts and other reports that have been documented before.

3.4 Data Collection

3.4.1 Document Analysis

The research will use secondary sources as an important approach to gathering of information. Through documents and literature that exists on the topic of discussion, there is a need analyze the texts existing to establish various facts on the topic of discussion (Clark & Vealé, 2018). The most appropriate strategy is content analysis that aims at a thematic interpretation of the topic of discussion. There is a need to use an exclusion and inclusion criteria as a way of ensuring that only relevant materials are captured. As an inclusion criterion, materials with feasibility, development status (results), research progress, deficiencies and challenges of developing sustainable urban drainage systems under the construction concept of SCs will be included for the study (Clark & Vealé, 2018). Materials that do not meet the inclusion criterion will be excluded from the study as they are irrelevant. The internet will form an important part of the research process, especially on collecting data from secondary sources. It will provide an opportunity to examine a wide range of materials that have crucial concept on the topic of discussion. There are over 100 articles journals and books to be reviewed in a bid to get a deeper insight into the topic under discussion (Clark & Vealé, 2018). However, approximately 30 resources or documents will be used in the final research as a way of arriving at a formidable conclusion. As such, content analysis will help gather information from documents, which is why it will be strategic to apply it during data collection.

3.4.2 Case Study Analysis

The research will use a case study technique to examine the issue of construction of SCs and their contribution to sustainability in urban drainage systems. The involved case study should illustrate a city that has developed the sponge system as a way of administering sustainability (Seawright & Gerring, 2008). The case under consideration is China, which has adopted the system of sponge cities. A case study approach allows a researcher to examine issues that affect a particular matter, in this case, challenges of developing sponge cities. Using a case study helps one understand urban water problems, which is the first step towards finding a solution on the same (Seawright & Gerring, 2008). China has practical cases of cities that have adopted the approach, which is why it is a favorite option to use in the research.

3.4.3 Rationale for Case study Application

It is important to understand the essence of using a case study approach towards examining the topic of discussion. For instance, Jinan illustrates a city that has embraced the SC strategy to improve water management approaches in the town. Learning through a case study provided an opportunity to examine theoretical framework in a practical manner. It was vital to choose cities that have done well in managing their urban drainage systems. There is a distinction in the construction process and resources applied in different towns, which is why using Jinan presents the best opportunity to understand the significance of SC. Using cities that have not embraced the construction of SC will limit the research to information that is less efficient for a detailed conclusion. The case study is the most strategic approach that the research can use to analyze the impact of legislation on the construction of SCs across many cities in the world.

3.5 Data Analysis

Collection of information should be followed by a rigorous analysis of the data gathered. The first approach used to analyze data is content analysis. There are various steps that the research can apply to gather information through content analysis (Leech & Onwuegbuzie, 2007). Through analysis, the research will check and establish meanings of content authored by other researchers on the topic of discussion. The approach will allow inference making on various concepts on the topic of discussion.

Jinan is an example of a city that has embraced the construction of SCs and using it as case study might help (Cambraia, Saurin & Formoso, 2010). Analyzing Jinan as a case study will help gather more insight on the essence of constructing improved urban drainage systems. The in-depth and detailed nature of a case study makes the approach the most appropriate in examining the topic of discussion. As such, case study analysis will form an important part of the research conducted. It is through a rigorous analysis that meaningful conclusions can be drawn. The approach will help the research gather important facts on the ground. Moreover, it is through a case study approach that one can learn challenges of a project (Cambraia, Saurin & Formoso, 2010). This will help improve future projects on the same or enhance efficiency.

4.0 Fieldwork and Results

It is vital to conduct an empirical analysis on the concept of construction of SCs as an approach to control urban water conservation practices. The empirical analysis will capture important metrics involved in the construction of SCs in urban places as a way of advancing sustainability (Zhang, He and Zhang, 2019). A case study approach will help analyze important cities in the world that have embraced the use of sponge cities. One of the urban places under consideration is Jinan, which has made great strides in advancing the policy on sponge cities. It is through an empirical analysis of the metrics involved that evaluations can be drawn for a detailed policy enactment. Failure to capture important data on the construction of such infrastructure might lead to misappropriation of funds (Zhang, He and Zhang, 2019). The construction of SCs is capital intensive ad requires one to conduct a rigorous analysis of financial implication before investing in the same.

China is a water-scarce country. Nationwide, per capita freshwater resources are 2,310 m3 (NBS 2011c), which is about onequarter the world average. In the dry regions of the North and Northeast, freshwater resources are only 785 m3 per person, about 200 m3 less than the international threshold for “severe” water stress, below which there is a high likelihood of frequent shortages and supply disruptions (see UNDP 2006). Agriculture continues to be the biggest user of water, followed by industry and households, as illustrated in figure B2.1. In 2010, the agricultural sector consumed 370 billion m3 of water; industry consumed 145 billion m3, and households in urban areas used 77 billion m3. The figure below (4) indicates water withdrawals in China since 1987.

Figure 4: Water Withdrawals in China by Sector, 1987-2010

There is strong evidence that the continued growth of agriculture and industry, coupled with the lifestyles of an increasingly affluent population, will increase demand for water in the coming decades (Rosegrant, Cai, and Cline 2002; Alcamo, Henrichs, and Rösch 2000; Alcamo et al. 2003; Alcamo, Flörke, and Märker 2007; 2030 Water Resources Group 2009; Hubacekand Sun 2005; Xionget al. 2010). In a reference case scenario, total withdrawals of surface water and groundwater could reach nearly 820 billion m3 by 2030 (2030 Water Resources Group 2009),9 an increase of 35 percent over 2010 (NBS 2011c). In a continuation of current trends, water use by industries and households in cities is projected to grow the fastest. Agricultural water use is projected to decline as more efficient irrigation technologies are introduced and the composition of China’s economic activity gradually shifts toward higher-value-added sectors, though it will continue to account for the largest bulk of water withdrawals (Rosengrant, Cai, and Cline 2002). These results indicate that the growth in demand for China’s scarce resources will continue to exacerbate water stress, even in the absence of climate change. Even under a balanced growth scenario in which local governments give higher priority to environmental protection, Xiong Wei et al. (2010) project that by 2050, all of the major basins currently experiencing severe water stress will face even greater shortages. Baseline projections from the Organisation for Economic Co-operation and Development (OECD) for global water stress by 2050 also show that stress for all major basins is expected to increase, with the Yellow, Hai, and Liao basins remaining under the greatest pressure (OECD 2012).

