Publications

From April 1993 to September 1995, the U.S. Geological Survey conducted a study of the occurrence and distribution of nutrients and pesticides in surface water of the Willamette and Sandy River Basins, Oregon, as part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program. About 260 samples were collected at 51 sites during the study; of these, more than 60...

No abstract available.

This report describes the results of a synoptic water-quality and algal investigation during July 1995 at 36 stream sites in a 1,350 square-mile area of the North Umpqua River Basin, Oregon. The study area includes a headwaters hydroelectric project area, a Wild and Scenic reach in the main stem immediately downstream, and the watersheds of several major tributaries. Additional data from...

In September 1996, a water-quality study was done by the U.S. Geological Survey, in coordination with the U.S. Forest Service, in headwater streams of Steamboat Creek, a tributary to the North Umpqua River Basin in southwestern Oregon. Field measurements were made in and surface-water and bottom-sediment samples were collected from three tributaries of Steamboat Creek--Singe Creek, City...

No abstract available.

This report describes the Cenozoic geology of the Willamette Lowland physiographic province, and the geologic framework of the regional ground-water flow system. Five regional hydrogeologic units are identified and described. The report includes maps showing the altitude of the top and the thickness of each hydrogeologic unit.

During 1992-93, 27 organochlorine compounds (pesticides plus total PCB) and 17 trace elements were analyzed in bed sediment and aquatic biota from 20 stream sites in the Willamette Basin as part of the U.S. Geological Survey's National Water-Quality Assessment Program. Data from each medium were compared to evaluate their relative effectiveness for assessing occurrence (broadly defined...

A ground-water flow model was used in conjunction with a particle-tracking program to demonstrate a method of evaluating ground-water vulnerability. The study area encompassed the part of the Portland Basin located in Clark County, Washington. A new computer program was developed that interfaces the particle-tracking program with a geographic information system (GIS). The GIS was used to...

This report is intended to summarize major findings that emerged between 1991 and 1995 from the water-quality assessment of the Willamette Basin Study Unit and to relate these findings to water-quality issues of regional and national concern. The information is primarily intended for those who are involved in water-resource management. Yet, the information contained here may also...

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) are highly hydrophobic compounds that have been implicated as carcinogens and, more recently, as estrogen disrupters. An occurrence and distribution study of these compounds in the Willamette Basin, Oregon, was conducted by the U.S. Geological Survey as part of the National Water-Quality Assessment Program. Bed sediment was...

This report summarizes the hydraulic characteristics of the materials that make up the Willamette Lowland aquifer system, ground-water movement in the aquifer system, estimates of ground-water recharge, ground-water quality characteristics, construction and use of cross-sectional numerical ground-water flow models, hydrologic controls on ground-water movement, water budgets and flow...

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) are related compounds that are of interest primarily because of their potential toxicity. They are considered carcinogens and have been implicated as hormone disrupters. An occurrence and distribution study of these compounds in the Willamette Basin, Oregon, was done by the U.S. Geological Survey in 1992- 1995. Bed sediment...