ECONOMIC AND ENVIRONMENTAL
IMPACTS OF STORMWATER
MANAGEMENT
Case study: Cost-effectiveness evaluation of Proposition O projects
ADRIAN MAHDIAN
School of Business, Society and Engineering
Course: Degree Project in Industrial Engineering and Management
Course code: FOA402
Subject: Industrial engineering and management
Credits: 30
Program: Industrial engineering and management
Supervisor: Anna Launberg Examiner: Pär Blomkvist
Task assigner: University of California Los Angeles Status at UCLA: Visiting graduate researcher (VGR)
Date: 2020-12-23 Email:
ABSTRACT
Stormwater Management (SWM) or Best management practices (BMPs) treat the stormwater runoff that carries pollutants. Pollutants in the waters and in the stormwater, negatively impact the environment, the ecology and natural resources. Stormwater Control Measures (SCM) are used in different projects to improve water quality and quantity. This thesis aims to understand the connection between SWMs, the economy and the environmental sustainabilty. This thesis evaluates the cost-effectiveness of SWMs in Mediterranean climates. The research aims to guide the next project managers to choose better SWMs based on cost-effectiveness, socio-economic, and environmental implications. Various studies suggest that the terms SWM, SWM and SCM are used interchangeably. The research methodolgy uses a mix of qualitative and quantitative data analysis The research was conducted in Los Angeles at the request of UCLA. Therefore, it focused on water quality improvement projects in Los Angeles. The costs for the projects, areas, and what SWMs are used will be acquired through data gathering and personal communication with experts. This thesis compares several projects which include different SWMs. It calculates the cost-effectiveness with two different methods, firstly, the cost per drainage area, and secondly, the cost per pollutant removed. Data is gathered from the city of LA and other secondary data sources to calculate the cost-effectiveness. The calculation results showed that the Glenoaks project and the Machado lake project were the most cost-effective. Glenoaks utilizes infiltration wells and grass swales, and the Machado lake is a large wetland. Based upon these facts, generally, wetlands and grass swales can be recommended for Mediterranean climates. The expensive total costs of SWMs or their inability to remove pollutants can strongly affect the cost-effectiveness of some projects, and produce a negative impact on economy. Quantitative assessment of study investigates cost-effectiveness of SWMs and for highlighting its economic impact. For qualitative assessment thematic analysis of 14 sample studies related to stormwater management (SWM) was carried out. Findings reveal that 78% of sample studies reflect the themes associated with the positive economic impact of SWMs. Additionally, the sample studies confirm 76% positive impact of SWMs on the environment and ecology of the region. Further research with better data and more accurate calculations are needed. It would be beneficial if other factors such as recreation and unquantifiable factors such as the aesthetic improvements and community benefits were incorporated into or considered together with the cost-effectiveness for future projects.
Keywords: Cost effectiveness, Cost-effectiveness, Green Infrastructure, Socio Ecological systems, Sustainable Urban Drainage Systems, GI, SES, SUDS, SCM, SWM, Stormwater, Water quality, Proposition O, Urban Runoff
PREFACE
This thesis is produced as a thesis for the Master of Science in industrial economics at Mälardalen University in Västerås, Sweden. The research has been conducted under the supervision of Anna Launberg and Pär Blomkvist of MDH.
The degree project is at the request of the University of California Los Angeles. This project can be useful for the City of LA and the stormwater board. These organizations will need to approximate the cost-effectiveness, socio-economic, and environmental impacts of SWMs for the future projects that they plan to pursue. This project shows how the completed projects compare with cost-effectiveness as the tool. The purpose of this thesis was iterated together with my supervisors Mi-Hyun Park and Professor Stenstrom.
I am humbled for this opportunity to come to UCLA under the guidance of my professor, Micheal K. Stenstrom, who helped me pursue the project and Mi-Hyun Park for supporting me in the process. I am also thankful to Anna Launberg and Pär Blomkvist, who helped me find the right social aspects suitable for this project. Thanks to everyone who participated in the seminars and shared valuable insights.
Västerås, September 2020 Adrian Mahdian
SAMMANFATTNING
Titel: Kostnadseffektivitet av SWMs i medelhavsklimat
Stormwater Management (SWM) or Best management practices (BMPs) behandlar avrinning av dagvatten som transporterar föroreningar. Föroreningar i vattnet och i dagvattnet påverkar miljön, ekologin och naturliga resurser negativt. Stormwater Control Measures (SCM) används i olika vatten behandlings projekt för att öka vatten kvantiten och kvaliteten. Denna examensarbete syftar till att förstå sambandet mellan SWM, ekonomin och miljömässig hållbarhet. Denna examensarbete utvärderar kostnadseffektiviteten för SWM i medelhavsklimat. Forskningen syftar till att vägleda nästa projektledare att välja bättre SWM baserat på kostnadseffektivitet, socioekonomiska och miljömässiga konsekvenser. Olika studier tyder på att termerna SWM, SWM och SCM används omväxlande. Forskningsmetoden använder en blandning av kvalitativ och kvantitativ dataanalys. Forskningen genomfördes i Los Angeles på begäran av UCLA. Därför fokuserade examensarbeten på projekt för förbättring av vattenkvaliteten i Los Angeles. Kostnaderna för projekten, områdena och vilka SWM som används kommer att förvärvas genom datainsamling och personlig kommunikation med vattenbehandlings experter. Denna avhandling jämför flera projekt som innehåller olika SWM. Den beräknar kostnadseffektiviteten med två olika metoder, för det första kostnaden per dräneringsområde och för det andra kostnaden per avlägsnad förorening. Data samlas in från staden LA och andra sekundära datakällor för att beräkna kostnadseffektiviteten. Beräkningsresultaten visade att Glenoaks-projektet och Machado-sjöprojektet var de mest kostnadseffektiva. Glenoaks använder infiltrationsbrunnar och gräsvalar, och Machado-sjön är en stor våtmark. Baserat på dessa fakta kan i allmänhet våtmarker och gräsvalar rekommenderas för medelhavsklimat. De dyra totala kostnaderna för SWM eller deras oförmåga att avlägsna föroreningar kan kraftigt påverka kostnadseffektiviteten för vissa projekt och ge en negativ inverkan på ekonomin. Kvantitativ bedömning av studien undersöker kostnadseffektiviteten för SWM och för att lyfta fram den ekonomiska effekten. För kvalitativ bedömning genomfördes tematisk analys av 14 provstudier relaterade till dagvattenhantering (SWM). Resultaten visar att 78% av provstudierna återspeglar de teman som är förknippade med SWM: s positiva ekonomiska inverkan. Dessutom bekräftar 76% av provstudierna positiv inverkan av SWM på miljön och ekologin i regionen. Ytterligare forskning med bättre data och mer exakta beräkningar behövs. Det skulle vara fördelaktigt om andra faktorer som rekreation och otydliga faktorer såsom estetiska förbättringar och samhällsfördelar införlivades i eller övervägs tillsammans med kostnadseffektiviteten för framtida projekt..
