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43 1.2.5. GKY Report, Chapter 6 Summary: 1.3. GOALS AND OBJECTIVES Research Program OF NCHRP 25-20(02) Based on the ranked research topic areas identified in NCHRP 25-20(02) will identify and describe research proj- Chapter 5, Chapter 6 presented a 12-project, 5-year research ects that will address priority needs in the area of highway program organized according to ranked problem statements. runoff management and control. The assessments described Each problem statement includes the research topic and in this document are based on DOT research priorities and needs, the project objectives, estimated budget and timeline, a broader search of the available data, studies, and DOT and the urgency and payoff potential of the project. The proj- research in progress than was available in the initial 25-20(01) ect titles and associated problem statements are listed in research. Final research statements will be presented in the Table 1-1. final report, subsequent to panel approval of the research team's assessment. 1.2.6. GKY Report, Overview and Conclusions 1.4. RESEARCH METHODOLOGY The GKY study identifies primary highway runoff manage- ment research topics in need of additional study. However, the This comprehensive highway runoff investigation includes context is broad and describes inadequately the research top- a review of readily available highway runoff literature and ics identified. For instance, the research topic of BMP effec- state highway transportation agencies' unpublished literature, tiveness and performance is extensive and may involve several current research efforts, and research priorities that could be levels of investigation. Furthermore, the GKY study defines acquired through contact with all 50 states. A discussion fol- neither BMP effectiveness nor performance even though there lows on the methodology used for each portion of the research are several different definitions currently in use (Strecker et for this project. al., 1999). The document focuses on ecological and biologi- cal impacts and provides some valuable references and iden- 1.4.1. Contact with Water Quality Professionals tifies some important topic areas. With regard to the broader range of highway runoff management research and research Realizing that information on stormwater quality research needs, the GKY findings require expansion in the areas of and needs may occur in different and often multiple parts of a receiving water impact assessment, highway runoff charac- state transportation agency, researchers contacted state trans- terization, BMP evaluation, systems planning, and data col- portation agencies and divisions within these agencies to lection and analysis. NCHRP 25-20(02) attempts to identify ascertain current practices, problems and issues, and research the gaps in the GKY study. related to stormwater quality. Research directors identified Based in part on the recommendations of the GKY study, on AASHTO's list of members for SCOR were contacted by the panel initiated Project 25-20(01): Evaluation of Best phone and e-mail to locate existing research and research in Management Practices for Highway Runoff Control. The progress. Lead stormwater professionals in each agency were project was contracted to Oregon State University and has asked about research in progress and research priorities. been combined with a study on low-impact development; the The practitioner contact effort for 25-20(02) started with final report is scheduled for completion in the winter of 2004. a long list of research needs areas, including questions raised The research will evaluate the basic scientific and technical in TRB Committee A2AO3, AASHTO's Natural Resources criteria that can be used for the quantitative assessment of Subcommittee, and through the Standing Committee on the wet-weather flow control alternatives (often referred to as Environment's Environmental Technical Assistance Pro- BMPs) for highways and other highway-related facilities and gram. Questions also were identified by calling leading state will apply the results of the evaluation to facilitate effective DOTs regarding water quality issues (California, Maryland, implementation of these controls. To avoid duplication of and Washington State). The list of potential questions was project 25-20(01), the current project, 25-20(02) limits the reviewed by practitioners and researchers in the aforemen- category of evaluation of best management control practices tioned states, by the NCHRP 25-20 Chair, and by the full to include only a summarization of related topics, gaps, and team of consultants involved in this effort. The resulting sug- research needs found during the literature review. A detailed gested revisions and additional questions were incorporated assessment of BMP unit processes and treatment perfor- into the list of priority research areas ranked by DOTs. mance in relation to BMP design will be provided in the All 50 state DOTs were contacted successfully to provide NCHRP 25-20(01) report. their level of prioritization of the final list of 45 research The GKY report includes an overview of potential fund- areas. Each state DOT provided a low-medium-high ranking ing sources. Identification of funding sources is not part of of research interest to attain a finer gradation of understand- the scope of NCHRP 25-20(02), but related information on ing of DOT research needs than indicated by the GKY study. potential funding sources is included in the original report. In addition, to ensure that the full range of potential research

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44 TABLE 1-1 Summary of potential research projects identified by GKY and Associates No. Project Title Problem Statement 1 Identification and Biological indicators can be used to assess receiving waters impacts of Development of Regional highway runoff and to evaluate the effectiveness of stormwater best Aquatic Biological Indicators management practices (BMPs). Practitioners need guidance on the to Assess Impacts of Highway appropriate use and interpretation of cost-effective methods of regional Runoff biological indicators. 2 Research Methods for Several toxicity testing methods are available to assess the acute and chronic Assessing the Toxicity of toxicity of water quality samples. However, results are highly variable Highway Runoff depending on the method used, and each method has a limitation on its applicability. Highway practitioners need toxicity testing protocols to address specifically the runoff entering different receiving water ecosystems. 3 Water Quality Management Highway practitioners rely on published literature for addressing highway Information System runoff management and control. Practitioners need a readily accessible, up- to-date information system for searching and reviewing existing studies and reports, as well as for adding new information as it becomes available. 