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N A T I O N A L C O O P E R A T I V E H I G H W A Y R E S E A R C H P R O G R A M NCHRP REPORT 728 Guidelines for Evaluating and Selecting Modifications to Existing Roadway Drainage Infrastructure to Improve Water Quality in Ultra-Urban Areas Geosyntec consultants Portland, OR oreGon state university Corvallis, OR venner consultinG Littleton, CO low impact Development center Beltsville, MD wriGht water enGineers Denver, CO Subscriber Categories Environmentâ â¢â HydraulicsâandâHydrologyâ â¢â Highways TRANSPORTAT ION RESEARCH BOARD WASHINGTON,âD.C. 2012 www.TRB.orgâ Research sponsored by the American Association of State Highway and Transportation Officials in cooperation with the Federal Highway Administration
NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Systematic, well-designed research provides the most effective approach to the solution of many problems facing highway administrators and engineers. Often, highway problems are of local interest and can best be studied by highway departments individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation develops increasingly complex problems of wide interest to highway authorities. These problems are best studied through a coordinated program of cooperative research. In recognition of these needs, the highway administrators of the American Association of State Highway and Transportation Officials initiated in 1962 an objective national highway research program employing modern scientific techniques. This program is supported on a continuing basis by funds from participating member states of the Association and it receives the full cooperation and support of the Federal Highway Administration, United States Department of Transportation. The Transportation Research Board of the National Academies was requested by the Association to administer the research program because of the Boardâs recognized objectivity and understanding of modern research practices. The Board is uniquely suited for this purpose as it maintains an extensive committee structure from which authorities on any highway transportation subject may be drawn; it possesses avenues of communications and cooperation with federal, state and local governmental agencies, universities, and industry; its relationship to the National Research Council is an insurance of objectivity; it maintains a full-time research correlation staff of specialists in highway transportation matters to bring the findings of research directly to those who are in a position to use them. The program is developed on the basis of research needs identified by chief administrators of the highway and transportation departments and by committees of AASHTO. Each year, specific areas of research needs to be included in the program are proposed to the National Research Council and the Board by the American Association of State Highway and Transportation Officials. Research projects to fulfill these needs are defined by the Board, and qualified research agencies are selected from those that have submitted proposals. Administration and surveillance of research contracts are the responsibilities of the National Research Council and the Transportation Research Board. The needs for highway research are many, and the National Cooperative Highway Research Program can make significant contributions to the solution of highway transportation problems of mutual concern to many responsible groups. The program, however, is intended to complement rather than to substitute for or duplicate other highway research programs. Published reports of the NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM are available from: Transportation Research Board Business Office 500 Fifth Street, NW Washington, DC 20001 and can be ordered through the Internet at: http://www.national-academies.org/trb/bookstore Printed in the United States of America NCHRP REPORT 728 Project 25-31 ISSN 0077-5614 ISBN 978-0-309-25860-9 Library of Congress Control Number 2012949591 Â© 2012 National Academy of Sciences. All rights reserved. COPYRIGHT INFORMATION Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein. Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, FAA, FHWA, FMCSA, FTA, or Transit Development Corporation endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP. NOTICE The project that is the subject of this report was a part of the National Cooperative Highway Research Program, conducted by the Transportation Research Board with the approval of the Governing Board of the National Research Council. The members of the technical panel selected to monitor this project and to review this report were chosen for their special competencies and with regard for appropriate balance. The report was reviewed by the technical panel and accepted for publication according to procedures established and overseen by the Transportation Research Board and approved by the Governing Board of the National Research Council. The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research and are not necessarily those of the Transportation Research Board, the National Research Council, or the program sponsors. The Transportation Research Board of the National Academies, the National Research Council, and the sponsors of the National Cooperative Highway Research Program do not endorse products or manufacturers. Trade or manufacturersâ names appear herein solely because they are considered essential to the object of the report.
