Tài liệu International low impact development conference 2018 getting in tune with green infrastructure

Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. International Low Impact Development Conference 2018 Getting In Tune with Green Infrastructure Proceedings of the International Low Impact Development Conference 2018 Nashville, Tennessee | August 12–15, 2018 Edited by Jon Hathaway, Ph.D., P.E. Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. INTERNATIONAL LOW IMPACT DEVELOPMENT CONFERENCE 2018 GETTING IN TUNE WITH GREEN INFRASTRUCTURE PROCEEDINGS OF THE INTERNATIONAL LOW IMPACT DEVELOPMENT CONFERENCE 2018 August 12–15, 2018 Nashville, Tennessee SPONSORED BY Environmental and Water Resources Institute of the American Society of Civil Engineers EDITED BY Jon Hathaway, Ph.D., P.E. Published by the American Society of Civil Engineers Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. Published by American Society of Civil Engineers 1801 Alexander Bell Drive Reston, Virginia, 20191-4382 www.asce.org/publications | ascelibrary.org Any statements expressed in these materials are those of the individual authors and do not necessarily represent the views of ASCE, which takes no responsibility for any statement made herein. No reference made in this publication to any specific method, product, process, or service constitutes or implies an endorsement, recommendation, or warranty thereof by ASCE. The materials are for general information only and do not represent a standard of ASCE, nor are they intended as a reference in purchase specifications, contracts, regulations, statutes, or any other legal document. 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Errata: Errata, if any, can be found at https://doi.org/10.1061/9780784481783 Copyright © 2018 by the American Society of Civil Engineers. All Rights Reserved. ISBN 978-0-7844-8178-3 (PDF) Manufactured in the United States of America. International Low Impact Development Conference 2018 Preface Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. The International Low Impact Development Conference was held in Nashville, Tennessee, in August of 2018. The Proceedings presented here represent a portion of the timely, innovative, and diverse content that was presented at the conference. The theme for this event was “Getting in Tune with Green Infrastructure,” so in addition to sessions focused on research, case studies, and municipal challenges, we highlighted the social aspects of stormwater management. Sessions associated with this topic included ways to educate, engage, and incorporate the public in our design and management programs. The 2018 LID Conference also included a number of “special sessions” proposed by the community to allow participant input into the conference program on topics that might be overlooked by the planning committee. We are excited at the continued interest and growth in Low Impact Development globally, we hope that these proceedings provide the in-depth information that you are looking for and look forward to seeing you at the next LID conference in 2019! Acknowledgments Preparation and planning are the key to a successfully executed conference, so we would like to recognize the hard work of the Conference Steering Committee and also others that are not mentioned here. Conference Chair Rebecca Dohn Metro Water Services, Nashville, TN Conference Co-Chair Crystal Bishop Tennessee Stormwater Association Technical Program Chair Jon Hathaway University of Tennessee Department of Civil and Environmental Engineering Technical Program Vice Chair Gale Fulton University of Tennessee, School of Landscape Architecture Local Host Chair Jennifer Watson Tennessee Stormwater Association © ASCE iii International Low Impact Development Conference 2018 Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. Committee Members Michael Clar, Tetra Tech James Lenhart, Contech Engineered Solutions Brian Bledsoe, University of Georgia Robert Traver, Villanova University Scott Struck, Geosyntec Consultants Finally, we acknowledge and thank the staff of the EWRI of ASCE, who, in the end, make it all happen. Director, EWRI Brian K. Parsons, M.ASCE Technical Manager, EWRI Barbara Whitten Conference Manager Mark Gable Conference Coordinator Nicole Erdelyi Sponsorship and Exhibit Sales Manager Sean Scully Registrar Susan Dunne Conference Scientific Committee Technical Program Chair: Jon Hathaway, University of Tennessee, Department of Civil Engineering Technical Program Vice-Chair: Gale Fulton, University of Tennessee, School of Landscape Architecture Bram Barth, Lose and Associates, Inc. Eban Bean, University of Florida Brian Bledsoe, University of Georgia Robert Brown, Ecological Planning Group Ted Brown, Biohabitats Kathlie Bulloch, City of Houston, Texas