International Low Impact Development Conference 2018: Getting In Tune with Green Infrastructure

Filtering of raw water for drinking purposes is limited in rural areas in Iraq. The limitation is mainly due to technical and logistical difficulties of the traditional method, as well as high initial and operation costs. Therefore, a less complicated system is needed to overcome this problem. As a result, a laboratory size compact ceramic system has been designed, constructed, and extensively tested. The system mainly consists of a reservoir and two modules of rotating ceramic discs. The discs have been made from red clay, sawdust, and water. The laboratory results suggest the proposed system could be used in water filtration. This system can be continuously operated with a constant flow rate and does not need the primary sedimentation water tanks that are typically used in the traditional method. The proposed system can be manufactured with different filtration capacities to satisfy the needs of the served areas; however, a large filtration capacity system has not been tested previously. A large capacity filtration system could help humanitarian aid organizations and military units since it is easy to transport and install. The study discusses the design and cost of manufacturing large capacity systems, and compares the finding with traditional filtration systems. This study also reviews the potential advantages of using the proposed system in rural areas in Iraq, as well as the challenges.

The Toronto and Region Conservation Authority, Lake Simcoe Region Conservation Authority, and Credit Valley Conservation Sustainable Technologies Evaluation Program collective within the Greater Toronto Area will present on the capabilities of the low impact development treatment train tool (LID TTT) to provide water quality [total suspended solids (TSS) and total phosphorus (TP)] target assessments. The targets are established by the regulatory agencies. The LID TTT calculates TSS and TP load reduction achieved from runoff volume reduction and LID filtration. The land cover based concentrations are used to estimate TSS and TP loading to the receiving LID(s) and LID removal efficiencies are used to estimate their load reductions from filtration. The tool provides default concentration and removal efficiency values, which can be edited by the user if the relevant agencies support different values. This presentation and paper will provide the water quality calculation methodology, results from a case study highlighting the water quality target assessment, and validation using monitored data from the case study sites. Based on the results and continued monitoring and research, recommendations for continued study and refinement of the land cover-based TSS and TP concentration and LID removal efficiency defaults for LID TTT Version 2.0 (+) will also be highlighted.

This paper presents a 17 year performance evaluation of Pembroke Woods, a 43 acre LID subdivision. This LID subdivision is one of the first subdivisions in the U.S. that was planned, designed, and constructed to meet the all the stated goals and objectives of LID including; minimization of impacts to the site, maintenance of ground water recharge, water quality control protection through volume control, and peak flow protection, also through volume control. The paper will review the planning and design steps taken by the subdivision. A field evaluation of the condition of the outlet points for the subdivision will be presented. The O&M plan developed for the subdivision will be summarized. The O&M plan developed for the subdivision will be summarized.

Low impact development practices (LID) are adaptation alternatives to assist traditional drainage systems, aiming to mitigate the risks of hydrological extremes. Current literature about LIDs practices do not call directly unified standard nomenclature which address the security of water-food-energy nexus. Here we discuss and propose a new nomenclature that can be used for LID, facing adaptation criteria and setups to tradeoff from changes in future scenarios. The nomenclature is proposed in terms of generations of LID practices, which address different goals of extremes mitigation (1st generation LID-1G: runoff excess from urbanization; 2nd generation LID-2G: runoff excess from urbanization and climate change; 3rd generation LID-3G: incorporate adaptation for reuse resources for water-energy-food security). Finally, in this study we propose new experimental criteria facing the implementation of a LID-3G, including the discussion under conditions of subtropical climate cities and growing urbanization.

