Publications

The water level of the navigation pools on the Mississippi River are maintained by the operation of tainter and roller gates at the locks and dams. Discharge ratings for the gates on Lock and Dam 12, at Bellevue, Iowa, were developed from current-meter discharge measurements made in the forebays of the gate structures. Methodology is given to accurately compute the gate openings of the...

Development and habitat alteration in the San Francisco Bay-Delta system have placed the remaining wetlands in jeopardy. The Bay-Delta wetlands will be mapped in a joint project of the U. S. Environmental Protection Agency (EPA) and the U. S. Fish and Wildlife Service (FWS). Maps at a 1:24,000 scale will be produced for the entire study area. High altitude color infrared photography from...

No abstract available.

Rapid expansion of irrigated agriculture in the western United States has prompted concerns for aquatic resources. Although the impacts of irrigation activities on quality and quantity of river water are well documented (e.g., high turbidity from soil erosion, eutrophication from nutrient runoff, pesticide contamination, reduced dis- charge), their effects on fish populations are still...

The U.S. Fish and Wildlife Service analyzed residues of organochlorine chemicals in 315 composite samples of whole fish collected in 1980–81 from 107 stations nationwide as part of the National Pesticide Monitoring Program (NPMP). The mean concentrations of total DDT and allp,p′-ho-mologs exceptp,p′-DDT showed significant but small declines relative to mean concentrations before 1978–79...

No abstract available.

No abstract available.

Meiofauna diets and behavioral patterns are relatively unknown despite the fact that in any system, predatory relationships and behavioral responses may play an important role in determining community structure. Therefore, observations on food preferences, feeding behavior, and encounter interactions of members of a meiofauna assemblage were made in the laboratory in dishes of natural...

No abstract available.

The purpose of this investigation was to determine the availability, quantity and quality of groundwater from three principal aquifers in West-Central Iowa, the alluvial, buried channel, Basal Pleistocene and the Dakota aquifers. Specific objectives were to: (1) determine the location, extent and the nature of these aquifers; (2) evaluate the occurrence and movement of groundwater...

No abstract available.

One of man's fundamental needs is water. Modern man needs both a safe and dependable supply of water to maintain his present economic, industrial, and cultural level. In order to use this natural resource in the most efficient and beneficial manner, a basic knowledge and understanding of water sources, and of the occurrence and potential of each source, needs to be gained. To provide...