Publications

In complementary studies of the chronic effects of heptachlor on bluegills, four similar earthen ponds were treated once with different concentrations of heptachlor, and the fish in six plastic pools were routinely fed different levels of heptachlor. A fifth pond and two plastic pools were used as controls. Higher dosages resulted in higher concentrations of heptachlor residues, more...

No abstract available.

Base-flow recession. curves for the summer months (June through September) were developed in this study for gaging stations on interior Iowa streams having five or more years of record. The tabulated data enables the user, starting with a known base flow at a gage, to estimate base flows for up to 20 days in the future. Rainfall during the period o£ the forecast will require that a new...

Factors influencing the uptake of the sodium salt of 2,4-dichlorophenoxyacetic acid (2,4-D), under conditions in which no net metabolism occurred, were investigated in an effort to determine both the significance of “non-metabolic” uptake as a potential agent in reducing pesticide levels and the mechanisms involved. Uptake of 2,4-D was affected by pH, temperature, and the presence of...

In two experiments 2,6-dichlorobenzonitrile was added to aquatic systems, and the residue levels were followed for about 6 months. A granular formulation applied to a farm pond at 0.6 p.p.m. produced highest residues in water and fish about 2 weeks following treatment whereas vegetation and soil samples had the highest levels within 1 or 2 days. Residues were still measurable after 188...

Laboratory bioassays were conducted with some chlorinated hydrocarbon insecticides, organophosphate insecticides, other insecticides and acaricides, and with herbicides to determine their relative toxicities and immobilization values for two species of daphnids, Daphnia pulex and Simocephalus serrulatus. Both species are satisfactory bioassay organisms for the determination of a wide...

This investigation was undertaken as a part of the cooperative program with the Iowa Institute of Hydraulic Research, the City of Des Moines, and the U.S. Geological Survey. The purpose of this report is twofold: 1. To present water-surface profiles and rating curves for existing channel conditions in the 4-mile reach of Raccoon River upstream from the mouth, and 2. To show the effect...

Factors influencing the uptake of the sodium salt of 2,4-dichlorophenoxyacetic acid (2,4-D), under conditions in which no net metabolism occurred, were investigated in an effort to determine both the significance of “non-metabolic” uptake as a potential agent in reducing pesticide levels and the mechanisms involved. Uptake of 2,4-D was affected by pH, temperature, and the presence of...

Highway engineers and many others use flood stages and discharges in the design of bridges and other structures or operations on the flood plain of a stream. These data are provided in the form of gaging-station and other flood records and as flood profiles. Flood-frequency data are used to compute the 25- and 50-year recurrence interval discharges along the Little Sioux River from mile...

Flood records for regular and partial-record gaging stations are contained in the following pages. Each listing contains the station number and name, descriptive paragraphs pertaining to the station, and a listing of the flood peaks available through the 1965 water year. Peaks above a base as well as annual peaks are listed. These provide the data for a partial-duration flood-frequency...

No abstract available

No abstract available