!!EVALUATING LOW IMPACT DEVELOPMENT PERFORMANCE ON THE SITE IN GRAND RAPIDS, MICHIGAN By Hongwei Tian A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of Environmental Design - Master of Arts 2016 !!ABSTRACT EVALUATING LOW IMPACT DEVELOPMENT PERFORMANCE ON THE SITE IN GRAND RAPIDS, MICHIGAN By Hongwei Tian Urbanization has increased the adverse impact of society, environment and economy. An urgent issue is associated with stormwater as impervious surfaces area increased. Low Impact Development (LID) is an innovative sustainable practice that can decrease the influence of adverse stormwater. It has also been widely applied to many sites. However, the effectiveness of LID is still associated with uncertain results, depending on different site conditions, design strategies and assessment approaches. This study evaluates the LID performance by examining four different design scenarios including two designs with LID and two without LID, through eleven variables in Grand Rapids, Michigan. The Friedman analysis of comparison method has been applied to the treatments to determine whether the designs with LID elements are more effective. The result shows that designs with LID elements are significantly greater than the existing condition (p!0.05). Key words: Landscape Architecture, Landscape Urbanism, Urban Design, Ecological Planning, Impact Assessment. !!"""!ACKNOWLEDGEMENTS I would like to thank my major advisor Dr. Jon Burley, FASLA, Professor, Michigan State University School of Planning, Design and Construction. Without his inspiration and support, it is hard to complete my thesis successfully. I would also like to my other two committee members, Dr. Patricia Machemer and Dr. Eunsil Lee, professors in Michigan State University School of Planning, Design and Construction, for all the advice and guidance. I appreciate all the team members and people who gave suggestions during the EPA competition. Also, the article ÒMetrics in Master Planning Low Impact Development for Grand Rapids MichiganÓ developed by Burley, J. B., Li, N., Ying, J., Troost, S. and myself, which is related to our EPA competition design and part of my thesis data analysis. This paper has facilitated my research and thanks for Li and BurleyÕs assistance concerning the methodology. Lastly, I am grateful to all my friends and families for their support throughout my university life. !!"#!TABLE OF CONTENTS LIST OF TABLES ....................................................................................................................... vi LIST OF FIGURES .................................................................................................................... vii Chapter1. Introduction ................................................................................................................. 1 Chapter2. Literature Review ....................................................................................................... 3 2.1 Low Impact Development Overview ................................................................................. 3 2.1.1 LID Development ........................................................................................................... 3 2.1.2 LID Design Principle and Process .................................................................................. 6 2.1.3 Benefit of LID ............................................................................................................... 10 2.2 Design Elements of LID .................................................................................................... 11 2.2.1 Rain Garden .................................................................................................................. 12 2.2.2 Bioswale ........................................................................................................................ 13 2.2.3 Constructed Wetland ..................................................................................................... 15 2.2.4 Green Roof .................................................................................................................... 16 2.2.5 Permeable Pavement ..................................................................................................... 17 2.3 Previous Studies about LID .............................................................................................. 18 2.4 Conclusion .......................................................................................................................... 19 Chapter 3. Methodology (including pre-results calculations) ................................................. 20 3.1 Design Scenarios Description ........................................................................................... 20 3.1.1 Existing Site .................................................................................................................. 20 3.1.2 LID with Cloud Design ................................................................................................. 23 3.1.3 LID Design .................................................................................................................... 31 3.1.4 Traditional Design ........................................................................................................ 