Long-Term Performance and Life-Cycle Costs of Stormwater Best Management Practices (2014)

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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 792 Long-Term Performance and Life-Cycle Costs of Stormwater Best Management Practices Scott Taylor RBF Consulting Carlsbad, CA Michael Barrett univeRsity oF texas Austin, TX Marc Leisenring Sheila Sahu Daniel Pankani Aaron Poresky Adam Questad Eric Strecker geosynteC Consultants Portland, OR Neil Weinstein low impaCt Development CenteR Beltsville, MD Marie Venner venneR Consulting Lakewood, CO Subscriber Categories Highways • Environment TRANSPORTAT ION RESEARCH BOARD WASHINGTON, D.C. 2014 www.TRB.org Research sponsored by the American Association of State Highway and Transportation Officials in cooperation with the Federal Highway Administration

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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 AUTHOR ACKNOWLEDGMENTS This study was conducted with funding provided through NCHRP Project 25-40, “Long-Term Per- formance and Life-Cycle Costs of Stormwater Best Management Practices.” NCHRP is supported by annual voluntary contributions from state departments of transportation. This document was prepared by Scott Taylor of RBF Consulting; Dr. Michael Barrett of the University of Texas; Marc Leisenring of Geosyntec Consultants; Neil Weinstein of the Low Impact Development Center; and Marie Venner of Venner Consulting. CRP STAFF FOR NCHRP REPORT 792 Christopher W. Jenks, Director, Cooperative Research Programs Christopher Hedges, Manager, National Cooperative Highway Research Program Nanda Srinivasan, Senior Program Officer Charlotte Thomas, Senior Program Assistant Eileen P. Delaney, Director of Publications Doug English, Editor NCHRP PROJECT 25-40 PANEL Field of Transportation Planning—Area of Impact Analysis Nicklas “Nick” Tiedeken, Minnesota DOT, St. Paul, MN (Chair) Jonathan B. “Jon” Armstrong, Vermont Agency of Transportation, Montpelier, VT Gregory E. Granato, U.S. Geological Survey, Northborough, MA Jeffrey S. MacKay, NTM Engineering, Inc., Dillsburg, PA Thomas Ryan McReynolds, U.S. Fish and Wildlife Service, Lacey, WA Nicole M. Peirce, Oregon DOT, Salem, OR Lucinda E. Soto, Texas DOT, Austin, TX Amy C. Tootle, Florida DOT, Tallahassee, FL Patricia A. Cazenas, FHWA Liaison Stephen F. Maher, TRB Liaison

F O R E W O R D By Nanda Srinivasan Staff Officer Transportation Research Board This report provides information on long-term performance and life-cycle costs for highway-related stormwater best management practices (BMPs). The report is accompanied by a CD-ROM containing a BMP evaluation tool in a spreadsheet format as a computational aid that provides average annual performance and whole life costs for treatment BMPs. The report will be of interest to state DOT highway design and environmental practitioners. The management of stormwater runoff from the highway network is a major concern for state departments of transportation (DOTs) and other transportation agencies. High- way stormwater runoff may affect receiving waters and ecosystems through changes in water quality and hydrology. Roadway surfaces and rights-of-way are subject to pollutants from motor vehicles, atmospheric deposition, maintenance operations, and offsite sources. Rainfall runoff and snowmelt can carry pollutants from the roadway surface into receiving waters and can be a cause for environmental concern. Preserving the quality of national waters is an important goal for highway agencies and a requirement of federal laws such as the National Environmental Policy Act, Clean Water Act (e.g., National Pollutant Discharge Elimination System and Total Maximum Daily Loads), and the Endangered Species Act. A wide range of treatment controls (commonly known as “best management practices” or BMPs) have been developed to manage stormwater. Treatment BMPs use various pro- cesses to mitigate the impacts of pollutants and altered hydrology; for example, by attenuat- ing the flow or reducing the volume of stormwater or by reducing pollutants with physical, biological, or chemical processes. There have been many guides to assist agencies with the selection of the most appropri- ate BMPs for specific site characteristics and agency objectives. However, the guidance was typically based on limited information about the BMP’s expected initial performance and installation cost. Even less information has been compiled on the long-term performance of BMPs, maintenance requirements over time, expected life span, and total life-cycle costs. Transportation agencies need guidance on how long-term considerations should influence the selection and maintenance of stormwater BMPs. Furthermore, they need guidance on how to collect long-term performance and life-cycle cost data to improve the decision- making process in the future. NCHRP Project 25-40 was conceived to provide this guidance. The research under NCHRP Project 25-40 was performed by Scott Taylor of RBF Con- sulting, Dr. Michael Barrett of the University of Texas, Marc Leisenring of Geosyntec Con- sultants, Neil Weinstein of the Low Impact Development Center, and Marie Venner of Venner Consulting. Information was gathered via literature review, survey of DOTs, and interviews with practitioners. Information for treatment BMPs was derived from DOT studies and the International BMP Database. The International BMP Database contains