Floods affected about 10 million hectares each year between 1977 and 2008. Since 1990, they have caused direct economic losses of 174 billion yuan annually (figure 6). These losses include damages to agriculture, forestry, aquaculture, transportation, water utilities, and other sectors. Intense rainfall, flooding, and other water-related hazards are particularly damaging to infrastructure assets. Erosion from such hazards shortens the life-span of road and rail networks and causes sudden drops in service levels (Ollivier forthcoming). Disruptions of transportation services in cities are exacerbated by poor drainage systems, many of which are inadequate to deal with current weather risks let alone with even more frequent or severe flooding events (Ollivier forthcoming; Jensen forthcoming). Floods and mudflows also have adverse impacts on hydropower reservoirs. As China’s stock of infrastructure assets continues to grow at a rapid pace, greater exposure to floods and other water-related hazards could lead to higher life-cycle costs and more expensive investments. The figure (7) below shows direct economic losses in China from flooding from 1990-2011.

Figure 5: Direct Economic Losses from Flooding in China, 1990-2011

Figure 6: Regional characteristics and general information of pilot SCs (Li et al., 2017)

4.1 The Case of Jinan, China

Jinan is one of the towns that have been hit by flush floods in the recent past, which prompted the authorities to seek alternative avenu8es to handling of the issue. The city is made up pluvial soil, which results into flooding due to the low level of infiltration (Hu et al., 2018). Construction of infrastructure in cities such as Jinan reduces the level of infiltration to the ground, which is why there is increased pluvial flooding. It is important to devise strategic approaches to handling of pluvial flooding as a strategy to improve urban drainage systems. Construction of SCs in various urban places might prove to be an important aspect towards promoting life in cities (Hu et al., 2018). Jinan has embraced the construction of SCs as the approach to help reduce the level of flooding in the in the city. In 2016, torrential rainfall resulted in pluvial flooding, which is resulted in some houses in many provinces being submerged. It is important to examine the historical background and policy enactments that allowed for the construction of an improved urban drainage system. It is important to note that the construction of SCs does not only help reduce flooding but improve water conservation approaches (Hu et al., 2018). The approach helps improve strategies that can lead to improve water management tools, which can help curb the increased effect of climate change. The table below labeled as figure 7 is a presentation of Chinese Cities that were put under pilot study on the construction of SCs.

Figure 7: Cities put under the program of SC (Yin-chuan et al., 2018)

Statistics indicate that more than 10 million people in China are migrating into urban places, Jinan being the target for a larger share of the population. The high population in urban places has led to restricting of drainage systems in a bid to improve the condition of the city (Li, Qin and Du, 2018). The quantity of buildings that have been constructed in China represents more than half of the houses built across different cities in the world. Under such circumstances, Jinan as a city saw the need to develop SCs as a way of reducing flooding and controlling water availability (Hu et al., 2018). Streets in the town have been made like a sponge that absorbs running water in a bid to reduce pluvial flooding with Jinan and its environs. It is important to examine the metrics involved in the construction of an underground drainage system in urban places. The aim of developing a SC in Jinan is to absorb surface water in a bid to reduce flooding, which is a major concern for most residents in Jinan town (Li, Qin and Du, 2018). The role of SCs is to capture or harvest the water during heavy rainfall seasons and later releasing it for use during low rainfall season. It is a comprehensive approach towards handling of the water shortage crisis in Jinan City. Time series research conducted on the rainfall recorded in 2017 is shown in the figure 8 below.

Figure 8: Time series plot of rainfall recorded by an onsite gauge (Li, Qin and Du, 2018)

The target control target of total run off in cities was proposed in the SC Development Technical Guide, which provided guidelines on how the process can be implemented for an improved effect. The initiative to construct SCs in China was launched in 2013, which has since helped most parts of urban places construct advanced drainage systems (Li, Qin and Du, 2018). In the year 2012, increased rainfall in Jinan town saw 79 people killed and 1.78 US dollars were recorded as an economic damage. It is important to note that Jinan had the necessity to improvise a strategic approach that could help reduce the level of flooding in town centers. The construction of SCs proved to be the most suitable alternative that China could use to reduce the potentially risk pluvial floods (Wang et al., 2020). The SC development guide issues by the Chinese authorities marked the onset of construction of a SC in Jinan in a bid to control water drainage systems. The enactment of legislation on the same is a step towards ensuring that important procedures and guidelines are followed in developing and improving standards of living within Jinan city. The city among the selected 16 towns put under pilot study in the construction of SCs and improved urban drainage systems (Ma, Zhao and Ma, 2019). The inclusion of Jinan was due to the fact that the town had experienced deadly floods in the past. All construction authorities in China were compelled to comply with the SC development guide criteria. The construction of improved drainage systems in Jinan proved fruitful as the town has managed to control the high level of flooding that was experienced before. Figure 9 listed below is an illustration of average monthly rainfall and temperature in Jinan City.

Figure 9: Average monthly rainfall in Jinan City

Jinan is the capital of Shandong province China and there was an urgent need to develop a SC to reduce negative impacts of increased rainfall. Unsustainable development in Jinan is detrimental to economic progress within the city and it is important to establish comprehensive approaches to improving standards of living in the urban place. The water absorbed is stored and recycled for use within the city, which is why the strategy has proved helpful in many ways (Ma, Zhao and Ma, 2019). The high level of flooding has been controlled and there are reduced damages associated with pluvial flooding. Statistics indicate that the recycling of 70% of flooding water is a strategic step towards improving water sustainability practices in the city. Jinan presents a case that can help understand the historical developments behind the construction of SCs in China. There are different towns that have embraced the approach as most have learnt from the case of Jinan. Both towns followed the set framework and guide on the construction of SCs in a bid to improve drainage systems in the cities (Li, Qin and Du, 2018). Equally, the increased urban population posed a problem as there was a need to provide food and clean water for residents. Using SCs in Jinan has led to improved water management approaches to ensure sustainability is achieved. Jinan is a suitable case study that helps highlight important aspects on the construction of sponge cities.