Urbanization increases runoff volume and velocity, resulting in higher risks of flooding and the higher amount of pollutants carried by stormwater. To mitigate these impacts, low impact development practices (LID), such as bioretention, have been used to treat stormwater runoff enhancing the sustainability of urban drainage systems. However, climate change is expected to alter the rainfall regime and, consequentially, the efficiency of LID controls, and its impacts need to be better evaluated. In addition, there are few studies analyzing LID performance under a subtropical climate, which has different rainfall regimes and runoff generation process when compared to temperate climates. This study, in particular, estimated the efficiency of a bioretention in Sao Carlos, Brazil, in a subtropical region, for 4 different future periods (2020-2039-2040-2059, 2060-2079, and 2080-2099) with estimated precipitation for 2 RCP scenarios (4.5 and 8.5), forced by HADGEM2-ES global model. These scenarios were based on the ETA regional climate model and downscaled to São Carlos by the Brazilian National Institute for Space Research and compared to the period of 1980-1999. The income and outlet of runoff and pollutants were modeled to estimate the bioretention efficiency during this century, with climate changes impacts on rainfall regime. The analyzed periods presented water retention efficacy closed to 80%, suggesting that climate change has little effect on it. However, the pollutants removal depends on their wash off characteristics, those with higher wash off rates have higher removal potential.

In 2012, Indianapolis hosted Super Bowl XLVI. In preparation for this huge event, many projects were executed to enhance the experience of the hundreds of thousands who would converge on the city. One of those projects was called the Georgia St. Promenade. This ordinary 4-lane street would be converted to a pedestrian plaza with wooden boardwalks, stone pavers, trees, and landscaping and steel canopies. This 12.5 million dollar project includes the installation of an innovative stormwater system that exemplifies the concept of limited impact development (LID). The system components were originally conceived to be made of cast-in-place (CIP) concrete, but was re-engineered to be a primarily precast concrete project solution. This paper contains information on how precast concrete contributed to meeting a tight schedule, staying under budget, and providing an innovative model for managing storm water in an urban setting.

To address serious water problems in urban areas, the sponge-style old community renewal (SOCR) was carried out in most of the old communities in China. Understanding the satisfaction of community residents with the SOCR projects is vital for evaluating the outcome of the SOCR projects and promoting residents’ engagement in sponge city construction. The aim of this study is to assess residential satisfaction (i.e., residents’ perception to meet their needs, expectations, and aspirations) with SOCR and examine the determinants which are the main factors that influence the residential satisfaction. Using a conceptual framework and old communities of Zhenjiang as a case study, important differences across different factors (such as age, education, income, community attachment, information acquisition, support for policy, and cognition) were identified using regression analysis. One critical finding is that a high level of residential satisfaction was recorded for residents who were younger, with higher education level, higher income, with a strong sense of belonging to the community, a high level of support for the SOCR policy, and greater awareness of the importance of the SOCR. The results provide critical information about enhancing the satisfaction of residents in old communities and promoting residents to engage in more effective implementation of sponge city alternatives.

Pervious concrete stormwater management systems are being adopted in many areas of the country. Additional applications might include erosion control by streams and other waterways, or as pavements in areas prone to flooding. Concrete in contact with waters typically increases the pH, especially in the first year of use prior to significant carbonation. Open system batch tank testing was performed on pervious concrete specimens of varying young ages to analyze the pH profiles that might develop over time. The results indicate that the higher pH values remain close to the specimens. These results imply that the use of pervious concrete near waterways will not have a large spatial impact on pH, especially under dynamic conditions.

There are concerns about negative impacts from chemical deicers (mainly MgCl₂ and CaCl₂) used on pervious concrete pavements in cold climate areas. This paper continues research started in 2016, where specimens were subjected to chemical treatments, by applying 200 ml solutions with 3% in mass of CaCl₂ or MgCl₂, and water or NaCl as controls, weekly, for 17 weeks. This phase of the research aimed to see if these chemical treatments affected strength using split tensile testing. Results indicate that the split tensile test does not seem to be the best method to study pervious concrete mechanical characteristics on specimens with vertical porosity distributions due to the variability of the locations of the voids in the specimens. The MgCl₂ treated specimens appeared to react differently from the other treatment implying impacts and age (amount of carbonation) appeared to have a slight positive influence on strength.