32 3.2 Comparable Elements Calculations ................................................................................. 34 3.2.1 Area Calculation ........................................................................................................... 34 3.2.2 Energy Use Ð Average tree water consumption ............................................................ 37 3.2.3 Climate Change Ð Shadow area .................................................................................... 44 3.2.4 Stormwater Management Ð Runoff, infiltration & evaporation .................................... 49 3.2.5 Ecosystem Ð Sparrow & squirrel habitat index ............................................................. 54 3.3 Friedman Statistical Test .................................................................................................. 58 Chapter 4. Result (including Friedman methodology) ............................................................ 60 !!#!Chapter 5. Discussion ................................................................................................................. 64 5.1 LID Evaluation Between Theory and Reality ................................................................. 64 5.2 Limitation ........................................................................................................................... 67 5.3 Recommendation ............................................................................................................... 68 5.4 Conclusion .......................................................................................................................... 69 BIBLIOGRAPHY ....................................................................................................................... 71 !!#"!LIST OF TABLES Table 1. List of different design elements area ............................................................................. 35!Table 2. Ranks of stormwater impact criteria ............................................................................... 37!Table 3. Plant species and average water consumption ................................................................ 41!Table 4. Ranks of the average water consumption per tree and tree quantity .............................. 44!Table 5. Building shadow area calculations ................................................................................. 47!Table 6. Rank of total shadow area ............................................................................................... 49!Table 7. The National Stormwater Calculator (SWC) parameters ............................................... 51!Table 8. SWC statistic results ....................................................................................................... 52!Table 9. Ranks of stormwater management results ...................................................................... 54!Table 10. Field sparrow HSI results and rank ............................................................................... 56!Table 11. Fox squirrel HSI results and rank ................................................................................. 58!Table 12. Ranks of variable values for treatments ........................................................................ 60!Table 13. Design Scenarios Differences ....................................................................................... 63! !!#""!LIST OF FIGURES Figure 1. Schematic of rain garden (adapted from SEMCOG, 2008) .......................................... 12!Figure 2. Schematic of bioswale (adapted from SEMCOG, 2008) .............................................. 14!Figure 3. Schematic of green roof (adapted from SEMCOG, 2008) ............................................ 16!Figure 4. Location and aerial view of existing site (adapted from Google earth ©2016) ............ 21!Figure 5. Functional diagram of site context ................................................................................ 22!Figure 6. Design process (LID with Cloud Design) ..................................................................... 25!Figure 7. Master plan and details (LID with Cloud Design) ........................................................ 27!Figure 8. Layer analysis (LID with Cloud Design) ...................................................................... 28!Figure 9. LID system analysis (LID with Cloud Design) ............................................................. 29!Figure 10. Implementing Phase Illustration (Copyright ©2016 Na Li with permission) ............. 31!Figure 11. Master plan and details (LID Design) ......................................................................... 32!Figure 12. Master plan and details (Traditional Design) .............................................................. 33!Figure 13. Sun position information (adapted from Find My Shadow, n. d.) .............................. 46!Figure 14. Location key (Existing Site) ........................................................................................ 46!Figure 15. Location key (Traditional Design, LID Design, & LID with Could Design) ............. 47!Figure 16. SWC runoff analysis results (adapted from SWC) ...................................................... 