4.2 Weather Conditions in Jinan, Shandong Province

It is vital to examine the weather conditions experienced in Jinan, which could have prompted the construction of Sponge City framework as a way of handling urban water drainage issues. There are different aspects of weather conditions that can be examined in Jinan to ascertain e essence of the SC concept. The graph in figure 10 shows important information on the max-min, average temperatures that are experienced in Jinan city, Shandong. Also figure (11) below shows average weather conditions exhibited in Jinan for a whole year.

Figure 10: min max, average temperatures in Jinan

Figure 11: Jinan weather by Month

It is also vital o examine the level of precipitation experienced in Jinan as part of collecting data that can be helpful in making formidable conclusions. The multiple-year average volume of water resource in Jinan city is 1.748 billion m3 but the per capita volume of water resource is only 290 m3 which is about 1/7 of the whole-country’s water resource per capita. It is a typical water shortage city and of great urgency to seek a new way to develop water resource such as rainfall harvesting or stormwater reuse. The graph below n figure 12 is a presentation of precipitation levels in Jinan city.

Figure 12: Average rainfall amount and rainy days

It is difficult to improve water quality by controlling the water pollution and stormwater runoff flowing into the Xiaoqing River. According to the water quality monitoring data of Xiaoqing River, the water pollution load brought by stormwater runoff could be more than 36.7% of the total pollution load. There are some limitations and challenges on the water quality control because almost all the urban wastewater plants are built around Xiaoqing River and there is not much land available to build new facilities to reclaim stormwater, therefore most of stormwater with pollutants is directly discharged to Xiaoqing River. The total length of the wastewater pipelines in Jinan is about 1,737 km and 16% of it is combined sewer. Combined sewer overflow may occur during and after a large rainfall event and the overflow of wastewater does discharge into the river directly and brings large pollution load. The figure below 13 is an illustration of Rainfall levels experienced in Jinan. Figure 14 shows the UV index in Jinan city.

Figure 13: Changes in precipitation

Figure 14: UV index in Jinan, China

The rate of rural to urban migration is high in China, which is the main reason for increased population in urban centers. The high population in such cities necessitates the construction of improved water drainage systems to avoid emergence of associated social problems (Li, Qin and Du, 2018). Jinan forms one of the cities in China where people move in daily in se arch for an improved standard of living. Water shortages in the town formed part of the basic reasons why the program on the construction of SCs the construction of SCs in China was triggered by heavy pluvial flooding in urban centres, the need to conserve water, and importantly, improve urban drainage systems in the country. Equally, the need to recycle water and improve sustainability approaches was among the contributors of the project. The figure below shows the average monthly rainfall experienced in Jinan. The graph in figure 15 below shows average monthly rainfall. Figure 16 is an illustration of days of sunshine experienced in Jinan city.

Figure 15: Average Monthly Rainfall

Figure 16: Daylight sunshine hours in Jinan City

4.3 Sponge City Concept and Construction of an Urban Drainage System

Landscaped gardens and green areas: Create open low impact development facilities, such as concave green areas, bio-retention facilities, and water-permeable public squares and parking lots, to enhance the standing water and seepage capabilities of landscaped gardens and green areas. Within the research zone, build 1.275km2 sunken green area, 0.017km2 bioretention facility, 0.167km2 rainwater wetland and 0.625km2 pond wetland.

Transforming road traffic systems: It is important to set up LID facilities in green areas, carry out rainwater permeation, storage and regulation, and enhance the role of roads in relation to rainwater seepage, standing water, purification, and drainage. Build a permeable paved road surface on urban trunk roads, increasing the permeable road surface area by 44hm2 for urban arterial roads, and increase permeable road surface area by approximately 90hm2 . For some sidewalks, construct approximately 3hm2 of permeable pavement; also build a total of 21hm2 of sunken green areas.

Residential neighbourhoods: Rainwater runoff from the roofs of buildings and neighbourhood pavement should undergo organized flow concentration and transfer; sewage will be intercepted, and following pre-treatment, channelled into LID facilities within green areas; further, build an additional 49m2 of green roofing, 63m2 of sunken green areas, and increase permeable pavement by 106m2 .

Public service administration and commercial areas: Construct 38m2 of green roofing, and 41hm2 of sunken green land, including building and setting up 1932m2 of new rainwater wetland in public service administration areas where green land is concentrated; build 55hm2 of new permeable pavement in neighbourhood roads and parking lots, and build 1.1hm2 of new water reservoirs.

4.4 Metrics on the Construction of Sponge Cities

SC construction design optimization aims to reduce total costs associated with the project, which is necessary for utilization of resources. The SC construction technical guide highlights important aspects that should be adhered to in a bid to ensure improved urban drainage systems (Zevenbergen, Fu and Pathirana, 2018). It is important 6that each project of constructing a SC focuses on m minimizing costs and using the most effective approach. An SPC plan should aim at lowering project costs for LIDs and effects of the same on construction of improved drainage systems in urban places. The optimization process takes place in three main steps including the design of SPC as mentioned in the technical guide, simulation and calculation of changes caused by runoff quantity and quality, and importantly, simulation of the minimum cost involved in the construction of a SC (Zevenbergen, Fu and Pathirana, 2018). It is vital to note that SC construction optimization designs should capture all the three steps as a way of ensuring that resource have been put into better use. The flow chart below shows a SPC optimization model that can be used in the event. It is important to examine the SC optimization strategy that Chinese cities have applied in their framework. Figure 17 illustrates an optimization framework that can be used.

Figure 17: Flow chart showing the proposed SC (SPC) design optimization process (Li, Qin & Du, 2018)

4.4.1 SPC Design

The SC construction design is reliant on data from the site where the construction should be done. For instance, it is important to examine the soil of a place and know the specific and hydraulic conditions that affect seepage and infiltration of water to the soil (Li, Qin & Du, 2018). Jinan presents a case of a city that is located on pluvial soil that has a low rate of infiltration. As such, the approach or design adopted should ensure that it considers soil conditions, local meteorological conditions and hydrological conditions. Failure to observe such aspects during the construction of SCs might be detrimental to a successful completion of the same project. Based on the SC construction development technical guide, primary objectives for an appropriate design should capture a reduction in the total runoff or surface water in the city in question (Li, Qin & Du, 2018). For instance, the model design used in Jinan ensured that surface runoff reduced its rate as intended. Equally, a design should purpose to increase the level of infiltration of surface water into the ground for conservation. Reducing the level of pollutants that get infiltrated into the ground is a significant factor that each design should consider in the event of construction. Designs that do not meet any of the mentioned standards are likely to fail in their quest to improve urban drainage systems.

