APPENDIX A- Person-to-Person Survey

Introduction

The Amplified Workplan for NCHRP 24-50 provided a detailed discussion of the Research Approach. Task 1 included a review of the NCHRP Project 20-07/417 final report, ADM, HDG, and all related information, along with a survey of state transportation departments.

The survey of state DOTs was completed to evaluate (1) how state DOTs would use an AASHTO Drainage Manual that addresses both drainage and stormwater management, (2) what topics it should include, and (3) their vision for the manual that expands its reach and establishes policy while restoring its past usefulness as a one-stop guide to advance DOT design policy and procedures. At the time of the survey, one suggested name for the new manual given the additional of stormwater management topics was the AASTHO Hydraulics and Water Resource Manual (AHWRM).

A comprehensive Task 1 report was prepared (dated February 18, 2022) detailing the survey method used and the results, including completed questionnaires from the participating states. This appendix provides a summary of the survey results based on the Task 1 report. The completed questionnaires in the Task 1 report exceeded 300 pages and are not included in this appendix.

Survey Method

The Proposal Review and Recommendations (PR&R) during the NCHRP proposal process recommended person-to-person interviews as the most effective way to conduct the survey. To initiate the survey, an email was sent to all state hydraulic engineers (or equivalent) providing the background and an overview of the project, and asking those who would be willing to have a phone call or videoconference with a Research Team member to reply with a preferred date and time that they would be available to discuss their use the current AASHTO Drainage Manual (ADM), and any emerging issues, unresolved topics, or gaps in understanding with which the DOTs require assistance. A list of questions was prepared in advance and used to guide the discussion, and to ensure each interview was conducted in a consistent manner:

1. Do you have a State Drainage/Hydraulics Manual?
2. How is your State Drainage/Hydraulics Manual made available to designers?
3. Is there a web link we can use to download your state’s manual(s)?
4. How is your State Drainage/Hydraulics Manual updated?
5. Do you have other complimentary or multiple manuals for drainage related policy and procedures (e.g., stormwater design, bridge scour, BMP design, etc.).
6. Do you use the AASHTO ADM? If yes, how is it used at your agency?
7. If you use the ADM, are there any parts of it that the State doesn’t use or doesn’t agree with?

8. Are there items that should be updated, added, or removed from the ADM to make it more viable for your State?
9. Are there innovative features in your State’s Manual or other documents that should be included in a new AASHTO manual?
10. Do you follow or use any of these FHWA HDS and HEC publications? (Please check all that apply on the following page)

11. Is fish passage or aquatic organism passage a design requirement in your State?
    • Are design procedures provided in your State’s Drainage/Hydraulic Manual or are they referenced to another agency’s Manual(s)?
    • What general procedures do you follow (e.g., hydraulic design, stream simulation, geomorphic design, etc.)?
12. Has your State developed strategies for handling roundabout drainage?
    • What design guidance do you use, such as maximum cross slope?
13. Does your State have a standard for ADA compliant gutter grates?
    • What procedures do you follow for ADA grate capacity analysis?
14. Does your agency/department have published policy, analysis procedures, and/or design standards to consider resiliency to climate-induced impacts (e.g., increased flood and fire recurrence) in the planning and design of your state’s highway projects?
15. Does your agency/department have published policy, analysis procedures, and/or design standards for selection of construction materials based on sustainability? For example, selecting construction materials based on design life and potential environmental impact including its production carbon footprint.
16. Do you use a risk management approach for any portion of your drainage design work (e.g., pavement drainage related to maintenance of traffic during construction, bridge scour, etc.)
17. What project delivery methods does your State utilize (e.g., design-build, design-bid build, progressive design-build, etc.) and is your Hydraulic/Drainage Manual written to handle each delivery method (e.g., utilizes contract language such as shall rather than should for design-build delivery methods)?
18. Has your agency/department collaborated with local jurisdictions or other agencies on stormwater or other hydrologic/hydraulic projects? For example:
    • Promoted partnership opportunities with local municipalities in the planning and design phases of highway projects.
    • Providing more emphasis during the Planning and PD&E Phase of a project to identify stakeholder engagement for water resource opportunities related to potable water supply, stormwater harvesting, wetland restoration or other beneficial water resource management strategies.
    • Utilized integrated planning (e.g., the “One Water” approach) with water agencies such as flood control districts, non-point source watershed cooperatives, wastewater districts, groundwater authorities, or drinking/water supply agencies?
    • Utilized off-site (off-project) and/or off-ROW pollutant trading/treatment schemes?
19. Does your agency/department have published policy, analysis procedures, and/or design standards for stormwater management including Best Management Practices (BMP’s) and/or Stormwater Control Measures (SCM’s) for water quality management? Note: by definition, a BMP refers to any practice used for stormwater

