Trends Spring 2016 - Page 8

Administration. The NCHRP provides practical, ready-to-implement solutions to pressing problems facing the transportation industry. In June 2013 NCHRP selected a team led by Ayres Associates to conduct an evaluation and assessment of environmentally sensitive streambank protection measures. The objective of the research project was to evaluate and assess existing guidelines for the design, installation, monitoring, and maintenance of environmentally sensitive bank stabilization and protection. Another goal of the project was to provide practical, quantitative design guidelines that engineers could use with confidence. Lagasse served as principal investigator, and Paul Clopper, director of applied technology at Ayres, served as a co-principal investigator for the project, which wrapped up in November 2015. The NCHRP research report is in the process of being published as NCHRP Report 822. Doug Shields, a hydraulic engineering consultant at Shields Engineering LLC and a member of the Ayres NCHRP research team for this project, agreed with Lagasse that the lack of data behind vegetative bank protection techniques was problematic for engineers. “Most people are willing to affirm the environmental value of a river or stream, but when you’re building a highway, you need to make sure the bank protection will hold up,” Shields said. “The problem was that there were no clear standards to do this.” METHODS PUT IN PLACE To start the project, the team reviewed a 2005 NCHRP study that focused primarily on using vegetation techniques for streambank stabilization. The study identified 44 different environmentally sensitive bank protection measures but did not test the techniques in real-world scenarios. The Ayres NCHRP study aimed to compare combinations of engineered and vegetative bank protection measures in a laboratory set up to mimic real stream conditions, Lagasse explained. In essence, the Federal Highway Administration recommends using a combination of