CONTENT
1 Introduction ... 1
1.1 Background ... 2
1.1.1 The source of the problem ... 2
1.1.2 Proposition O and its contribution to SWMs ... 3
1.1.3 Stormwater Management (SWM) ... 4 1.1.4 Cost-effectiveness ... 6 1.1.5 Problem Statement ... 7 1.2 Purpose/Aim ... 8 1.3 Research question ... 8 1.4 Delimitation ... 8 2 Literature Review ... 10
2.1 Environmental Impact of Stormwater Management ... 10
2.2 Economic Impact of Stormwater Management ... 11
2.3 Theoretical Framework ... 12
2.3.1 Stormwater Resource Management ... 14
2.3.2 Green Infrastructure (GI)... 15
2.3.3 Social-Ecological Systems (SES) ... 18
2.3.4 Sustainable Urban Drainage Systems (SUDS) ... 19
2.4 Stormwater Management (SWMs): ... 23 2.4.1 Stormwater Wetland ... 23 2.4.2 Detention tank ... 24 2.4.3 Infiltration Trench ... 24 2.4.4 Porous pavements ... 25 2.4.5 Grass Swales ... 26 2.4.6 Filter strips ... 29 2.4.7 Bio Retention... 30
2.5 Study site: Mediterranean climate ... 31
2.6 Pollution Estimation... 31
2.6.1 Runoff coefficients (RCs) and Land use consideration ... 31
2.6.2 Event mean concentration (EMC) ... 32
2.6.3 Total costs and construction costs ... 33
3 Methodology ... 34
3.1 Overview ... 34
3.2 Calculations ... 36
3.2.1 Cost-effectiveness by drainage area ... 36
3.2.2 Cost-effectiveness by pollutant removal ... 36
3.3 Thematic Analysis ... 43
4 FINDINGS ... 45
4.1 The selected Proposition O projects, their costs, and SWMs ... 45
4.1.1 Mar Vista Recreation Center ... 45
4.1.2 Westside Rainwater Park ... 46
4.1.3 Los Angeles Zoo Parking Lot ... 47
4.1.4 Hansen Dam Wetlands ... 48
4.1.5 South Los Angeles Wetlands Park ... 49
4.1.6 Oros Green Street ... 50
4.1.7 Echo Park Lake ... 51
4.1.8 Glenoaks/Sunland Stormwater Capture ... 52
4.1.9 Elmer Avenue Phase II: Elmer Paseo ... 53
4.1.10 Albion Riverside Park ... 54
4.1.11 Peck Park ... 55
4.1.12 Rosecrans Recreation Center ... 56
4.1.13 Machado Lake & Wilmington Drain ... 57
4.2 Acquisition of additional empirical data ... 58
4.3 Studies Selected for Thematic Analysis ... 59
5 RESULTS ... 61
5.1 Cost-effectiveness by drainage area ... 61
5.1.1 Total cost and drainage area ... 62
5.1.2 Construction cost and drainage area ... 63
5.2 Cost-effectiveness by pollutant removal ... 64
5.2.1 Total cost and TSS removal ... 64
5.2.2 Construction cost and TSS removal ... 66
5.3 Findings of Thematic Analysis ... 67
6 Analysis ... 70
6.1 Analysis of Themes ... 70
6.1.2 Environmental Series ... 71
6.2 Lack of financial resources ... 73
6.3 The Importance of the local communities ... 74
6.4 Cost effectivity and community benefits ... 74
7 Discussion ... 77
8 Conclusion ... 80
9 Suggestions for further work ... 82
APPENDIX 1: POLLUTANT REMOVALS FOR MAR VISTA AND WESTSIDE RAINWATER PARK
APPENDIX 2: POLLUTANT REMOVALS FOR ALBION PARK AND ECHO PARK
APPENDIX 3: POLLUTANT REMOVALS FOR ELMER AVE, GLENOAKS AND HANSEN DAM APPENDIX 4: POLLUTANT REMOVALS FOR LA ZOO, OROS GREEN ST. AND SOUTH LA WETLANDS
APPENDIX 5: POLLUTANT REMOVALS FOR PECK PARK, MACHADO LAKE AND ROSECRANS PARK
APPENDIX 6: EFFLUENT CONCENTRATIONS FOR TSS FROM THE INTERNATIONAL SWM DATABASE
APPENDIX 7: EFFLUENT CONCENTRATIONS FOR COPPER FROM THE INTERNATIONAL SWM DATABASE
APPENDIX 8: EFFLUENT CONCENTRATIONS FOR LEAD FROM THE INTERNATIONAL SWM DATABASE
APPENDIX 9: EFFLUENT CONCENTRATIONS FOR ZINC FROM THE INTERNATIONAL SWM DATABASE
LIST OF FIGURES
Figure 1 Structural SWM wetland Echo Park Lake ... 5
Figure 2 A street sweeper machine... 6
Figure 3 How the fields of interest are connected ... 14
Figure 4 The Sustainability Pyramid with GI as its base ... 17
Figure 5 Multitier approach to SES ... 18
Figure 6 The interconnection of the hydrological cycle ... 20
Figure 7 The SUDS triangle ... 21
Figure 8 The public perception of SUDS aspects ... 22
Figure 9 Stormwater wetland Schematic ... 24
Figure 10 Infiltration trench Schematic ... 25
Figure 11 Porous pavement Schematic ... 26
Figure 12 Grass swale Schematic ... 27
Figure 13 Grass swale ... 28
Figure 14 Grassed swale ... 28
Figure 15 Filter strips in adjacent to a parking lot ... 29
Figure 16 Bioretention in a parking lot car ... 30
Figure 17 “The calculation tree” Illustration ... 37
Figure 18 Mar vista recreation center with playgrounds and tennis fields ... 45
Figure 19 Westside rainwater park grassed swale ... 46
Figure 20 Los Angeles Zoo Parking lot porous pavement and bioswales ... 47
Figure 21 Hansen dam ... 48
Figure 22 South Los Angeles wetlands park and fountain ... 49
Figure 23 Oros green street gardens and infiltration galleries ... 50
Figure 24 Echo Park Lake and the lotus flower ... 51
Figure 25 Glenoaks infiltration well and sloped parking lot ... 52
Figure 26 Elmer avenue and the vegetated swale ... 53
Figure 27 Albion riverside park bioswales ... 54
Figure 28 Peck Park Canyon Grass Swale ... 56
Figure 29 Rosecrans recreation Center bioswale ... 57
Figure 30 Machado lake wetland ... 58
Figure 31 Total cost / drainage area ... 62
Figure 32 Construction cost / drainage area ... 63
Figure 33 Total cost / TSS removed ... 65
Figure 34 Construction cost / drainage area ... 67
Figure 35 Significance of Themes ... 69
Figure 36 The five least cost-effective projects marked ... 75
LIST OF TABLES
Table 1: RC values ... 32
Table 2: Peck park canyon RC and area table ... 39
Table 3: Calculation steps example ... 42
Table 4 Coding Themes ... 43
Table 5 General Information of Studies for Thematic Analysis ... 59
Table 6: Cost-effectiveness by drainage area table ... 61
Table 7: Total cost / pollutant removed ... 64
Table 8: Construction costs / pollutant removed ... 66
Table 9 Thematic Analysis –Economic Series ... 67
Table 10 Thematic Analysis –Environmental Series ... 68
ABBREVIATIONS
Abbreviation Description
BMPs Best management practices
CALEPA The California Environmental Protection Agency
Cu Copper
SWM Stormwater Management EMC Event Mean Concentration
LA Los Angeles
Pb Lead
SCM Stormwater control measures TMDL Total maximum daily load
TSS Total Suspended Solids
UCLA University of California Los Angeles
Zn Zinc
GI Green Infrastructure SES Socio-Ecological Systems
SUDS Sustainable Urban Drainage Systems SWM Stormwater Management
DEFINITIONS
Definition Description
Mediterranean
climate Arid climates with distinct wet and dry periods Dry weather
flow Runoff flows during dry periods Wet weather
flow Runoff flows during wet periods Project
Drainage Area The total area that precipitation will cover, and the runoff will eventually drain into the project Watershed The surface area where the water flows into a certain body of
water such as a river or Lake
BMP Best management practices are techniques that improve the water quality and reduce runoff
SCM Stormwater control measures are measures taken that improve the water quality and reduce runoff
SWM Stormwater Management are methods used that improve the water quality and reduce runoff
GI Green Infrastructure is natures life support to humans and the interconnectedness of green areas is essential for human benefits.
