Publications

Stream hydrographs show that throughout the Grand Ronde area most precipitation follows surface or shallow subsurface pathways to streams, resulting in rapid runoff and little natural water storage within the basin. Limited storage and low aquifer permeability restrict base flow to streams, and streamflows therefore decline rapidly once precipitation ceases. Shallow ground water and...

Water-temperature, air-temperature, specific- conductance, wind-speed, and solar-radiation data are presented from a study conducted in the Tualatin River Basin in northwestern Oregon during 7-month periods from May 1 through November 30, 1994 and May 1 through November 30, 1995. The study was done to assist local and State agencies in understanding temporal and spatial patterns of water

No abstract available.

Available information on aquatic biota of the Willamette Basin was reviewed and summarized to describe current and historical conditions as part of the U.S. Geological Survey's National Water-Quality Assessment Program. Biological parameters emphasized include the status, distribution, and trends of aquatic biota, particularly algae, macroinvertebrates, and fish; the condition of aquatic...

This report describes the results of a study in which chlorofluorocarbon-age dating was used to evaluate the results of a ground-water particle tracker for the Portland Basin in Oregon and Washington.

Upper Klamath Lake and the connecting Agency Lake constitute a large, shallow lake in south-central Oregon that the historical record indicates has likely been eutrophic since its discovery by non-Native Americans. In recent decades, however, the lake has had annual occurrences of near-monoculture blooms of the blue-green alga Aphanizomenon flos-aquae that are thought to be a result of...

This report describes the capacity of the Tualatin River to assimilate oxygen-demanding material during winter streamflow conditions, with an emphasis on peak-flow and winter base-flow conditions. The study examined major processes governing concentrations of dissolved oxygen (DO) in the river under different streamflow conditions, as well as the effect of streamflow and temperature on...

Sediment oxygen demand (SOD) rates were measured by U.S. Geological Survey (USGS) personnel at 20 stream sites in the Tualatin River Basin from 1992 through 1996 as part of an investigation into the sources and sinks of dissolved oxygen in the Tualatin River. During the low-flow summer periods of 1992 through 1994, 97 measurements were collected at 9 sites on the main stem of the river...

No abstract available.

Biological investigations were conducted in the Yakima River Basin, Washington, in conjunction with a pilot study for the U.S. Geological Survey's National Water-Quality Assessment Program. Ecological surveys were conducted at 25 sites in 1990 to (1) assess water-quality conditions based on fish, benthic invertebrate, and algal communities; (2) determine the hydrologic, habitat, and...

Floods from failures of natural and constructed dams constitute a widespread hazard to people and property. Expeditious means of assessing flood hazards are necessary, particularly in the case of natural dams, which may form suddenly and unexpectedly. We revise statistical relations (derived from data for past constructed and natural dam failures) between peak discharge (Qp) and water...

This report is an evaluation of the effects of nutrient loading on water quality in the South Umpqua River Basin. The study was done by the U.S. Geological Survey in cooperation with Douglas County, Oregon. Five wastewater-treatment plants were shown to contribute less than 15 percent of the flow, but more than 90 percent of the nitrogen and phosphorus, in the South Umpqua River during...