Karina Bynum, TDEC Water Resources Michael Clar, Ecosite, Inc. Jane Clary, Wright Water Engineers Brad Collett, University of Tennessee, Knoxville © ASCE iv International Low Impact Development Conference 2018 Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. Rebecca Dohn, City of Nashville, Tennessee Jay Dorsey, Ohio State University Hunter Freeman, WithersRavenel Kathy Gee, Longwood University Robert Goo, US Environmental Protection Agency Ruth Hocker, City of Lancaster, Pennsylvania Bill Hunt, North Carolina State University Mikael Isensee, Washington Conservation District, Minnesota Anand Jayakaran, Washington State University Matthew Jones, Hazen and Sawyer James Lenhart, Contech Engineered Solutions Keith Lichten, California Environmental Protection Agency Kelly Lindow, CityScape Engineering Bill Lord, North Carolina State University Andrea Ludwig, University of Tennessee, Knoxville Susan McCrary, Metropolitan St. Louis Sewer District Trisha Moore, Kansas State University Elodie Passeport, University of Toronto Holly Piza, Urban Drainage and Flood Control District, Denver, Colorado Saya Qualls, Hazen and Sawyer Andrew Reese, Wood Group Amy Rowe, Rutgers University David Sample, Virginia Polytechnic Institute John Schwartz, University of Tennessee, Knoxville, Tennessee David Smith, Interlocking Concrete Pavement Institute Jonathan Smith, Tetra Tech Scott Struck, Geosyntec Consultants Robert Traver, Villanova University Steven Trinkaus, Trinkaus Engineering LLC Harris Trobman, University of the District of Columbia Bridget Wadzuk, Villanova University Ryan Winston, Ohio State University Jason Wright, Tetra Tech © ASCE v International Low Impact Development Conference 2018 Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. Contents Using a Compact Ceramic System to Filter Raw Water in Iraq: Challenges and Opportunities ..................................................................................................................... 1 Riyadh J. M. Al Saadi and Ahmed Jalil Al-Bayati Water Quality Target Assessment Using LID TTT for Better SWM Designs in Ontario .................................................................................................................................. 7 Steve Auger, Tim Van Seters, Amanjot Singh, and John Antoszek A 17-Year Performance Evaluation of a LID Subdivision .................................................... 18 Michael Clar Decentralized Low Impact Development (LID) Practices Addressing the Security of the Water-Energy-Food Nexus ............................................................................ 30 Marina Batalini de Macedo, César Ambrogi Ferreira do Lago, Eduardo Mario Mendiondo, and Marcio Hofheinz Giacomoni The Effects of Climate Change on Low Impact Development (LID) Performance—A Case of Study in Sao Carlos, Brazil ........................................................... 40 César Ambrogi Ferreira do Lago, Marina Batalini de Macedo, Eduardo Mario Mendiondo, and Marcio Hofheinz Giacomoni Precast Concrete and LID: A Super Bowl-Size Case Study .................................................. 46 Claude Goguen Assessment and Determinants of Residential Satisfaction with Sponge-Style Old Community Renewal: A Case Study in Zhenjiang, China ............................................. 51 Tiantian Gu, Dezhi Li, and Yanqing Wang pH Profiles around Pervious Concrete in Fresh Water ......................................................... 64 Qin Qian, Fernando Aleman, Hayden Rice, Andre Trottier, Liv Haselbach, and Harley Myler Deicer Impacts on Pervious Concrete Specimens: Phase IIa; Split Tensile Testing ..................................................................................................................................... 71 L. Haselbach, N. Almeida, and M. Ross Spatial and Temporal Analysis of Hydraulic Conductivity, Snow Depth, and Soil Properties of a Bioretention System ......................................................................... 81 Alwish Ranjith John Gnanaraj and Jennifer Drake Laboratory Study on the Performance of Bioretention for Stormwater Management in Cold Climates ............................................................................................... 90 Hannah Kratky, Zhan Li, Xiangfei Li, and Tong Yu © ASCE vi International Low Impact Development Conference 2018 Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. Experimental and Model Study of Road-Bioretention System............................................ 101 Xiaoning Li, Xing Fang, Junqi Li, Jianlong Wang, Nannan Tu, Qingzhu Yang, Pengshu Li, and Yongwei Gong Analysis of Low Impact Development Using Continuous Simulation Hydrologic Modeling............................................................................................................. 