SES Socio- Ecological Systems are the interaction between the human societies and the ecological systems around them and is part of the Green Infrastructure.
SUDS Sustainable Urban Drainage Systems are multiple SWMs in a train and is part of the larger term, Socio- Ecological Systems
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INTRODUCTION
Urbanization has historically led to the degradation of wildlife, environment, and natural habitats (Jiménez Ariza et al., 2019). Urbanization is followed by the decreased quality of life for humans, which leads to social and economic problems (Alcock et al., 2014). Many ideas have been developed around urbanization, and they all point to the same issues and concerns about the sustainability of the economy, government, environment, and society (Shen et al., 2011). With these issues in mind, Sustainable Urban Drainage Systems (SUDS) offers a solution to these problems and provides additional environmental, economic, and social benefits (Duffy et al., 2008; Keeley et al., 2013; Poustie et al., 2015). Pollutants in the stormwater negatively impact the environment, the ecology and the natural resources (Butler & Parkinson, 1997). Stormwater Management (SWM) is one of the main branches of SUDS. Stormwater Management (SWM) is used to treat the stormwater runoff that carries pollutants. This research aims to study the economic and environmental impacts of Stormwater Management (SWM).
Practices of SWM have been subject of criticism for its societal and environmental challenges. Study by Goulden et al. (2018) came up with the recommendation that regional and urban planning systems perform an instrumental role in advancing the conventional process towards a more sustainable SWM, or SWMs. Researchers identified a three-pillared socio-institutional framework to meet various economic, sociological, hydrological, and ecological goals by implementing Sustainable SWMs and SWMs. Moreover, countries and cities world over, have recognized the need for adopting SWM, and SWM goals and measures. This thesis explores the economic and environmental impacts of SWMs using a thematic analysis across 14 studies. A quantitative analysis regarding the cost effectiveness of the various SWMs has also been implemented into this thesis.
According to Lopez-Bellesteros et al. (2019) SWMs are the best solution for non-point source pollution reduction and water utilization. Extant amount of sediment are carried in stormwater which is a major cause of environmental degradation. Consequently, the sustainability of SWM and SWM will eventually have an everlasting impact on natural disaster mitigation across the world, especially in Mediterranean climates. Disasters such as floods as a result of heavy rain falls may be mitigated to some extent. The construction of small dams in areas through where storm water passes in ravines, or in the form of flash floods. The water carries with it all sorts of pollutant material ranging from plastic, toxic waste, and rocks. Therefore, the construction of small dams is a feasible option to mitigate natural disasters and save the country millions of dollars by mitigating the chances of disasters in the first place.
For instance, in a certain Mediterranean locality, there is a continuous rain storm for a week. If the SWM or SWMs, are implemented appropriately, in the shape of small water reservoirs (dams), Sustainable Urban Drainage Systems (SUDS), Green Infrastructure (GI), Socio-Ecological Systems (SES), and Stormwater Management (SWMs), all of these strategies work together to gather stormwater, and stop it from flowing into seas and oceans. Moreover, the pollution can be
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filtered easily through the aforementioned mechanisms in place at the appropriate times. According to Goulden et a. (2019) storm water is a resource, and can be utilized for urban development. The stored stormwater as a result of SWMs in place, the Urban community can benefit from additional water resource, by using it for developmental, industrial, and household consumption purposes.
1.1
Background
In this section, the source of the problem is described. The research question and purpose of this thesis will emerge as this chapter goes deeper into the problem.
1.1.1 The source of the problem
As mentioned above, uncontrolled urbanization is one of the main reasons that natural filtration and storage systems have become obsolete, as observed by Booth & Jackson (1997). As of now, Los Angeles is the second-largest city in the US with a population of 3 990 000, according to United States Census bureau (2018) and urbanization has led to the reduction of natural filtration and storage systems. Impervious surfaces such as concrete are frequently used which redudes the infiltration capability. This further leads to higher amounts of runoffs. Because of the increased runoff and the depletion of natural and biological processes such as trees and plants, the natural cleansing processes of pollutants become non-existent (Braune & Wood, 1999; Lee et al., 2010). The Stormwater runoff is often very polluted. Unlike industrial dischargers and wastewater treatment plants, non-point source runoffs are much harder to trace back to their sources. Hence the name, non-point sources. These pollutants can be very spread out throughout a watershed, which makes it challenging to detect and prevent (D’Arcy & Frost, 2001).
1.1.1.1.
Why it is hard to solve
Stormwater management is more complicated than wastewater treatment because of the nonpoint source nature of the pollution and the challenge to hold people accountable. The ownership of stormwater problems has also been unclear. Ha & Stenstrom (2008) point out source discharges such as industries that pollute the waters have been regulated since 1987. The problem is that they are not the only polluters, and non-point source discharge is also of great concern. The non-point source discharge also originates from stormwater runoff but does not have a specific source, which makes it harder to prevent and treat (Ferreira & Stenstrom, 2013).
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1.1.1.2.
Environmental regulation with Total maximum daily loads (TMDLs)
The California Environmental Protection Agency (CalEPA) is the regulator of wastewater discharges under the California Porter-Cologne Water Quality Control Act of 1970 and the US Clean Water Act of 1972. The federal clean water act requires permitting authorities to allocate total maximum daily loads (TMDLs) to all discharge sources that are polluting the waters. California takes the approach of limiting TMDLs and penalizing those who do not conform to the regulations (Swamikannu et al., 2003).
1.1.2 Proposition O and its contribution to SWMs
In order to help the city of LA, not exceed the TMDLs, proposition O was created based on the Federal Clean Water Act. The amount of stormwater flow per day can go up to 38 billion liters per day on wet weather days and 380 million liters a day on dry weather days. The dry weather flows are combined with wastewater to get treated in a plant. However, the stormwater runoff is left untreated and pours into the lakes and oceans without filtration treatment. The water in the LA watersheds exceed the bacteria and Total Suspended Solids levels allowed. Proposition O aims to protect rivers, lakes, and the ocean. It aims to preserve the drinking water and capture stormwater for reusability. There is also an element of flood reduction for decreasing urban runoff in the projects of Proposition O. According to Park et al. (2008) the city of Los Angeles issued $500 million in bonds to fund the projects.
