Stephen Kalkhoff

Stephen Kalkhoff  is currently a hydrologist with the U.S. Geological Survey, Central Midwest Water Science Center located in Iowa City, Iowa.


Since 1994, he has been the chief of the Eastern Iowa Basins(EIWA) study unit of the USGS National Water-Quality Assessment program. Responsibilities have included planning to incorporate both National and local program objectives, collection of water quality data, and interpretation of the results. He is currently evaluating the trends in nutrients and pesticide concentrations and transport  during the last decade in Iowa’s major rivers. Kalkhoff also is documenting the concentrations and transport of nitrogen and phosphorus in the Missouri River basin during floods in 2011.

Kalkhoff  has both coordinated and participated in research on agricultural impacts on water resources that investigated the occurrence and changes in agricultural chemicals in the Nation’s water resources. In 1997, he participated in a Midwest regional synoptic study to evaluate relation between stream water quality and biological communities. In 2004-2005, he was the leader of a study to determine the occurrence of perchlorate in surface and ground water across the United States.

Kalkhoff is currently a member of the Iowa DNR's Stream Aquatic Life Nutrient Criteria and Nutrient LoadsTechnical Advisory Committees


Graduate courses-- Natural Resources, University of Minnesota        Fall 1979
B.S. Aquatic Biology--Bemidji State University, Bemidji, MN                Spring 1978

Professional Experience

2011-Present Supervisor of the Water Quality and Environmental Health Unit U.S. Geological Survey Central Midwest Water Science Center
1994-2012 Chief of the Eastern Iowa Basins(EIWA) study unit
USGS National Water-Quality Assessment program
2004-2008 Project chief --Transport of nutrients and pesticides to the Missouri and Mississippi River study Cooperative Iowa DNR /USGS project 
Project chief--  Perchlorate reconnaissance of surface and ground water in the United States
2004-2005 USGS Central Region Integrated Science program  (CRISP)
2000-2002 Team member – Heinz Center Report on the State of the Nation’s water resources
1986-1994 Project chief – Big Spring project (study impact of changing land use practices on water quality in an area of karst topography in Iowa) Cooperative Iowa DNR /USGS project
1982-1986 Project chief – Brine contamination of surface and ground water in Mississippi Cooperative Mississippi DNR/ USGS project 
1980-1982 Hydrologist – collected water samples and prepared reports for waste assimilation studies in Mississippi

Professional Activity

Member of the Iowa DNR Aquatic Life Nutrient Criteria Technical Advisory committee

Conference and Symposium Presentations

Effect of Drought on the Transport of Nitrate in a Midwest Stream by Kalkhoff, S. J.,Garrett, J.D. and Holt, K. presented at 9th National Monitoring Conference, April 28-May 2, 2014, in Cincinnati, OH
Changing Stream Water Quality During the Last Decade in Two Midwestern Agricultural Watersheds by Kalkhoff, S.J., Tomer, M., Garrett, J.D., Fallon, J.D., and Lampe, D.C, 2010, presented at the 2010 Iowa Department of Natural Resource Water Monitoring Conference
Perchlorate occurrence in surface waters, groundwater, and biota of the north-central and southwest USA, 2006, Gregory L. Linder, Stephen J. Kalkhoff, Sarah J. Stetson, Edward E. Little, Richard B. Wanty, presented at the ASTM International Symposium on Perchlorate: Exposures from Food and the Environment, February 9, 2006, Phoenix, AZ
Monitoring perchlorate in shallow ground water in the Central United States, 2006, Stephen J. Kalkhoff, Lynne S. Fahlquist, W. Andrew Jackson, Sarah J. Stetson, Richard B. Wanty, and Gregory L. Linder, presented at National Water Quality Monitoring Council meeting, May 7-11, 2006, San Jose, CA.
Perchlorate Occurrence in Ground Water in the North Central United States, 2005, Stephen J. Kalkhoff, Sarah J. Stetson, Richard B. Wanty, and Gregory L. Linder, presented at the Iowa Groundwater Association Fall 2005 meeting, October 27, 2005, Iowa City, IA
Preliminary Analyses for Perchlorate in Selected Natural Materials and Their Derivative Products, 2004, Stephen J. Kalkhoff, Richard B. Wanty, Gregory L. Linder presented at U.S. EPA’s Technical Advisory meeting held in Sacrameto, CA on October 19, 2004.
The occurrence of chloroacetanilide and triazine herbicide degradates in streams in eastern Iowa, by Kalkhoff, S.J., Schnoebelen, D.J., and Thurman, E.M., 2001, presented at the Agriculture and the Environment: State and Federal Water Initiatives Conference: Iowa State University, Ames, Iowa March 5-7, 2001
Major Ground-Water Findings from the National Water-Quality Assessment Program (NAWQA) in Iowa, by Kalkhoff, S.J., 2000, presented at the Iowa Groundwater Association Fall 2000 Meeting
Occurrence of acetochlor and acetochlor metabolites in alluvial aquifers in Iowa, by Kalkhoff, S.J., Savoca, M.E., Sadorf, E.M., Kolpin, D.W., and Thurman, E.M., 1999, presented at the 218th ACS National Meeting: American Chemical Society, New Orleans, LA. August 22-26, 1999.
Occurrence and distribution of chloroacetanilide and triazine pesiticide metabolites in streams in eastern Iowa: by Kalkhoff, S.J. and Thurman, E.M., 1999. Presented at the Seventh Symposium on the Chemistry and Fate of Modern Pesticides, Lawrence Kansas, Sept 14-16, 1999.
Water-Quality Differences Between Urban and Agricultural Areas of Alluvial Aquifers in Eastern Iowa and Part of Southern Minnesota, 1997. by Kalkhoff, S.J., and Savoca, M.E., 1998, presented at the 110th Session of the Iowa Academy of Science meeting, April 25, 1998, Mason City, Iowa.
Organochlorine pesticides in a sediment core from Coralville Reservoir, Iowa. by Kalkhoff, S.J., VanMetre, P.C., and E. Callender, 1997, presented at the Geological Society of America North-Central Section meeting, May 1-2, 1997, Madison, Wisconsin.
Selected herbicides and herbicide metabolites in groundwater in Iowa, Summer 1995: by Kalkhoff, S.J., Kolpin, D.W., Sneck-Fahrer, D.A., and Goolsby, D.A., 1996, presented at the Geological Society of America North-Central Section meeting, May 2-3, 1996, Ames, Iowa.
Plan for water-quality assessment of the Eastern Iowa Basins, by Kalkhoff, S.J., 1994 presented at the 106th Session of the Iowa Academy of Science meeting, April 23, 1994, Davenport, Iowa.
Relation between stream water-quality and geology in Roberts Creek, Clayton County, Iowa: by Kalkhoff, 1992 presented at the Iowa Academy of Sciences annual meeting
Effect of agricultural chemicals on water quality of Corydon Reservoir, Corydon, Iowa: by Kalkhoff, S.J., 1991, presented at the Regional Lake Management Conference, Des Moines, Iowa, June 1991
Quality of surface water discharged from the Big Spring basin, Clayton County, Iowa: by Kalkhoff, S.J., 1989, presented at the Iowa Academy of Sciences annual meeting
Oil-field brine disposal effects on shallow ground- water and stream-water quality in Mississippi: by Kalkhoff, S.J., 1985 presented at the Mississippi Academy of Sciences annual meeting
Apparent brine contamination of freshwater aquifers and streams in petroleum producing areas in Mississippi  by Kalkhoff, S.J., 1984 presented at Seminar of the Protection of Public Water Supplies from Ground-Water Contamination: EPA, Atlanta, GA August 1984.