Oregon DOT Stormwater Treatment and Management Program: A Framework for Adapting toChanging Pollutants, Regulations, and Practices

The purpose of the Oregon Department of Transportation (ODOT) Stormwater Management Program is to provide a framework that can support effective project delivery and adapt to rapidly changing water quality requirements. The Program provides guidance and technical support to planning, design, construction, and maintenance staff to help ODOT enhance project delivery by achieving compliance with state and federal laws and regulations, promoting species recovery, and improving Oregon‘s water quality Stormwater management has increased in complexity and importance for ODOT, the Federal Highway Administration (FHWA), and the natural resource agencies. In May 2006, ODOT, FHWA, the National Marine Fisheries Service (NMFS), Oregon Department of Environmental Quality (DEQ), the U.S. Fish and Wildlife Service (USFWS), the U.S. Environmental Protection Agency (EPA), and the Oregon Department of Fish and Wildlife (ODFW) embarked on a collaborative venture to promote improved management of stormwater, to ensure that all parties are in alignment on expectations for stormwater management, permitting requirements and to enhance streamlined permitting. The primary product of the effort of the multi-agency working group was Stormwater Treatment Guidance, incorporating the Best Management Practices (BMP) Selection Tool, which provides the framework for addressing highway project water resources issues. Technical guidance on stormwater was informed and guided by the results of comprehensive literature reviews. Discipline experts were also consulted during the development of the water quality and flow control (water quantity) design storm definitions. The final selections of the design storms and elements of the BMP Selection Tool were consensus decisions by ODOT, FHWA, and the natural resource agencies. The BMP Selection Tool focuses on selecting preferred (i.e., effective) BMPs for each pollutant of concern. It includes metrics and ratings for treatment effectiveness for pollutants of concern, site suitability and physical constraints, maintenance needs and constraints, and costs. In an attempt to address the issue of varying removal efficiencies reported in the literature, members of the development team agreed that treatment effectiveness be defined in terms of their "primary treatment mechanisms" (or "unit operations or processes") rather than by removal efficiency data reported for specific BMPs. A primary treatment mechanism is that which results in the removal or chemical breakdown of a given compound. The approach identifies a given treatment mechanism that effectively treats a specific target pollutant, and if a BMP employs that treatment mechanism, then by definition the BMP would be considered effective at treating for the pollutants of concern. Ratings of "high, medium, low" are used. The resulting program easily adapts to changing pollutants of concern, BMP technology, and science. If a new pollutant is identified, the response is easy – simply determine the primary treatment mechanism associated with the target pollutant and assign BMPs that operate via that mechanism. New BMPs can be added in much the same way. When "preferred" BMPs (ratings of "high") are selected for projects in the design stage, the resulting review and permit processing are streamlined.