In 2004, proposition O was passed by the voters in the City of Los Angeles. This allowed for the authorization of $500 million of Clean Water Bond referendums. This general obligation bond was aimed to protect public health and improve the environment by reducing pollutant concentrations in the city’s beaches, lakes, and rivers. The city of LA has ambitions to ensure that all its waters are complying with the federal Clean Water Act. The stormwater drains are improved to reduce pollution. This pollution is also called non-point source pollution or stormwater runoff. Proposition O was presented to the voters to achieve water quality goals because of pollution reduction. Bacteria, trash, heavy metals, and petrochemicals can damage the environment and people’s health. The projects that are proposed are subdivided into four different categories. These categories according to LA sanitation (2018) are
1) To protect the water quality of rivers, lakes, beaches, and bays 2) To conserve potable water and its sources
3) To reduce floods and building green barriers that prevent urban runoff and improve the quality of the water
4) To capture stormwater and to reuse it
Proposition O proposal was aimed to help the City of Los Angeles to reach the TMDL goals set by the Clean Water Act. These projects under the Proposition O proposal are mainly focused on improving the water quality and reducing pollutant loads. The most effective single projects remove up to 13% of the pollutants. No single project can meet TMDL goals. Many projects together can strive towards TMDL compliance, which is an ambitious goal. However, as of now,
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all these projects as a whole, do not meet the TMDL goals. This should not be a disappointment because the goal of Proposition O was not removing all pollution from the waters of the City of Los Angeles (Park et al., 2007).
The goal is to reduce pollution and achieve more sustainability over time. Moreover, Proposition O project is a suitable template project for other Mediterranean regions to implement the resource management theory in practice and achieve substantial results. Solve their issues related to SWMs. More specifically, water as a resource needs to kept from being wasted. Every form of water is able to be filtered and reused for other purposes if unsuitable for human consumption. This project will contribute towards reduction in stormwater runoff and pollution and ensure resource utilization to promote sustainable development. The purpose of SWMs in Mediterranean climates is to increase the overall water quality in the watershed .
1.1.3 Stormwater Management (SWM)
Stormwater Management (SWM) and Stormwater Control Measures (SCMs) are partial solutions for controlling the quality and quantity of urban runoff. There are structural SWMs such as filter strips and detention basins and wetlands. There are also non-structural SWMs such as land planning, public education, regulations, and maintenance procedures. SWMs are suitable for different situations, and they can vary a lot in function and form. Water quality control, groundwater protection, and flood prevention are all objectives of SWMs, and they depend on each specific site (Braune & Wood, 1999; Marsalek & Chocat, 2002). Combining structural and non-structural SWMs help in making the TMDLs more achievable. Additionaly these practices help improve the quality of the waters (Geldof, 2001). By being vague, the term SWM was not the best choice for what it stood for. Therefore, as part of the US National Research Council on the National Academies of Engineering and Science, ordered a review of SWMs. This led to the finding that abandonment of the term SWM in favor of SCMs should be considered. This has not been very successful as many old manuals and a large part of the literature and community of research at large are still using SWM instead of SCMs (Fletcher et al., 2015). So, for the time being, both are equally used and interchangeable in the literature.
Structural Stormwater Control Measures (SCMs) or structural SWMs consist of methods that employ materials and equipment in a new way, which requires substantial capital investment and operations and management costs. These control measures treat stormwater, either at the point of generation or the point of discharge (Silverman et al., 1986). These SWMs include ponds, stormwater wetlands, vegetative biofilters, sand, organic filters, and other technology options such as water quality inlets (Field & Tafuri, 2006). Moreover, structural
In figure 1 below, a stormwater wetland has been built in the city of Los Angeles. The project is called Echo Park lake, and this is a typical structural SWM.
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Figure 1 Structural SWM wetland Echo Park Lake
Source: (LA Sanitation, 2018)
Note. Reprinted from “City Of Los Angeles Clean Water Initiative Update.”, by LA Sanitation, 2018, p. 12.
1.1.3.1.
Non-structural SWMs
The non-structural SWMs aim at reducing the pollutants before they enter the watershed. They do this by implementing various techniques that discourage the release of pollutants into the environment. Limiting pollutant discharge at the source and cleaning the pollutants before mixing with stormwater are two non-structural techniques. Non-structural SWMs also contribute in the forms of economic incentives, penalties, and government regulations. However, the performance data is not available for non-structural SWMs because they prevent pollution, and it is difficult to estimate pollutant prevention (Silverman et al., 1986). According Field and Tafuri (2006), the public education, planning and management, street and storm drain maintenance, illegal dumping controls, stormwater reusability, spill prevention, and clean-up are all examples of non-structural SWMs.
In figure 2 below, an example of a non-structural SWM has been reprinted, which is a street sweeper machine.
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Figure 2 A street sweeper machine
Source: (Bortek Industries, 2020)
Note. Reprinted from “Street sweeper rentals”, by Bortek Industries., (2020, May 05). Retrieved from https://www.bortekpwx.com/street-sweeper-rentals/
Underground SWM projects have been shown to improve the use of stormwater and to solve flooding problems while not hurting the recreation area that the community enjoys (Higgins K. & Roth C., 2005). Storage basins, porous pavements, and green roofs for controlling runoff at the course before it enters the draining network are some SWMs in use. These SWMs lower the frequency and severity of flood events. The advantages of the SWMs have been known for some time, but what SWMs should be chosen, what size they should be, and the decisions regarding the location are challenging when several SWM options are available (Lee et al., 2010). No single SWM will remove all target pollutants. Therefore, there is a need to consider combinations of cost-effective SWMs to reach the goals for a site (Raghavan R. et al., 2001; Schueler, 1992).
The motivation to comply with Total maximum daily loads (TMDLs) pushes for more SWM funding, both structural and non-structural. Although there are many different SWMs in use across the Mediterranean regions, and their pollutant removal method and efficiency is known, there is not enough cost-effectiveness assessment that prioritizes SWMs that should be initiated. Providing cost-effectiveness analysis makes it easier for decision-makers to increase the implementation of cost-effective SWMs to reach the TMDL goals faster (Hodgson et al., 2020).
1.1.4 Cost-effectiveness
Cost-effectiveness evaluation is done with two different methods. The first method is the total cost of the project per the drainage area it treats ($/acre). The second method is the total cost per unit pollutant load removed ($/kg) (Park et al., 2007).
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1.1.5 Problem Statement
The problem with stormwater is that it is unpredictable in nature. Besides, stormwater is non-point source which may create certain challenges associated with disaster management. Additionally, raising environmental concerns that are created by stormwater runoff into the rivers and oceans. The pollution hazards associated with stormwater runoff are much greater in proportion than those associated with industrial pollution. This thesis further suggests that stormwater carries with it excessive amount of pollutant material which is harmful for ecological sustainability of natural, sea, and wildlife.