53!Figure 17. Field sparrow suitability indices for the variables (adapted from Sousa, 1983) ......... 55!Figure 18. Fox squirrel suitability indices for the variables (adapted from Allen, 1982) ............. 57!!!$!Chapter1. Introduction Along with the development of cities, counties, and towns, more impervious surfaces have been created. Stormwater runoff flows over impervious surfaces and contains contaminants including residual oil, bacteria, sediments and other chemicals that find their way into lakes and streams that provide people their daily drinking water (USEPA, 2012b). The United States Environment Protection Agency (USEPA) has reported that the most important sources of the pollution in the stream, rivers, and lakes are caused by stormwater (Lehner, Aponte Clark, Cameron, & Frank, 1999). Besides pollution, stormwater runoff also can cause flooding, erosion, habitat destruction, and sewer overflows (Jacoby, 2012). To reduce the excess water runoff, numerous innovative stormwater management techniques, especially LID are applied into neighborhoods, which create sustainable wildlife habitats, and recharge groundwater while also improving water quality and slowing the flow of runoff (Jacoby, 2012). LID is a best-management practice (BMP) approach to managing stormwater, and is accomplished by minimizing impervious surfaces, and promoting more natural infiltration and evapotranspiration. (Darner & Dumouchelle, 2011). Also, as an alternate comprehensive approach to stormwater management, LID has been implemented into new developments, redevelopment, or as a retrofit to existing development (Kibert, 2012). As LID technology becomes more mature and the LID concept has been embraced by communities throughout the United States as well as many other parts of the world, the application of LID will become extensive. But the previously research and study of LID is limited and uncompleted, it is critical to provide more scientific evidences about the LID performance, especially in the area of !!%!benefits and shortcomings. The purpose of this study is to evaluate the LID performance with eleven variables based on the four design scenarios. By comparing the results, the impact of LID will be clearly presented. The aim of this study includes: (1) presenting LID strategies and comparable strategies; (2) explaining the specific variables of each design; (3) calculating the results and identifying if the designs with LID are better than the other design scenarios; and (4) considering the limitation, providing recommendations and explaining why this study is important for designers, governments, and future researchers. !!&!Chapter2. Literature Review 2.1 Low Impact Development Overview 2.1.1 LID Development What is LID and why use LID? Freeman, H. (2010, p.1067) demonstrated that, Òwhile conventional stormwater permitting is often simplified into a few primary performance goals Ð usually peak flow and nutrient removal Ð LID permitting is significantly more complicated.Ó And Southeast Michigan Council of Governments (SEMCOG, 2008, p.1) said, ÒLID is the cornerstone of stormwater management.Ó Clean water is the key to keep the economic vitality, which requires a balanced hydrologic cycle (SEMCOG, 2008). In the water cycle, water percolates downward through the soil and reaches the water table, then provides baseflow for streams, rivers and lakes under the effect of gravity (SEMCOG, 2008). However, Victorian Stormwater Committee (1999) indicated that with massive urbanization, the densely developed inner urban area is an almost impervious surface, which reduces the water infiltration and completely transforms rainfall into runoff. The SEMCOG (2008, p. 6-7) reports that adverse impacts include: increased flooding and property damage, degradation of the stream channel, less groundwater recharge and dry weather flow, impaired water quality, increased water temperature, loss of habitat, and decreased recreational opportunities. In the past, traditional stormwater management approaches were applied to control the adverse impact of urbanization, including storm sewers, deep tunnels, stormwater retention ponds, and other engineered strategies (Dane, 2012). These gray infrastructure approaches have !!'!been proven to be destructive to the environment, society and economy, leading to the deterioration of species biodiversity and the destruction of recreational landscape (Dane, 2012). In contrast, the green infrastructure Ð LIDÕs main goal is to present the pre-development hydrology and reduce the impact to the soils, habitat and aquatic system on the site by minimizing the disturbance, rather than just mitigating the runoff (Dietz, 2007). LID becomes a recommended alternative way to the traditional stormwater management (Dietz, 2007). From a stormwater management point of view, LID is the use of strategies that imitate the regular water cycle by using a basic standard: manage the runoff by utilizing procedures that infiltrate, filter, store, evaporate, and detain the runoff (SEMCOG, 2008). Moreover, the United States Environmental Protection Agency (USEPA) indicated LID as Òan approach to land development (or re-development) that works with water to manage stormwater as close to its source as possibleÓ (USEPA, n.d.). Summarizing the LID working