Upper Klamath Lake (UKL) and Agency Lake in south-central Oregon are hypereutrophic due to phosphorus (P) loading from both geologic and agricultural sources in the watershed. Restoring historic lake-fringe wetlands to provide P sinks around the lakes has been accepted as a favorable means of reducing lake P levels and...
The objective of this study was to evaluate the use of aerial photos as a substitute for multiple-year pre-removal field data to assess the downstream channel changes associated with a small dam removal. The Brownsville Dam, a 2.1 m tall concrete dam on the Calapooia River, Oregon, was removed in...
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DesireeD. Tullos
The objective of this study was to evaluate the use of aerial photos as a
Re-establishing connectivity is a primary restoration activity for enhancing the
recovery of migratory fishes, but actions are often limited by lack of funds and
understanding of the benefits of individual projects. The objective of this study was to
develop a Bayesian Network (BN) to assess priorities for restoration of aquatic...
Proper use of vegetation in streambank bioengineering practices requires a comprehensive understanding of the influence of vegetation density on streambank hydraulics. A series of studies were conducted to investigate the relationship between independent variables vegetation density, bank angle, and discharge and dependent variables channel velocity, resistance, turbulence, and shear stress....
Upper Klamath Lake (UKL) and Agency Lake (AL) in southern Oregon are both hypereutrophic, in large part due to natural and anthropogenic loading of phosphorus (P), resulting in annual blooms of blue-green algae. Reduction of P loading to the lake is considered crucial to reduce the blue-green algae blooms, maintain...
Management of small dams may have profound implications for the health and integrity of small rivers and freshwater diversity. Global indicators suggest future growth in the small hydropower sector, particularly in developing countries. As a renewable energy source, it is often presumed that small hydropower entails fewer and less severe...
Hydrologic processes within mineral flat wetlands, along with their
connections to groundwater and downstream surface water in lowland agricultural
catchments are poorly understood, particularly under different land uses. In the three
field studies included in this thesis, we examined infiltration, wetland hydroperiod,
groundwater recharge dynamics, surface runoff generation, and water...
The re-introduction of large woody debris (LWD) into streams and rivers for stream restoration purposes is rapidly growing. Engineered log jams (ELJs) are man-made structures intended to mimic natural LWD structures, designed and installed to protect stream banks from erosion while increasing habitat diversity. Several studies have evaluated the flow...
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DesiréeD. Tullos
The re-introduction of large woody debris (LWD) into streams and rivers
Discussions around adapting water management systems to climate change often express the need to increase the flexibility and adaptive capacity of current systems, and to implement robust strategies going forth. While these topics lie at the center of many climate change discussions, transforming adaptation recommendations into tangible tools and information...
Multipurpose management of hydrosystems face a number of uncertainties related to hydrologic variability and nonstationarity. Anticipated air temperature increases in the Pacific Northwest region are projected to alter the timing and quantity of streamflow associated with precipitation shifting from snow to rain, including shorter winter runoff periods, earlier spring runoff,...
Even though cloudburst events in high mountain areas can be highly destructive and result in significant losses of life, little is known definitively about these flood events. An exact
understanding of the driving processes, typical precipitation rates, and impacts of cloudburst events remain uncertain. This study seeks to advance knowledge...
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Desirée Tullos
Even though cloudburst events in high mountain areas can be highly
Extreme, flood-producing precipitation events in mountains threaten human life and local and national economies. In the Himalayas, scarce meteorological data historically limited understanding of the underlying processes driving extreme events. However, the capacity to observe, measure and quantify precipitation on regional scales has increased tremendously over the last three decades...
As dams approach the end of their useful life, there is need to predict where and how accumulated sediment will move following their removal to estimate impacts on aquatic habitat and infrastructure. Flume studies suggest that sediment pulses disperse in place for most dams, but it is hypothesized that a...
Reed Canarygrass (RCG) is an aggressive invader in aquatic ecosystems that swiftly modifies the environment and decreases biodiversity. A physical model was used to investigate the mechanisms by which RCG spreads. Experimental trials were implemented to examine feedbacks between a mid-channel patch of the flexible RCG, hydraulics, and bedform evolution...
Floods remain the world’s most destructive natural hazard, despite centuries of efforts to minimize losses. Understanding public preferences for flood mitigation measures, and the impacts of these measures, is key to minimizing flood-induced losses. This study quantified tradeoffs between flood mitigation measures and determined factors that influence public preferences for...
This study examines different fate and transport processes of N and P based on uncultivated grass, contour crop, and livestock management across different topographies (i.e. 5% vs. 30% slope) found within the tropical mountains of volcanic pedogenesis in the Ambato river catchment. The hydrologic, cultural, and agricultural properties of the...
This research asserts that flood risk perception of individuals living in floodplains influences their preparedness for taking actions to protect themselves from flood hazards. The results of this research are backed up by quantitative analysis of survey responses of individuals living in floodplains of Corvallis, OR in the USA. The...
In the face of increasing demand for and reduced supplies of water, methods to augment water supply and storage capacity are becoming increasingly important. In some areas, this has taken the form of aquifer storage and recovery (ASR), which involves injecting water into a well during a time of water...
This study was conducted to determine if a time-integrated Phillips sampler was able to estimate sediment yield when compared to a reference produced by an automated sampler. Time-integrated samplers are easier to use, more cost effective, and can withstand storm events better than automated samplers, but are not designed to...
Floating guidance structures are intended to promote safe in-stream passage for juvenile salmon migrating downstream through reservoirs. However, the ability of an engineered structure to guide fish to safe passage has been primarily tested either after large-scale implementation in existing reservoirs or in laboratory studies and computer simulations without live...
The majority of dam removals are small structures that are governed primarily by state and local bodies. The objective of this study is to characterize and evaluate the governance that has driven recent decisions to remove small dams. In the governance literature on small dam removals, three aspects remain unclear....
Reservoir drawdown is a management technique increasingly used in maintenance of aging infrastructure, decommissioning dams, and to promote the flushing of fish and sediment to downstream reaches. Erosional processes in the reservoir may result in excessive delivery of sediment to downstream habitats and infrastructure, a critical long-term consideration. Typically, numerical...
This study assessed suitability of annelid habitats under current baseflow conditions and evaluated the mobility of suitable annelid substrates under a 2-year peak flushing flow. Outputs from a 2020 Bureau of Reclamation SRH-2D model were combined with field measurements of annelid presence/absence and habitat variables including depth, velocity and d50,...
After over two decades of advocacy and planning, the four hydroelectric facilities on the Klamath River will be decommissioned and removed starting in 2023. Significant positive changes are expected to result, from reduced severity of Harmful Algal Blooms (HABs) to nearly a two-fold increase in accessible habitat for native salmonid...
Low-tech habitat restoration techniques, including Stage 0 treatments, are increasingly applied but often lack robust evaluation of their effects. In 2018, one kilometer of the South Fork McKenzie (SFMK) River, OR was modified to the Stage 0 condition for the benefit of ESA-listed Chinook by raising the incised channel to...
Estimating how large instream wood (LW) may impact local hydraulics is critical both for mitigating flood hazards and for ensuring intended habitat benefits of the LW are produced. In practice, the design of forms such as LW is limited by a lack of mechanistic tools for estimating how LW features...
Estimating how large instream wood (LW) may impact local hydraulics is critical both for mitigating flood hazards and for ensuring intended habitat benefits of the LW are produced. In practice, the design of forms such as LW is limited by a lack of mechanistic tools for estimating how LW features...