Braune & Wood (1999) mentioned that natural and biological systems that treat stormwater and remove pollutants had been depleted due to urbanization. Los Angeles is a large city, the second-largest urban center in the US (United States Census Bureau, 2018). Pollutants harm humans and the environment, and it is essential to contain and treat them (Haile et al., 1999). The City of LA has acted with implementing Proposition O that has funded multiple projects in order to make Los Angeles more environmentally sustainable (LA, Sanitation, 2018). These projects remove the pollutants to some degree, but not completely. A barrier for implementing Green Infrastructure is the lack of information on cost-effectiveness (Flynn & Davidson, 2016). Research suggests that the polluted waters will, at some point, reach the lakes and the oceans. Consequently, the polluted waters cause serious problems, especially because it contains toxic substances, heavy metals, sediments, and pathogens (Corbett et al., 1997; Marsalek & Chocat, 2002). Evidence of polluted waters in ocean was discovered at the San Francisco bay area, where the amount of fish had declined to 25% of the amount in 1965. Moreover, oyster and crab populations had also significantly decreased. Hydrocarbons might be one of the suspects for these issues. Scientific tests have found that the pollution in the waters can exceed the limit set for industrial dischargers, which points out how seriously polluted Stormwater runoff could be. The pollution in the form of oil and grease levels exceeded 10-15mg/l, which is the usual limit set for point source dischargers (Silverman et al., 1986).
Watersheds are the land surface that drains the rain and transforms it into rivers, lakes, and they usually end up in the ocean. Topographical barriers usually separate the rainwater. Different waterborne chemicals and sediments follow the water where it goes, so watersheds are used to study hydrologic cycles, how humans interfere with these cycles (Brooks et al., 2012). According to Los Angeles County Public Works (2016), the LA county watershed produces water pollution which contains heavy metals and bacteria that exceed water quality standards for wet and dry weather days. A significant quantity of these emissions end up in the ocean. Silverman et al. (1989) argued that 31 percent of all oil and grease pollution in the oceans originates from non-point discharge, such as the stormwater runoff that washes the dirty pollutants off of the streets where all kinds of pollutants are and enters the storm drains. Most of the discharge is coming from commercial and industrial areas such as roads and parking spots as opposed to undeveloped areas, also in drier areas with Mediterranean climates such as Los Angeles.
When people come in contact with water that receive untreated stormwater runoff have exhibit intensification of health problems because of bacteria and viruses present in these waters. Haile et al. (1999) studied Industrial stormwater and found that it is rainwater that encounters the manufacturing, processing, and storage and then enters the drainage systems. In 1987, congress introduced the National Pollutant Discharge Elimination System (NPDES) program, and this
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increased the number of permits needed for the industrial plants to qualify as point source dischargers (National Academies of Sciences et al., 2019).
Research by Burian et al. (2002) found that quality and quantity of runoff are correlated with land use. Land use in Urban areas is also crucial for predicting what kind of pollutants will likely be in the Urban Runoff. Most of the oil and grease come from commercial and industrial areas, and controls that are applied there, such as permeable parking lots and driving surfaces, may significantly improve the water quality (Heaney & Pitt, 2000; Silverman et al., 1989). Other relevant toxic sources are related to different land uses. Urban areas might have lots of nutrients and pesticides because of the landscaping of lawns and heavy metals from the roofing particles (Heaney & Pitt, 2000).
More research is needed to see which SWMs remove the most pollutants for the least cost, and Proposition O gives this thesis a chance to evaluate the cost-effectiveness for SWMs in Mediterranean climates. The cost of SWMs has direct connections to the of water economy and therefore the economy in general. Meanwhile, implementing SWMs also have social and environmental benefits which need to be considered. Moreover, the current study intends to highlight the importance of stormwater as a natural resource.
1.2
Purpose/Aim
The purpose of this thesis is to deeper understand the connection between SWMs, the economy and the environmental sustainabilty. Starting by evaluating the cost-effectiveness of the selected projects in Mediterranean climates. This thesis aims to guide the next project managers to choose better SWMs based on cost-effectiveness, socio-economic and environmental implications.
1.3
Research question
What is the economic impact of SWMs ?
What are the environmental impacts of SWMs?
1.4
Delimitation
In this thesis, the thematic analysis across various studies was done based on a limited amount of reoccurring themes and due to time limitation other themes were not taken into consideration. The studies analyzed in the thematic analysis were 14. The studies in the analysis were mostly chosen to be based in urban and mediterreanean environments. However studies based in other regions across the world were also selected to reflect a broader understanding of the economic and environmental imapcts of SWMs. Due to limited time and resources, this quantitative analysis was limited to the study of the cost-effectiveness of Proposition O. The proposition O
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included 29 projects in a total of which two were canceled. City of LA provided Sixteen excel sheets for the drainage areas. Two of the projects have not been completed or built yet and are still in the design phase. Also, one of 14 remaining projects does not treat the stormwater, which, in the end, leaves 13 projects to compare and analyze. The projects will be evaluated on a cost-effectiveness basis. The thesis is limited to four pollutants, namely, Copper (Cu), Zink (Zn), Lead (Pb), and Total Suspended Solids (TSS), and it does not include all other pollutants found in stormwater runoff. Although the project took into consideration these four components, because TSS concentration is highly correlated with the other metals and widely accepted as an indicator of runoff quality. This thesis will only use TSS to compare and analyze the results. Also, primary data will not be used in this project as it has not been perceived as feasible in the time frame and scope of this work. This thesis focuses on SWMs and their cost-effectiveness in Arid/Mediterranean climates. The costs considered are Total costs, and the construction costs funded by Proposition O and other types of cost, such as operations and maintenance costs, were not considered. Total costs and construction costs are further described in section 3.5. The projects analyzed are located in Los Angeles, California, where the research for this thesis was conducted.
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2
LITERATURE REVIEW
This section of the research comprises of review for previously conducted studies related to the Stormwater management and SWMs. The literature reviewed in this section consists of SWMs related to stormwater management (SWM), stormwater control measures (SCM). The literature review aims to build a foundation for understanding the environmental and economic impact of stormwater management SWMs. Here SWMs and BMPs mean the same thing –the management of stormwater. Lastly, a brief explanation of the Mediterranean climate is included in this chapter, and short descriptions of SWMs with illustrative figures are also included here. Then the literature on pollution estimation is presented at the final section. The literature review section of the research will help us understand how the studies focusing on SWM are conducted and what the impacts of SWM are on the environmental and the economy. Moreover, it helps develop a researched and factful understanding of the environmental consequences of stromwater mis-management. Subsequently, the literature review section also delivers detailed and calculated information regarding the cost of certain SWM projects and its cost-effectiveness.
2.1
Environmental Impact of Stormwater Management
Environmentalists have raised concerns regarding the management of stormwater. Research by Barbosa et al. (2012) indicates that stormwater carries with it excessive waste and pollution, which produces water quantity and quality issues. Consequently, the pollution in stormwater affects public health. SWMs provide possible solutions which are feasible for pollution problems, specifically those associated with stormwater (Lopez-Bellesteros et al., 2019). Sustainable SWM strategies are required at the political, local, or regional levels (Goulden et al., 2018). Qiao et al. (2020) recommend the optimum combination of conventional and sustainable SWM to mitigate environmental hazards associated with it. Due to alternating periods of drought and flooding have raised the importance of sustainable water management by harvesting rain and stormwater (Ward et al., 2012). The planners and decision-makers must understand the possibilities and their consequences for each decision made. SWMs provide the opportunity to develop social, ecological and environmental conditions in urban SWM. Moreover, the SWMs are significant initiative for improving environmental quality.
The major pollutants found in stormwater are solids, heavy metals, biodegradable material, organic micropollutants, and nutrients. The solid pollutants comprise construction material, and anthropogenic waste (Barbosa et al., 2012). Subsequently, heavy metals related to vehicle parts, oils, tire material, and industrial waste. However, other pollutants such as plastic are not characterized as a stormwater pollutant. Plastic is one of the significant sources of pollution. Brown et al. (2013) researched the urban transition to advanced stormwater quality treatment. The study concluded that a network bridge bringing together members of public, private, and government, and scientific professionals were responsible for advancing in stormwater quality improvement.