110 Patrick L. McMahon, Clive L. Sorhaindo, and William K. Barry Towards Dual Thinking of Ecology: Raingardens Design in Northern China ................... 119 Xiaoying Meng, Can Wang, and Yubo Zou Memoir of a Reviewer: The Basics ....................................................................................... 125 Maria E. Price Water Energy Nexus in the United States and Saudi Arabia Low Impact Development .......................................................................................................................... 130 Tony Rizk and Mary Rizk Monitoring Infiltration Movement through the Soil Profile in Urban Rain Gardens ................................................................................................................................. 140 Matina Shakya, Robert Traver, and Bridget Wadzuk Community Land Trusts: An Emerging Case Study in Ripple-Effect Infrastructure Economics ..................................................................................................... 149 Jeremy Stand, Blaine Stand, Tara Stand, and Petr Stand Community Land Trusts: A New Model for Urban Equity and Environmental Resilience ............................................................................................................................... 159 Jeremy Stand, Blaine Stand, Tara Stand, and Petr Stand Improving the Design of Curb Openings in Green Stormwater Infrastructure ................. 168 Sarah Stoolmiller, Ali Ebrahimian, Bridget M. Wadzuk, and Stephen White Investigating the Impacts of Green Roofs’ Vegetation Properties on Their Function in Controlling Urban Runoffs ............................................................................... 176 Mohammadsoroush Tafazzoli Enhancing the Functionality of Pervious Concrete Pavements through Design and Maintenance ................................................................................................................... 184 Mohammadsoroush Tafazzoli Canadian Low Impact Development Retrofit Approaches: A 21st-Century Stormwater Management Paradigm .................................................................................... 193 W. R. Trenouth and W. K. Vander Linden Understanding the Roles of Biodiversity and Functional Diversity in Provision of Co-Benefits by Stormwater Biofilter Plant Communities ............................................... 203 B. K. Winfrey, E. G. I. Payne, and R. F. Ambrose © ASCE vii International Low Impact Development Conference 2018 Novel Irrigation Technologies for Urban Landscaping ....................................................... 213 Wei Zhang, Uriel Akiva, and Hailing Yang Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. Performance Evaluation of Combined LID Facilities on Runoff Reduction—A Case of Taipei Tech Campus in Taiwan ............................................................................... 223 Chi-Feng Chen, Jen-Yang Lin, Chia-Chun Ho, and Chao-Ting Kuo LID Practices for Reservoir Water Quality Management: Case Studies in Taiwan ................................................................................................................................... 230 Jen-Yang Lin, Shyh-fang Kang, Wen-Yi Wei, and Shaw L. Yu © ASCE viii International Low Impact Development Conference 2018 Using a Compact Ceramic System to Filter Raw Water in Iraq: Challenges and Opportunities Riyadh J. M. Al Saadi, Ph.D.1; and Ahmed Jalil Al-Bayati, Ph.D., P.E., M.ASCE2 Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. 1 Lecturer, Dept. of Civil Engineering, College of Engineering, Kerbala Univ., Iraq. E-mail: [email protected] 2 Assistant Professor, Kimmel School of Construction Management, Western Carolina Univ., Cullowhee, NC 28723, U.S. E-mail: [email protected] ABSTRACT 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. INTRODUCTION Most rural regions in the world suffer from deficient water. The availability of potable water is a challenge in most rural and remote regions due to the fact that there are no existing traditional water treatment systems (TWTS) in these areas. Traditional water treatment systems that use surface water are usually fixed and expensive to build and maintain. These plants consist of the following components: surface water steel intake structure, sedimentation tank, filtration tank, alum mixer and tank (i.e., flocculating tank), and chlorination system, see Picture 1. Several studies have been carried out to improve current filtration systems, as well as propose new systems. Al-Kathily (2014), for example, conducted an empirical study aimed to eliminate sedimentation phase from TWTS. Al-Kathily built a laboratory direct filtration unit that includes four main units: an axial flocculating unit, a filtration