techniques, LID emulates the water cycle by 1) minimizing the volume of runoff; 2) reducing the peak rate of runoff; 3) maximizing infiltration and groundwater recharge; 4) maintaining stream baseflow; 5) controlling evaporation; and 6) improving water quality (SEMCOG, 2008). As an environmentally friendly approach, LID has cooperated with many sustainable programs, such as the Best Managements Practices (BMPs), Smart Growth, and the U.S. Green Building CouncilÕs Leadership in Energy and Environmental Design (LEED). The core concept of BMPs is reducing soil erosion, sediment and treating the diverse levels of the containments (Yu, J., Yu, H., & Xu, 2013). As the component of the BMPs, nonstructural BMPs have less structural form, but wider planning and design approaches, which are the factors of LID site in !!(!the pre-development stage (Clary et al., 2011; SEMCOG, 2008). From a stormwater management perspective, the nonstructural BMPs are the cluster development in purpose of minimizing soil compaction and disturbed area, protecting natural flow system, riparian buffer and sensitive area, and reducing impervious surface and stormwater disconnection (SEMCOG, 2008). In nonstructural BMPs, the basic characteristic of LID is keeping stormwater runoff from the site (SEMCOG, 2008). As post-development strategies, the structural BMPs require LID to mitigate the runoff through bioswale, bioretention, rain garden, green roof, and porous pavement (SEMCOG, 2008). The principles of smart growth and the requirements of the LEED program also meet the mission of LID (SEMCOG, 2008). For example, the smart growth guideline, include encouraging community and stakeholder collaboration and making development decisions predictable, fair and cost effective, is also suitable for the LID design concept. LEED has created a rating system with certification for various development scenarios in order to augment global adoption of sustainable green building practices (SEMCOG, 2008). Actually, LID is compatible with the LEED requirement, which optimize each design scenario into the LEED policy (SEMCOG, 2008). There are several challenges existing during the LID application. When implementing LID, different organizations will confront various stormwater regulations and some regulations may contradict with LID techniques (SEMCOG, 2008). Lack of basic awareness, technical knowledge and financial support of LID will also exert negative impacts on LID development (SEMCOG, 2008). In addition, some existing site conditions could constrain the LID application, such as bad soil or geology (SEMCOG, 2008). !!)!Even though there are lots of challenges, we have still witnessed significant progress in the LID development. Some institutions with jurisdiction over the stormwater and land use their purview to improve LID application (SEMCOG, 2008). For instance, according to the USEPA report (2012d), the City of Philadelphia has offered multiple incentives to move LID forward, including LID implementation fee credits, LID practice grants, compensation for installing LID as well as contests and awards for LID projects. Also the integrated regulation and monitor system is imperative for LID improvement. Public education and participation provide people an opportunity to embrace the concept of LID stormwater management, which also has the support of the public, elected officials, and some environmental organizations (SEMCOG, 2008; Davis, 2005). 2.1.2 LID Design Principle and Process Without an integrated design principle and process manual, LID application cannot be successful. In order to achieve this, the Southeast Michigan Council of Governments (SEMCOG, 2008, p.9) and other organizations have summarized the combination of several principles, which includes: ¥ Plan first. When applying LID stormwater management practice, the process of combining with the community planning and zoning process can help minimize stormwater impact and maximize the benefits of LID (SEMCOG, 2008). ¥ Prevent firstly, then mitigate. The essential goal of LID is to prevent stormwater runoff by preserving natural features and minimizing impervious surfaces, which also requires the incorporation of LID into the nonstructural practice during the design process !!*!(SEMCOG, 2008). Then, structural BMPs can be prepared for post-development to mitigate the runoff (SEMCOG, 2008). ¥ Minimize disturbance. During the LID design process, the limitation of disturbance can decrease the amount of stormwater runoff and maintain the natural hydrology (SEMCOG, 2008). Also, the cluster development enables the protection of existing open spaces and scenic views (Kibert, 2012). ¥ Manage stormwater as a resource Ð not a waste. Different than the conventional design understanding that stormwater is a problem, LID treats runoff as a resource for groundwater recharge, stream base flow, lake and wetland health, water supply, and recreation (SEMCOG, 2008). ¥ Imitate the natural water cycle. LIDÕs working mechanism emulates the natural water cycle, including peak rate control, runoff volume reduction, groundwater recharge and water quality protection. ¥ Disconnect. Decentralize. Distribute. Instead of gray infrastructure, such as catch basins, piping, and stormwater ponds, LID manages stormwater as close to the source as possible. (Kibert, 2012). Also, depending on the location of the runoff point, the pattern of LID is decentralized across the site (SEMCOG). ¥ Integrate natural systems. As green infrastructure, LID not only protects the water system, but also preserves natural resources (SEMCOG). Moreover, LID utilizes natural resources to work for the project, such as biological drainage and retention (Kibert, 2012). !!