The Amazon Tropical Rain Forest is the largest tropical rain forest system, comprising approximately 65% of such forests on earth. Since the 1960's, human populations in the Brazilian Amazon have increased from two to over 20 million. Concomitant urbanization, forest conversion, and economic dependence on resource extraction have exerted severe...
The West Eugene Wetlands, Eugene, Oregon, which provide habitat for number of endemic and endangered plant species, are currently threatened by a Reed canarygrass (Phalaris arundinacea L.) invasion. This study addresses the hypothesis that Phalaris spread can be explained in part by using watershed-scale landuse patterns as surrogates of the...
In July of 2001, the Environmental Protection Agency (EPA)
activated the Total Maximum Daily Load (TMDLs) provisions of the
Clean Water Act. As the first river in Oregon to implement TMDL
regulations, people and agencies in the Tualatin basin face many
challenges. Non-point source pollution affects water quality in the...
Linkages between land use and its influence on the atmosphere have been a long-standing research area. For example, what is the impact of irrigated agriculture on downwind rainfall? Global-scale models show that moisture recycling is an important source of water for inland regions around the world, but they do not...
Human activities may contribute to the eutrophication of surface waters by
providing nutrients to aquatic ecosystems. Phosphorus is frequently identified as a
nutrient that is limiting to most aquatic ecosystems under natural conditions. Sources of
phosphorus contributing to eutrophic conditions often include nonpoint sources that are
dispersed across the landscape....
The Willamette River and its floodplain in northwest Oregon have changed dramatically since European settlement. At one time, the river was a vast complex system of braided channels with a broad floodplain forest; it has now been simplified by channelization and dams, and the forest has been removed to support...
This report presents estimates of land uses, concentrating on agricultural land in the Tualatin drainage basin. Acreage in different crop groups and agricultural water use and distribution in the watershed were estimated. The total amounts of nitrogen and phosphate applied to agricultural land and the average loading of nutrients per...
The Calapooia River, a major tributary of the Willamette River in western Oregon, is a watershed typical of many found in the Willamette Basin. Public and private forested lands occur in the steep Upper Zone of the watershed, mixed forest and agriculture lands are found in the Middle Zone, and...
Reservoir systems in the western US are managed to serve two main competing purposes: to reduce flooding during the winter and spring, and to provide water supply for multiple uses during the summer. Because the storage capacity of a reservoir cannot be used for both flood damage reduction and water...
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Table 2.4. The total area of land in developed use within the WRB mainstem floodplain, under
Since the early 1980s, satellite imagery has been commonly used to detect change
in wetlands. The overall objective of this study is to utilize remote sensing and
Geographic Information Systems (GIS) technology to determine the extent of change of
the wetland area and of other land use and land cover...
Land use alters the physical and biological structure of stream ecosystems and potentially alters their capacity to process nitrogen (N), an essential nutrient that has nearly doubled in abundance on the biosphere
during the past century from human activities. In this dissertation, I quantified uptake and transformation of nitrate (NO₃⁻)...
The growing population of Oregon’s Willamette River Basin places an increasing demand on the basin’s surface waters. Watershed-scale research addressing spatial trends of dissolved nitrogen (DN) and its relationship with landuse and soil N dynamics, such as N mineralization, is sparse in the Willamette Basin. I measured DN along 124...
To better understand the impact of land use on stream nutrient export, a synoptic sampling of 57 sub-basins within the Willamette River basin was conducted during winter baseflow conditions (February 2009). I assessed whether stream dissolved organic carbon (DOC), NO₃⁻ and Cl⁻ and specific ultra-violet absorbance (SUVA) values were correlated...
The U.S. Bureau of Fisheries (now National Marine Fisheries Service) conducted stream habitat surveys in the Upper Grande Ronde River Basin in 1941. This survey was part of an extensive inventory of stream habitat conditions for anadromous salmonids (Oncorhynchus spp.) throughout the Columbia River Basin. The survey systematically
inventoried 158...
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,...
Water quality and stream flow data for tliree representative land uses in the Tualatin River Basin were evaluated to determine the comparative levels of various pollutants. In addition, the data were used in an effort to identify the extent to which observed concentrations of total and ortho phosphorus could be...
The primary goal of this research was to identify the impacts that individual agricultural land uses have on fish communities in small streams located in the Willamette Valley of western Oregon. The diverse nature of the land use features of the valley provided a challenging but useful system for the...
This thesis examines prehistoric land use patterns of the entire North Santiam subbasin, located on the western slopes of the Oregon Cascade Range. The objective of this analysis is three-fold: 1) to contribute to reconstructing the cultural chronology of the area; 2) to address the use of raw material by...
This ethnographic study explores the social aspects of agricultural land-use in the Marys River region. The study seeks to understand how farmers define sustainability and how their views on agricultural issues help to define a sense of place and identity in the Marys River region, within the context of the...