unit, injection unit for pumping coagulants and clay materials, and a backwashing unit. In another study, Mahanna et al. (2015) constructed an experimental pilot plant to improve turbidity removal and developed a simple regression model between turbidity and the sand filter’s depth. The results of the proposed model showed a good correlation (r2 = 0.88) within the observed data, indicating that the most significant parameters that affect turbidity are sand media depth and filtration rate. © ASCE 1 Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. International Low Impact Development Conference 2018 2 Sedimentation Tank Intake Structure Sand Filters (Filtration Tank) Alum Dosing Tanks, Mixers & Pumps Backwash Valves Chlorination System Picture 1. TWTS components – Babil Province, Iraq Somewhat differently, several studies have investigated the use of ceramic filters (CF) due to their availability and initial low cost. Jassim (2010) conducted a study on water filters made from Iraqi local ceramic materials with different additives. The study found that all produced ceramic filters have high removal efficiency of suspended materials. On another study, Musa (2010) investigated the advantage of adding sawdust to the ceramic filter’s components in order to increase its porosity. The results indicated that adding sawdust could improve filtration up to a © ASCE Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. International Low Impact Development Conference 2018 specific percentage; filtration capability drops after that. In yet another study, Al Zubaidy et al. (2017) investigated the use of a rotating ceramic discs (RCD) system. The research team designed, constructed, and operated a laboratory scale ceramic water filter to examine the efficiency of RCD as a medium for water filtration. Ceramic water filters made of two different mixtures, as well as two rotating interfered modules, were tested. The main objective of rotating modules was to generate shear force between water and the surfaces of discs to reduce the thickness of the layer of rejected materials on the filter’s surface. The experimental study showed that the resulting thinner layer of rejected material improved the filtration process. This paper will also discuss the design, advantages, and challenges of a rotating disc system. Figure 1. A schematic diagram of the water filtration system (Credit: Al Zubaidy et al. (2017)) WATER FILTRATION SYSTEM DESIGN The system in the current study consists of a storage tank, filtration tank, two ceramic filtration modules, backwash tank, two treated water storage tanks, peristaltic pump, and an electrical control board, see Figure 1. The dimensions of the storage tank are 34 cm width, 66 cm length, and 34 cm depth. The tank is supplied with raw water through a pipe of 12 mm inner diameter. The water flow to the tank is controlled by an electrical float valve used to preserve a water head of 30 cm. Four submersible water pumps are used to circulate raw water in order to prevent settling of the suspended materials. The storage tank supplies raw water to the filtration tank. The filtration tank is the main unit of filtration system of the RCD. A drainpipe of 50 mm fixed at the bottom of the filtration tank is controlled by a mechanical valve to wash or empty the © ASCE 3 Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. International Low Impact Development Conference 2018 filtration tank, and is also used for taking samples. The filtration tank consists of two rotating interfered modules. Each module has seven filtration units. Each unit is constructed from two discs separated by a PVC ring of 3 mm, see Picture 2. Disc dimensions are 12 cm diameter and 2.5 mm thickness. A pipe with holes at each filter unit is used to fix these units and to collect the filtered water from each unit. The pipe dimensions are 20 mm outer diameter and 12 mm inner diameter. The discs of the first module were made of mixture 90% red clay and 5% sawdust with 10% water by weight formed under a press pressure of 40 MPa and a firing temperature of 1070˚. The discs of the second module were made of mixture 92.5% red clay and 7.5% sawdust with 10% water by weight formed under a press pressure of 20 MPa and a firing temperature of 1070˚C. A synthetic raw water of total suspended solids ranging between 500 and 7000 mg/l were used to test both modules. The results showed that the average measured hydraulic conductivity of the first module was 13.7 mm/day and was 50 mm/day for the second. In addition, the results also indicated that both modules have high removal efficiency of total suspended solids up to 100%, and turbidity up to 99.94%. The experiment suggests that RCD could produce a constant flow rate of purified water. A motor was used