Similarly, research by Pitt and Lalor (2001) contribute to advancing research in pollution prevention methods in SWM. The study finds that there is a growing trend to develop and use
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environmentally friendly construction materials as a cost-effective component to SWM. Moreover, major cities around the world have put a ban on plastic bags to reduce plastic pollution and its hazardous impacts on the environment.
Eventually, all the pollutants that combine with stormwater runoff are destined to converge with water streams, lakes, rivers and oceans with gets polluted and contributes to the degradation of the environment, wildlife, and ecology. Due to the increase in Urban developments over recent years, challenges such as disturbing natural water cycles have emerged. Ando (2011) found that impervious surfaces in urban areas such as road and house and building's rooftops block the water from being absorbed by the ground. Under such conditions, water travels over the impervious surfaces accumulating toxic waste, and pollution, which eventually ends up in rivers and streams, producing hazards for wildlife, and sea life.
Correspondingly, Prudencio and Null (2018) identified that scholars encourage green stormwater infrastructures which include bio-swales, retention basins, wetlands, rain gardens, parks and recreation areas to reduce the impact of the storm and support the water absorption at ground level. Moreover, the infrastructure is aimed to recharge groundwater and improve the quality of water. Such kind of practices produces an ecosystem which benefits humans, animals, plants, trees, and the environment as a whole. The study recommends the development of metrics to quantify and assess ecosystem costs and benefits from green stormwater infrastructure.
2.2
Economic Impact of Stormwater Management
The management of stormwater requires human capital, financial capital, technology, infrastructure, and effective management systems. It is a known fact that everything in this world comes with economic costs. According to Vesely et al. (2005), stormwater management is an effective way to conserve storm and rainwater and minimize the economic expense through saving and conserving water. However, the first step in Stormwater Management requires resources and investment. Economic resources are of significant importance to initiate SWMs to manage the stormwater runoff, by channelling it into reserves, filtering it and further utilizing it. The endgame may prove cost-effective in the long run. However, the actualization of SWMs and economically sustaining its operations in the short run will require a sufficient amount of economic, technological, and human resource (Jayasooriya & Ng, 2014). According to Goulden et al. (2018), SWMs are an essential element for promoting a sustainable environment and economic goals. Moreover, the use of SWMs for managing the stormwater provides economic opportunities for the local community. It gives them a chance to contribute their efforts for the betterment of the environment in exchange for economic compensation. The water gathered through SWMs can be filtered, stored, and used for future use (Magavern et al., 2016). Such SWMs are established to reduce the expenditure on treating stormwater, protecting other (clean) water resources, important landscapes, and fostering economic activity. Concurrently, Goulden et al. (2018) identified the importance of stormwater as a resource. The stormwater resource can be utilized for urban development purpose and the rising demand for water due to rapid urbanization. Consequently, the cost-effectiveness of SWMs (SWM) is crucial for its economic viability. If the SWMs are not cost-effective, then it should not be implemented at all. Existing SWMs which are
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economically costly should be reconsidered and stop funding it to diver the funds to alternative cost-effective SWM implementation.
2.3
Theoretical Framework
The theoretical framework revolves around the social science theory of Resource Management and associates it with the cost-effectiveness of water resource management such as SWM. The theory of resource management suggests that resources are limited, and whatever resources there are readily available within a society, it should utilize those resources to meet the basic requirements of its people. The stormwater can become a valuable resource as it can be harvested for agriculture, industrial uses and raising the groundwater levels and subsequently benefiting the environment. The problem with stormwater is that it is a non-point source making it hard to determine the specific area for implementing SWMs.
However, historical data regarding stormwater management and its intensity is essential to assess potential stormwater hotspots and priorities areas for SWM implementation accordingly. Moreover, the SWM implementations in those specific areas, such as the construction of water reservoirs in areas where stormwater management previously cost millions of dollars to rehabilitate the affected areas by stormwater. In this context, the water reservoirs act as flood mitigation and water filtration platform (Prudencio & Nulll, 2018). Moreover, the water reservoirs will benefit the local economy by saving millions of dollars that would have been spent on rehabilitation, and reconstruction of stormwater affected areas. Furthermore, the stormwater gathered within specially constructed reservoirs contain within it all sorts of pollutants that come along the way. Consequently, the containment of pollutants within reservoirs will benefit sea life by contributing less to the water pollution caused by stormwater.
The literature connected to this thesis and the fields of interest with the latest research on three terms, which are essential to the core of this research will be presented. These research terms are Green Infrastructure (GI), Socio-Ecological Systems (SES), and Sustainable Urban Drainage Systems (SUDS) (Benedict et al., 2006; Ferguson et al., 2013; Hager et al., 2013; Zhou, 2014). The green Infrastructure is the largest field, and SES is a part of this larger field. GI is mostly used for more prominent strategies that large organizations adapt to grow towards a greener and more sustainable future. The term "Green Infrastructure" is highlighting and stressing that the reason it is called infrastructure is that it is crucial and essential for the functionality and sustainable growth of urban communities, just like any other type of infrastructures, such as electricity or roads. Tzoulas et al. (2007) acknowledged that Green infrastructure plays a significant role in shaping the environment, adding that the concept was constructed long ago. Benedict et al. (2006) studied the importance of Green Infrastructure and presented a theory that younger generations are becoming better educated in matters of the environment. As urban centres grow and rural populations move toward urban centres, the term is becoming more critical and relatable (Benedict & McMahon, 2002).
The next term being introduced is Socio-Ecological Systems (SES), which is a smaller part of the more extended term Green Infrastructure. This term highlights the fact that there is an essential connection between society and ecological systems. This term was inspired by Socio-Technical
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Systems (STS), which is relatively older. According to Ostrom (2007), Socio-Technical Systems reveal the complexity of society and technology at large. SES models are flexible in development; however, critical functions are dependent upon, resource systems, resource units, and governance. All of which are in constant co-evolution in time and space. Ostrom (2007) recommends that critical functions are worth consideration while developing larger systems that are essential parts of society, ecology, and policies. They need to be developed to account for the complexities and intricacies of these systems. SES aims to make sustainable systems to fuel the growth of communities small or large by providing high quality and quantity of natural resources (Ostrom & Cox, 2010). The third part dives deeper into the term Sustainable Urban Drainage Systems (SUDS), which is a part of SES. From this point on, it becomes extra relevant for this thesis. SUDS are closely related to the subject being studied, which is SWMs. SUDS aim to treat runoff locally and recognize water as a local natural resource. It is understood slightly differently in various regions of the world (Charlesworth, 2010).
However, the idea behind it is the same everywhere and is at the core of a Green Infrastructure (GI) solution. A system of multiple SWMs builds a treatment train, which is SUDS. There are less political and sociological aspects in SUDS compared to the more significant fields of GI and SES (Ostrom & Cox, 2010). SUDS focuses on natural resources and amenities. This can be seen in figure 7 with the SUDS triangle where sustainability is the intersection of water quality, quantity, and the amenities and wildlife potential provided. In figure 3, the connection between GI, SES, and SUDS is depicted by the author of this thesis, and it can be seen that SUDS is a field within the field of SES, which in turn is a part of the more significant term GI. These terms will be explored below and is aimed at consolidating the knowledge in the fields.
