Stormwater Practices Research Project Final Report
Stormwater Practices Research ProjectFinal ReportApril 24, 2012Prepared by:Comprehensive Environmental Inc.
Stormwater Practices Research ProjectFinal ReportPrepared by:Comprehensive Environmental Inc.225 Cedar Hill StreetMarlborough, MA 01752April 24, 2012
ACKNOWLEDGEMENTSThe VTrans BMP/STP Research Project has been completed under the direction of and incollaboration with a Steering Committee representing a cross-section of VTrans professionals aswell as representatives of the Vermont Agency of Natural Resources (ANR). The followingpersonnel participated on the Steering Committee:Gina Campoli, Project ManagerEnvironmental Policy Manager,Policy, Planning, and Inter-Modal DevelopmentVermont Agency of TransportationCraig DiGiammarinoEnvironmental Program Manager,Operations DivisionVermont Agency of TransportationWayne GammellMaintenance District Administrator,Operations DivisionVermont Agency of TransportationGeorge McCoolDistrict General ManagerOperations DivisionVermont Agency of TransportationJonathan Armstrong, P.E.Stormwater Management EngineerProgram Development Division Environmental SectionVermont Agency of TransportationNick Wark, P.E., CFMHydraulics EngineerProgram Development DivisionVermont Agency of TransportationDaniel D. DutcherAssistant Attorney GeneralVermont Agency of TransportationPadraic MonksStormwater Program ManagerVermont Agency of Natural ResourcesChristy WittersEnvironmental AnalystVermont Agency of Natural Resources
Executive SummaryThe Vermont Agency of Transportation (VTrans) conducted the Stormwater PracticesResearch project to identify and evaluate best management practices/stormwatertreatment practices (BMPs/STPs) for post-construction stormwater runoff fromtransportation infrastructure. The study explored potential technologies that wouldexpand upon or supplement those practices currently identified by the Vermont Agencyof Natural Resources (ANR) in the Vermont Stormwater Management Manual. Thestudy’s objective was to identify practices that are suited for the linear configuration ofVTrans facilities, sensitive to the constraints of limited rights-of-way in the context ofVermont’s geography and land use, practical and affordable to permit and implement,and able to comply with state and federal regulatory requirements.A Steering Committee representing a cross-section of VTrans professionals andrepresentatives of the ANR stormwater program directed the study. VTrans engagedComprehensive Environmental Inc. (CEI) to work collaboratively with the SteeringCommittee to identify and evaluate Stormwater practices for further development byVTrans as it advances its stormwater management program.The research project included the following components: A broad-based search of literature, transportation and environmental agencyresources, and other stormwater technical sources, to identify innovations instormwater management technology, for consideration by this study. Steering Committee review of the findings of this initial research, screening of theinitial list of potential BMPs/STPs, and selection of candidate BMPs/STPs forfurther evaluation. Identification of criteria for the evaluation of the selected technologies, including:ooooooPollutant removal effectiveness,Cost effectiveness of structural practices,Consistency with roadway design integrity,Operational consistency with roadway safety,Suitability for regional climate, andPotential for ANR acceptance. Evaluation of the selected BMPs/STPs applying the agreed evaluation criteria,resulting in the development of detailed descriptions of the practices. From thisevaluation, the team compiled the summary comparison matrix presented inAppendix A of the Final Report, to enable a quick comparative review of thepractices considered in the study. Appendix B of the Final Report presents thedetailed descriptions of the selected BMPs/STPs. Steering Committee review of the technical findings of the BMP/STP evaluationand confirmation of the list of selected BMP/STPs.VTrans Stormwater Practices Research ProjectApril 2012
Identifying methods to account for volume reduction of infiltration practices inthe sizing of facilities to control runoff rates and volumes. Preparation of the Final Report summarizing the research and evaluation processand presenting the findings regarding the selected BMPs/STPs.From this research effort, the Steering Committee and its study team recommend thefollowing practices be considered for inclusion in the list of available tools for addressingstormwater management objectives of VTrans infrastructure; detailed descriptions areincluded in Appendix B:Infiltration PracticesInfiltration bermsPervious pavement systemsBioretention Practice VariationsMicro-bioretention (rain gardens)Media Filter Drains and Embankment Media FilterCompost Amended Vegetated Filter StripsFilter System PracticesMicro-filter systems, including:Gutter filtersOhioDOT “ExfiltrationTrench”VTrans “Micro-pool Filter”Minnesota DOT “Permeable Ditch Blocks”Open ChannelsBioswaleNon-structural practicesVegetated Buffers and Filter StripsLimited applicability practicesOpen Graded Friction CourseForebay with Forced Hydraulic JumpThese BMPs/STPs are intended to be used in the context of VTrans’s overall stormwaterprogram, which also includes operational practices that contribute to the control of runoffand the pollutants in runoff, or to the mitigation of the effects of runoff. Examples ofthese practices, which are addressed under other VTrans initiatives, include:Drain-on controlStreet sweepingSump cleaningPond maintenanceOther stormwater system maintenanceSpill preventionIllicit discharge preventionVegetation managementSand-use reductionSalt managementOther snow management measuresVTrans Stormwater Practices Research ProjectApril 2012