+!¥ Maximize the multiple benefits of LID. LID has provided numerous benefits to stormwater management, as well as the environment, society and economy (SEMCOG). When implementing LID, the communities should be aware of these other benefits, which can increase the extent of LID application (SEMCOG, 2008). ¥ Apply LID everywhere. LID techniques can be used in any development stage by integrating into early planning stages in undeveloped areas and incorporating with existing sites to solve problems in developed areas (USEPA, 2012b). The form of the LID performance is also variable, from rain gardens, bioswales, green roofs, to pervious pavements. ¥ Make maintenance a priority. Understanding the maintenance requirements and organizing a maintenance program are crucial components of the LID program (SEMCOG, 2008). ¥ Follow the monitor system. The monitoring programs of the LID design are important because they provide a science-based evaluation of stormwater management practices and present LID achievement of runoff management to the public (Shuster, Morrision, & Wedd, 2008). Based on the explicit design principles, the LID design process is also essential to land development. SEMCOG (2008, p. 50-52) has offered nine sequential design steps to help integrate LID into the site successfully. ¥ Step 1: Property purchasing and land use analysis. Before purchasing property, the developer should learn about land use that belongs to residential, commercial or !!,!industrial use, which determines the price of the property. ¥ Step 2: Inventory and analysis of the site. In the LID pre-development phase, it is significant to assess the basic information of the site, especially the natural system, which may create challenges and/or opportunities of the stormwater management. The natural resource systems that need to be evaluated include floodplains, riparian areas, wetlands, all the drainage ways, soils and topography, geology, groundwater, and vegetation. ¥ Step 3: Blend municipal, county, state and federal requirements. In the design process, it is crucial to update the information of land development regulation, which varies between county, state, federal and all stakeholders. ¥ Step 4: Develop initial concept design with nonstructural BMPs. Based on the previous steps, the initial design concept can be integrated into nonstructural BMPs, such as cluster development, natural flow pathway, riparian buffer and sensitive area protection, disturbed area control, and impervious surface reduction. ¥ Step 5: Make a preÐproposal meeting and site visit with local decision makers. It is necessary to have a pre-meeting between municipal leaders and the developers, which offers a chance to incorporate everyoneÕs perceptions into the design concept. ¥ Step 6: Integrate corrections into the development concept. According to the previous information, an acceptable revision should be applied. ¥ Step 7: Decide the structural BMPs selection. In structural BMPs, different types of LID designs should be determined depending on the particular stormwater management !!$-!requirements of the site. ¥ Step 8: Apply calculation and methodology. Calculation and methodology should be applied in order to fulfill the LID design criteria encompassing groundwater recharge, runoff volume control, peak rate control, stream channel protection and water quality purification. ¥ Step 9: Finish the preliminary site plan. According to the completion of the previous steps, the preliminary site plan about stormwater management and existing natural resource practice can be merged and presented to the local government. It should be comprehensive and satisfying for both developers and the community. 2.1.3 Benefit of LID The practices of LID have offered numerous benefits and the following paragraphs present the details of these benefits in the areas of society, economy and environment. Society Ð The LID design elements have served as green infrastructure to social aesthetics, which create beautiful sustainable park-like elements to neighborhoods, increasing green streetscape and offering recreational opportunities (USEPA, 2013a). LID not only improves citizensÕ life quality, but also provides people environmental education opportunities (SEMCOG, 2008). Economy Ð For communities, agencies and the public, LID has decreased municipal infrastructure and utility maintenance costs, and saved energy costs for heating, cooling and irrigation (SEMCOG, 2008). Also, LID has increased the propertiesÕ marketing values by improving the environmental quality and creating more green space (USEPA, 2012c). For !!