to rotate RCD at rate of 15 rpm. The rotating provides an unsuitable environment for micro-organism growth and reduces the thickness of the accumulated rejected materials by the filters. Backwashing is necessary to remove the rejected material within and over the ceramic filter during operation. The backwash tank has a square base of 32×32 cm and a depth of 28c m. The backwash process is carried out by a pump that operates at a maximum rate of 20l/min and a minimum rate of 8l/min. The filtration system is supplied by two treated water storage tanks of 17.5 cm width, 21 cm length, and 16 cm depth. Each tank receives treated water from one filtration module. Each tank has a tap of 12 mm diameter that is used for water sampling. Picture 2. The filtration modules (Credit: Al Zubaidy et al. (2017)) CHALLENGES AND OPPORTUNITIES An RCD water filtration system can be constructed on a large capacity scale containing one filtration tank with multiple interfered RCD units. The numbers of modules and ceramic filter discs used depend on the size of the water filtration tank. The main advantage of the large capacity system is the expected low cost due to the availability of raw material, as well as the © ASCE 4 Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. International Low Impact Development Conference 2018 fact that a sedimentation tank will not be required. Moreover, this system can be constructed to be portable and easy to move from place to another, which represents a high advantage when compared to a traditional system. In addition, the proposed system can be continuously operated using a constant flow rate. The rejected materials reach a steady thickness so that the system can be operated continuously without a need for periodic cleaning and maintenance, which requires additional cost and time. On the contrary, traditional systems require primary stages before filtration, and operate with a need to periodically be completely stopped for cleaning and maintenance. Finally, the system has a high removal efficiency of total suspended solids up to 100%, and of turbidity up to 99.94%. Construction of water treatment plants in Iraq is managed by the government. Recently, Iraqi government has invested in employment of additional staff and building. Funding a research study to develop a new filtering system is not an interest. There are many reasons as why it’s difficult to adopt new system such as organizational risks, approval process, and technology risk (West et al. 2016). As a result, testing a large-scale RCD system is a real challenge. Accordingly, it is not expected to see RCD systems operating in needed areas any time soon. Municipality operating systems and equipment used in Iraq are normally tested and manufactured outside of Iraq; however, given the results of this study, the authors hope interested researchers and agencies who are able to secure the needed funds will conduct field experiments on a large-scale RCD system. CONCLUSIONS An RCD system has many advantages over traditional methods, which makes it more practical to be used in needed regions of Iraq. The raw material of the proposed system are widely available across Iraq, and their prices are also available at low cost. The main advantages of the system over the traditional system are: (1) there is no need to have a preliminary sedimentation tank, and (2) the system can be continuously operated with a constant flow rate without requiring a complete stop for cleaning and maintenance. In addition, the proposed system can be manufactured as a portable unit, which makes it an efficient solution for refugee camps in the Middle East. However, a large-scale field experiment does not seem feasible at the current time due to research environment and political conditions in Iraq. In addition, the adoption of this system requires awareness and a lot of education, which is not feasible as well due to a lack of funds. Therefore, nonprofit organizations and investors seem to be the only possible resource to carry out a field experiments that may lead to adapting the proposed system. REFERENCES Al Zubaidy, R. Z., Al-Khafaji, M., Al-Saadi, R. J. M. (2017) “ Rotating Ceramic Water Filter Discs System for Water Filtration.” Journal of Engineering, 23, 59–78. Al-Kathily, F. (2014). “Direct Filtration for Drinking Water, Habbaniyah Lake (Iraq).” Global Journal of Researches in Engineering Civil and Structural Engineering, 14(2), 1–13. Jassim, S., Abdul-Razak, 2010, Evaluation of Water Purifier Cartridge Made of Local Ceramic Materials, Ph.D. dissertation, Department of Water Resources Engineering, College of Engineering, University of Baghdad, Iraq. Mahanna, H., Fouad, M., Radwan, K., Elgamal, H. (2015). “Predicting of Effluent Turbidity from Deep Bed Sand Filters