|Shields Jr, Fletcher|
Submitted to: Journal of Hydraulic Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/7/2007
Publication Date: 9/27/2007
Citation: Slate, L.O., Shields Jr, F.D., Schwartz, J.S., Carpenter, D.D., Freeman, G.E. 2007. Engineering design standards for stream channel modification or restoration. Journal of Hydraulic Engineering. 133(10):1099-1185. doi:10.1061/(ASCE)0733-9429(2007)133:10(1099).
Interpretive Summary: A heated controversy currently exists among workers in stream restoration regarding the best approach for channel design. Many agency personnel and regulators favor a popular empirical approach taught through a series of short courses, while professional engineers favor more classical mechanistic approaches. The controversy is examined, and implications for professional liability of design engineers are identified. Proposed is a design approach led by engineers in collaboration with a wide range of life and earth science disciplines. Use of a paper recently published in the Journal of Hydraulic Engineering as an interim design standard is advocated. This essay will provide engineers with a tool for explaining their objections to forced use of the empirical approach to clients.
Technical Abstract: Hydraulic engineers are often called upon to prepare stream channel restoration designs by clients who require use of a specific design approach, known as the Rosgen or empirical-analog method. An engineer who prepares and seals a design incurs a degree professional liability, even if the engineer is forced to use design procedures that are against better judgment. The situation is exacerbated by at least two factors: good restoration design requires participation by workers trained in a wide spectrum of disciplines (engineering, life and earth sciences), and there are currently no widely-accepted engineering design standards for stream channel restoration. This essay argues for a collaborative approach to design, with participation from a range of disciplines, but with engineering activities governed by rigorous design standards that allow engineers to select the best method for a given project. Until more thorough design guidelines appear, use of the approach described by Shields et al. (2003) is recommended.