performance records for treatment BMP evaluations throughout the United States. The research included conducting a large number of computer simulations using the U.S. EPA’s Stormwater Management Model (SWMM) to quantify runoff volume reduction through the BMP. The report is accompanied by a CD-ROM containing a BMP evaluation tool in a spreadsheet format as a computational aid that provides average annual performance and whole life costs for treatment BMPs. A guide (Planning Tool Handbook) is provided as Appendix F to quickly orient the user to the basic functions of the tool provided on the CD-ROM.

C O N T E N T S 1 Summary 8 Chapter 1 Introduction 8 1.1 Statement of Project Need and Objectives 8 1.1.1 Statement of Need 8 1.1.2 Objectives 9 1.2 Scope of Report 10 1.3 Intended Users and Uses 11 1.4 Relationship with Other NCHRP Publications 13 Chapter 2 Literature Review and Survey Findings 13 2.1 Background 13 2.2 BMP Effectiveness and Long-Term Performance of BMPs 13 2.2.1 Most Commonly Used BMPs 13 2.2.2 Summary of Previous Studies on BMP Performance 22 2.3 Current Asset Management, Inspection, and Maintenance Practices 22 2.3.1 Asset Management and Inspection Needs 26 2.3.2 Current Maintenance Practices 28 2.4 BMP Life-Cycle Costs 28 2.4.1 Life-Cycle Cost Factors for BMPs 30 2.4.2 Tracking Actual BMP Maintenance Costs 31 2.4.3 Historic Data and Studies Relating to BMP Life-Cycle Cost 34 Chapter 3 Hydrologic Performance Assessment Methods and Data Sources 34 3.1 Conceptual Framework 35 3.1.1 Continuous Hydrologic Simulation 36 3.1.2 Precipitation Data Sources 36 3.1.3 Volume-Based BMPs and Volume Reduction Estimation 37 3.1.4 Flow-Based BMPs 37 3.2 Percent Capture Nomographs 38 3.2.1 Volume-Based BMP Percent Capture Nomographs 38 3.2.2 Flow-Based BMP Nomographs 38 3.2.3 Using the Percent Capture Nomographs 43 Chapter 4 Water Quality Estimation Methods and Data Sources 43 4.1 BMPs and Constituents Analyzed 44 4.2 Highway Runoff Water Quality Data 44 4.3 BMP Influent and Effluent Concentrations 44 4.3.1 Estimating Influent Concentrations 47 4.3.2 Estimating Effluent Concentrations 48 4.3.3 Statistical Difference Between Influent and Effluent Quality

