Publications

Groundwater is the major source of water in Linn County and the surrounding area. Approximately 90 percent of the groundwater production is from Silurian, Devonian, and Quaternary aquifers. The Silurian and Devonian aquifers consist of limestone and dolomite with minor shale beds, which have a regional dip to the southwest of approximately 20 feet per mile. The Silurian aquifer in east...

No abstract available.

The surface-water resources of the United States, the focal point for this National Water Summary, are extensively developed and managed to provide water supplies, hydroelectric power, navigation, recreational opportunities, and sufficient instream flows to maintain fish and wildlife habitats and adequate water quality. Surface water represents 77 percent of the Nation's total freshwater

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 13, at Fullerton, Illinois, 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...

Changes in seepage flux and head (groundwater level) from groundwater drainage into a surface coal mine can be predicted by a technique that considers drainage from the unsaturated zone. The user applies site-specific data to precalculated head and seepage-flux profiles. Groundwater flow through hypothetical aquifer cross sections was simulated using the U.S. Geological Survey finite...

Record flood-peak discharges occurred in June and July, 1982, in southwestern, south-central, and east-central Iowa. The record flood peaks resulted from rainfalls of 6 to 8 inches on soil saturated from persistent moderate to heavy rainfalls that began in May and continued through mid July. May was the wettest across Iowa since 1959, averaging just over 7 inches statewide to rank as...

Flood profiles and discharges for the great floods of 1981 and 1982 in south-central Iowa are given. The profiles cover the South River, Squaw Creek, Otter Creek, White Breast Creek, Cedar Creek, North Cedar Creek, Chariton River and the South Fork Chariton River. The July 3, 1982, flood-peak discharge at the Cedar Creek gaging stations (05489000) near Bussey was 4.4 times that of the...

The water level of the navigation pools on the Mississippi River are maintained by the operation of tainted and roller gates at the locks and dams. Discharge ratings for the gates on Lock and Dam 22, at Saverton, Missouri, 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 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...