At present, the size of cities has exceeded a threshold limit where centralized drainage and sewer treatment systems are no longer physically viable. Bioretention cells (BC) are a low impact development (LID) technology developed to provide distributed storm water quantity and quality control closer to the source through infiltration, retention, and evapotranspiration of storm water. Although water quantity and quality research has been done on BCs, most research envisages BC as a black box with specific temporal processes between the input and the output. Our research aims to consider BCs as heterogeneous systems with different physical processes occurring in different magnitudes spatially and temporally. For this study, a 4-year-old BC at the Kortright Centre for Conservation in Vaughan, Ontario, is used as an investigation area. Snow depth and soil properties are measured physically in seventeen points throughout the BC. More than a hundred hydraulic conductivity (K) measurements are measured using Guelph permeameters. K has been measured during freezing/non-freezing temperatures in winter, spring, summer, and fall. Snow depth contour maps show that low-lying water flow paths and sloppy locations in the BC thaw more rapidly. K_sat is spatially negatively correlated with moisture content. Temporally, K_sat was found to be larger during late winter/early spring thaw (~0.10 mm/s) than the summer or fall (~0.0228 mm/s). Design recommendations for BCs have been proposed based on the research findings.

Bioretention has shown effective stormwater volume and peak flow reduction and acceptable stormwater quality improvement in warm and temperate climates. However, the applicability of bioretention for successful stormwater management in cold and semi-arid regions is still not well understood. In this study, a novel concept of bioretention cell configuration was developed, which makes bioretention cells suitable for both summer/fall and winter/spring weather conditions in cold climate. Four large column bioretention cells were set up in a controlled laboratory and monitored for 5 months under high loading conditions. Synthetic stormwater was applied weekly to investigate the hydrological and water quality improvement performance of two different soil types, with and without a phosphorus adsorption amendment, additional carbon source, and an internal water storage layer. During simulated storm events, influent and effluent flows were monitored and analyzed for total suspended solids, phosphorus, nitrogen, and chemical oxygen demand. Bioretention cells were shown to weaken peak flow and effectively remove TSS, ammonia, and phosphorus regardless of cell configuration. An internal water storage layer was shown to contribute to nitrate degradation via denitrification. After a period of establishment, the four columns were gradually subjected to freezing conditions (as low as minus 20 degrees Celsius). They were provided time to freeze and then gradually thaw to simulate a typical Edmonton, Alberta, winter and spring melt event. Hydraulic and water quality performance were consistently monitored to investigate the impact of freezing temperatures and salts. This project aims to fill gaps in knowledge regarding the performance of bioretention systems in cold climate and develop design modifications of bioretention systems for application in cold climate.

The urban stormwater management philosophy named sponge city (SPC) was put forward in 2014 as a comprehensive stormwater management strategy in China. The SPC development involves the source control measurements similarly to low impact development or green infrastructure (LID or GI) practices; the urban pipe/channel drainage system dealing with the normal frequency storm events; and the major drainage system handling the potential flood inundation due to extreme rainfall events. The road-bioretention system is widely used as a source control measurement in urban stormwater management. A large-scale laboratory road-bioretention system (road part is 18 m×4 m, bioretention part is 10 m×1 m) was constructed with rainfall simulator system. The road and bioretention are connected via the road curb inlet that allows the runoff generated on the road surface flows into the bioretention. The experiments were conducted with the road surfaces of various longitude and cross slopes and the curb inlet of different lengths under various rainfall intensities. The runoff into the underground pipe drainage through a grate inlet and the bioretention through curb inlet, and the discharge flowing further downstream along the road surface were monitored during the rainfall events. A road-bioretention simulation model was developed using the 2D overland flow modeling program (FullSWOF-SX) and calibrated with the experimental data. The model can be used to simulate the complex rainfall-runoff process on pervious and impervious surfaces, i.e., dynamic flow and infiltration process of the road-bioretention cell. The experimental data and simulation results were analyzed and discussed aims to provide/develop guides for the design of road-bioretention systems.

