BACKGROUND

Distributed rainfall-runoff models (DRRMs) are an important tool for assessing future precipitation impacts to the transportation system. With climate change raising the risk of more intense and frequent storms, water-related stressors, such as flooding, in-stream structure scour, and aggradation, could likely worsen for transportation corridors. DRRMs provide the capabilities needed to assess the impacts of future rainfall patterns and amounts on the transportation system. As detailed in NCHRP Synthesis 602: Resilient Design with Distributed Rainfall-Runoff Modeling, such modeling tools are cited in 54% of the hydrological design guidelines from all state transportation agencies, including state departments of transportation (DOTs) and pertinent state agencies, yet only 33% of the responding DOTs (16 out of 48) reported applying DRRMs. Without DRRM guidelines, transportation planning and modeling professionals will be limited in effectively leveraging innovative data sources, including the ATLAS 15 future precipitation dataset under development by the National Oceanic and Atmospheric Administration (NOAA).

Accordingly, research is needed to begin transforming the state of practice in transportation hydraulic and hydrologic modeling and provide essential guidelines needed to fully leverage the ATLAS 15 future precipitation data and other future data sources. 

OBJECTIVE

The objective of this project is to develop resources that will facilitate state transportation agency adoption of DRRMs for planning and design.

At minimum, these resources will include:

• A practice guide,
• A compendium of case studies demonstrating innovative deployments, and
• A roadmap describing when and how DRRMs should be implemented in place of legacy methodologies and designed to institutionalize their use within state DOTs with varying resources, knowledge, and organizational commitment. 

Accomplishment of the project objective will require at least the following tasks.

TASKS

PHASE I: Planning and Initial Outreach

Task 1. Conduct a literature review of relevant sources, including state DOT; other state, local, and regional agency; international; NOAA; National Weather Service; Federal Emergency Management Agency; United States Geological Survey; and National Aeronautics and Space Administration resources and practices. The literature review should also explore the range of available methods for assessing the effectiveness of DRRMs in designing transport structures for future climate conditions and the strengths and weaknesses of these methods.

Task 2. Identify the DRRM state of practice. Building on Task 1, summarize the state of practice for DRRMs, including stakeholders, disciplines, data sources, data management, computing options, and products that DRRMs deliver for multimodal transportation for planning, design, operations, asset management, and traffic management during storm events. This task will include targeted outreach to relevant stakeholders, including participants in NCHRP Synthesis 602, advanced adapters, and non-users who may provide insight on implementation barriers. Submit technical memorandum #1, including the results of Task 1 and the plan developed in Task 2. NCHRP approval of the technical memorandum is required before work on subsequent tasks may begin. 

Task 3. Administer and summarize the stakeholder outreach. Submit technical memorandum #2, including a summary of the results of the stakeholder outreach. NCHRP approval of the technical memorandum is required before work on subsequent tasks may begin.

Task 4. Characterize available methods and tools for integrating projections of precipitation and other essential boundary conditions for project lifetimes useful for application in DRRMs. Assess the strengths and weaknesses of these methods and tools and emerging solutions to this challenge.  

Task 5. Propose a method to achieve the project objective to be fully developed in Phase II. At minimum, the method will include annotated outlines for:

• A practice guide;
• A series of case studies on the application of DRRMs in the context of hydrological analysis and transportation illustrating effective practices for model development, stakeholders, data, implementation, and the use of DRRM tools to build resilience; and
• A roadmap exploring pathways for DRRM integration within state transportation agencies, including a business plan and considering factors such as resource availability, training needs, and successful implementation.

Task 6. Prepare Interim Report No. 1, which documents Tasks 1 through 5 and provides an annotated outline for the practice guide, and an updated work plan for the remainder of the research. The updated plan must describe the process and rationale for the work proposed for Phase II.

PHASE II: Execute the Method and Produce Final Deliverables

Task 7. Execute the research method according to the approved Interim Report No.1.

Task 8. Develop the practice guide, case study compendium, and roadmap. The practice guide, case study compendium, and roadmap shall be submitted for NCHRP approval no later than 6 months before the contract end date.

Task 9. Conduct a virtual practitioner workshop introducing the draft deliverables. In addition to eliciting feedback, the workshop will introduce a strategic vision for DRRMs and their application to transportation resilience, knowledge gaps, and implementation challenges.

Task 10. Prepare the draft final deliverables, which shall include the following:

• A conduct of research report documenting the entire research effort;
• The final practice guide, case study compendium, and roadmap;
• Public outreach materials, including a PowerPoint presentation with speaker notes; and
• A stand-alone technical memorandum titled “Implementation of Research Findings and Products”, with an emphasis on application to transportation resilience, implementation challenges, and identification of knowledge gaps.

STATUS: Proposals have been received in response to the RFP. The project panel will meet to select a contractor to perform the work.