Publications

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...

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

No abstract available.

"The general welfare of the people of the state of Iowa requires that the water resources of the state be put to beneficial use to the fullest extent of which they are capable." This can be achieved only by a knowledge and understanding of the water resources - their use, their source, their quality, their availability, and the demands place upon them. To provide such knowledge and...

The insecticidal properties of rotenone and pyrethrum have been known for many years. Both toxicants have long histories of extensive use for control of a variety of insect pests. Rotenone has been also employed as a management tool by fishery biologists to rehabilitate fishing waters, and its toxicity to fish in a number of ecological situations is well established. Pyrethrum's toxicity...