Used in Water Treatment.” International Journal of Scientific & Engineering Research, (6) 9, 621- 626. Musa, K., 2010, Performance of Ceramic Water Filters Made from Selected Uganda Clays for © ASCE 5 International Low Impact Development Conference 2018 Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. Point-of Use, M.Sc. thesis, The Graduate School, Makerere University, Uganda. West, C., Kenway, S., Hassall., M., and Yuan, Z. (2016). “Why do Residential Recycled Water Schemes Fail? A Comprehensive review of Risk Factors and Impact on Objectives,.” Water Res, 102, 271–281. © ASCE 6 International Low Impact Development Conference 2018 Water Quality Target Assessment Using LID TTT for Better SWM Designs in Ontario Steve Auger1; Tim Van Seters2; Amanjot Singh3; and John Antoszek4 Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. 1 Lake Simcoe Region Conservation Authority, 120 Bayview Pkwy., Newmarket, ON L3Y 3W3. E-mail: [email protected]; [email protected] 2 Toronto and Region Conservation Authority, 101 Exchange Ave., Vaughan, ON L4K 5R6. E-mail: [email protected]; [email protected]; [email protected] 3 Credit Valley Conservation Authority, 1255 Old Derry Rd., Mississauga, ON L5N 6R4. E-mail: [email protected]; [email protected] 4 Ontario Ministry of the Environment and Climate Change, Foster Bldg., 9th Flr., 40 St. Clair Ave. W., Toronto, ON M4V 1M2. E-mail: [email protected] ABSTRACT 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. KEYWORDS: Low Impact Development; Treatment Train; Preliminary Design; Modeling; Stormwater Volume Retention; Infiltration; Water Balance; Total Phosphorus Reduction; Total Suspended Solids Reduction; Water Quality Targets; Phosphorus Offsetting 1.0 INTRODUCTION The Low Impact Development Treatment Train Tool (LID TTT) has been developed by Lake Simcoe Region Conservation Authority (LSRCA), Credit Valley Conservation (CVC) and Toronto and Region Conservation Authority (TRCA) Sustainable Technologies Evaluation Program (STEP) collaborative within the Greater Toronto Area, along with technical oversight and partial funding support from the Ontario Ministry of the Environment and Climate Change (MOECC). The LID TTT is a tool to help developers, consultants, municipalities and landowners understand and implement more sustainable stormwater management (SWM) planning and design practices in their watersheds. 1.1 SWM Quality Targets in Ontario Stormwater quality targets have been set in Ontario to address aquatic habit preservation © ASCE 7 International Low Impact Development Conference 2018 and/or restoration needs in receiving water, as mandated by the federal Fisheries Act (Subsection 36(3)) that prohibits the deposit of deleterious substances in water (MOECC, 2003). Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. Total Suspended Solids Level of Protection (MOECC) The latest MOECC SWM Manual released in 2003 stipulates the following long-term average total suspended solids (TSS) removal protection levels:  Enhanced (previously referred to as Level 1) corresponding to average removal of 80% TSS;  General (previously referred to as Level 2) corresponding to average removal of 70% TSS; or  Basic (previously referred to as Level 3) corresponding to average removal of 60% TSS. For areas that have not done detailed studies to determine performance criteria for stormwater management facilities the MOECC SWM Manual provides storage volume requirements based on impervious area for SWM feature types (i.e., infiltration, wetlands, hybrid wet pond / wetland, wet pond, and dry ponds). Total Phosphorus Targets Studies evaluating wet pond or pond/wetland systems for TSS control typically showed a 4050% removal for total phosphorus (TP) (MOECC, 2003). TP targets in Ontario vary between different jurisdictions, with specific considerations for local receiving water capacity for TP levels, based on known information including the Provincial Water Quality Objectives (PWQOs) for TP of 0.02 mg/L for lakes and 0.03 mg/L for streams. However, with the above correlation between TSS and TP in mind, Conservation Authorities (CAs) have defined their own specific targets for TP. Some highlights from the Greater Toronto Area (GTA) CAs are highlighted below. Lake Simcoe Zero TP Export Policy LSRCA’s Zero TP Export Policy is the target that drives the Lake Simcoe Phosphorus Offsetting Program. As new urban growth occurs, phosphorus loads will be controlled to the maximum extent possible. Any remaining stormwater phosphorus that cannot be controlled would require an “offset" to achieve a zero net target. This policy was approved by the MOECC through amendment to the Ontario Water Resources Act (75.1.7) that supports water quality trading including ‘(b) parameters to which water quality trading