$$!developers, LID helps reduce land clearing and grading cost, as well as property damage costs caused by flooding (SEMCOG, 2008; USEPA, 2012b). Moreover, LID, as an alternative stormwater management practice, has contributed to conventional stormwater construction payment reduction (SEMCOG, 2008). Environment ÐLIDÕs benefits for environment is abundant. First of all, LID has improved water quality by impeding runoff pollutants and filtering the water through green construction (SEMCOG, 2008; USEPA, 2012b). Second, LID practices retain the rainfall on-site instead of channeling into ditches or drains, which ameliorates groundwater recharge (USEPA, 2012b). The third, LID has preserved ecological and biological system, especially the aquatic habitat, through retarding the runoff speed and controlling bank erosion (SEMCOG, 2008; USEPA, 2012b). Fourth, as the green infrastructure, LID has enhanced carbon sequestration and improved air quality (SEMCOG, 2008). Fifth, LID also diminishes the urban heat island effect and climate change (USEPA, 2012b). 2.2 Design Elements of LID Different types of LID design have been applied based on the concern of the specific site conditions and stormwater management requirements. Bioretention, typically referred to as rain garden, is adequate in removing concentrations and storing the runoff (Dietz, 2007). Pervious pavement is also effective in penetrating the stormwater runoff (Dietz, 2007). Moreover, an average 63% of rainfall can be captured by green roof in different climates (Dietz, 2007). Thurs, the comprehensive understanding of different types of LID is significant and necessary to achieve the best result of stormwater management. !!$%!2.2.1 Rain Garden Rain Gardens are the shallow low-lying land covered by specific native plants, which retain and infiltrate runoff from buildings, streets and potentially parking lots (SEMCOG, 2008). As the result of this process, the runoff volume and peak discharge rate will decrease, as well as sediment and pollutants can be separated from rainfall (SEMCOG, 2008). In addition to managing stormwater, rain gardens also strengthen site aesthetics, habitat suitability and air quality. However, there are inherent limitations that restrict the effectiveness of rain garden due to high maintenance cost and inflexible plant selection (SEMCOG, 2008). Figure 1. Schematic of rain garden (adapted from SEMCOG, 2008) Figure 1 illustrates the fundamental construction of rain garden, which demands detailed design in pond depth, plant selection, soil type, infiltration bed, penetration of under-drainage and overflow structure depending on the stormwater management functional requirement !!$&!(SEMCOG, 2008). In addition to the basic rain garden structure, several considerations should be involved into design process. To be suitable for the rain garden, the area must have at least a 0.25-inch per hour infiltration rate and the slope should not be deeper than 20% (SEMCOM, 2008; DES, 2007). The flow entrance and positive overflow system is created with erosion control and appropriate surplus runoff conveyance (SEMCOG, 2008). The total surface area and ponding area should be able to support runoff volume without exceeding the depression depth (SEMCOG, 2008). In order to keep vegetation health, planting soil should be mixed with a composted organics that can remain soil PH between 5.5 and 6.5 and designed between 18 to 48 inches deep (SEMCOG, 2008). Additionally, selecting plants should follow two guidelines Ð 1) runoff entrance area is not acceptable to woody plant material caused by soil erosion; 2) the depth of ponding is unequal, which requests pay attention to different plant saturation tolerances (DES, 2007). After deciding the plants species, vegetation will be placed from mid-April to early June or mid-September to mid-November (SEMCOG, 2008). Also, a 2-3 inches mulch cover can protect vegetation from erosion and pollutants (SEMCOG, 2008). A gravel-subsurface infiltration bed that requires no less than six inches deep should have plenty of space to store 40 percent runoff at the minimum, enfolded by geotextile fabric (SEMCOG, 2008). Finally, under the condition of more than 48 hours drainage period, underdrain system should be applied to the site (SEMCOG, 2008). 2.2.2 Bioswale Bioswale, also referred to as Ògreen engineered ditchesÓ, offers effective routing for stormwater runoff with low cost, which can be applied in various locations including highways, !!$'!farms, residential, industrial and commercial areas (Borst et al. 2008). As an enhancement of conventional stormwater piping, bioswale has many advantages, such as reducing volume of runoff and improving infiltration and groundwater recharge at the same time by utilizing soil, vegetation and microbes (Clark & Acomb, 2008). This versatile runoff conveyance can also improve landscape aesthetic and biodiversity (Clark & Acomb, 2008). The major limitation of bioswale is insufficiency in runoff peak rate and volume control (SEMCOG, 2008). Figure 2. Schematic of bioswale (adapted from SEMCOG, 2008) As figure 2 presents, bioswale surface is covered by grass, while subsurface incorporates with four vertical layers Ð an impervious liner located in bottom serves as segment isolator and over infiltrated water protector; sitting on the impermeable membrane, a clean washed gravel aggregate should be designed from 12 to 24 inches; an inserted pipe surrounded by gravel conveys all infiltrating water to a targeted point; the top layer is a 2 to 8 inches deep media separated by a porous fabric from the gravel (Borst et al., 2008; SEMCOG, 2008). According to bioswale design criteria, the size of bioswale is designed for 10-year storm event peak discharge !!