4.4.2 Stormwater Management Model

The Stormwater Management Model (SWMM) is widely used by the USA Environmental Protection Agency and is frequently used to model the effects of LID [9, 10]. It is especially useful in predicting how the system performs in reducing flood flows (Yin-chuan et al., 2018). Temporally, it can be used for both the long-term simulation of runoff quantity and quality, or for short-term predictions (e.g., a single event). It is most suitable for modeling the hydrological/stormwater implications of LID in small areas and/or catchments. During the present study, a local 10-year (2005–2015) precipitation and evaporation record was obtained from statistical reports, based on the tables, the design precipitation under design control targets can be acquired, then the corresponding 24-h time series could be acquired, which will be used as input for SWMM. The figure 18 listed below illustrates precipitation data for the city for 10 years, while figure 19 is an illustration of evaporation data that is experienced.

Figure 18: Historical Precipitation data (Li, Qin and Du, 2018)

Figure 19: Historical Evaporation data (Li, Qin and Du, 2018)

Figure 20: Changes (%) in Runoff Quantity for Scenarios (Li, Qin and Du, 2018)

Figure 20 above shows a table with detailed information of average flow rate of surface water and peak flow reduction under the SC system. Runoff water quality monitoring data collected during individual flood events at the test site between 3 March and 7 December 2017, and 15 July and 30 August 2017, were used to calibrate the water quality parameters in the SWMM model (Li, Qin and Du, 2018). The exponential function model inherent in SWMM can most effectively estimate the accumulation and erosion of surface pollutants. Thus, it was used in both the pollutant accumulation model and the scour model. The timing between individual runoff events was set at 7 days. It is vital for the research to understand geographical partitioning of sample cities that have been put under the SC program in China. The table in figure 21 is elaborate on data that indicate number of sample cities in different geographical locations.

Figure 21: The number of sample cities in geographical regions and the average value of each index (Zhang, He and Zhang, 2019)

The System for Urban Stormwater Treatment and Analysis Integration (SUSTAIN) is a decision-support system developed by the USEPA (United States Environmental Protection Agency). SUSTAIN can be used to analyze stormwater flow, pollutant discharge, and management options on multiple scales, temporally ranging from a single storm event to long-term, multi-year simulations [13]. By using SUSTAIN, BMP options can be selected and evaluated based on the BMP’s cost and cost-effectiveness (Yin-chuan et al., 2018). The SUSTAIN modeling approach includes seven key components that are integrated into an ArcGIS platform. It includes a framework manager, ArcGIS interface, watershed model, BMP model, optimization model, post-processor, and Microsoft Access database. The optimization equation can be formatted as below.

The objective is to: Minimize ∑ n i=1 Cost (BMPi), i − 1. . .n (1)

For cost minimization, subject to: Nj ≤ Nmaxj and/or Mk ≤ Mmaxk, where BMPi the ith BMP/LID associated with location i, which forms the decision matrix; Nj and Nmaxj represent the computed number of water quantity factors, and the maximum (max) value of the water quantity factor targeted at the assessment point j; Mk and Mmaxk represent the computed number of water quality loading factors, and the maximum (max) value of the water quality loading targeted at the assessment point k.

For cost-effectiveness, subject to: Nmaxj1 ≤ Nj ≤ Nmaxj2, which represents the range of the flow volume-based stormwater management target; and/or Mmaxk1 ≤ Mk ≤ Mmaxk2, which represents the range of the pollutant load-based stormwater management target.

To help define the nature of the optimization problem, SUSTAIN was provided with the evaluation factors listed below: Factors Based on Flow: Peak discharge, annual average flow volume, the frequency of flow exceedance; Factors Based on Pollutants (TSS, TN, TP, or User Defined): Annual average load, annual average concentration, maximum days for average concentration; Factors Based on Sediments: Annual average load, annual average concentration, maximum days for average concentration (Li, Qin and Du, 2018). During the present study, SUSTAIN was used to simulate the minimum cost and cost-effectiveness of optimal combinations of LIDs. The annual average flow volume was selected as an evaluation factor. The factor (target) was derived from the SWMM simulation and equated for S1 to a 37.78% reduction in flows for events with a 10-year period return (Li, Qin and Du, 2018). The unit parameter (i.e., width, length, and cost) and unit variables (i.e., threshold, maximum, and increment) were used as typical variables and constraints.

4.5 Comparison of Stromwater Management before and after Construction of Sponge Cities

Stormwater management is a priority for mot SC construction models used and there is a need o compare changes realized after the construction of such infrastructure. The first aspect that can be noted from the comparison is that the new strategy proves efficient in reducing surface water that results in pluvial flooding. Traditional approaches to drainage systems in Jinan were overwhelmed by the high rate of surface run-off. There was a need to develop strategic methods that could help reduce surface run-off and promote infiltration. Pluvial flooding in Chinese cities in the past has resulted in death and destruction of property to a large extent. As such, SC construction in Jinan has been helpful in reducing the negative impact of storm water significantly. The SC concept allows the city to collect water that could otherwise cause problems running on the ground. The water can be collected through spongy infrastructure on top of roofs and other areas.

It is important to note that with the construction of SC in Jinan, water shortage issues have been reduced to a significant extent. He water shortages experienced in Chinese cities are attributed to high population and poor urban drainage strategies. The SC system has improved water harvesting strategies, which has proved important in solving water problems in Jinan. The stormwater is collected and stored to avoid a run-off that can destroy property. The collected water is treated using appropriate strategies to make it clean water for use. The clean water is stored and re-used within the city during a shortage. In essence, construction of sponge cities has enabled cities to collect, treat and store stormwater for use in the city when need arises. The traditional model could no tore enough water that could reduce water problems in Jinan. There is a notable difference in strategies applied traditionally and the new model that follows the construction of SCs. Most cities with SCs have done well in reducing water shortage problems as a result of the S framework. Figure 22 below shows a graph of data on the annual rainfall in Jinan, deaths from flooding and water needs before and after the construction of an SC system in the city.