Other considerations addressed in this report were methods for quantifying the benefits ofdispersed infiltration in the sizing of stormwater peak rate control practices. Currently,the Vermont Stormwater Management Manual only offers credits towards water qualityvolumes and recharge volumes when infiltration practices are used. The reduced runoffvolume cannot currently be applied in the sizing of structures to meet channel protectionand flood protection standards. The “Modified Runoff Curve Number Method,”described in Section 6 of the report, provides a means to quantitatively account for thereduction in runoff volume resulting from various Low Impact Development practices inthe sizing of facilities to control runoff rates and volumes. Acceptance of this or a similarmethodology would reduce the size of peak control structures required to meet ANR’sdesign standards. This would provide a significant benefit to VTrans and othertransportation agencies that have limited space for BMP/STP implementation.This research study completes an important initial step in expanding the “Tool Box” ofstructural and non-structural practices for use by VTrans designers and maintenance staffin addressing stormwater treatment needs. Future collaborative effort by VTransExecutive Staff, Operation Staff, and Designers, working closely with ANR, will berequired to develop design standards for these BMPs/STPs, incorporate them into VTransguidance manuals and procedures, and provide for their application within Vermont’sstormwater regulatory framework. In the meantime, those considering these practicesshould consult the referenced literature for more specific information on the selection,design, and implementation of these practices.VTrans Stormwater Practices Research ProjectApril 2012
VTrans Stormwater Practices Research ProjectApril 2012
Table of ContentsExecutive SummaryTable of ContentsAcronyms Used in this Report1.Introduction . 12.Initial Research .53.Evaluation Criteria . 114.STP Evaluations . 135.Recommendations Regarding STPs. 176.A Quantitative Hydrologic Method to Account forInfiltration and LID Practices . 237.References . 31Appendix A:STP Comparison MatrixAppendix B:STP DescriptionsVTrans Stormwater Practices Research ProjectApril 2012
Acronyms Used in this ReportANRVermont Agency of Natural ResourcesBMPBest Management PracticeCAVFSCompost Amended Vegetated Filter StripCPChannel ProtectionEDExtended DetentionESHGWEstimated Seasonal High GroundwaterGSRDGross Solids Removal DeviceHSGHydrologic Soils GroupLIDLow Impact DevelopmentMFDMedia Filter DrainOGFCOpen Graded Friction CourseRCNRunoff Curve NumberSTPStormwater Treatment PracticeTSSTotal Suspended SolidsVTrans Stormwater Practices Research ProjectApril 2012
Page 11.IntroductionThe Vermont Agency of Transportation (VTrans) conducted the Stormwater PracticesResearch project to identify and evaluate best management practices/stormwatertreatment practices (BMPs/STPs) for post-construction stormwater runoff fromtransportation infrastructure. The study explored potential technologies that wouldexpand upon or supplement those practices currently identified by the Vermont Agencyof Natural Resources in the Vermont Stormwater Management Manual.The objectives of the study included the identification of practices that: Are suited for the linear configuration of VTrans facilities; Are sensitive to the constraints of limited rights-of-way within the context ofVermont’s topography and patterns of land use; Enable VTrans to comply with state and federal regulatory requirements; and Are practical, affordable solutions that reduce permitting time and costs andprovide regulatory and operational efficiencies for both VTrans and the Agencyof Natural Resources (ANR).This report describes the Stormwater Practices Research project, and summarizes theresults.Overview of the Research and Evaluation ProcessTo undertake this study, VTrans established a Steering Committee representing a crosssection of agency professionals involved in project planning and development, hydraulicsand environmental design and permitting, operations, and legal considerations. Inaddition, this Committee included representatives of the Vermont Department ofEnvironmental Conservation involved in the ANR stormwater program. VTranscontracted with Comprehensive Environmental Inc. (CEI), whose staff workedcollaboratively with the Steering Committee to identify and evaluate BMPs/STPs forfurther development by VTrans as it advances its stormwater management program.The program of study included the following:1.A project initiation meeting, to confirm the overall direction and scope of thestudy and initiate the search for potential BMPs/STPs for evaluation.2.An initial search of literature, transportation and environmental agency resources,and other stormwater technical sources, to identify innovations in stormwatermanagement technology, for consideration by this study. This initial research,summarized in Section 2, compiled a list of candidate Stormwater TreatmentVTrans Stormwater Practices Research ProjectApril 2012
