Record Display for the EPA National Library Catalog


OLS Field Name OLS Field Data
Main Title Field-to-stream transport of agricultural chemicals and sediment in an Iowa watershed. Part 1, Data base for model testing (1976-1978) /
Author Johnson, H. P.
Other Authors
Author Title of a Work
Baker, J. L.
Publisher U.S. Environmental Protection Agency, Environmental Research Laboratory,
Year Published 1982
Report Number EPA/600-S3-82-032
OCLC Number 456547909
Subjects Watersheds--Iowa. ; Water--Pollution--Iowa. ; Erosion--Iowa.
Internet Access
Description Access URL
Library Call Number Additional Info Location Last
EJBD ARCHIVE EPA 600-S3-82-032 In Binder Headquarters Library/Washington,DC 04/11/2018
EJBD  EPA 600-S3-82-032 In Binder Headquarters Library/Washington,DC 11/14/2018
Collation 4 pages : illustrations ; 28 cm
Caption title. At head of title: Project Summary. Distributed to depository libraries in microfiche. "EPA/600-S3-82-032." "Sept. 1982."
Contents Notes
Data on the field-to-stream transport of sediment and chemicals from an agricultural watershed were collected in a three-year study to provide information for testing and evaluating mathematical models under development for predicting agricultural non-point source pollution. These models are prepared as tools to evaluate the effectiveness of different farm management practices in controlling losses of nutrients, pesticides, and sediment in field drainage to receiving waters. In the study, data were collected for small corn, soybean, and pasture fields; for two larger mixed-cover watersheds; and at three drainage-stream sites. During the study (1976-1978), annual rainfall (753 mm) and streamflow (124 mm) averaged a little below normal. Sediment losses were also low because of a lack of intense rains, averaging 2.6 t/ha from row-crops and 0.9 t/ha from the watershed as a whole. Soluble chemical losses (NH4-N, NO3-IM, PO<-P, Cl and TDS) in surface runoff were less than that deposited with rainfall. Because IMO3-N, Cl and TDS were concentrated in subsurface drainage, losses from the watershed as a whole due to streamflow (surface plus subsurface drainage) were significantly larger than losses from surface runoff alone. Average annual pesticide losses from the field were least for the shortest-lived herbicide (0.2% of that applied) and greatest for the most persistent (1.6%). No runoff event occurred within a week of application. On the basis of percentage applied, losses or export from the watershed as a whole were about 25% of the losses from the two individual fields studied. With the exception of the strongly adsorbed paraquat, at least 80% of the losses occurred in the water phase as opposed to that adsorbed on sediment.