Figure 22: Comparison of water shortages, flooding and annual average rainfall

Total planned water use in 2015 of 620 billion m3 or about 445 m3 per person per year. (12th FYP statistic) In 2012 there was a 50 billion m3 shortfall. (MWR) Water usage to be held to below 670m3 per person by 2020. On 3 of the 7 major river systems (Hai, Yellow and Liao) exploitation levels have reached 106%, 82% and 76% against the internationally recognized maximum of 40%. (MEP official reported in Jinghua Shibao 17/4/15) 28,000 rivers have disappeared across China in the last 20 years.

It is important to note that the table shows information on rainfall, deaths as a result of flooding and water needs in Jinan. Examining the city’s water needs, floods and other water related problems indicates that the city is making progress under the sponge city system. Floods have reduced and its effects on society have changed significantly. The contrition of an SC in Jinan has promoted urban water management practices, which has led to reduced economic damages as a result of flooding. For instance, the number of deaths hat were being registered in the city have reduced in the event of proper urban water management system. Equally, water needs in the t0wn have changed and the high population can get safe and clean water through re-using. The high population in Chinese cities has led to a high demand for clean water for use in cities. However, the SC system has promoted water conservation practices in the city leading to a reduction in water problems in city. The water harvested through the sponge city system is not enough to serve the whole town, even though it has improved the state and reduced water issues.

5.0 Analysis and Evaluation

It is important to examine data collected and highlight important aspects on the topic of discussion. The main aim of the research is to examine whether the construction of SCs is the right framework that can help improve urban drainage systems in China. Jinan forms an important case study that has helped highlight important facts on the construction of SCs as the approach to improve drainage systems (Jiang, Zevenbergen and Fu, 2017). Also, it is important to examine whether the finding agree to the research question, which aims to examine whether legislation can help promote the implementation of such projects in cities. China is one country that has made tremendous efforts in improving drainage systems in urban places for an improved standard of living. Poor drainage systems in cities might result in flooding that can cause death and destruction of property. As such, it is the duty of very municipality to consider using designs that are appropriate to controlling of surface water. Much of the existing literature on the construction of SCs suggests that enacting a framework that requires urban places to transform into SCs (Jiang, Zevenbergen and Fu, 2017). The discussions part should include an analysis of the impact of legislation on the construction of sponge cities. It is also vital to analyze the importance of constructing SCs as a framework to manage water flow in urban places. It is also vital to examine challenges that are associated with the construction of SCs as a framework to control flooding in cities.

5.1 Use of the SC Concept to Develop Urban Drainage Systems

It is important to note that construction of SCs in China is a strategic approach aimed at improving urban drainage systems (Liu, Jia and Niu, 2017). Chinese cities have faced constant flooding during heavy rains season, which prompted the government to act and seek a possible solution to the menace. Several people in the country have been affected to the extent of some losing their lives due to pluvial flooding. The high level of flooding in the cities is caused by high an increased level of surface water as a result of rain. The nature of soil in most Chinese cities has a low rate of infiltration, which results in accumulation of surface water. As such, the Chinese government had the reason to find a solution towards the high level of flooding that has had a huge economic impact (Jiang, Zevenbergen and Fu, 2017). Also, there is a need to note that most of Chinese cities have high population, which has exerted pressure on water resources that are available. There is an imminent shortage of water in most cities, which is why SCs were introduced to help recycle water.

The move taken by Chinese authorities is a long-term strategy that is helping the country change its sustainability practices. There are different aspects that can results due t the loss of an urban drainage system. For instance, increased waterlogging in urban places is one aspect that makes the construction of SCs necessary. The nature of soil in Chinese cities such as Jinan explains why there is increased waterlogging, especially during the heavy rain season. In 2012, pluvial flooding in Jinan resulted in 79 deaths and millions of dollars were lost as damages to the same (Liu, Jia and Niu, 2017). Such losses can be avoided by constructing sponge cities, which increase infiltration of water to the ground. It is important that cities with similar issues adopt the strategy of constructing SCs as a way of enhancing urban standards of living.

It is vital to mention that construction of SCs requires the application of an optimization design. Optimization designs are helpful in weighing attached costs in a bid to adopt the most effective and cost-friendly approach (Li, Qin and Du, 2018). The first objective that an optimization design must meet is that it has to purpose on reducing the rat of peak flow of runoff water. Runoff water causes pluvial flooding, which challenged authori6ties to introduce construction of SCs as a way of combating the same. A design that fails to capture important aspects on reducing the peak flow might prove ineffective in combating pluvial flooding. Low-impacts developments require strategic handling and some of them might not handle high precipitation. The second aspect that a design must objectively purpose to meet is increase the infiltration or seepage of surface water to the ground for harvesting. Designs that do not purpose to increase infiltration are less effective in improving urban drainage systems. It is the duty of the research to establish the importance of a design increasing infiltration of water to the ground. With increased infiltration, there is an immediate reduction in the peak flow rate, which is a step towards changing the scope of the urban drainage system (Hu et al., 2018). The third aspect that models should consider is the fact that pollutant that flows in water might be toxic to water bodies. The model to be adopted at any time must incorporate an objective of reducing the level of allowed pollutants that get infiltrated into the soil. Much of the pollutants allowed in water bodies have resulted to death of aquatic life, which could otherwise be avoided (Li, Qin and Du, 2018). In essence, Jinan and Jinanadopted the construction of SCs as a strategy to reduce flow rate of surface runoff water, increase seepage and abet the high level of pollution that is experienced. The Chinese authorities had every reason o adopt the strategy in a bid to improve urban drainage systems in various cities.