2 PagePractices (STPs), developed criteria for their evaluation, and summarized thefindings in the initial project deliverable, Technical Memorandum #1.3.A second working meeting of the Steering Committee and CEI, to reviewTechnical Memorandum #1 and screen the initial list of potential STPs. Thismeeting resulted in a short list of candidate technologies to be explored further inthe remainder of the study. The meeting also confirmed the screening criteria.4.An evaluation of the selected STPs, including additional literature research andthe development of a detailed description of each practice, applying the agreedscreening criteria. This phase of the study also developed a summary comparisonmatrix to enable a quick comparative review of the practices considered in thisstudy. This phase of the work effort was summarized in the second projectdeliverable, Technical Memorandum #2.5.A third working meeting of the Steering Committee, to review TechnicalMemorandum #2, discuss its findings, and provide direction in the preparation ofthis final report. This meeting confirmed the list of selected STPs and thefindings of the evaluation effort.6.Preparation of this report, the final project deliverable. The Steering Committeereviewed a draft of the final report, with comments incorporated into the finaldocument.Organization of this ReportThe results of this research effort are reported in the following pages, with topicsaddressed as follows: Section 2 summarizes the initial research effort, which canvassed transportation,regulatory, and institutional agencies and resources for information on emergingstormwater management technologies and developed a list of candidate STPs forfurther evaluation. Section 3 describes the evaluation criteria developed for reviewing each of thecandidate practices. Section 4 summarizes the results of the evaluation, and introduces a series of factsheets prepared for each BMP/STP. The evaluation is summarized in a matrixattached as Appendix A. The fact sheets are provided in Appendix B. Section 5 presents preliminary recommendations regarding the STPs evaluated inthe study. Section 6 presents a non-structural methodology for accounting for infiltrationand Low Impact Development (LID) practices in the sizing of downstreamVTrans Stormwater Practices Research ProjectApril 2012
Page 3stormwater management facilities. This methodology enables accounting forcapture and infiltration of runoff when sizing stormwater management facilitiesfor controlling peak rates to achieve channel protection, overbank flows, andflood protection.VTrans Stormwater Practices Research ProjectApril 2012
4 PageIntentionally left blank.VTrans Stormwater Practices Research ProjectApril 2012
Page 52. Initial ResearchInitial research efforts comprised the search of various sources for information on newlydeveloping stormwater management technologies, to compile a list of candidatestormwater management practices for further evaluation for their applicability forVermont’s transportation system. The study team contacted multiple transportationagencies, environmental agencies, research institutes, and other technical resources for aninitial screening of current research and innovative practices for stormwater management.The team concentrated on agencies and institutions active in the development ofstormwater technologies, and an effort was made to include organizations withexperience in the application of stormwater management measures in cold climates.Organizations contacted under this effort included the following:Transportation Agencies:California Department of Transportation (CALTRANS)Kansas Department of Transportation (KDOT)Maine Department of Transportation (MaineDOT)Maryland Department of Transportation (MDOT)Massachusetts Department of Transportation (MADOT)Michigan Department of Transportation (MDOT)Minnesota Department of Transportation (Mn/DOT)New Hampshire DOT (NHDOT)New York State DOT (NYSDOT)Ohio Department of Transportation (ODOT)Oregon Department of Transportation (ODOT)Rhode Island Department of Transportation (RIDOT)Washington State Department of Transportation (WSDOT)Wisconsin Department of Transportation (WDOT)Research Boards and Centers with Stormwater Programs:Transportation Research Board (TRB)University of New Hampshire Stormwater Center (UNHSC)University of Vermont Rubenstein School of Environment and Natural ResourcesUniversity of Vermont Transportation Research CenterIn many cases, the study team retrieved and reviewed stormwater treatment practicesmanuals and guidance documents publicly available from each of the aboveorganizations. In some cases, the team was also able to obtain draft or progressdocuments summarizing ongoing work, including: Oregon DOT provided a draft of water quality guidance currently in development;VTrans Stormwater Practices Research ProjectApril 2012
6 Page The Transportation Research Board provided draft guidance regarding ultra-urbanstormwater management practices;Minnesota DOT provided working sketches and information regarding the studyand development of a practice known as “Permeable Ditch Blocks;”Michael E. Barrett of the Center for Research in Water Resources, University ofTexas, provided a copy of a paper by Eck, et.al., “Water Quality of Drainage fromPermeable Friction Course,” accepted but yet to be copy-edited for publication inthe Journal of Environmental Engineering.In addition to contacting organizations as noted above, the team also canvassed internetresources for research and guidance literature from other agencies and organizations,including the following:Other Agencies/Organizations Accessed for Relevant Publications:American Association of State Highway and Transportation