Continuous simulation (CS) refers to the computational modeling of a physical system in which the model continuously tracks and accounts for system responses to changes over time. This branch of deterministic modeling is well suited to the study of complex systems with multiple interactive feedback mechanisms. There are a wide range of applications in fields that include medicine, engineering, space exploration, and defense. The use of CS in hydrologic analyses was first implemented in the United States in 1960, with the development of the Stanford watershed model under Dr. Ray Linsley at Stanford University. Hydrologic analysis using CS remained fairly uncommon outside of academia up to and beyond the advent of modern desktop computing and the age of big data. This has remained so due in part to the perception that the data needs are too large and the processing times are too extensive. Another barrier to a more broad use of this technique is perhaps the lack of guidance and documentation for using this technique within existing and well established modeling platforms such as the U.S. Army Corps of Engineers Hydrologic Engineering Center hydrologic modeling system (HEC-HMS) and the U.S. Environmental Protection Agency’s storm water management model (SWMM). The application of CS in the hydrologic analysis of low impact development (LID) implementation in the urban and suburban watershed offers the ability to perform predictive analysis of system performance under both static and changing land use and watershed management strategies. It offers a tool to evaluate the potential influence of LID on the sources of hydromodification and pollutant loading. Applying statistical analyses to the output from CS provides the ability to assign probability to observed system responses. For instance, what effect does a particular watershed management or development activity have on the recurrence interval for the bank full flow within a receiving stream? This paper presents a brief introduction to CS, a discussion of the LID modeling capabilities of SWMM, an introduction to CS capabilities of SWMM, and a simple example of a CS simulation of LID.

LID practices have been booming in China since Sponge City Directives—Low Impact Development Rainwater System Construction released in 2014. Functional or technical indicators required the regulation of sponge city are involved to evaluate the implementation of LID, which is leading much more attentions technology, such as to deal with rainwater qualities and quantities, but less on humanity. Values and behaviors of human play a vital impact on solving essentially ecological issue based spiritual ecology. Dual thinking of ecology in this article would addresses both technical and human of thinking in ecology. The purpose of this article would demonstrate that design of raingardens in northern China participated by authors how to combine technical and human ecology as one whole to fulfill the amenity of stormwater management. Creations of four raingardens with different type and scale in northern China would be discussed and analyzed further including UP+S raingarden (200 m²), campus raingarden (1400 m²), raingardens in residential area (7 hm²), and raingardens in Business Park (20.5 hm²) in which not only amenity for users are created with pavilions, spatial recreation, and art installation, but promoted users to more ecological perception of rainwater, even strengthened their ecological ethics by employing eco-revelatory design.

Along the road from plan review to inspection and maintenance agreement, there are many opportunities to prevent recurring issues during construction through policies, checklists, notes on plans, and pre-construction inspections to name a few. Varying types of buffers are a good concept, but how do you ensure they are adequately communicated and respected? Flooding is always a hot topic and a public safety hazard, so even if the stormwater control measure (SCM) was designed per regulations with good engineering practices, and constructed as approved, ensuring it continues to function as designed plays a key role. Reviewers see a wide range of design concepts, design standards, and overall quality. Policies and procedures are integral in keeping a standard for items involving public health, safety and welfare, and industry best practices. The goal of this paper is to offer some lessons learned and possible solutions to recurring issues throughout the many facets of a construction project.

Reclaimed water is an attractive option to use in low impact development projects in arid parts of the globe. Residential, commercial, and infrastructure development projects require inordinate amounts of water for dust control, landscape irrigation, and other utility uses. These needs can be in conflict with industrial uses, particularly the oil and gas exploration, power generation, and petroleum refining. Affected communities must develop their own unique reclaimed water use and water storage strategies. This paper will examine the water energy nexus in the country of Saudi Arabia, and the United States, in California and Texas. These are regions of the world that are rich in natural resources, including oil and gas, but have limited water resources. They have large populations and urban development projects, as well as massive agricultural and oil and gas industries. The choices of water consumption and storage made by each of these regions is unique to their regional needs and priorities. A comparison of the different responses of these regions to water needs and lessons learned are relevant to many other parts of the developing world with similar water challenges for their growing populations and developing industries. The paper will conclude with guidelines for the safe and practical utilization and storage of reclaimed water in low impact development projects.