4 Isolation of Pollutants in Highway runoff has been recognized as a potential contributor to water Transportation Runoff resources impairment, but the specific water quality parameters causing impairment are not well known. Practitioners need access to statistically significant runoff quality data from highway facilities for the development of cost-effective monitoring programs. 5 Causal Analysis of Pollutants In order to manage effectively the quality of highway runoff at the source, in Transportation Runoff practitioners need to understand the factors that influence the chemical characteristics of the highway runoff, such as average daily traffic, climate, rainfall chemistry, construction materials, and more. 6 Integration of The goals of highway runoff quantity management and runoff quality Multidisciplinary Methods for management often conflict. Practitioners need methods and alternatives for Evaluation of Transportation dealing with both issues of highway runoff management. Runoff Impacts to Aquatic Ecosystems 7 Expert System for Practitioners need readily available access to BMPs information and a means Transportation BMPs of quickly applying applicable portions of the information to site-specific situations. 8 Design Criteria for Bridge NCHRP Project 25-13 is investigating the impacts of bridge runoff on BMPs receiving waters. When the project is complete, practitioners will need design guidance on BMPs for bridge runoff. 9 Heavy Metals Management Heavy metals are known highway runoff pollutants that tend to migrate from Options the roadway to receiving streams. Practitioners need effective ways to confine heavy metals to the rights-of-way. 10 Demonstration of Ultra-Urban Practitioners need access to case studies that evaluate the performance of BMPs ultra-urban BMPs, so that applicable and effective space-limited BMPs can be selected. 11 Hydraulics and Hydrology of Practitioners need practical guidance for retrofitting existing flood control BMP Retrofitting and drainage structures to maximize water quality benefits. 12 Enhanced Expert System for Building upon the system developed under No. 7, an enhanced expert system Transportation BMPs would include additional information and results made available since the system's initial deployment.

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45 interests was covered, DOTs were asked to describe agency erences. In conjunction with the literature review below, the research interests in an open-ended manner for design, con- input has provided a solid foundation for identified research struction, maintenance, and receiving water assessment. This needs. intensive interview and survey effort was designed to pro- duce a current and accurate basis for identifying present gaps 1.4.2. Review of Literature and research needs. The following DOT professionals par- and Current Research ticipated in identifying and ranking research needs: Information on current practices, problems and issues, and Environmental, stormwater, and civil engineers; research related to highway runoff management was reviewed Research engineers; to identify relevant work and where the work is occurring. Senior hydraulics engineers and heads of hydraulic Data sources included, but were not limited to, the following: divisions; Chiefs of design; 2001 GKY report (materials related to the survey effort Directors of location and environment; were not available from GKY and Associates); Managers of roadside development sections; ASCE/EPA BMP Database and other ASCE publications; Agronomists, geologists, and landscape architects; FHWA studies and publications; Environmental program managers and other section EPA publications; chiefs; Water Environment Research Foundation and Ameri- Wetlands unit supervisors; can Water Works Research Foundation; Bioengineering managers (for Section 401 and 404 Environmental research in progress online database at concerns); the Center for Transportation and the Environment; TRIS database at TRB; Natural resources specialists and unit managers; TRB A2A03 Hydrology, Hydraulics, and Water Quality Water quality and resources specialists; and Directors of university stormwater research centers who, Committee; University water research centers online publications; and on referral, worked closely with the DOTs. Recent, current, and planned research by state DOTs (internally conducted research or research conducted in The survey, included as Appendix A in this report, was conjunction with universities and other contractors). conducted by phone and on line. All information was entered into an online system, so that results may be viewed easily (go A database was created using the above sources to hold the to and click "View available citations as well as to enable the categorization of Results"). In an effort to minimize inconvenience to DOT the publications. Researchers identified and obtained more participants and to rationalize the broad scope of information than 2,500 annotated bibliographies related to highway run- being collected, two state-initiated water-quality surveys were off management. More than 900 of the most relevant cita- combined. Researchers pooled the existing data, voluntarily tions were categorized on the basis of various combinations assisted the Virginia Transportation Research Center (VTRC) of key word searches. The categorization scheme in the data- in completing the survey effort they had started, and focused on base was designed to reflect closely the major categories of reaching all 50 state DOTs for participation in sections 2 this document. Table 1-2 shows a breakdown of the number through 8, which provide information most directly pertinent of documents under each primary category. to NCHRP 25-20(02). In addition to the primary categories, each citation is cat- At the same time they were completing previously started egorized further with objective statements and by document surveys, researchers solicited information on the whole set of type. The database was created with an initial set of objective questions and presented the current state of knowledge about statements that represented various areas of interest and pos- practice in each state for completion and updating as neces- sible knowledge gaps on the subject of highway runoff man- sary or desired by the DOT. A large number of states con- agement. The ability to extend the initial set of the objects tributed information, facilitating related research efforts at was built into the database enabling researchers to add objec- VTRC and providing a basis for further research and infor- tive statements as the need arose during the literature review mation sharing about water quality best practices. DOT process. The number of unique objective goals is more than research directors were contacted separately to report on the 300 for the categorized documents. More than 400 of the cat- water quality research performed or funded by their state egorized documents were assigned more than one objective. DOT and to provide electronic copies or online links if avail- Researchers further grouped the research objectives under able. In many cases researchers were referred to the water each primary category into groups such as general objectives, quality practitioners who were the focus of the survey effort. water quality objectives, hydrologic/hydraulic objectives, This wide level of involvement produced input about exist- and in some cases, economic objectives and public percep- ing research programs and about state DOTs' research pref- tion objectives. In addition to categorizing object statements,