$(!and one-inch storm event storage requirement (SEMCOG, 2008). Also, slope ratio of bioswale should be arranged from 3:1 to 5:1 (SEMCOG, 2008). Finally, a critical consideration component is soil type, which should be compliant to plant growth, restrict infiltration rate and isolate the heavy metals and nutrient contaminants from runoff (Borst et al., 2008). SEMCOG (2008, p. 320) also recommends, Òsoil should be at least 12 inches of loamy or sand with an infiltration rate of at least 0.5 inches per hour.Ó 2.2.3 Constructed Wetland As the multifunctional shallow water detention, constructed wetlands utilize the natural process to treat stormwater efficiently through storing, filtering and cleaning runoff in both temperate and tropical climates. (Moat, Simpson, Ghanem, Kandasamy, & Vignerswaran, 2008). Constructed wetland treats wastewater and stormwater as a resource by reducing the levels of nutrients, sediments, pathogens, heavy metals and hydrocarbons in the water, which also builds the wetland habitats and environmental aesthetics (Moat, Simpson, Ghanem, Kandasamy, & Vignerswaran, 2008). Although constructed wetland is effective in reserving runoff, the capability of volume reduction and peak rate control is limited (SEMCOG, 2008). In order to receive a long-term success, there are several considerations should be noticed during the wetland installation (SEMCOG, 2008). The characteristics of the wetland plant species should fulfill the criteria that require a tolerance of the local climate, pollutant and water-saturated condition, as well as satisfy the surrounding ecosystem (Moat, Simpson, Ghanem, Kandasamy, & Vignerswaran, 2008). Also, topsoil that blends with medium textures silty to sandy loans is the essential component of a successful aquatic-plant establishment (Moat, !!$)!Simpson, Ghanem, Kandasamy, & Vignerswaran, 2008). Moreover, the constructed wetland is flexible in boundary, shape, width and depth based on the local geography and stormwater treatment requirements (SEMCOG, 2008). 2.2.4 Green Roof Green roof serves as a vegetated rooftop constructed by multiple layers that are displayed in figure 4 (SEMCOG, 2008). Considered as a stormwater best management practice (BMP), green roof can retain plenty amounts of rainfall and detain the infiltration rate to the drainage system (Sutton, 2015). Furthermore, green roof can absorb atmospheric pollutants and contaminants in precipitation (Sutton, 2015). Especially in a densely populated city where the tree planter area is limited, green roof is an effective air pollution control tool. (Yang, Yu, & Gong, 2008). Green roof also has effective microclimate function to mitigate the city heat island and climate change, while enhancing habitat quality and city aesthetics. (Sutton, 2015; SEMCOG, 2008). The restrictions of green roof include high installation and plant maintenance cost, as well as disconnection with ground, which means it canÕt treat runoff from other place (SEMCOG, 2008). Figure 3. Schematic of green roof (adapted from SEMCOG, 2008) !!$*!A standard green roof design involves multilayers (figure 3) including vegetation, growth media, filter layer, drainage layer, protection layer and waterproof membrane (SEMCOG, 2008). The growth media criteria recommend a soil-like combination with organic content that should be less than 15 percent of entire media (SEMCOG, 2008). Also, the roof slope greater than 45 degree is inapplicable for green roof system (SEMCOG, 2008). Irrigation is only required in first two year to establish the drought tolerant vegetation and after that, the annual rainfall is adequate to maintain plants (SEMCOG, 2008). 2.2.5 Permeable Pavement As an alternative to the conventional impermeable asphalt and concrete pavement, porous pavement allows runoff infiltrate into pavement and temporarily retain the water through several layers (Collins, Hunt, & Hathaway, 2008). Therefore, permeable pavement can mitigate runoff volume and peak rate and produce groundwater recharge (Collins, Hunt, & Hathaway, 2008; SEMCOG, 2008). The limitations are high maintenance budget and restricted site conditions. Soil quality is the most significant consideration in pervious pavement design. The permeable pavement design doesnÕt accept compacted soil, while poorly draining soil should be designed with adjoining swale, wetland or rain garden in case of overflow (SEMCOG, 2008). The bottom elevation of infiltration bed must be flat (SEMCOG, 2008). Moreover, the infiltration bed requires a two-year storm event storage capability and also incorporates with perforated pipe based on the storage requirement (SEMCOG, 2008). Finally, appropriate winter maintenance can keep the snow removal and deicing working effectively (SEMCOG, 2008). !!