applies’. The Zero TP Export Policy now supersedes the LSRCA’s Technical Guidelines for SWM Submissions that stipulates the removal of 80% of the annual TP load from all major development areas will be required. Other CAs Additional Quality Control Criteria A minimum requirement for other watershed jurisdictions for stormwater quality control is captured through enhanced level of water quality protection, as highlighted above in the TSS section. It is acknowledged in both TRCA’s and CVC’s SWM Criteria documents (TRCA, 2012; CVC, 2012) that this target may be superseded by the results of additional studies and/or municipal requirements. Sites draining to Lake Wilcox within the Town of Richmond Hill must consider phosphorus removal as part of the treatment strategy is one example of a municipal TP requirement. © ASCE 8 Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. International Low Impact Development Conference 2018 Table 1: Land Cover Default EMCs Land Cover TSS (mg/L) TP (mg/L) Paved Surface 1 90 0.23 2 Roof 7 0.09 Landscaped Area 3 100 0.32 4 Row Crop 100 0.23 4 Open Space/Parkland 27 0.20 Forest 4 55 0.23 4 Wetland 13 0.81 Data sources: 1. STEP/TRCA and CVC water quality data from various public road and private parking lot sites in the GTA. A conservative value for asphalt would utilize the average of the 75th percentile values. These concentrations for TP and TSS are 0.23 and 90 mg/L, respectively, and are consistent with other northern US studies cited. Recommended for use with parking lots and/or arterial roadways. 2. STEP water quality data from four local roof runoff studies. Utilizing the 75th percentile values, conservative TP and TSS values for roof runoff in the LID TTT are 0.09 and 7 mg/L respectively. 3. The landscaped area data are from experimental soil plots designed to evaluate feasible alternatives to standard topsoil management practices in new residential developments. As a conservative value, we recommend using the 75th percentile values for TP from a compost amended plot with the addition of 15% for potential synthetic fertilizer applications by property owners or landscape professionals. The TSS EMC default for this land cover has been assigned based on a general correlation only. 4. International Stormwater BMP Database (2018). 1.2 Overview of Stormwater Quality Computations in LID TTT The LID TTT using the Stormwater Management Model Version 5 (SWMM5) software program developed by the United States - Environmental Protection Agency (EPA) can be utilized to develop stormwater quality (TSS and TP) predictive routines to address post development SWM quality targets for design consideration. At this stage, as the LID TTT gains a practitioner audience and support from varying approval agencies, the acceptance of the computational results to support meeting targets is at the discretion of the approval representative. The LID TTT is also used to provide a preliminary water budget to determine the amount of runoff volume that will be reduced through infiltration, evapotranspiration, or re-use. The water budget calculation is based on site conditions (including soil texture and vegetation cover), best management practice (BMP) design (including impervious to pervious area ratio, underdrain configuration, and storage available for re-use), drainage area treated by LID, and other site specific factors. As highlighted by Graham et al., 2004, more accurate representation of water balance modelling has numerous benefits for the transition to LID, including more accurate water quality computational results. 2.0 WATER QUALITY PARAMETER INPUT AND COMPUTATIONS The LID TTT provides concentration and load based water quality results. Influent concentrations are obtained from default or user defined event mean concentrations (EMCs) for selected land cover types. EMCs for different land covers within a catchment draining to a stormwater BMP are area weighted by the tool to arrive at an overall influent EMC for the catchment. An option is provided in the tool to input a land use EMC for the catchment rather than using the default land cover EMCs. This feature permits the user to adjust the area weighted © ASCE 9 International Low Impact Development Conference 2018 Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. EMC to account for lower runoff generation from pervious areas, where appropriate. Table 2: LID/BMP Concentration Based Removal Efficiencies for TP and TSS LID/BMP TSS Removal Efficiency TP Removal Efficiency (%) 1 (%) 1 Bioretention 2 75 25 Permeable Pavement 75 60 3 Infiltration/Exfiltration Systems 75 60 Vegetated Filter Strips / Buffer 30 20 Strips Enhanced Swales 40 25 Green Roofs 0 -45 Sand or Media Filters 75 40 Specialized Phosphorus Media 75 70 Filters Wet Retention Ponds 80 60 Dry Detention Ponds 60 20 Constructed Wetland 80 60 Oil Grit Separator 50 0 Data sources: 1. Performance monitoring studies conducted by GTA CAs; International Stormwater BMP Database. 