Many state departments of transportation (DOTs) and local agencies are required to provide treatment to the runoff from on-grade pavements, but collection and treatment or other mitigation strategies for bridge runoff management pose particular challenges. Addressing increasingly stringent highway runoff regulatory requirements by applying on-grade runoff management practices to bridges is not only costly but may compromise worker and road-user safety with undetermined benefits to water quality. The objective of this research was to develop a guide, for DOTs and others, for managing bridge runoff to protect environmental quality and meet regulatory requirements. The guide is intended to address several critical issues:
- Characterization of bridge runoff and its effects on quality of receiving waters
- Current and emerging runoff management strategies that may be beneficial and cost-effective for application to bridges
- Criteria for identifying appropriate runoff management strategies for particular bridges
- How bridge owners may establish appropriate levels of effort to address bridge runoff issues at a particular location
- How bridge owners may identify "best managment practices" (BMPs) for bridge runoff and select or develop BMPs for a particular location
The research team reviewed available literature and recent research, then systematically identified available bridge runoff management strategies and their likely benefits, lifecycle costs, and effectiveness in various settings. Using the information gathered, the team described a process and criteria DOTs can use to select BMPs for specific conditions where bridge runoff management is called for. The guide presents the process and runoff treatment practices in a way designed to facilitate use by practitioners; the guide document is accompanied by computational spreadsheets. The document has been published as
NCHRP Report 778; the spreadsheets are availavle for download as well.
