VDOT Climate Change Resilience Planning

As a subcontractor to Stantec on their Statewide MS4 contract with VDOT, True Environmental led two tasks supporting resilience and climate change planning. True developed a draft of a new chapter, Chapter 18 – Resilience & Adaptive Design Criteria, for the VDOT Drainage Manual. The objective of this chapter is to establish the practices and specific requirements, also referred to as Adaptive Design Criteria (ADC), of the Location and Design Division for designing roadway drainage and stormwater management accounting for climate change and sea level rise (SLR).  Resiliency (or being resilient), as used in this chapter to describe roadway drainage and stormwater management in Virginia, is taken to mean the successful integration of transportation mobility, increasing precipitation adaptation measures, and sea level rise (SLR) adaptation measures into design decisions at both the planning and project delivery levels. True developed adjustments to rainfall intensity-duration-frequency values based on MARISA projections for Virginia counties and detailed how these adjustments can be used in calculating flows and resulting drainage design to accommodate future climate change rainfall.

True Environmental has completed several adaptive hydraulics case studies in different areas of Virginia for VDOT.  In each of these case studies, True performed hydrologic and hydraulic modeling to redesign drainage infrastructure for MARISA climate change rainfall projections and calculated the cost implications of design for higher rainfall intensities.  These case studies are being used by VDOT to evaluate economic impacts of potential design requirements to accommodate future climate change rainfall.