Minnesota Water Science Center Newsletter

Potential for Spring Flooding

The National Weather Service (NWS) is concerned about potential flood conditions this spring due to several conditions: (1) abnormally wet soil moisture due to the wet fall; (2) a deep frost that can both enhance snowmelt runoff by inhibiting groundwater infiltration and increase river-ice thickness, contributing to ice jams and causing localized flooding; and (3) a significant seasonal snowpack. Conditions are not as severe as a year ago at this time. Based on exceedance probabilities of flooding for current conditions and simulations,using more than 50 years of historical streamflows, the NWS notes that in Minnesota, the river basins with the greatest probability of flooding inlcude the Red River, Upper Minnesota and Middle Mississippi. More information is available at http://www.crh.noaa.gov/ncrfc/. Contact James Fallon.

Report released on chloride in waters of the northern States may be of interest because of Minnesota's application of road salt

Water samples from shallow wells in urban areas had the greatest concentrations of chloride, followed by water samples from agricultural and forested areas. Surface-water samples from several watersheds had chloride concentrations greater than the U.S. Environmental Protection Agency's recommended chronic criterion concentration for aquatic life. Statistical analyses showed that the density of roads, evapotranspiration and overland flow were significant factors in describing the range of maximum chloride concentrations.
Reference: "Chloride in groundwater and surface water in areas underlain by the glacial aquifer system" by J. R. Mullaney, D. L. Lorenz and A. D. Arnston
Contact: Dave Lorenz

Trends in nutrient and sediment concentrations in streams show signs of improvement

Many actions have been taken to reduce nutrients and suspended-sediment in streams as a result of the Clean Water Act and subsequent regulations. A recently released report describes trends in concentrations and loads of nutrients and sediment in streams in the Midwest. Most forms of nitrogen, with the exception of ammonia, increased during the period from 1993-2004. The downward trend in dissolved ammonia concentrations indicates that some of the ammonia reduction goals of the Clean Water Act are being met. Flow-adjusted trends in total phosphorus concentrations were generally upward although trends in total phosphorus concentrations were mixed and showed no spatial pattern. The reduction in phosphorus fertilizer use and manure production east of the Mississippi River could explain most of the observed trends in dissolved phosphorus. Flow-adjusted trends in total suspended-material concentrations showed distinct spatial patterns of increasing tendencies in the west and decreasing concentrations in the east. Long term, non-monotonic trends in total nitrogen, total phosphorus, and suspended-material loads for 1975 to 2003 were described by local regression ‘LOESS’ smoothing for six sites. The statistical significance of those trends cannot be determined; however, the long-term changes found for annual streamflow and load data indicate that the monotonic trends from 1993 to 2004 should not be extrapolated backward in time. The report was published as USGS Scientific Investigations Report 2008-5213.
Contact Dave Lorenz

New report documents water-quality benefits along riparian corridors

A new report assesses water-quality and biological characteristics in three streams in the Minnesota River Basin. Total nitrogen, suspended-sediment, chlorophyll-a, and fish-resource quality improved with increasing agricultural land retirement. Data and analyses from this study can be used to evaluate the success of agricultural land retirement programs for improving stream quality and may have implications for prioritizing land in retirement programs. The project was conducted in cooperation with the Minnesota Board of Water and Soil Resources and with funding from the Legislative-Citizens Commission on Minnesota.
Reference: "Water Quality and Biological Characteristics and Responses to Agricultural Land Retirement in Three Streams of the Minnesota River Basin, Water Years 2006-08, USGS Scientific Investigations Report 2009-5215
Contact: Vicki Christensen

Collaborative efforts study sources of emerging contaminants

Recent work has identified emerging contaminants, including endocrine active chemicals and pharmaceutical compounds, in streams, lakes and groundwater, and other studies have raised questions about the effects of these compounds on fish. These compounds may enter the environment from wastewater treatment plants, septic-system effluent, or runoff from urban and agricultural lands. Given the large number of streams and lakes in Minnesota at risk from point and non-point sources of emerging contaminants, there is a need for relevant information concerning fish responses to chemical exposure in terms of development and reproduction. Several Water Science Center (Center) projects are providing insights about the extent of this problem at a statewide scale. Staff from the Center, the USGS National Research Program (NRP), and the USGS National Water Quality Laboratory (NWQL) are working in cooperation with St. Cloud State University, the University of St. