Inspecting and Maintaining State DOT Post-Construction Stormwater BMPs

State Departments of Transportation (DOTs) are mandated by the federal Clean Water Act to adhere to the National Pollutant Discharge Elimination System (NPDES) permit regulations. These regulations necessitate routine inspection and maintenance of stormwater control measures, commonly known as Best Management Practices (BMPs). Additionally, certain states impose further compliance obligations on DOTs, aligning with federal, tribal, and state stormwater laws. Given that state DOTs oversee numerous post-construction stormwater BMP assets spanning vast geographic areas, several innovative outsourcing strategies have emerged to ensure compliance with these stringent permit requirements. The objective of this study is to provide an overview of the current state of the practice regarding the outsourcing of post-construction stormwater BMP inspection and maintenance compliance activities. By documenting existing approaches and experiences, the study aimed to shed light on the effective implementation of an outsourced inspection and maintenance program. The scope of this study is confined to the extent of outsourcing by state DOTs, factors affecting the decision to outsource, procurement and contracting methods, funding sources, and contractor oversight. This study of state DOT outsourcing programs can assist state DOTs in considering more cost and time effective approaches for these activities while also aiding those in the developmental phase of an outsourcing program.

Full Abstract: Post-Construction Stormwater Best Management Practices (BMPs) are engineered facilities designed to manage and treat stormwater runoff from developed sites, aiming to reduce runoff and enhance water quality by removing pollutants. Due to the limited capacity of state Departments of Transportation (DOT) maintenance staff, outsourcing inspection and maintenance of these BMPs to third-party contractors has become essential. A synthesis was conducted to document state DOT practices regarding outsourcing post-construction stormwater BMP inspection and maintenance compliance activities. The study utilized a three-step methodology involving a literature review, a web-based survey distributed to state DOTs, and semi-structured virtual interviews with six state DOTs. Key findings from the research suggest that 1) while substantial research exists on BMP design and operation, little guidance is available for conducting inspections and maintenance, especially within state DOT rights-of-way, 2) of the 41 state DOTs surveyed, 35 own and/or manage post-construction stormwater BMPs, with 19 outsourcing inspection and/or maintenance activities, 3) the primary driver for state DOT stormwater programs is NPDES MS4 Phase II for urbanized areas, and 4) BMP inspection funding typically comes from statewide capital or operating budgets, while BMP maintenance funding is often from district/region operating budgets. The synthesis also identifies areas for further research to aid state DOTs in developing outsourced inspection and maintenance programs, including developing inspection guidelines, BMP commissioning guidelines, maintenance contractor prequalification training, cost analysis for effective contracting strategies, and BMP life-cycle cost analyses. Lastly, industry professionals will provide valuable insight into how they work alongside state DOTs to achieve inspecting and maintenance goals.