Conference Papers
Science Quality and Integrity
The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
Browse almost 5,000 conference papers authored by our scientists and refine search by topic, location, year, and advanced search.
Filter Total Items: 5321
Source of atrazine and desethylatrazine in a river, during base flow
A budget of atrazine and desethylatrazine loads was computed for a 116-kilometer reach of the Cedar River in Iowa to determine where these compounds enter the river during base-flow conditions. Loads were determined by measuring discharge and concentrations of the compounds for four main-stem sites along the Cedar River and for 27 tributaries on September 20-22, 1989. Tributaries contributed 17 pe
Authors
Paul J. Squillace, E. Michael Thurman, Edward E. Fischer, Phil J. Soenksen
Spatial Data Transfer Standard and efforts to develop a federal Profile for Vector Data
The ongoing efforts to create a more accessible and user friendly Spatial Data Transfer Standard include the development of a Profile for Vector Data and the development of a library of public domain software tools to support the encoding and decoding process. A profile is, in effect, a limited subset of the standard. The best way to use the standard is to first define a profile containing a limit
Authors
Matthew H. McDermott, Anthony DeWitt
Strontium isotopes in carbonate deposits at Crater Flat, Nevada
Strontium isotope studies of carbonates from soils, veins, eolian dust and Paleozoic basement sampled near Crater Flat, southwest of Yucca Mountain, provide evidence for the origins of these materials. Vein and soil carbonates have nearly identical ranges of 87Sr/86Sr, and eolian material has 87Sr/86Sr ratios at the lower end of the pedogenic range. The average 87Sr/86Sr of Paleozoic basement from
Authors
B.D. Marshall, K. Futa, Z. E. Peterman, J. S. Stuckless
Survey of rural, private wells. Statistical design
Half of Illinois' 38 million acres were planted in corn and soybeans in 1988. On the 19 million acres planted in corn and soybeans, approximately 1 million tons of nitrogen fertilizer and 50 million pounds of pesticides were applied. Because groundwater is the water supply for over 90 percent of rural Illinois, the occurrence of agricultural chemicals in groundwater in Illinois is of interest to t
Authors
Edward Mehnert, Susan C. Schock
Techniques and strategies for data integration in mineral resource assessment
The Geologic and the National Mapping divisions of the U.S. Geological Survey have been involved formally in cooperative research and development of computer-based geographic information systems (GISs) applied to mineral-resource assessment objectives since 1982. Experience in the Conterminous United States Mineral Assessment Program (CUSMAP) projects including the Rolla, Missouri; Dillon, Montana
Authors
Charles M. Trautwein, John L. Dwyer
Testing a method-of-characteristics model of three-dimensional solute transport in ground water
A new three-dimensional model of solute transport in groundwater that is based on a widely used two-dimensional method of characteristics model and is coupled to a modular finite-difference flow model is under development. The model's accuracy for ideal aquifers having homogeneous properties, uniform boundary conditions, and steady flow along a grid direction is demonstrated by comparison with con
Authors
Daniel J. Goode, Leonard F. Konikow
The application of current techniques in molecular biology for detection and control of infectious diseases in salmonid aquaculture
No abstract available
Authors
A.C. Fox, C.K. Arakawa, J. R. Winton
The ecological and evolutionary consequences of body size: Introductory remarks
No abstract available.
Authors
John F. Piatt
Tidal mass exchange between a submersed aquatic vegetation bed and the main channel of the Potomac River
Tidal mass exchange between a submersed aquatic vegetation (SAV) bed and the main channel of the Potomac River was investigated. Water levels were recorded at 5 minute intervals from August (when plants were present) through December (when plants were absent). Velocities were measured during individual tidal cycles both in the presence and absence of plants. Flow patterns were found to be altered
Authors
Harry L. Jenter, Nancy B. Rybicki, Robert A. Baltzer, Virginia Carter
Tolerance of juvenile lake trout exposed to gas supersaturation
No abstract available at this time
Authors
W. F. Krise, R. A. Smith
Ultrasonic velocity meter used in stream gaging
Many streams and canals in Florida are affected by tides or control structures and experience very low flow velocities at times. For example, the St. Johns River in northeastern Florida is affected by tides for about 140 miles upstream from its mouth and many canals in the Miami area of southeastern Florida are controlled by manmade structures and other elements that cause a variable backwater eff
Authors
L.D. Fayard
Uncertainty in climate change and drought
A series of projections of climate change were applied to a watershed model of the Delaware River basin to identify sources of uncertainty in predicting effects of climate change on drought in the basin as defined by New York City reservoir contents. The watershed model is a calibrated, monthly time-step water-balance model that incorporates the operation of reservoirs and diversion canals, and ac
Authors
Gregory J. McCabe, David M. Wolock, Gary D. Tasker, Mark A. Ayers