This research focuses on calculating and comprehending the movement of infiltrated water as it travels through urban rain garden soils at different depths in a bio-infiltration stormwater management practice. Three rain gardens or bio infiltration stormwater management practices (SMP C, SMP D, SMP G) were constructed in Philadelphia, PA, by the Pennsylvania Department of Transportation to mitigate impervious surfaces created during the reconstruction of Interstate-95. The study is ongoing, and a year of field-based data has already been collected. The monitoring system consists of soil moisture meters at 10cm, 35cm, and 60cm for SMP C; 10cm, 35cm, and 55cm for SMP D; and 10cm, 35cm, 66cm, and 83cm for SMP G. Rainfall and ponding depth measurements are also measured at the site. The research goal is to track the water movement through these distinct soil levels and understand the saturation profile, based on which the soil characteristics are present.

Low impact development (LID) systems, when implemented wholistically, have the ability to create economic ripples in the communities in which they are built. When land, housing, open space, and infrastructure are understood as natural resources that can be managed locally to improve service delivery and reduce costs, these systems can have knock-on effects that are felt throughout neighborhoods both locally and regionally. This approach also enables broader-based municipal planning and coordination between agencies, utilities, and the communities they service. LID methods, taken as a systematic approach, create a suite of tools and opportunities for improving urban quality of life, health, and economic development.

Community land trusts (CLTs) are a developing trend in community land ownership and stewardship. As American cities continue to grow, gentrification, densification, and displacement are issues that threaten many existing neighborhoods. Using the lens of the South Bronx Land and Resource Trust (SBxLCRT), we will examine the CLT’s roots under the leadership of We Stay/Nos Quedamos Inc., a 25-year old community development corporation active in planning and development in Community Districts 1, 2, and 3 in the Bronx, New York City. This will explore the CLT’s implications in the formation of municipal policy, environmental resilience, and community equity.

The Green City Clean Waters Research Center (GCCWRC), a partnership between Villanova University and the Philadelphia Water Department, has identified several key areas of research needs related to green stormwater infrastructure (GSI). The work of this partnership addresses specific concerns of the water department and is performed under contract with specific deliverables. Curb opening design is a key area that is underrepresented in published technical literature and GSI research. Major considerations are opening size needed to capture the desired stormwater flow volume into stormwater management practices (SMPs) and flow path configuration needed to keep trash, debris, and sediment out of the SMP to avoid blockage. The design equations from the Federal Highway Administration (FHWA), which are usually used to size the curb openings, are created for large scale highway projects and do not result in appropriate results for GSI. To address this problem, field investigations were performed on more than 140 curb openings in Philadelphia, PA, including surveying and visual inspections for measuring dimensions and slopes, and evaluating the general condition of curb openings. Based on the results of the field investigations, curb openings were categorized in different design groups. Computational fluid dynamics (CFD) modeling of curb openings was performed to analyze the efficiency of different design schemes and to investigate how and where modifications can improve efficiency.

The continuous replacement of permeable surfaces, that could previously infiltrate stormwater runoffs, with asphalt, concrete, and other impervious surfaces in urban areas, in addition to the numerous environmental damages caused by the transfer of pollutants, and heavy metals by these runoffs to the municipal water systems indicate a critical need to enhance the control of stormwater runoffs in urban areas. Green roofs have been shown to be one of the most effective best management practices in controlling urban runoffs. Considering the relatively short history of this technology, the impact of the green roof’s components in controlling runoffs needs further identification. This paper focuses on the impacts of the vegetation-related factors through a review of the research findings. These impacts are discussed in three categories of 1) plants’ resistance, 2) irrigation needs, 3) plants dependence on fertilization and pesticides. For each of the factors, recommended policies are provided. In addition, potentials for future studies that can fill the gap of inconsistent findings, and limited or non-existing knowledge about the green roof hydrological performance are discussed.

Stormwater runoffs in urban areas are the primary cause of multiple environmental issues such as pollution of water bodies, reduction of groundwater recharge, and increase in the rivers’ water temperature. Each of these impacts has a wide range of environmental ripple effects. Runoffs can be effectively controlled by applying the best management practices. Pervious concrete pavements are one of the most effective tools for implementing these practices in urban stormwater management. Numerous environmental benefits of these pavements have caused them to be widely replaced with the conventional concrete. However, considering the relatively short history of these pavements, there are still common issues in their application. Additionally, further enhancement of pavement technology depends on resolving certain limitations through further research. This paper discusses the major common issues in design, construction, and maintenance of these pavements that can lower the permeability in the surface, lead to functional deterioration, decrease service life, and reduce the efficiency of pervious pavements as a system in collecting runoffs. Recommended policies to resolve each of the issues are provided. The paper also discusses different existing limitations such as low compression strength and resistance against freeze-thaw and suggests potentials for further research to enhance the permeability and durability of the pervious concrete pavements.

Southern Ontario and, more generally, urban areas throughout Canada, have seen the implementation and successful operation of a number of pilot scale low impact development (LID) projects. Despite demonstrated success and a proclivity to outperform design expectations, adoption of LID practices—particularly on predeveloped private property—has not occurred. This is true even in the face of ongoing urban flooding and water quality impairment issues. While several factors have been identified as barriers hindering broad scale LID implementation, market research conducted in the Greater Toronto Area (GTA) indicates that the high up-front costs and long or non-existent payback period are the largest barriers inhibiting LID adoption. To address this, a mix of innovative policy and market-based tools, incentives, and approaches are needed. The Drainage Act, a 183 year old piece of legislation unique to the Province of Ontario, has been intensely scrutinized and found suitable as a vehicle to facilitate cost-optimized, community-based retrofit implementation. However, to incentivize the use of the Drainage Act process, a paradigm shift in how municipalities approach stormwater management is required to address the up-front costs and long payback periods associated with LID retrofits. Recognizing the offsite benefits provided by private property adoption and rewarding appropriately will promote an approach to managing stormwater that is not only cost effective and affordable, but linked and integrated at a watershed scale in a way that meets water quality targets in the face of increasing urbanization and climate change.

Given their wide adoption in places like Melbourne, Australia, biofilters have a potential to provide significant ecosystem services and ecological values (together referred to as co-benefits) by retaining and treating stormwater runoff, providing esthetic and amenity value, and increasing urban biodiversity. With the exception of stormwater runoff treatment and retention, these co-benefits are not well documented in stormwater biofilters but their value is increasingly recognized. Provision of these co-benefits may be strongly related to plant functional diversity (i.e., the diversity of functional traits among the ecosystem) as is commonly the case in natural and other ecologically engineered ecosystems. A functionally diverse plant community incorporates a variety of plant types (e.g., graminoids, forbs, shrubs, trees), growth types (e.g., clustering, spreading, rhizomatous, etc.), and varying degrees of morphological characteristics (e.g., leaf area, root area, root length, root diameter, etc.). Some of these traits are good indicators of stormwater treatment, but traits associated with other co-benefits and combinations of these traits have not been investigated. Here, we review the literature and describe how incorporating functional traits into plant selection processes may improve biofilter function.

