Publications

Air pollution, harvesting practices, and natural disturbances can affect the growth of trees and forest development. To make predictions about anthropogenic impacts on forests, we need to understand how these factors affect tree growth. In this study the effect of disturbance history on tree growth and stand structure was examined by using a computer model of forest development. The...

Water resources data for the 1986 water year for Iowa consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; ground-water levels and ground-water quality. This report contains discharge records for 110 stream-gaging stations; stage and contents for 8 lakes and reservoirs; water quality for 8 stream-gaging stations...

This report provides techniques and procedures for estimating the probable magnitude and frequency of floods at ungaged sites on Iowa streams. Physiographic characteristics were used to define the boundaries of five hydrologic regions. Regional regression equations that relate the size of the drainage area to flood magnitude are defined for estimating peak discharges having specified...

The water levels 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 17, at New Boston, Illinois, were developed from current meter discharge measurements made in the forebays of the gate structures. Methodology is given to compute the gate openings of the...

This report presents stations descriptions and tables of peak stages and discharges for 280 continuous- and partial-record gaging stations in Iowa. Data for the annual flood series for each gaging station and partial-duration series, at stations where available, are contained in the report.

The population served by ground-water supplies in Iowa (fig. L4) is estimated to be about 2,392,000, or 82 percent of the total population (U.S. Geological Survey, 1985, p. 211). The population of Iowa is distributed fairly uniformly throughout the State (fig. IB), with 59 percent residing in rural areas or towns of less than 10,000 (U.S. Bureau of the Census, 1982). Surficial aquifers...

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Samples of bluegills (Lepomis macrochirus) and common carp (Cyprinus carpio) collected from the San Joaquin River and two tributaries (Merced River and Salt Slough) in California were analyzed for 21 organochlorine chemical residues by gas chromatography to determine if pesticide contamination was confined to downstream sites exposed to irrigated agriculture, or if nonirrigated upstream...