Portland State University PDXScholar Dissertations and Theses Dissertations and Theses Fall 12-16-2019 Flood Dynamics in the Portland Metropolitan Area, Past, Present, and Future Lumas Terence Helaire Portland State University Follow this and additional works at: https://pdxscholar.library.pdx.edu/open_access_etds Part of the Environmental Engineering Commons, and the Water Resource Management Commons Let us know how access to this document benefits ou.y Recommended Citation Helaire, Lumas Terence, "Flood Dynamics in the Portland Metropolitan Area, Past, Present, and Future" (2019). Dissertations and Theses. Paper 5354. https://doi.org/10.15760/etd.7227 This Dissertation is brought to you for free and open access. It has been accepted for inclusion in Dissertations and Theses by an authorized administrator of PDXScholar. Please contact us if we can make this document more accessible:
[email protected]. Flood Dynamics in Portland Metropolitan Area, Past, Present, and Future by Lumas Terence Helaire A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Civil and Environmental Engineering Dissertation Committee: Stefan A. Talke, Chair David A. Jay Joseph Jurisa Heejun Chang Portland State University 2019 Abstract The Portland area has an extensive flood history since it was founded in 1845. In the late 19th century, the Portland area was prone to flooding from snowmelt freshets (3-6 months duration) and brief winter rain or rain-on-snow events. Since that time the magnitude of spring freshets has been curtailed by 45% due to climate change, flow diversions, and reservoir management. Along with changes in hydrology, the bathymetry of the Lower Columbia River has been altered by the dredging of the navigation channel, diking, and land reclamation.