Trees are a natural biofilitration approach to managing stormwater runoff for the development of green infrastructure that provides many community benefits as our urban areas expanding. These benefits include stormwater retention, erosion and pollution reduction, biodiversity and habitat restoration, esthetic and other environmental and social benefits. But growing a tree in the over-saturated soil (typical case during storm time) could kill a tree, too. On the other hand, 80% of the U.S. territory suffers at least a seasonal drought annually according to National Oceanic and Atmospheric Administration. Trees and plants typically suffer much during droughts. This presentation will review the new irrigation technologies that are suitable for urban landscaping, which are quite different from farm fields. Conventionally, development of irrigation technologies is driven by agriculture industry so that these technologies are more suitable for farm use than for typical urban settings. For example, road median plantings are too difficult to use drip irrigation system because of legislation and logistics reasons. Irrigation systems can also be very cost inefficient compared to farm fields where acres of plants can share a system, while road median is the opposite in terms density of plantings. In addition, harsher environment and vandalism may cause damages. Novel irrigation technologies that are best for urban plantings and cope with the harsher growing urban environment will be discussed with case studies. The goal of this session is to educate and to recommend the best technologies for urban environments. The criteria include making best usage of natural precipitation water, stormwater holding and slow releasing capability, reducing labor cost, saving water, suppressing invasive species, and protecting plantings against harsher growing conditions than farms: heat island effect, excessive sunlight from reflections from buildings and road surfaces, limited soil volume, compacted soil, pollution from road maintenance and emission, vandalism, more flooding (within in the concrete forest), etc.

National Taipei University of Technology (Taipei Tech) in Taipei, Taiwan, gradually modified its campus as an eco-campus since 2000. Several low impact development (LID) facilities were designed and built in the campus. In order to assess the performance of the LIDs, flow monitoring was started in 2014. The flow meter was set in a part of the eco-campus to measure the combined performance of permeable pavement, wet detention pond, and bio-detention cells. The total drainage area is 1.54 ha. There are 8 types of permeable pavements and the different permeable pavements presented high infiltration rate, ranged from 3*10^-7 to 7*10^-5 m/s. The 22 rainfall events were monitored in 2014 and 2015. The results of site monitoring is for the area with LIDs but no data for the area without LIDs. For the reason, the SWMM model was applied and was verified with the observed data. The results of the model showed that the combined LIDs could reduce 16.7% of runoff in the scenario of designed storm, which is a 5 return year and 78.8 mm/hr rainfall, the standard of drainage system of Taipei City. For a long-term simulation, the combined LIDs reduced 35.2% of runoff for the campus. Even in the extreme typhoon event, the simulations showed that they can contribute 9.8% of runoff reduction. With the site monitoring and model application, the performance of LIDs in the Taipei Tech campus is manifested and its reaction to different rainfall events is more clearly understood.

Taiwan has abundant rainfall but because its rivers are very short and with steep slopes, reservoirs have long been the main drinking water sources. There are more than 90 reservoirs on Taiwan of which 20 are major drinking water sources. Due to the sub-tropical climate and continuing development activities, many reservoirs are having or facing water quality issues relating to eutrophication, sedimentation, and other pollutant loadings. It is imperative to protect the water quality of the reservoirs so a sustainable use of water resources could be achieved. The National Taipei University of Technology (NTUT) Water Environment Research Center (WERC) research team has been contracted by the Taiwan Environmental Protection Administration to lead a three-year (2017-2020) study on reservoir water quality protection. Three major reservoirs located in Northern, Central, and Southern Taiwan were chosen for the study. Major work elements include: 1) a survey and assessment of the current pollutant loadings using conventional as well as innovative sampling methods such as auto mobile boats, sampling drones, etc.; 2) a strategy for water quality management under climate change scenarios; 3) use of “green” technology for pollutant reduction; and 4) decision support models and economic incentives. The paper presents results regarding Task #1 and #2, i.e., reservoir pollutant sources and “hot spots”; loading estimates and their relationship with land use and other factors; and flows into the reservoirs under extreme weather conditions due to climate change and their impact on water quality. The use of “green” practices such as bioretention cells (Task #3) for runoff and pollutant reduction is discussed. On-site innovative treatment technologies, such as multi-soil-layering (MSL) systems are considered and planned for implementation in the reservoir watersheds.