Green Infrastructure (GI) Social-Ecological systems (SES) Sustainable Urban Drainage Systems (SUDS) Stormwater Management (SWM)/ Stormwater control measures (SCMs)
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Figure 3 How the fields of interest are connected
Note, this picture is just for illustrating which fields are part of the other. However, it is not to
scale, nor is it proportional.
2.3.1 Stormwater Resource Management
Stormwater resource management is part of GI which combines the industrial engineering with the field of social science. Because, GI is an infrastructure intensive project, for the purpose of community, and social development while giving priority to the economic and environmental concerns. GI is contested by socio-economic and environmental theory (Wright, 2011). According to the study, GI is gaining momentum as a politically motivated agenda. GI has become the object of gaining political mileage rather than meeting environmental protection standards and ensuring clean drinking water for the betterment of community life. Goulden et al. (2018) explored the theoretical value of GI as an alternative to conventional SWM in Sub-Saharan Africa. According to Manugi et al. (2016), there is a dire need for Urban water management, especially in cities situated in the developing world. The developing world’s cities experienced rapid urbanization due to which challenges such as household water drainage is also affected (Goulden et al., 2008). Consequently, Sustainable SWM is used in places to serve a multipurpose goal comprising of economic, environmental, developmental, and social objectives. The study used institutional theory to explain the importance of Sustainable SWM, and the consideration of how the institutional environment influences social choices and decisions.
Research by Maeda et al. (2018), explored the challenges associated with effective implementation of SWM among residents based on Knowledge Attitude and Practice (KAP) in the context of water resource management (SWMs). Ownership theory explains the rented household respondents express less knowledge and commitment to SWM in contrast with landlords and administrator of homeowner's associations who exhibit adequate knowledge of SWMs and express commitment to SWM. Moreover, Maeda et al. (2018) suggest that the resource management theory employed by empirical studies (Bohman et al., 2020; Cook & Spray, 2012; Hoang & Fenner, 2016) reflect a series of economic, social, and cultural factors associated SWM. Further the theory provides explanation of the factors the influence human perception of the environment, and also the ability to contemplate on conservation or management practices such as SWMs. Previous researches are limited to prioritization of solutions to technically reduce nutrient pollution and disregarding the socio-cultural and economic repercussions in policy-planning and decision-making framework (Magette et al., 1989). Effectiveness of SWM depends upon engagement and active participation of the residential communities. If the SWM is done in collaboration with the community's efforts, pollution and environmental challenges can be addressed at the source. Study by Flynn and Davidson (2016) employed social-ecological system (SES) framework to identify variables that produce and influencing impact on urban stormwater governance.
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2.3.2 Green Infrastructure (GI)
The Green Infrastructure (GI) contributes to improving and enriching outdoor life, beautiful experiences, and improved health conditions. GI is regarded by Jayasooriya and Ng (2014) as the sustainable model for stormwater management. Additionally, GI also helps in achieving local and international, sustainability and environmental goals. GI solutions are designed to keep the stormwater separate from urban drainage systems through establishments such as rain gardens, permeable pavement, green rooftops, and plantations (Magavern et al., 2016).
From a historical perspective, the GI movement started 150 years ago (Benedict et al., 2006). The two components of this idea are linking parks and green spaces for the wellbeing of the people and linking natural habitats for wildlife biodiversity. Biologists have emphasized that to preserve and protect biodiversity; integrated biosystems are needed. In 1999 the US President's Council on Sustainable Development identified GI as one of the five strategies to benefit communities in the long term. GI aims to reduce the loss of natural ecosystems, reduce the large distance between open spaces, minimize degradation of water quality, and not to hinder nature's ability to respond to climate change (Benedict & McMahon, 2002). GI has its roots in landscape architecture and networks of green spaces.
Moreover, GI and natural areas conserve natural ecosystems, their functions, and their values. Providing clean air and water and giving many benefits to individual health and wildlife. Green Infrastructure is a framework where the environment, economic health, and social health are all interconnected. GI is humanity's life support infrastructure. By the 1990s, sustainability was a national and global interest. Natural areas need to be connected to protect the earth's natural resources and wildlife (Benedict et al., 2006).
GI is continually and gradually being used by the governments of the world (Amati & Taylor, 2010). The governments understand that stormwater management benefits are a small part of the ocerall benefits of GI. Increasing public recreational benefits and human mental wellbeing is another benefit of implementing GI (Tzoulas et al., 2007). Adopting the GI method activates a feedback loop where stormwater policy requirements incentivize building and conserving GI, and GI initiatives result in stormwater management practices being implemented. Adopting GI as a standard will provide more distributed and treatment of stormwater at its source (Fletcher et al., 2015). Green Infrastructure is the network of wildlife habitats, ranches, forests, waterways, wetlands, woodlands, greenways, and parks. This infrastructure, just like any other type of infrastructure, provides social and economic sustainability. The growth of communities, quality of life, and health of the citizens depend on this infrastructure. Natural and restored ecosystems act as hubs for this infrastructure, and the green links are the connections between these hubs. GI shows a path for sustainability the same way long-range transportation provides a blueprint for future development. GI provides a future where natural resources are not depleted, and the growth of future generations is secured (Benedict & McMahon, 2002; Tzoulas et al., 2007). The adoption of green Infrastructure into SCMs and SWMs are also known as low impact development, which aims to increase sustainability which will be discussed more detailed in section 3.6. Restoring the natural biology of development sites and preserving natural areas is the goal of GI. These systems are derived from natural systems, and they capture and treat stormwater and improve the hydrological nature of the area. The system reduces the risk of flood and urban heat while improving water harvesting (Flynn & Davidson, 2016; Shuster & Garmestani, 2015).
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GI has limited practical application as the maximum capacity for holding and infiltration of stormwater can be easily reached. Biophysical and social influences have pushed for a complex GI program. For exploration purposes, the urban watershed system can be viewed and comprehended as a Social-ecological System (SES) that changes through the evolution of the smaller parts that interact within it, and this will be further discussed in section 3.2. SES is divided into actors, water systems, source water, groundwater, stormwater, wastewater, and institutions (Flynn & Davidson, 2016). Increasing the usage of GI for the development of stormwater control measures can bring several benefits for the community instead of only being point source solutions (Baptiste et al., 2015; Shuster & Garmestani, 2015).
Constructively, Prudencio and Null (2018) identified GI as the melting pot for natural landscapes that provide benefits to the ecosystem. The services brought forth by the implementation of GI range from improving the hydrological cycle to productivity, biodiversity and habitat pro-creation, pollination, pest control, aesthetical values, and the wellbeing of people. Nature is the best example to follow for designing and creating buildings and functional cities and regions. Following nature will bring sustainability through ecologically inspired structures and designs, which may be economically and functionally beneficial and more desirable. Steiner et al. (2013) provide scientific evidence for people moving to more green areas, where GI is implemented and can increase the green area for recreational space and improve sustainability for the health and wellbeing of the citizens. In this sense, GI plays a vital role in social and economic stabilization with the improvement of environmental quality (Alcock et al., 2014). The economic importance of implementing GI can also be seen in the case of southern California, where the water for irrigation and municipal use is imported, and the local water cycle is not very efficient. The leaking pipes for the imported water and the over irrigated agricultural land has led to river levels rising and groundwater recharging faster.