50 4.4 Influent Highway Runoff Water Quality Methods 50 4.5 BMP Effluent Quality Performance by Pollutant 53 4.6 Load Reduction Assessment 55 Chapter 5 BMP Operation and Maintenance Requirements 55 5.1 Background 56 5.2 Caltrans Prototype BMP Field Investigation 57 5.2.1 Vegetated Swales 57 5.2.2 Vegetated Strips 57 5.2.3 Extended Detention Basin/Dry Detention Basin 58 5.2.4 Wet Basin 58 5.2.5 Sand Filters 58 5.3 Literature Review 60 5.4 Vegetation and Sediment Accumulation Rates in BMPs 60 5.4.1 Vegetated Strips 61 5.4.2 Vegetated Swale 62 5.4.3 Dry Detention Basin 62 5.4.4 Bioretention 63 5.4.5 Retention/Wet Pond 65 5.4.6 Sand Filter 66 5.4.7 Permeable Friction Course 67 5.5 Suggested Maintenance Tasks 67 5.5.1 Vegetated Strips 67 5.5.2 Vegetated Swale 68 5.5.3 Dry Detention Basin 69 5.5.4 Bioretention 69 5.5.5 Retention/Wet Pond 70 5.5.6 Sand Filter 70 5.5.7 Permeable Friction Course 70 5.6 BMP Life Span 71 5.6.1 Vegetated Strips 71 5.6.2 Vegetated Swale 71 5.6.3 Dry Detention Basins 71 5.6.4 Bioretention 71 5.6.5 Retention/Wet Pond 71 5.6.6 Sand Filters 71 5.6.7 Permeable Friction Course 72 Chapter 6 Capital and Operation and Maintenance Costs 72 6.1 Capital Costs 72 6.2 Maintenance Costs by BMP 72 6.2.1 General Inspection 72 6.2.2 Vegetated Strips and Swales 73 6.2.3 Dry Detention Basins 74 6.2.4 Bioretention 74 6.2.5 Wet Pond or Retention Pond 75 6.2.6 Sand Filters 75 6.2.7 Permeable Friction Course 77 Chapter 7 Whole Life Cost Model 77 7.1 Whole Life Cost Tool

78 7.2 WLC Tool Calculation Foundations 78 7.2.1 Capital Costs 79 7.2.2 Maintenance Costs 82 7.2.3 WLC Tool Calculator Guide 82 7.2.4 WLC Tool Inputs 91 Chapter 8 Performance of Nonstructural BMPs 91 8.1 Introduction 91 8.1.1 Control Description 92 8.1.2 BMP Efficiency 92 8.1.3 Whole Life Costs 92 8.1.4 Social, Institutional, or Other Barriers 92 8.1.5 Sustainability Rating and Suggestions 92 8.2 Storm Drain Cleaning 92 8.2.1 Control Description 94 8.2.2 BMP Efficiency 95 8.2.3 Social/Institutional Barriers 95 8.2.4 Sustainability and Suggestions for Practitioners 96 8.3 Street Sweeping 96 8.3.1 Control Description 98 8.3.2 BMP Efficiency 100 8.3.3 Physical Barriers 101 8.3.4 Sustainability and Suggestions for Practitioners 101 8.4 Smart Landscaping Practices 101 8.4.1 Control Description 103 8.4.2 Physical/Institutional Barriers 103 8.4.3 BMP/Control Evaluation 105 8.5 Trash Management Practices 105 8.5.1 Control Description 107 8.5.2 BMP Efficiency 109 8.5.3 Social/Institutional Considerations 110 8.5.4 Sustainability and Suggestions for Practitioners 110 8.6 Elimination of Groundwater Inflow to Storm Drains 110 8.6.1 Control Description 112 8.6.2 Physical, Social, and Institutional Barriers 112 8.6.3 BMP/Control Efficiency 114 8.6.4 Sustainability Rating 115 8.7 Slope and Channel Stabilization 115 8.7.1 Control Description 116 8.7.2 Physical, Social, and Institutional Barriers 116 8.7.3 BMP Efficiency 119 8.7.4 Sustainability and Suggestions for Practitioners 120 8.8 Winter Maintenance BMPs 120 8.8.1 Control Description 123 8.8.2 Social and Institutional Barriers 124 8.8.3 BMP Efficiency 125 8.8.4 Sustainability and Suggestions for Practitioners 126 8.9 Irrigation Runoff Reduction Practices 126 8.9.1 Control Description 127 8.9.2 Social/Institutional Barriers to Better Irrigation Runoff Management