$+!2.3 Previous Studies about LID As the new technology, the studies and researches of LID are still not complete and comprehensive. Base on the numerous literature reviews, the current articles about LID can be separated into three categories: 1) Basic concept and information of LIDÕs characterization, application, benefit, and limitation; 2) Evaluating the LID performance in a single area, such as stormwater management, pollutant remove, sediment control, or air quality improvement with few variables; 3) Monitoring method and calculation method applied into evaluation. The first category has been well described in the previous sections. For the second category, there are many studies cases about LID performance. In Michigan, several developments that have intergraded LID BMPs into their designs has been presents in SEMCOG. The Pokagonek Edawat Housign Development located in Dowagiac has applied different type of LID in order to maximize stormwater infiltration and recharge of groundwater (SEMCOG, 2008). LID BMPs have been utilized into Mid Towne Village redevelopment in Grand Rapids, Michigan, which helps reduce the impervious surface and reuse the rainwater through cisterns (SEMCOG, 2008). In other state, the applications of LID are diverse, which not only provide the benefits of stormwater management, but also bring advantages to both air and water quality. In Chicago, the 19.8 ha of green roofs have removed a total of 1675kg air pollutants that constituted of !!(52%), !"!(27%), !"!"(14%), and !"!(7%) in one year (Yang, Yu, & Gong, 2008). The LID study cases have also been found in other counties. A calibrated hydrodynamic model and water quality model have been applied to Sazlidere Watershed, in Istanbul, Turley, which predicate the both peak flow rate and total suspended solid will decrease after implementing different types of !!$,!LID (Gulbaz & Kazezyilmaz-Alhan, 2015). Jia, Lu, Yu and Chen indicate that, comparing with the existing site, the recommended LID BMPs could reduce, respectively, 27% and 21% of total runoff volume and the peak flow rate in Beijing Olympic Village (2012). The methodologies applied for existing LID study cases are mainly based on the database from different monitoring system. The evaluation of designed scenarios is generally predicted by the specific equations or models. The EPA Storm Water Management Model (SWMM) has been utilized widely in numerous study cases. As a computer software, \SWMM can calculate the dynamic hydrologic situation including the change of rainfall intensity, flow rate and pollutant concentration for a site based on the design strategy (Gulbaz & Kazezyilmaz-Alhan, 2015). 2.4 Conclusion In conclusion, based on the previous reviewed material, the application of LID performs widely and effectively with multiple benefits, but the limitations cannot be neglected depend on different cases. Thus, to achieve the full range of possible, it is significant to have further studies about how LID can be integrated into urban stormwater facilities successfully. !!%-!Chapter 3. Methodology (including pre-results calculations) The experimental design of this study is to develop four design scenarios. Then apply eleven LID related variables to the four scenarios. Finally, after calculating the variables, compare the four scenarios across the eleven variables, with the Friedman One-way Analysis of Variance Test. 3.1 Design Scenarios Description The methodology of this thesis is developed based on four design scenarios Ð Existing Site, Traditional Design, LID Design and LID with Cloud Design. These designs are based on the United States Environmental Protection Agency (USEPA) campus RainWork competition that our team has participated in and produced in 2015. The challenge requires student teams to design a green infrastructure project for their campus with the purpose of effectively managing stormwater runoff, improving the campus community and environment, and involving the climate change concept (USEPA, 2015). Our team members, including Na Li, HaoxuanXu, Yanzhi Xu and myself, designed a master plan and several details for Michigan State UniversityÕs (MSU) new medical campus area and its neighborhoods in Grand Rapids, Michigan, which integrates numerous innovative LID design elements into the selected site. The LID with Cloud Design scenario is the final submission we provided to the USEPA completion and the rest of the design scenarios are created based on this project. Therefore, after introducing the existing site, the LID with Cloud Design will be described. 3.1.1 Existing Site The site (figure 4) is located besides the Grand River in the city of Grand Rapids, Michigan, !!%$!and occupies 98.5 acres. The selected area contains the MSU Grand Rapids Research Center (GRRC), the MSU College of Human Medicine (CHM) Ð Secchia center, Butterworth Hospital: North Office Building Radiology that besides the Secchia center and partially the North Monroe business district. Figure 4. Location and aerial view of existing site (adapted from Google earth ©2016) The Secchia center is located between Gerald R. Ford Freeway and Michigan and encompassed by several eminent hospitals and therapies. As the headquarters for the Michigan State University College of Human Medicine, the Secchia Center serves as a privately funded medical education building, which cost 90 million dollars and opened on September 2010 (MSU, n.d.). The mission of the Center Secchia is to addresses the sustainability at both social and environmental level. From the community perspective, the Secchia Center is designed for ."/0"123!45236!728"69!."/0"123!:;!4<52=6!7>!?@56!?AB!.@35@