officialsCenter for Watershed ProtectionIzaak Walton LeagueMaine Department of Environmental ProtectionNational Cooperative Highway Research ProgramNew Hampshire Department of Environmental ServicesNew York State Department of Environmental ConservationOregon Department of Environmental QualityPennsylvania Department of Environmental ProtectionThe Low Impact Development CenterU.S. Department of DefenseU.S. Environmental Protection AgencyWashington State Department of EcologyAlso, although not specifically listed above, research studies specific to variousstormwater management practices are available through a number of educationalinstitutions, industry associations, and product sources. These are noted in citations inrelevant sections of this report.There is considerable redundancy or overlap among the lists of BMPs/STPs from thesesources, and many of the practices are familiar ones, already reflected in the list ofBMPs/STPs currently approved by the Vermont ANR. Nevertheless, the team was ableto identify a selection of innovative measures, as well as variations of previouslydeveloped concepts, that merited further review by this study.The canvass of organizations and scan of the literature yielded a list of candidateStormwater Treatment Practices (STPs) for discussion and initial screening with input bythe Steering Committee. The potential list of practices is provided below, organized bycategories consistent with the discussion of Stormwater Treatment Practices in ANR’spublication, The Vermont Stormwater Management Manual, Volume I StormwaterVTrans Stormwater Practices Research ProjectApril 2012
Page 7Treatment Standards. This list of practices primarily includes measures not currentlyincluded in the ANR listed practices. However, the list does include some practices fromthe ANR list where design variations or recent performance studies suggest exploringthese practices further. Candidate STPs included the following:Infiltration Practices: Pervious pavement systems with direct infiltrationo Porous asphalto Pervious paverso Vegetated gridsInfiltration BermsFiltering Practices: Enhanced sand filtrationMicro-bioretention (rain gardens)1Media filter drainEmbankment media filterCompost Amended Vegetated Filter StripPervious pavement systems – underdrainedGutter filtero Porous concrete paved gutter filter (Ohio “Exfiltration Trench”)Permeable ditch block (under development by the Minnesota DOT)Open Channels Bioswale (variant of bioretention)Non-structural practices Vegetated Buffers and Filter StripsLimited applicability practices Open Graded Friction Course (OGFC)Catch basin modifications: deep sumpsCatch basin retrofits: inserts/treatment systemsGross solids removal devices (GSRD)1ANR guidance documents include bioretention, and discuss application of this practice in conjunctionwith
VTrans as it advances its stormwater management program. The research project included the following components: A broad-based search of literature, transportation and environmental agency resources, and other stormwater technical sources, to identify innovations in stormwater management technology, for consideration by this study.
NPDES: Stormwater Best Management Practice— — Stormwater Wetland Stormwater Retrofit A stormwater retrofit is a stormwater control (usually structural) that a community puts into place after development to improve water quality, protect downstream channels, reduce flooding or meet other specific objectives.
Green Stormwater Infrastructure Maintenance Manual 7 1.1 Introduc on The City of Philadelphia relies in part on Green Stormwater Infrastructure (GSI) systems—comprised of one or more decentralized stormwater management prac ces (SMPs) such as rain gardens, stormwater tree trenches, and green roofs—to reduce stormwater volume and pollutants
Green Stormwater Infrastructure Maintenance Manual 7 1.1 Introduc on The City of Philadelphia relies in part on Green Stormwater Infrastructure (GSI) systems—comprised of one or more decentralized stormwater management prac ces (SMPs) such as rain gardens, stormwater tree trenches, and green roofs—to reduce stormwater volume and pollutants
Pennsylvania Stormwater Best Management Practices Manual December 2006 Stormwater Best Management Practices Manual Cover and Table of Contents Chapter 1 - Introduction and Purpose Chapter 2 - Making The Case For Stormwater Management Chapter 3 - Stormwater Management Principles and Recommended Guidelines
1.3 New Jersey Stormwater Best Management Practices (BMPs) Manual The New Jersey Stormwater Best Management Practices Manual (BMP Manual) of April 2004, as amended, was developed to provide guidance to implement the standards in the Stormwater Rules. The BMP manual provides examples of ways to meet the standards required by the Stormwater R
Stormwater Management Plan Best Management Practices This Stormwater Management Plan groups stormwater best management practices according to permit requirements into the following sections: 1. Illicit Discharge Detection and Elimination . 2. Industrial and Commercial Facilities . 3. Construction Site Runoff Control . 4. Education and Outreach . 5.
The Clark County Stormwater Manual: Book 4 - Stormwater Facility Operations and Maintenance is adapted from the Clark County Stormwater Facility Maintenance Manual, 2009 and the Stormwater Management Manual for Western Washington, Volume V, (Ecology, 2019). Illustrations are courtesy Washington Department of Ecology or redrawn from Washington
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