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Will we need to change the rules : assessing the implications of climate change for dam operations in Oregon's McKenzie River Basin

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dc.contributor.advisor Grant, Gordon E.
dc.creator Danner, Allison G.
dc.date.accessioned 2013-04-11T17:51:47Z
dc.date.available 2013-04-11T17:51:47Z
dc.date.copyright 2013-03-21
dc.date.issued 2013-03-21
dc.identifier.uri http://hdl.handle.net/1957/38119
dc.description Graduation date: 2013 en_US
dc.description.abstract Dams and reservoirs are important components of water resource management systems, but their operational sensitivity to streamflow variability may make them vulnerable to climate change. Climate change is likely to affect the magnitude and timing of streamflow, motivating the assessment of potential impacts on dams and reservoirs. Here I examine a case study of Cougar Dam, a multipurpose dam in Oregon, USA, to assess potential impacts of future climate change on operational performance. In the first portion of this study, I examine the historical operation of Cougar Dam, to understand (1), whether operational objectives have been achievable in the past despite operational variability, and (2) how climatic variation is expressed in operational trajectories. By analyzing historical streamflow and operations data using a set of metrics, I characterize variability in past operations and how that variability relates to streamflow. I also employ a reservoir model to distinguish operational differences due to streamflow variability from variability due to other factors that affect operations. I find that operational objectives have been achievable, despite variability in operations and departures from the ideal operational trajectory. Throughout the historical period, flood control operations have almost always kept reservoir outflows below the desired maximum outflow. Although filling occurs 9 days late on average, the reservoir has filled in all but 6 out of 37 years. Although drawdown occurs 47 days early on average, early drawdown does not generally impact recreation and allows minimum outflows to be met every day during all but the driest year. I also find that total seasonal inflow is correlated with measures of operational performance, and that other factors besides climate play an important role in determining operational trajectories. I conclude that operations of Cougar Reservoir are vulnerable to climate change, but that operational flexibility may mitigate some of the potential impacts. In the second portion of this study I assume that current operating rules will be kept in place and I aim to understand what types of operational impacts may be expected, when they may be expected to occur, and whether the operational impacts may necessitate changing operational rules. I employ both a traditional climate impacts assessment approach to assess changes over time as well as a scenario-neutral approach to generalize relationships between streamflow and operations of Cougar Dam. I find that projected increases in winter streamflow could result in up to twice the number of downstream high flows than in the past and that projected decreases in summer streamflow could result in earlier reservoir drawdown by up to 20 days on average. Additionally, filling of the reservoir may occur up to 16% more often or 11% less often than in the past, depending on spring flow magnitude and timing. I also find that there are strong general relationships between total inflow volume and flood control performance, and that there are total inflow thresholds for whether or not the reservoir will fill or will be full enough for recreation in late summer. I conclude that future modification of operating policies may be warranted, but that there will likely be tradeoffs between operating objectives in the future even if operating rules are modified. en_US
dc.language.iso en_US en_US
dc.relation Oregon Explorer en_US
dc.subject climate change en_US
dc.subject impacts assessment en_US
dc.subject reservoir operations en_US
dc.subject dams en_US
dc.subject streamflow en_US
dc.subject.lcsh Climatic changes -- Oregon -- McKenzie River Watershed en_US
dc.subject.lcsh Climatic changes -- Oregon -- Cougar Dam en_US
dc.subject.lcsh Climatic changes -- Oregon -- Cougar Reservoir en_US
dc.subject.lcsh Water levels -- Oregon -- Cougar Reservoir en_US
dc.subject.lcsh Flood control -- Oregon -- McKenzie River Watershed en_US
dc.subject.lcsh Cougar Dam (Or.) -- Management en_US
dc.subject.lcsh Water-supply -- Effect of global warming on -- Oregon -- McKenzie River Watershed en_US
dc.subject.lcsh Streamflow -- Oregon -- McKenzie River Watershed en_US
dc.title Will we need to change the rules : assessing the implications of climate change for dam operations in Oregon's McKenzie River Basin en_US
dc.type Thesis/Dissertation en_US
dc.degree.name Master of Science (M.S.) in Water Resources Engineering en_US
dc.degree.level Master's en_US
dc.degree.discipline Graduate School en_US
dc.degree.grantor Oregon State University en_US
dc.contributor.committeemember Tullos, Desiree
dc.contributor.committeemember Santelmann, Mary V.
dc.description.peerreview no en_us


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