The imported water costs a significant amount of capital and energy loss, which could be decreased by the implementation of GI (Townsend‐Small et al., 2013). Financing poses one of the most considerable challenges for the implementation of GI. Governing organizations usually lack the resources to enforce GI projects. Another barrier is the lack of information for the cost-effectiveness of GI. The SWMs are usually selected to meet the pollutant regulations. Environmental services and recreational benefits which are harder to assess have not been in focus for selecting SWM projects. The ecological and relative cost-effectiveness will usually influence the decision-makers more than the social factors (Flynn & Davidson, 2016).
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Figure 4 The Sustainability Pyramid with GI as its base
Note. Reprinted from "Green Infrastructure: Linking Landscapes and Communities", by Benedict
et al., 2006, p. 59.
The figure 4, illustrated above shows GI at the foundation of other types of capital essentially required for human societies that are taken for granted. The man-made surrounding is enabled by the viable ecosystem and its natural resources. The food that we eat and the air we breathe are all products of a functioning ecosystem. The GI provides even the raw materials we use (Flynn & Traver, 2013). GI must be recognized by its potential for human and societal development. These values are economic, social, environmental, and cultural. Recently the focus has been on the protection of natural resources and not the production of goods. This is changing as architects and planners are also incorporating the economic benefits of GI into their GI analysis. By doing economic evaluations, a trade-off model can be used to see what values in that context bring more benefits to the community. Cost-benefit analysis is a standard tool used by decision-makers for implementing GI policies (Sim et al., 2011). Economically-deprived communities are often situated in urban areas with a need for more GI, and economical analysis should be done for what GI can bring to these communities in the long term.
Trees give many benefits to the urban environment, which can be highlighted to give a perspective of how complex the calculation of its economic value can be. Trees as a pillar of GI keeps the air clean. They reduce the sun's UV rays and therefore reduce skin cancer. They absorb stressful noises by 50%, they decrease mental stress, encourage walking, promote healing, reduce heatstroke, and exhaustion, they provide food for us. Counting all these values and calculating them can be extremely complex, but there is a need for it in order to do a cost-benefit analysis for construction projects and decisions (Pearlmutter et al., 2017).
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2.3.3 Social-Ecological Systems (SES)
The themes of sustainability and transformation of systems point towards two main scholarship areas for integrated systems, these areas are Socio-Technical Systems and resilience of social-ecological systems. Knowing these areas allows governance and management to better design systems for sustainability for future generations. The literature aims at recognizing patterns and processes for sustainability, and the resilience literature focuses on how a system can withstand disturbances to maintain its functions. The Socio-Ecological Systems (SES) framework has been established to analyze complex resource systems. SES explores the resource units, the actors, resource systems, and governance. All these parts are embedded in a broader picture of societal, economic, political, and environmental impacts. The entities in SES interact with each other, and the patterns produced by the interactions and outcomes change over time and space (Ferguson et al., 2013; Ostrom, 2007; Ostrom & Cox, 2010). The watershed can be viewed as a Socio-Ecological System, where the common pool resources are stormwater flows and storage capacity. The water quality and the storage volume available will decrease as stormwater flows through the SES. This forces the public authorities to introduce regulations and standards to control and manage stormwater. According to Flynn and Davidson (2016), the role of technology in a stormwater SES is fundamental because it provides the connection between social and ecological structures. This ensures that the technologies developed help the SES function, and become sustainable. The technology is also the feedback loop that corrects the relationship between the social and the ecological systems of the SES (Ferguson et al., 2013). Revitalization efforts are the cause of quality of life and water quality improvements. These revitalization efforts show the connection between ecological and social systems for the urban watersheds. It has been observed that revitalized SES in urban areas increases outdoor activities and neighbourhood satisfaction compared to other areas (Hager et al., 2013). The SWM implementations can also educate the public about environmental protection and preservation. It is shown that underserved neighbourhoods can be revitalized with SWMs with immense potential benefits. Socio-Ecological based approaches are also a better bottom-up solution for renewals of communities. Traditional gentrification or immigration approaches for neighbourhood renewals are a top-down approach. Hager et al. (2013) studied the growing interest for GI and raised concern that GI systems may not be viewed as a solution to all stormwater management problems. Therefore, a multitier model was developed to shed light on the complexity of these problems and the different actors in these systems (Ostrom, 2007).
19 Source: (Ostrom, 2007)
Note. Reprinted from "A diagnostic approach for going beyond panaceas", by Ostrom E., 2007,
p. 15182.
SES is affected by more extensive systems and smaller entities. Figure 5 above shows a simple and general framework. Resource systems are fisheries, lakes, and farmland, for example. The resource units generated by those systems are fishes, water, and crops. The users are the consumers of the resources, and there is also the governance system. All 4 of these entities are connected and are in a sophisticated Socio-Ecological System (Ostrom, 2007). Following figure 5, urban stormwater policymakers need to consider multiple benefits for the users and the different resources that the SCMs will affect, to choose the best SWMs for each situation. Each of the four systems can be further expanded as well, known as a decomposable system. This is a flexible system and should be interpreted and adapted to each analysis (Ostrom & Cox, 2010). This system is developed and is aimed at reducing the use of traditional and straightforward solutions where the government or private ownership is the only way to solve climate change issues and biodiversity loss. Ostrom (2010) found that the SES model intersects as a common perspective between different disciplines of social, economic, and ecological backgrounds.
2.3.4 Sustainable Urban Drainage Systems (SUDS)
Urban drainage is one of the oldest fields which can be dated back to 3000 BC (Fletcher et al., 2015). Currently, the applications of Sustainable Urban Drainage Systems (SUDS) are variable from region to region, but the idea behind it stems from the same root. Drainage systems were initially thought to serve two primary purposes, flood protection and cleaning the wastewaters in urban areas. This view has recently been shifted to include environmental and recreational benefits (Charlesworth, 2010; Zhou, 2014). The social effects of SUDS often get dismissed while new projects are being developed, even though these social impacts are immensely crucial to their urban environments. With the flood events and water pollution on the rise in urban communities, the importance of runoff treatment is becoming clear, and SUDS bring useful insights and solutions for these dense urban areas (Apostolaki et al., 2006). SUDS encourage water primarily to be infiltrated and treated locally. Charlesworth (2010) considered a stormwater as a natural resource instead of being driven away out of sight which is the traditional way of dealing with stormwater These devices and measures that consider SUDS are called Best Management Practices (BMPs) in the US. In Europe, SUDS are used to build sustainable structures to protect the public wellbeing, water resources, water quality, biological diversity, and natural resources (Butler & Parkinson, 1997; Hellström et al., 2000).
At the same time, in Australia, a similar system called Water Sensitive Urban Design (WSUD) and SUDS was a part of that bigger picture where technology was integrated into the fabric of the city to be sustainable. SUDS is known as Low Impact Development in the US and Canada, and this emphasizes the importance of natural ecosystems and the preservation of these systems for water management success (Hellström et al., 2000). This approach is aimed at conserving natural habitats in combination with smaller-scale water management technologies to counteract the effects of urbanization (Department of Environmental Resources, 1999). According to Roy et al. (2008), SWMs are the best example of this approach.