The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. On the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Ralph J. Cicerone is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Charles M. Vest is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, on its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academyâs purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Ralph J. Cicerone and Dr. Charles M. Vest are chair and vice chair, respectively, of the National Research Council. The Transportation Research Board is one of six major divisions of the National Research Council. The mission of the Transporta- tion Research Board is to provide leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisciplinary, and multimodal. The Boardâs varied activities annually engage about 7,000 engineers, scientists, and other transportation researchers and practitioners from the public and private sectors and academia, all of whom contribute their expertise in the public interest. The program is supported by state transportation departments, federal agencies including the component administrations of the U.S. Department of Transportation, and other organizations and individu- als interested in the development of transportation. www.TRB.org www.national-academies.org
C O O P E R A T I V E R E S E A R C H P R O G R A M S CRP STAFF FOR NCHRP REPORT 728 Christopher W. Jenks, Director, Cooperative Research Programs Crawford F. Jencks, Deputy Director, Cooperative Research Programs Christopher Hedges, Senior Program Officer Danna Powell, Senior Program Assistant Eileen P. Delaney, Director of Publications Natalie Barnes, Senior Editor NCHRP PROJECT 25-31 PANEL Field of Transportation PlanningâArea of Impact Analysis William Fletcher, Oregon DOT, Salem, OR (Chair) Gregory E. Granato, U.S. Geological Survey, Northborough, MA G. Scott McGowen, California DOT, Sacramento, CA Le Chi Nguyen, Washington State DOT, Seattle, WA Judy A. Ruszkowski, Earl Engineering Services, Lyons, MI John C. Taylor, Mississippi DOT, Jackson, MS Christopher I. Thornton, Colorado State University, Fort Collins, CO Patricia A. Cazenas, FHWA Liaison Stephen F. Maher, TRB Liaison
F O R E W O R D ByâChristopherâHedges StaffâOfficer TransportationâResearchâBoard NCHRP Report 728 provides guidelines to evaluate and select hydraulic modifications to existing drainage infrastructure that will help mitigate potential impacts of highway runoff on receiving waters. The guidelines are directed specifically at roadway facilities in dense urban areas that can be particularly difficult and costly to retrofit because of space limi- tations, high pollutant loadings, hydrologic flashiness, hydraulic constraints, legacy con- tamination, utility conflicts, and other issues. They will assist transportation agencies in meeting regulatory requirements under the Clean Water Act, National Pollutant Discharge Elimination System (NPDES) permits, Total Maximum Daily Load (TMDL) allocations, endangered species protection, and watershed protection initiatives. The guidelines are accompanied by a MicrosoftÂ® Excel-based design and sizing tool on a CD-ROM bound into the back of this report. The tool generates best management practice (BMP) performance curves that relate the performance and design criteria for selected BMP controls described in the guidelines for each of the 15 U.S. rain zones. One of the significant features of the tool is that it allows users to explore BMP performance and retrofit sizing and design options based on user-selected design criteria and inputs. The guidelines will be of particular inter- est to planners, designers, and engineers with a basic understanding of the technical issues of BMP selection and design as applied to ultra-urban retrofit settings. The transportation community is faced with a need to reduce pollutant loadings from existing facilities to achieve watershed Total Maximum Daily Loads (TMDLs) or to meet other regulatory requirements. Existing infrastructure was designed for efficient drainage and flood control and offers several possibilities for retrofits to enhance water quality. The literature on retrofitting of storm drainage systems to improve effluent water quality is divided into two broad areas. The first assumes the availability of land or right-of-way suf- ficient to place new or off-line best management practices (BMPs) for treatment; the second is usually referred to as âultra-urban,â meaning that the right-of-way is limited and there is little or no permeable surface. The latter condition is the focus of this work. Under NCHRP Project 25-31, a research team led by Geosyntec Consultants and includ- ing Oregon State University, Venner Consulting, Inc., the Low Impact Development Cen- ter, and Wright Water Engineers, Inc. developed guidelines for evaluating and selecting hydraulic modifications to existing drainage infrastructure in order to reduce pollutant loads and concentrations in ultra-urban areas. The research team conducted a thorough review of existing technologies and reviewed available options for BMP retrofitting and methods to evaluate their effectiveness. A methodology for a retrofit strategy process and method was developed, which takes into account not only effectiveness but also instal- lation and longer-term maintenance costs. The report includes seven case studies that
illustrate how departments of transportation have successfully met the challenges of ultra- urban retrofits. The contractorâs final report is also available on the NCHRP Project 25-31 page of the TRB website (http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=1642).