5.2 Benefits Associated with the Construction of Sponge Cities

It is important to examine benefits associated with the construction of SCs in China. The first and most important aspect is reducing pluvial flooding, which has claimed many lives in Chinese cities in the recent past (Wang et al., 2019). It is important to note that with the construction of SCs much of the flooding is controlled, which improves urban water management practices. For instance, Jinan suffered 79 deaths in 2012, which prompted authorities to think alternative approaches to handling of the menace. Increased rainfall in urban places increases the amount of surface runoff water, which causes flooding in towns. Such flooding might led to economic implications as noted from the mentioned case studies. It is a priority for each government to protect its citizens from such disasters, which is why the SC development technical guide framework was established. In essence, construction of SCs has helped China control urban flooding, especially in Jinan (Hu et al., 2018). Failure of Chinese cities o adopt the system could have had far much reaching consequences for the authorities. It is important that the project was implemented as an approach to improve important water management practices.

The second benefit associated with the construction of SC is increased sustainability practices. It is vital to note that the construction of SCs in China has converted paths into Greenfields that are adorable. Water is an important aspect to growth of plants and development of a habitat that supports biodiversity. Failure to construct required SCs would prove problematic towards the handling of water issues within the city (Hu et al., 2018). As such, the fact that SCs promote sustainability measures within the environment is a significant factor to consider implementation of such projects. One of the approaches to enhance sustainability in any circumstance is reduce the level of pollution experienced. It is through appropriate optimization designs that a city can learn on reducing pollutants allowed into the environment. Some of the pollutants are harmful to the life of both plants and animals in the environment (Wang et al., 2019). As such, construction of SCs purposes to reduce the level of pollution for an improved sustainable measure. SCs are beneficial as they have helped make some streets green due to strategic water management approaches employed. In essence, improved urban drainage systems have led to improved sustainability measures across many cities in the Chinese context.

Third, construction of SCs ensures proper management of water including shortage issues in cities. For instance, most Chinese towns experience water shortages due to increased population that has exerted pressure on the existing water bodies (Nguyen et al., 2019). As such, constructing SCs helps harvest runoff water, which can be recycled for use by the residents of the city in future. The water collected is stored, treated and directed to the city for use as a way of ensuring shortage issues are handled. It is interesting to note that instead of the water causing damage to property and kill people, it is only important to store the water for future use. Water shortages in urban places can potentially be as risky as heavy rainfall that causes flooding in cities. As such, it is important to adopt the construction of SCs as an approach to increase strategies of harvesting running water. Water that is harvested can be used for various uses within cities including improving sanitation practices for residents. Towns with poor water harvesting practices face shortages that might result in more social issues. as such construction of SCs in China and other places is a step towards improving water conservation practices.

Another benefit of the construction of SCs in urban places is that it helps the government reduce costs attached to damages for every pluvial flooding. It is vital to note that flooding causes a significant financial implication on the economy of a country (Nguyen et al., 2019). For instance, the year 2012 can be remembered when the government spent over 1.7 million dollars on the handling of damages in Jinan as a result of pluvial flooding. In essence, it is the duty of government to enact policies that can help prevent further expenditures in future. Failure to enact important policies that compel urban places to develop SCs might have been costlier to 6he Chinese government so far. However, the fact that the same was implemented several years ago is an indication of its intention to curb financial implications associated with pluvial flooding (Nguyen et al., 2019). The construction of SCs has provided a sustainable approach towards extra spending that the Chinese government would incur fixing damages due to lost urban drainage system. An examination of benefits associated with the construction of SCs indicates that other urban places should embrace the project as a way of enhancing sustainability measures.

5.3 Challenges Associated with Construction of Sponge Cities

It is important for the research to establish various challenges associated with the construction of sponge cities, especially in China. The fist associated issue is the financial implication that the project has on the economy of a country (Li et al., 2017). It is important to note that the construction of SCs is a costly exercise that requires the ministry of finance to pump in millions of dollars. The process requires strategic planning and budgeting to avoid financial upsets at later stages. The Ministry of Housing and Urban-Rural Development (MOHURD) in China estimates the cost of constructing one kilometer square to be between 100 to 150 million Yuan. Since 2015, the MOHURD has spent over 400 million Yuan in financing projects related to construction of SCs within the country. Not all countries can afford constructing SCs in their urban places due to the financial implication associated. China has done its best in the last few years, injecting millions of money into SC construction, which has proved helpful in improving urban drainage systems, especially in Jinan. Poor financial budgeting for such projects could prove a challenge to any city that aims to improve it drainage systems (Li et al., 2017). Inadequate resources will lead to stalling of the project, which might be costlier to a government. As such, financial attachment involved in the construction of SCs in urban places proves to be a challenge.

The second challenge associated with construction of SCs is financing of the projects. The Chinese government covers a portion of the costs associated with the construction of SCs in urban places. Much of the costs should be met by the local governments and the private sector. It is also vital to note that local governments do not have the same ability in terms of finances (Li et al., 2017). As such, some might end up laying substandard infrastructure for the same, which might not withstand or achieve the primary aim. The financial implication associated should be huge enough to make involved stakeholders construct a durable and sustainable urban drainage system. The fact that different places in the country have different abilities to finance such projects makes it difficult to have a standard quality or design towards the construction of SCs in urban places. The national government provides approximately 15-20% financing of the projects while the rest of the funds have to come from local governments and private business people. The issue of having to look for funds from other players in the urban place makes it a challenge for the efficient and immediate construction of SCs (Jiang, Zevenbergen & Fu, 2017). There is a need to establish a special kitty that handles the construction of SCs without involving local governments and private sector. It is important to note that financial challenges associated with cities differ, which is why the costs associated and scope of construction varies in most circumstances.

The fact that new constructions in the country have to comply with set standards challenges successful achievement of the objectives. For instance, there are set standards that each SC must meet by 2030. Old cities will find it challenging refurbishing already constructed infrastructure due of the financial implication associated (Jiang, Zevenbergen and Fu, 2017). The major issue is that local governments need to involve private business people in a bid to lobby for funds towards the same. However, the private sector is hesitant to participate in the refurbishing of the drainage systems since business opportunities promised are not clear. It is vital to note that this challenges the refurbishing of old towns to meet the standards required by 2030. There should be clear guidelines on the financing of such projects as local governments are getting overwhelmed with the issue of raising funds for renovation and construction of improved drainage systems. Better, the government should make clear of opportunities to arise with the involvement of the private sector in the construction of SCs (Jiang, Zevenbergen & Fu, 2017). Refurbishing old towns within the time stipulated is a major challenge that is facing the construction of SCs in China. Much should be done to address the issue of financing of such projects in each urban place.

