The purposes of this report are to describe the quality of shallow ground water in alluvial aquifers of the Willamette Basin and to identify relationships between shallow ground-water quality and various natural and anthropogenic factors. Several natural and anthropogenic factors (soil characteristics, cumulative thickness of clay above open interval of...
The basaltic landscapes of the Oregon High Cascades form a natural laboratory for examining how geologic setting and history influence groundwater flowpaths, streamflow sensitivity to climate, and landscape evolution. In the High Cascades, highly permeable young basaltic lavas form extensive aquifers. These aquifers are the dominant sources of summer streamflow...
An ASR metric and site rating index applied to over 120 municipal and agricultural locations across Oregon, combined with comparison to case study data from existing ASR sites, indicate that more than 50% of selected sites are hydrogeologically suitable for ASR. The ASR metric is a ratio of aquifer storage...
Harney County contains defining characteristics of regions containing arsenic within the groundwater such as its location in the western United States, unique closed basin geography, complex geology, and seasonal groundwater level fluctuations. Confirmation of arsenic concentrations above the Maximum Contaminant Level Drinking Water Standard of 10 μg/L has been observed...
This thesis presents a hydrogeologic study of the Parrett Mountain Region,
located approximately 20 miles south of Portland, Oregon. The aim of the study was
to investigate the impacts of Columbia River Basalt on the regional groundwater
system, to expand our understanding of flow through fractured basalt, to improve
management...
Elevated groundwater nitrate (NO3
-) concentrations in the Southern Willamette
Valley (SWV) caused the Oregon Department of Environmental Quality (ODEQ) to
declare a Groundwater Management Area (GWMA) in Spring, 2004. To better
understand direction of groundwater flow, groundwater age, and nitrate transport
pathways of the SWV we developed a steady-state...
Low-permeability geologic units may offer significant chemical and hydraulic protection of adjacent aquifers, and are important for managing groundwater quality, especially in areas with significant non-point source contamination. Nitrate in the Willamette Valley is attenuated across the Willamette Silt, a semi-confining unit overlying a regionally important aquifer. To quantify the...
Precipitation data from 1988-1995 for 13 rain gauges of the Department of Forest
Engineering rain gauge network, and a longer precipitation record, 1976-1995, at Mapleton were analyzed. The objectives were to assess the spatial and temporal distribution of precipitation intensity and antecedent precipitation, and understand the role of these characteristics...
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,...
Benton County has experienced substantial growth in the past 30 years, and is expected to continue growing (BCWP 2008). Continued development has occurred in the Willamette Valley, housing development in the nearby hills of the Coast Range is growing. New houses in the foothills of the Coast Range may not...