127 8.9.3 BMP Efficiency 129 8.9.4 Sustainability and Suggestions for Practitioners 130 Chapter 9 DOT BMP Planning Tool 130 9.1 BMP Evaluation Tool Overview 130 9.1.1 Tool Assessment Functions 130 9.1.2 Tool Inputs 132 9.1.3 Tool Results and Interpretations 133 9.1.4 Tool Supporting Data 133 9.2 Worked Example of Tool 133 9.2.1 BMP Evaluation 134 9.2.2 Swales 135 9.2.3 Bioretention 135 9.2.4 Wet Pond or Retention Pond 135 9.2.5 Vegetated Filter Strips 135 9.2.6 Dry Detention Basins 135 9.2.7 PFC Overlay 136 9.2.8 Sand Filter 136 9.2.9 Comparison of Results 138 9.2.10 Effects of Routing 142 9.3 Tool Customization 142 9.4 Tool Intended Uses 142 9.4.1 Direct Tool Uses 142 9.4.2 Indirect Tool Uses 144 References Appendices B through F are on the CD-ROM included with this report. Appendix A is unpublished.

A c r o n y m s A n d A b b r e v i A t i o n s ASCE American Society of Civil Engineers BMP Best Management Practice BMPDB (International Stormwater) BMP Database BOD Biochemical Oxygen Demand Caltrans California Department of Transportation CDOT Colorado Department of Transportation CERCLA Comprehensive Environmental Response, Compensation, and Liability Act CIPP Cured-In-Place Pipe COD Chemical Oxygen Demand COOP Cooperative Observer Program CSP Corrugated Steel Pipe CWA Clean Water Act DDT Drawdown Time DelDOT Delaware Department of Transportation DOT Department of Transportation DP Dissolved Phosphorus DREE Division Roadside Environmental Engineer E. coli Escherichia Coli ENR Engineering News Record ET Evapotranspiration FC Fecal Coliform FHWA Federal Highway Administration GIS Geographic Information System GPS Global Positioning System HDPE High-Density Polyethylene HIDOT Hawaii Department of Transportation HRDB Highway-Runoff Database IC/ID Illicit Connection/Illegal Discharge IDOT Illinois Department of Transportation IPM Integrated Pest Management IRVM Integrated Roadside Vegetative Management IRWD Irvine Ranch Water District LCCA Life-Cycle Cost Analysis LOS Level of Service MAD Median Absolute Deviation MAP Maintenance Accountability Process

MassDOT Massachusetts Department of Transportation MDOT Michigan Department of Transportation MDSHA Maryland State Highway Administration MnDOT Minnesota Department of Transportation MS4 Municipal Separate Storm Sewer System MUSLE Modified Universal Soil Loss Equation MWD Metropolitan Water District NCDC National Climatic Data Center NCDOT North Carolina Department of Transportation NCEEP North Carolina Ecosystem Enhancement Program NCHRP National Cooperative Highway Research Program NJCAT New Jersey Corporation for Advanced Technology NMDOT New Mexico Department of Transportation NO3 Nitrate NPDES National Pollutant Discharge Elimination System NPV Net Present Value NSQD National Stormwater Quality Database NYSDOT New York State Department of Transportation NWIS National Water Information System O&M Operation and Maintenance OCWD Orange County Water District ODOT Oregon Department of Transportation OGFC Open-Graded Friction Course OP Orthophosphate PCBs Polychlorinated Biphenyls PFC Permeable Friction Course PVC Polyvinyl Chloride RCP Reinforced Concrete Pipe RIDOT Rhode Island Department of Transportation ROW Right-of-Way RUSLE Revised Universal Soil Loss Equation RVTS Roadside Vegetated Treatment Study SR State Route SWMM Storm Water Management Model TAPE Technology Assessment Protocol Ecology TCu Total Copper TDA Tributary Drainage Area TDS Total Dissolved Solids TKN Total Kjeldahl Nitrogen TN Total Nitrogen TP Total Phosphorus TPb Total Lead TSS Total Suspended Solids TxDOT Texas Department of Transportation TZn Total Zinc UDFCD Urban Denver Drainage and Flood Control District UOP Unit Operations and Processes USDA-NRCS United States Department of Agriculture–Natural Resources Conservation Service

U.S. EPA United States Environmental Protection Agency USGS United States Geological Survey WEF Water Environment Federation WERF Water Environment Research Foundation WLC Whole Life Cost WSDOT Washington State Department of Transportation