C O N T E N T S 1 Section 1â Introduction 1 1.1 Motivation and Objectives 2 1.2 What Is an Ultra-Urban Highway? 2 1.3 What Is a Highway Water Quality Retrofit? 3 1.4 Characteristics of Retrofitting 3 1.5 Challenges of BMP Retrofitting in Ultra-Urban Highway Environments 6 1.6 Document Organization 8 Section 2â Ultra-UrbanâHighwayâRunoffâCharacterization 8 2.1 Retrofit Benefits of Water Quality Characterization 8 2.2 Pollutants of Concern for Ultra-Urban Highway Retrofits 15 2.3 Ultra-Urban Influences on Highway Runoff Quality 19 2.4 Sources of Water Quality Information to Support Retrofit Planning 20 Section 3â RetrofitâDriversâandâPractices 20 3.1 Regulatory Drivers of BMP Retrofits 22 3.2 DOT Retrofit Experiences 24 Section 4â BMPâOptionsâforâUltra-UrbanâHighwayâRetrofits 24 4.1 Overview of BMP Options 24 4.2 Catch Basin Retrofits 30 4.3 Gross Solids Removal Device Retrofits 32 4.4 Hydrodynamic Device Retrofits 35 4.5 Oil-Water Separation Retrofits 37 4.6 Detention Retrofits 46 4.7 Media Filtration Retrofits 55 4.8 Vegetative Filtration/Media Retrofits 57 4.9 Infiltration Retrofits 61 4.10 Pavement Retrofits 65 4.11 Advanced Treatment Retrofits 66 4.12 Information Sources for Treatment BMPs 69 Section 5â EvaluatingâBMPâEffectiveness 69 5.1 Evaluating the Relevant BMP Treatment Processes 73 5.2 Evaluating BMP Performance 77 5.3 BMP Testing Protocols and DOT Certification 79 5.4 BMP Performance Data 79 5.5 BMP Evaluation Guidance 83 Section 6â BMPâSizingâandâDesign 83 6.1 BMP Sizing and Design Analysis Approach 89 6.2 Sizing and Design of Detention-Based BMPs 92 6.3 Sizing and Design of Media Filtration-Based BMPs 93 6.4 Summary of Spreadsheet Sizing Tool
94 Section 7â MaintenanceâandâMonitoring 94 7.1 Types of Maintenance 94 7.2 Maintenance Factors That Affect Performance 95 7.3 Maintenance Considerations for Ultra-Urban Highways 98 7.4 Maintenance Practices 98 7.5 BMP Monitoring and Performance Assessment 104 Section 8â RetrofitâCosts 104 8.1 Cost Elements 105 8.2 Cost Factors in Ultra-Urban Settings 106 8.3 BMP Cost Estimates 107 8.4 Cost Reduction Strategies 109 Section 9â RetrofittingâStrategiesâandâProcess 109 9.1 Types of BMP Retrofits 109 9.2 Retrofit Prioritization Approaches 110 9.3 Attributes of Successful Retrofitting 110 9.4 Project Planning and Coordination 112 9.5 Retrofitting Process Framework for Specific Retrofit Sites 124 Section 10â CaseâStudies 124 10.1 ODOT Highway Retrofit with a Media Filter Drain 130 10.2 WSDOT Bridge Replacement with BMP Retrofit 136 10.3 WSDOT I-405/I-5 to SR-169 Stage 2 Widening 142 10.4 IDOT Mississippi Bridge Tri-Level Interchange Drainage 145 10.5 MnDOT Crosstown/I-35 Highway Retrofit 152 10.6 District of Columbia Department of Transportation Interchange Retrofit Evaluation 156 10.7 Maryland State Highway Administration Concrete V-Ditch Conversion Pilot Study 161 References Note: Many of the photographs, figures, and tables in this report have been converted from color to grayscale for printing. The electronic version of the report (posted on the Web at www.trb.org) retains the color versions.