19. quality control management, while a SCM would be a subset of BMP’s defining individual stormwater control elements such as basins, swales, wetlands, manufactured treatment products, etc.
    • Which of the following standards are included:
      • Peak Flow Rate,
      • Volume Control,
      • Water Quality Control Limits (e.g., discharge concentrations, concentration reductions, load reductions)
      • Trash Retention Performance
      • other?
    • How are volumes determined?
      • Design storm depth
      • Continuous simulation methods
      • other
    • Are your sizing standards for SCM’s tailored to the unique characteristics of linear transportation projects (e.g., small time of concentration and high imperviousness)?
    • Which of the following SCM’s does your agency/department consider for stormwater [quality] control, and for those used do you have standard details?
      • Constructed wetlands
      • Wet ponds
      • Buffer zones/natural dispersion
      • Strips (vegetated sheet flow over embankments)
      • Embankment filters/media filter drains
      • Swales
      • Bioretention/rain gardens
      • Detention basins
      • Dual-use basins (dual-stage volume and outlets for flood and water quality)
      • Filtration
      • Manufactured products
      • Infiltration trenches or vaults (backfilled or below-ground)
      • Infiltration basins
      • Drywells (infiltrating to vadose zone)
      • Porous pavement (full-depth over porous reservoir/soils)
      • Porous overlay (thin-lift friction course over traditional pavement)
      • Sediment/traction sand traps
      • Trash-specific technology (e.g., drop-inlet cages, separators, baffled vaults, break-away bags, inlet deflectors, etc.)
      • other
20. Does your agency/department have published policy, analysis procedure, and/or design standards to minimize adverse impacts from concentrated infiltration? For example, groundwater mounding or pre-treatment prior to infiltration?

21. Does your agency/department have specific stormwater and runoff management standards for any of the following?
    • Areas with traction sand application
    • Highway (high-speed) environment
    • Surface (curb/sidewalk) streets
    • Maintenance stations
    • Park and ride (ride-share lots)
22. Does your agency/department have published policy, safety analysis procedures, siting, and/or design standards for SCM’s to address errant vehicle safety?
23. Does your agency/department have published policy and/or analysis procedures to address maintenance worker safety in and around SCM’s (e.g., minimize exposure, guard rail, set backs, minimize maintenance frequency)?
24. Does your agency/department have published policy and/or analysis procedures for selection of SCM’s based on:
    • Life-cycle cost?
    • Pollutant removal effectiveness?
    • Ease of maintenance?
    • Locally-sourced products?
    • Other
25. Does your agency/department have published policy and/or design standards for drainage infrastructure (e.g., curb use) to enhance the collection of debris by street sweepers?

Survey Results

There were responses from a total of forty states representing an 80% return rate. Each interviewer made detailed notes using the survey questionnaire, and/or some states provided written responses. In some cases, the initial contact provided a follow-on person in the department for additional information or details, and follow-up contacts were made as needed.

The completed questionnaires were included in the Task 1 Report providing detailed information for each State. A summary of the results was also created in a spreadsheet for easy reference and comparisons. The following paragraphs provide an overview of the major conclusions and results from the survey effort.

State Drainage Manuals

Nearly every state had a separate drainage manual that was available online. A few states had drainage information included in some other manual, one state had drainage criteria but no design manual, and one state had no published guidance at all relying only AASHTO standards. Many states had complimentary manuals addressing topics such as stormwater management, bridge scour, fish passage and erosion and sediment control issues.