Also, it is critical note that the process has not lasted for long since its implementation in China, which is why costs might go higher. For instance, it is very difficult to predict whether maintenance costs will go higher in the next few years (Wang et al., 2019). As such, ascertaining facts on the likely expenditure on the construction of SCs is difficult for both policymakers and financiers. The government might find it challenging to maintain a standard urban drainage system in each city, which will be a detrimental aspect to construction of sponge cities. Contexts in each city differ considerably and applying a standard approach might challenge successful development of urban drainage infrastructure (Wang et al., 2019). It is also difficult to measure or assess the significance of constructing the SCs as they are expensive to maintain. There are different aspects that can be include in the process of constructing a SC, which is why there are varied expenditure plans on the same (Wang et al., 2019). The uncertainty of the benefits and associated costs is a major challenge to establishment of improved urban drainage systems in China. Much experience can be gained from conducting different pilot projects in the country.

5.4 Relevant Policies and Laws on SCs

It is vital that the research establishes relevant policies and laws that encompass the concept of SC construction in Chinese cities. The first enactment that contained important information on the establishment of SCs is the SC Development Technical Guide (SCDTG). The framework outlines important aspects that must be followed by each individual or government that aims to establish SCs (Xiang et al., 2019). It is vital to note that the technical guide offers a guideline on what should be done first and other important aspects such as the funding of SC projects. The technical guide is a framework of rules and strategies that can be applied in the event of Construction of an SC. The policies that China enacted as a country were meant to promote urban sustainability practices. The high level of pluvial flooding in towns such as Jinan prompted the national government to come up with a strategy to improve urban drainage systems (Xie et al., 2020). The policy on SC construction is a avenue that set new approaches to control urban flooding and harvest water for recycling. The technical guide established highlights important aspects that must be considered in the event of constructing SC as a strategy to advance water management practices in Chinese cities.

The essence of enacting policies or developing the technical guide is to ensure that important guidelines are followed in a bid to achieve the set objectives. The main objective is to improve urban drainage systems. One of the most important contributions of legislation on construction of SCs is the framework on funding of the projects (Dai et al., 2018). It is vital to note that the construction of SCs is a costly process, which requires a strong financial support for objectives to be achieved. The Chinese national government has spent billions of money to establish SCs between the year 2015 and 2017. However, it is important to note that the national government provides a fraction of the funding and the rest should be accumulated from other sources. According to the policy in the technical guide established, local governments and private business people must contribute towards improving urban drainage systems. The national government provides approximately 15-20% of the total budget while the rest has to be raised by private business people and local governments (Wang et al., 2018). The enactment of a policy that compels local government and private businesses to participate is an indication of the seriousness in the execution of the SC project. Without stringent policies on the same, most businesses might not agree to be part of the concept, which can derail development.

Enactment of legislation on the construction of SCs in China has proved effective as private business people and local governments have to comply. The policies set are elaborate on what should be done to improve urban drainage systems (Wang et al., 2018). It is vital to note the fact that legislation has improved execution and implementation of various policies that support the concept as a way of advancing sustainability issues. Failure to enact a law that compels stakeholders to take part in the construction of SCs might be detrimental to changing or handling of water related issues in town. In essence, legislation on the SC concept was put in place to compel urban places and private business people to participate towards advanced sustainability measures. It is important to note that China established a pilot program that would see some cities changed into SCs as a strategy to avert water related issues (Xiang et al., 2019). Examples of towns that were put under pilot study include Jinan, Shanghai, Beijing, Wuhan and Lancaster. The SC concept represents an idea that can be used to reduce flooding, harvest water and recycle it for use within the same urban place. The legislation put in place has helped set standards for local governments on what should be done to improve urban drainage systems.

5.5 Policy Implications in the Construction of Sponge Cities

It is important to examine policy implications associated with the construction of SCs in Chinese cities. The first important aspect is that policies that support the same might prove important in improving living standards in urban places (Budge, 2005). Policies will compel local governments and other stakeholders to act fast and establish sponge cities. Failure to put in place policies that can help promote the same gives other cities option out of the project, which puts residents at risk. Equally, sustainability practices are challenged with poor policing on the same. China introduced the construction of SC development technical guide in 2015 to help provide approaches towards handling of such projects (Budge, 2005). Since then, the country has recorded lower economic damages associated with pluvial flooding. As such, the enactment of policies that support construction of SCs assures residents of reduced flooding and increased infiltration. Policymakers should purpose to make a more rigorous framework that will ensure each city follows suit in a bid to reduce damages associated with poor urban drainage systems (Budge, 2005). The construction of SC projects proves to be efficient and effective when supported by legal framework and reputable policies.

Policy enactment on the development of SCs across all urban places will ensure a sustainable approach towards water conservation strategies. It is important for policymakers to borrow a leaf from one of the case studies and purpose to learn from the same (Gu et al., 2019). In the event, much can be discovered on the benefits and challenges of constructing improved urban drainage systems. Chinese SCs have led to growth of biodiversity and important aspects that support the well-being of residents. The success of such projects highly depends on the policies implemented on the same. Weak policies will lead to collapse of the project, which I why stringent regulations should be put in place to control the process (Gu, et al., 2019). Sustainability is one of the most important aspects that can help future generations meet their obligations. The standard should be set by involving policymakers, who can come up with a specific criterion that can be applied in every project involving the construction of sponge cities. Reducing flooding and increasing infiltration of water for storage indicate strategic approaches towards achieving sustainability in urban stormwater management (Gu, et al., 2019). Policymakers should consider other important aspects such as financing to avoid construction of substandard infrastructure in some regions due to financial implications.

6.0 Chapter 6: Conclusion and Recommendations

6.1 Recommendations

After an interpretation of the findings obtained from the study, it is important to give recommendations that can help shape the scope of construction of SCs in most Chinese cities. The first aspect that is important is improving legislation the same in most parts of the country (He et al., 2019). Existing legislation laid the foundation for the construction of SCs in China, which is why there is need to add more legal framework to the same as a way of polishing it. Improved legislation will guarantee standard construction of improved urban drainage systems. It is through policymaking that finances can be allocated to carry out such projects within a particular time. Failure to put in place the right policies on the construction of SCs might be detrimental to sustainability practices. Appropriate policies include finance related issues and strategies to be used. There are different designs that can be used to optimize the effect and impact of costs associated with the same (Ma, Wang & Ding, 2018). Increased or stringent legislation on the same will ensure proper use of allocated resources by local governments and other involved parties. The role of legislation is to provide funds, avenues and ways of handling issues that arise from the same.

