Assessing Water Contamination Levels from Bridge Deck Runoff in Virginia
Research Idea Scope
Bridge maintenance along with traffic, weather, and other related activities are continuous sources of pollution for the water bodies under the bridge. In Virginia, where are more than 10,000 bridges, winter maintenance operations involve applications of various amounts of chemicals for roadway and bridge deicing treatments several times within a 4 to 5 months period. As a consequence, these chemicals damage the bridge structure by attacking and corroding the deck and its reinforcement through chloride ions infiltration. Once deteriorated, these bridge decks will start to spall and delaminate exposing certain reinforced sections and newer surfaces to the elements. In this scenario, rainfall-runoff events will transport contaminants such as metals, deicing chemicals, and oils from bridge decks directly into the water bodies from underneath. Other events such as spills, deck surface deterioration, and/or drains cleaning are contributing pollution factors to the surface waters. The methodology developed for this research will cover state of practice of various states, assessment procedures in determining the bridge deck runoff impact on receiving water quality, mitigation approaches and solutions sought for best management practices. The scope of the proposed research is to study the effect of the bridge deck runoff on the ecosystem of the nearby receiving waters. As runoff from a bridge deck contributes to receiving water quality impairment in areas with elevated pollutants due to urbanization, solutions to managing this contribution need to be found in order to improve water management practices performance while minimizing remediation costs and ensure sustainability. The following tasks may be necessary to conduct the proposed work: 1) Select bridge locations with relatively high traffic levels and maintenance activities, 2) Evaluate the pollution source and types of contaminants delivered to the surface waters, 3) Employ novel technologies to determine the impact level of the contaminants on the water quality, 4) Seek mitigation approaches to reduce the degradation of the ecosystem, and 5) Develop implementation strategies based on the research findings to validate the conceptual mitigation methodology.
Urgency and Payoff
Due to traffic and weather factors that exhibit continuous sources of pollutants and cannot be captured for treatment, evaluation of the impact of these pollutants on the water quality is challenging. In this respect, results from this study may provide a practical approach to assist state practitioners in this regard and to develop guidelines for best management decision processes. Benefits from this research may include 1) Improved methods for treating bridge runoff leading to cost-effective alternatives, 2) New bridge design and construction approaches, 3) Increased average annual runoff capture methodology, and 4) Improved advance planning and coordination with multiple projects.
Cristian Druta Virginia Tech Transp. Institute