Use of the AASHTO Drainage Manual

In general, there was an even split between the number of states that use the current AASHTO Drainage Manual (ADM) in some manner, either directly or as a cited reference source, and those that never use it or refer to it for any reason. In contrast, all states indicated they use the FHWA Hydraulic Design Series (HDS) and Hydraulic Engineering Circulars (HEC) publications, with most states typically using all but 2 or 3 of the seventeen documents listed in the survey. About one third of the states indicated that their drainage manual was developed using the ADM (or the predecessor Model Drainage Manual) as a guide. Most all states that use the ADM had no significant concerns or disagreements with the information provided in the document, although one state noted that the 2014 document had unnecessary text resulting from the switch to the two-volume format, along with too much reprinting of information from FHWA manuals. Another commented on how in the past the document was provided for free which made it more available to state DOT personnel.

Suggested Improvements and Additions to the ADM

Topics where better information is needed in the ADM included hydrology (e.g. time of concentration, continuous simulation modeling), spread criteria, pedestrians/bikes/ADA (Americans with Disabilities Act) facilities, geomorphology, stormwater management, BMP’s (Best Management Practices) and SCM’s (Stormwater Control Measures), climate change and resilience, roadway overtopping analysis, LFRD (Load Factor Resistance Design) based scour analysis, fire related debris/sediment issues, roundabout drainage, expanded coverage of inverted siphons, advanced hydraulic analysis tools (2D and 3D modeling), use of drones, and GIS (Graphical Information Systems) data management.

Aquatic organism Passage Requirements

Of the forty states surveyed, ten states (25%) indicated they had no aquatic organism passage (AOP) requirements. The remaining thirty states had widely varying AOP design practices. Half of those (15 states) indicated their primary requirement was to simply embed their culverts. Nine states specifically referenced that the FHWA HEC 26 procedure is, or can be used, and three specifically referenced the USFS (U.S. Forest Service) method, with several others describing procedures that were some variations of these two stream simulation based methods. A few states use a hydraulic design method (e.g., matching species-specific swimming speeds) and one state was doing a full geomorphic design process involving detailed hydraulic, sediment and geomorphic analyses for each road crossing. Several states indicated they had the flexibility to use any method (hydraulic design, stream simulation, or full geomorphic based design), depending on the type of crossing and the issues involved.

Roundabout Drainage and ADA Compliant Grate Inlets

Very few states had specific roundabout drainage design guidance, and/or said they just deferred to standard pavement design practices given most roundabouts are designed with curb and gutter sections. Similarly, very few states had specific ADA compliant grate standards, with many indicating they try to avoid placing grates in cross walk areas.

Climate Resiliency Policy and Procedures

Design policy, procedures, and standards to consider resiliency to climate induced impacts was also limited but based on the survey a number of states are starting to consider this issue. No states seemed to have any policy, procedures, or standards for selection of construction materials on the basis of sustainability, with most indicating material selection was based more on design life and life-cycle cost.

Risk Management, Project Delivery Methods, and Agency Coordination

Other than for bridges, risk management considerations such as maintenance of traffic during construction was another area with states indicating little formal guidance. A few states had some general guidance based on the duration of construction, but mostly this was considered the responsibility of the contractor. Regarding project delivery methods, a few states use all available methods, however, most seemed to use the traditional design-bid-build method, and occasionally design-build for larger projects. And most of them indicated that their design manuals were typically written assuming design-bid-build project delivery. Collaboration to some extent with local jurisdictions or other agencies was common, most often on stormwater management projects related to water quality issues.

Stormwater Management Policy and Procedures

Most all states have policy, procedures, and standards for BMP’s and SCM’s, with much of that work done by, or coordinated through, an environmental office/division. However, about half the states surveyed said they had no policy, procedures, or standards to minimize adverse impacts from concentrated infiltration, and very few had any stormwater management standards for sanded roadways or maintenance facilities, or for the use of street sweepers to enhance collection of debris. Very few states indicated they had specific policy or procedures for selection of SCM’s, however, many indicated that pollutant removal efficiency was a consideration, and a few other states also mentioned ease of maintenance. Life-cycle cost or use of locally sourced materials was seldom considered for SCM selection. No states indicated they had specific policy, procedures, or standards for errant vehicle safety around SCM’s, instead relying largely on established clear zone practices. Similarly, policy and procedures to address worker safety in and around SCM’s were typically based on established roadway safety standards.