The second recommendation is to promote proper use of water and existing infrastructure. Urban drainage systems designed should be protected from vandalism of any kind as it risks the position of residents in the city. It is the duty of very individual or resident to take responsibility and conserve water. In the event, water shortage problems in Chinese urban centers can be minimized to a large extent (Zhang, Sun & Xue, 2019). However, the careless use of water resources by some players risks the position of the rest. Urban drainage systems should be used properly and reduce among of waste that is disposed to the environment. The fact that everybody should take responsibility should be made clear to each individual as a way of enhancing sustainability practices. It is proper for authorities to put in place stringent measures that can punish those who defy sustainability measures existing. Taking responsibility, disposing waste the right way and ensuring that water is used conservatively might help improve sustainability in urban drainage systems management (Ma, Wang & Ding, 2018). Equally, companies and other players from the private sector should take responsibility and carryout programs that are aimed at sensitizing the society. This will help explain to many the need to take responsibility and improve on sustainable practices towards urban stormwater management.

The third recommendation is to embrace inclusivity during policy enactments on the same as a way of ensuring that everyone’s opinion is considered. Inclusivity is an important element that promotes understanding and mutual coexistence among different players or institutions (Zhang, Sun and Xue, 2019). It is through a mutual agreement that local governments can team up with the private sector to promote water management practices. Governments that make decisions n such projects without making the necessary consultations might end up wasting resources. It is only fair for authorities to involve locals, who might give important suggestions to promote policy enactment in the same. Policymakers should form it a habit of including other stakeholders in a bid to enhance mutual co-existence. The fact that the Chinese government has done its best towards achievement of a common goal is indicative of its inclusive nature to coordinate various players (He et al., 2019). The urge to solve issues related with pluvial flooding should compel each party to work closely in an attempt to give the residents an improved standard of living. Inclusivity is crucial and can help the country make huge strides in the development of sponge cities.

6.2 Conclusions

To sum it up, construction of SCs is a project that has helped Chinese towns reduce pluvial flooding. It is vital to note that flooding due to surface runoff water has caused much damage to the Chinese residents, which is why the country resolved to construct modern urban drainage systems. The research used a mixed method approach to gather important information on the construction of sponge cities. Jinan forms an important case study that has been used to establish facts on the topic of discussion. In the paper an elaborate understanding of the SC initiative is given. Equally, document analysis conducted helped highlight important facts from existing literature on the construction of SCs in China. In choosing an appropriate design for optimization of the project, There is need to consider there important objectives. The first is to ensure that water infiltration to the ground has increased. Second, the design must take into account the fact that the rate flow of water at peak is reduced. The third aspect that should be considered is the reduction in the level of pollutants that are allowed to infiltrate the ground. A design that maintains the three aspects among its objectives assures residents of improved urban drainage systems. The construction of SCs has had various benefits to Chinese cities such as Jinan including improved level of sustainability and water management practices.

The construction of SCs can be used to control water management disasters that have crippled economic progress in JInan. A comparison of the traditional strategies applied to solve water flooding issues and the new SC system indicates that the latter is efficient. The cities that have adopted the construction of SC have improved urban drainage systems for their residents. The research has concentrated on examining how successful the SC concept can be in handling pluvial flooding in Chinese cities. It is important to note that enacting policies that compel governments to invest in construction of SCs might be helpful towards reducing urban water issues. The new SC strategy has helped harvest water, reduces surface runoff and ensured recycling of water as a way of reducing associated problems. Traditional models did not provide a solution to water shortages and increased pluvial flooding within the Chinese Cities. It is vital to note that the construction concept has faced challenges in the country including high costs attached and lack of expertise n the same. The construction of SC in Jinan is the framework that can promote and improve urban drainage systems. Legislation through policies can help improve and promote its effect in a bid enhance improved water management strategies.

In summary, the review of literature also implies that construction of SC can also be understood from three distinct perspectives. First, construction of SC involves protection the urban natural economy. It implies that the construction of drainage system focuses on preservation of natural resources such as rivers, forests, wetlands and trenches within the urban areas. Second, SC initiative also involves restoring ecology, implying that the construction process leads repairing of ecological system that is destroyed by increased urbanization. For instance, construction of infrastructures such as buildings is the leading cause of increased ecological degradation. SC initiative can also be understood from the perspective of low impact development system construction. This implies that SC is about minimization of negative impacts of urbanization to the environment in urban areas. Generally, existing literature support the argument that construction of SCs in China is be best remedy to the increasing challenge of poor drainage system. China is experiencing rapid urbanization, hence the need to have a system in place to control the impact of urbanization on the environment. The review of previous study shows that most urban areas in China have traditional drainage system because of the gaps that existed during the construction process. The existing literature shows a focus on addressing existing gap in the construction of drainage system in urban areas. It is important to note that enacting laws that promote the construction of SCs is an important step towards improving urban drainage systems. From the case studies conducted, it is clear that SCs help improve aspects of urban drainage systems. For instance, the project has led to decreased economic damages associated with pluvial flooding in Jinan. The high rainfall experienced in such places has proved to be detrimental to economic efforts made. It is the interest of Chinese authorities to handle matters with flooding and sustainability, which can guarantee future generations of meeting their obligations. The construction of SC in Jinan has improved the drainage system from a traditional model to a modern strategy that is sustainable. The problem of water shortage can be managed by establishment of SCs as a strategy towards harvesting of water. The harvested water has since been cleaned and treated for re-use within the same cities as a strategy to monitor water conservation practices. in essence, water problems in the towns have become manageable under the SC program, which proves to be a strategic approach to improved urban drainage systems. Legislation has played an important part in compelling authorities and other stakeholders to commit towards the program for improved sustainability. The SC program in China is the appropriate framework that can see urban places improve drainage conditions such as waterlogging, pluvial flooding and shortage of water.

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