The growth of urban areas and the resulting community demand for increased mobility has required more versatile solutions for large transportation projects. This may result in several challenges that require an outside-the-box perspective for temporary and permanent stormwater quality mitigation, especially if the transportation project corridor intersects various permits of Authorities Having Jurisdiction (AHJs) and the National Pollutant Discharge Elimination System (NPDES). The California Department of Transportation (Caltrans) has its own Phase I Municipal Separate Storm Sewer System (MS4) permit which includes compliance with its Project Planning and Design Guide, but in Southern California, Caltrans stormwater quality master plans may be applicable to the project. This process typically involves the associated Local Transportation Planning Agency (LTPA). And regardless of the extent of Caltrans impact to the project, the Storm Water Data Report is required to inform the project-wide temporary erosion control approach (California Construction General Permit (CGP) related). As for a railroad corridor (freight and transit), the challenge is making sense of the overlapping requirements from the LTPA, railroad owner (i.e., BNSF, UPRR, California High Speed Rail, etc.), Phase I and Phase II MS4 permits, as applicable. Furthermore, the various requirements from the overlapping local AHJs can overwhelm the project for a coordinated approach. Reaching out to the respective AHJs and resource agencies may facilitate their approvals and streamline the schedule. And if that was not challenging enough, certification via sustainability organizations (i.e., LEED, Envision, etc.) for applicable project features with consideration of stormwater-related credits require an effective approach to clarify intersected MS4, AHJs and owner requirements. This presentation will highlight how complex large transportation projects may address stormwater quality mitigation and the challenges to navigate the various related NPDES, AHJs and owner requirements for on-site and off-site locations. In addition, discussion will be presented regarding voluntary certification via sustainability organization and how those stormwater credits may play a role. Moreover, Best Management Practices (BMPs) typical of a transportation corridor will be presented along with their limitations, how they vary depending on the AHJs and NPDES permit in question, and how they are considered during planning, design and construction. This abstract topic corresponds to the 2025 StormCon Transportation and Construction Stormwater Management track. Polls will be used throughout the presentation to engage the audience and create an interactive experience.