Publications

Oxygen-isotope compositions of authigenic-layer silicates (

Although considerable effort has been expended during the past two decades to control nonpoint-source contamination of streams and lakes in urban and rural watersheds, little has been published on the effectiveness of various management practices at the watershed scale. This report presents a discussion of several parametric and nonparametric statistical techniques for detecting changes...

The U.S. Geological Survey began a research project at the site of a crude oil spill near Bemidji, Minnesota in 1983. The project is part of the U.S. Geological Survey's Toxic Substances Hydrology Program. The objectives of research at this site are to obtain an understanding of the mobilization, transport, and fate of petroleum derivatives in the shallow subsurface and to use this...

PROBLEM: Surface-water information is needed for surveillance, planning, design, hazard warning, operation, and management in water-related fields such as water supply, hydroelectric power, flood control, irrigation, bridge and culvert design, wildlife management, pollution abatement, flood-plain management, and water-resources development. An appropriate data base is necessary to...

Water levels, locations, depths, and aquifers tapped are given for 107 observation wells. Tabulated data include a listing of ground-water reports in Michigan, extremes of water levels for calendar year 1990 and for the period of record, pumpage of most major ground-water users in the State, and a map showing previous collected water-quality data from selected wells. In 1990, the two...

The U.S. Geological Survey collected water samples from the five major tributaries to Green Bay, Lake Michigan, to determine the load of total polychlorinated biphenyls (RGB's) entering the bay. These samples were collected from January 1989 through early May 1990 from the Escanaba, Menominee, Peshtigo, Oconto, and Fox Rivers. Sampling sites were located near the mouth of each river and...

Rates of water movement through the unsaturated zone greatly affect the amount and concentrations of agricultural chemicals that may reach the water table. For example, recharge can flush chemicals to the water table which have accumulated in the unsaturated zone during dry periods. A better understanding of how topography influences recharge and the movement of agricultural chemicals is...

No abstract available.

No abstract available.

This report presents the annual results of the U.S. Geological Survey's (USGS) watershed-management evaluation monitoring program in Wisconsin. The overall objective of each individual project in the program is to determine if the water chemistry in the receiving stream has changed as a result of the implementation of land-management practices in the watershed. This is accomplished...

Accurate delineation of recharge areas for wells is an important requisite to protecting ground-water quality. Zones of transport and zones of contribution are two types of recharge areas that can be delineated. Analytical-calculation, numerical-modeling, and hydrogeologic-mapping methods were used to delineate recharge areas for two high-capacity wells (greater than about 200 gallons...

In 7-m3 outdoor tanks filled with lake water, the presence/absence of omnivorous young-of-the- year Micropterus salmoides), zooplanktivorous Menidia beryllina , and herbivorous larval Hyla chrysocelis was experimentally manipulated. A cross-classified design was used to assess the interactive effects of these vertebrate consumers on the experimental food webs. The primary effects of the