Susan Wherry
Science and Products
Water-Quality Modeling Group
The USGS Oregon Water Science Center water-quality modeling group develops and uses models at a range of scales, from those that focus on a specific reservoir or river reach to large-scale nutrient models of the entire Pacific Northwest.
Future Climate Effects on Columbia and Willamette River Levees
USGS research directly helps local public agencies that are responsible for the design and maintenance of the levees that surround the northern Portland metropolitan area with the goal of protecting life and property in the event of flooding from the Columbia and Willamette Rivers that surround the city.
Factors affecting nitrate concentrations in stream base flow
Elevated nitrogen concentrations in streams and rivers in the Chesapeake Bay watershed have adversely affected the ecosystem health of the bay. Much of this nitrogen is derived as nitrate from groundwater that discharges to streams as base flow. In this study, boosted regression trees (BRTs) were used to relate nitrate concentrations in base flow...
Wherry, Susan; Tesoriero, Anthony J.; Terziotti, Silvia
Assessment of Columbia and Willamette River flood stage on the Columbia Corridor Levee System at Portland, Oregon, in a future climate
To support Levee Ready Columbia’s (LRC’s) effort to re-certify levees along the Columbia and Willamette Rivers and remain accredited, two 2-dimensional hydraulic models, Adaptive Hydraulics and Delft3D-Flexible Mesh, were used to simulate the effects of plausible extreme high water during the 2030 to 2059 period. The Columbia River was simulated...
Wherry, Susan A.; Wood, Tamara M.; Moritz, Hans R.; Duffy, Keith B.
A metabolism-based whole lake eutrophication model to estimate the magnitude and time scales of the effects of restoration in Upper Klamath Lake, south-central Oregon
A whole lake eutrophication (WLE) model approach for phosphorus and cyanobacterial biomass in Upper Klamath Lake, south-central Oregon, is presented here. The model is a successor to a previous model developed to inform a Total Maximum Daily Load (TMDL) for phosphorus in the lake, but is based on net primary production (NPP), which can be...
Wherry, Susan A.; Wood, Tamara M. Comparison of mercury mass loading in streams to atmospheric deposition in watersheds of Western North America: Evidence for non-atmospheric mercury sources
Annual stream loads of mercury (Hg) and inputs of wet and dry atmospheric Hg deposition to the landscape were investigated in watersheds of the Western United States and the Canadian-Alaskan Arctic. Mercury concentration and discharge data from flow gauging stations were used to compute annual mass loads with regression models. Measured wet and...
Domagalski, Joseph L.; Majewski, Michael S.; Alpers, Charles N.; Eckley, Chris S.; Eagles-Smith, Collin A.; Schenk, Liam N.; Wherry, Susan
Simulation of deep ventilation in Crater Lake, Oregon, 1951–2099
The frequency of deep ventilation events in Crater Lake, a caldera lake in the Oregon Cascade Mountains, was simulated in six future climate scenarios, using a 1-dimensional deep ventilation model (1DDV) that was developed to simulate the ventilation of deep water initiated by reverse stratification and subsequent thermobaric instability. The...
Wood, Tamara M.; Wherry, Susan A.; Piccolroaz, Sebastiano; Girdner, Scott F
Revision and proposed modification for a total maximum daily load model for Upper Klamath Lake, Oregon
This report presents Phase 2 of the review and development of the mass balance water-quality model, originally developed in 2001, that guided establishment of the phosphorus (P) total maximum daily load (TMDL) for Upper Klamath and Agency Lakes, Oregon. The purpose of Phase 2 was to incorporate a longer (19-year) set of external phosphorus loading...
Wherry, Susan A.; Wood, Tamara M.; Anderson, Chauncey W.
New USGS study identifies key factors affecting nitrate concentrations in stream base flow in Chesapeake Bay watershed
A new USGS study has identified factors that contribute to high nitrate in base flow in streams flowing into Chesapeake Bay. Land use, organic carbon in soils, and geology were among the most important factors affecting nitrate in stream base flow, based on data collected at 156 stream sites.