2. Includes dry swales, planter boxes and bioswales. 3. Includes infiltration trenches, infiltration chambers and soakaway pits. Concentration based removal efficiencies for stormwater BMPs are set as default, which could be modified by the user. The tool applies the removal efficiencies to the influent EMC to generate effluent EMCs for selected BMP types. The land cover hydrologic characteristics are captured in part by the Curve Number (CN) value assigned to each subcatchment area, along with the percentages of varying land cover and associated pervious and impervious percentages within each subcatchment. This input will also influence the load based results, since it will influence the runoff volume generated for each land use area. More details on the EMCs and removal efficiencies, along with the computational procedures to produce concentration and load based TSS and TP results, are provided in the following subsections. 2.1 Land Cover Event Mean Concentrations The LID TTT provides the user with default land cover EMCs as shown in Table 1 below, along with an ‘Other’ land use option that provides flexibility for either additional land cover options, modifications to the land cover EMC defaults, and/or mixed land use EMCs. 2.2 LID/BMP Removal Efficiencies The LID/BMP removal efficiencies for TSS and TP were selected for each LID depending on the filtration or detention mechanism involved. STEP performed a technical review of the various water quality monitoring results for a number of study sites throughout the GTA to validate the default values for TSS and TP concentration-based removal efficiencies selected for the various LIDs and BMPs highlighted © ASCE 10 Downloaded from ascelibrary.org by RMIT UNIVERSITY LIBRARY on 01/03/19. Copyright ASCE. For personal use only; all rights reserved. International Low Impact Development Conference 2018 above. The median influent and effluent concentrations from the sample size for each type of LID/BMP were used to determine a removal efficiency to recommend. This analysis also used data from the United States BMP database (reference) to support these values and any fine tuning needed. These default values have been vetted with both the MOECC and GTA CAs Technical Review Managers. The removal efficiencies provided in this section only consider removal from filtration and do not include removal by an LID/BMP due to volume reduction. It is recognized that these efficiencies are still known to be highly variable due to a number of influences, including seasonal variations in loading, rainfall-runoff response time, intensity, and associated energy that affects the feature’s removal capabilities. Therefore, it is important for the practitioner to present the default values or any modifications to these defaults with the relevant approval agencies, for acceptance ahead of project submission. 2.3 Specific Stormwater Quality Computations in LID TTT Contaminant loads are calculated as the product of runoff volume and respective EMCs. The influent load is calculated from the area weighted influent EMC for the catchment multiplied by the catchment runoff volume. The effluent load is calculated as the product of the effluent EMC for the selected BMPs and the model generated effluent volumes, which are reduced based on modeled water losses through the BMP from infiltration and/or evapotranspiration. Load based removal efficiencies are calculated as the influent load minus the effluent load, divided by the influent load. When stormwater BMPs are placed in series, the influent EMC and influent load for the downstream BMP is generated from the effluent EMC and effluent load from the upstream BMP. Therefore, water quality is improved as runoff travels from upstream to downstream BMPs. Equation 1 –Weighted Catchment EMC n EMC  Land Cover   Area  Land Cover   mg  EMC Catchment      Area Total   L  Land Cover 1 Equation 2 – Catchment Loadings from Area-Weighted Mixed Land-Use EMC  mg  ( EMC  catchment     Runoff Volume  catchment   L ) L   Catchment Loading  kg   106 Equation 3 – Outflow EMC  mg   mg  EMC  Effluent     EMC Catchment    1  removal efficiency   L   L  Equation 4 – Effluent Loading  mg  ( EMC  Effluent     EffluentVolume  L ) L   Effluent Loading  kg   106 2.4 Water Balance relationship with Water Quality Computations The Water Balance results in the LID TTT for a given annual or event based scenario, provides rainfall, infiltration, evapotranspiration, and outflow volumes. LID TTT uses the SWMM5 engine to estimate the values in the water balance with the following results © ASCE 11