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46 TABLE 1-2 Database document summary by primary categorization Primary Category Number of Documents Evaluation of Stormwater Control Facilities and Programs 332 Watershed-Based Approaches 73 Highway Runoff Characterization and Assessment 232 Receiving Waters Impact Assessment 80 Design of Stormwater Control Facilities and Programs 108 Other 59 TOTAL 884 researchers reviewed the BMP types and pollutants studied Subject areas that were assigned lower priorities by DOTs and discussed in the documents and extracted study loca- were assigned lower rankings. The literature review rankings tions, study goals, and monitoring information where avail- are based on the availability of documents on the subject able. The BMP names were selected from a list of more than matter and the amount of research that has been done or is 100 practices, some of which may refer to similar BMPs. being done on the subject as well as on the recommended Currently, the database contains links to more than 300 full- areas of additional research often included in the conclusion text online documents. The database was used mainly as a of reported research. Using a rating scale from 1 to 5, well- tool to expedite the literature review process; however, with covered subject areas are assigned a lower ranking and less additional refinement, an online version of the database could covered subject areas are assigned a higher ranking. The third become a valuable information exchange tool for DOTs, con- ranking--the ranking from the researchers--is based on a sultants, and researchers. combination of the literature review ranking, the DOT rank- ing, and professional judgment of the research gaps and needs encountered in the extensive work in the field of stormwater 1.4.3. Delivery of Findings management. The third ranking also is based on a scale of The knowledge gleaned from the survey of state DOTs 1 to 5, with 1 being assigned to lower priority research needs and the literature review was compiled to identify and prior- and 5 being assigned to higher priority research needs. itize research needs and gaps in highway runoff management and receiving waters impacts. For the most part, researchers 1.4.5. Document Organization found that the gaps and needs identified during the literature review agreed with the gaps and needs identified by the sur- The document begins with an overview of the 45 research vey of state DOTs. However, a few research areas not iden- priority areas ranked by DOT water quality practitioners and tified during the literature search were identified by state an overview of further (often overlapping) research topics DOTs and vice versa. This paired approach arguably offers recommended by DOTs (in their own words, in various cate- a more comprehensive compilation of research needs than gories). This section is followed by the literature review, would have resulted if the review of literature were conducted which attempts to summarize key studies and knowledge in first and the survey second, as the research team would have each area, and in some cases, provides examples for use in recommended in a more lengthy research period. developing the prioritized research needs. The literature The findings of the DOT survey are presented primarily as review is not an exhaustive discussion of the details of all tables of ranked and sorted research priorities and associated related highway runoff research work that has been completed. text. The findings of the literature review are presented in Due to the nature of the primary research categories, an summary paragraphs identifying potential research gaps and individual study may include components of multiple cate- needs for each subtopic area. The findings of both investiga- gories or subcategories, making these studies difficult to clas- tions are compiled and summarized in a final narrative and sify. Effort was made to cross-reference studies that span matrix of ranked and sorted research topic areas. more than one category or subcategory for the maximum ben- efit to the reader and for a more complete assessment of 1.4.4. Ranking of Research Needs research gaps and needs. Study classification is partially sub- jective and dependent upon the depth of information included The three separate rankings were used to prioritize (on a in the reviewed literature, which in many cases is limited to scale from 1 to 5) the research needs shown in Table 5-1. The only an abstract. Consequently, it is possible that the reader DOT rankings are based on the results of the practitioner sur- may not completely agree with the inclusion of some research veys, which include both the average score assigned to each topics within a chosen research category. Therefore, in addi- topic area and the self-identified research gaps and needs. tion to cross-referencing studies, effort also was made to

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47 describe the rationale for including some studies under a par- Research statements developed by the team are included in ticular research category for those studies where classifica- the Executive Summary. tion was not obvious. Following this introductory section, the main section This report includes a table of the identified research needs headings are DOT Research Preferences, Review of Pub- with explanations on how the needs were ranked by the state lished Literature and Potential Research Needs, and Sum- DOTs as well as the researchers' assessment of the needs mary of Identified Research Gaps and Needs. The review of based on the literature. Researchers then gave an overall published literature has been organized according to the pri- ranking to a research need and identified the top priorities. mary research categories identified in Table 1-2.