Document Type
Pre-Print
Publication Date
9-7-2022
Subjects
Water Temperature, Climatic Changes -- Effect of human beings on, Anthropogenic Effects, River regulation
Abstract
Using archival research methods, we found and combined data from multiple sources to produce a unique, 140 year record of daily water temperature (Tw) in the lower Willamette River, Oregon (1881–1890, 1941–present). Additional daily weather and river flow records from the 1850s onwards are used to develop and validate a statistical regression model of Tw for 1850–2020. The model simulates the time-lagged response of Tw to air temperature and river flow, and is calibrated for three distinct time periods: the late 19th, mid 20th, and early 21st centuries. Results show that Tw has trended upwards at ~1.1 °C /century since the mid-19th century, with the largest shift in January/February (1.3 °C /century) and the smallest in May/June (~ 0.8 °C /century). The duration that the river exceeds the ecologically important threshold of 20 °C has increased by ~20 days since the 1800s, to ~60 d yr-1. Moreover, cold water days below 2 °C have virtually disappeared, and the river no longer freezes. Since ~1900, changes are primarily correlated with increases in air temperature (Tw increase of 0.81 ±0.25 °C) but also occur due to increased reservoir capacity, altered land use and river morphology, and other anthropogenic changes (0.34 ±0.12 °C). Managed release of water influences Tw seasonally, with an average reduction of 0.27 °C and 0.56 °C estimated for August and September. System changes have decreased daily variability (σ) by 0.44 °C, increased thermal memory, and reduced interannual variability. These system changes fundamentally alter the response of Tw to climate change, posing additional stressors on fauna.
Rights
© Author(s) 2022.
This work is licensed under a Creative Commons Attribution 4.0 International License.
Locate the Document
This is the pre-print version. A definitive version will be published in Hydrological Earth System Sciences.
DOI
10.5194/egusphere-2022-793
Persistent Identifier
https://archives.pdx.edu/ds/psu/39805
Citation Details
Talke, S.A., Jay, D.A., & Diefenderfer, H. (2023 submitted). Warming of the Willamette River, 1850–present: the effects of climate change and direct human interventions. submitted to Hydrology and Earth System Science, August 2022. EGUsphere [preprint], https://doi.org/10.5194/egusphere-2022-793
Metadata
Included in
Civil and Environmental Engineering Commons, Environmental Studies Commons, Water Resource Management Commons
Description
This is the author’s version of a work that was accepted for publication in Hydrological Earth System Sciences. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version will be published in Hydrological Earth System Sciences.
The data that supports this article is available in PDXScholar:
https://doi.org/10.15760/cee-data.06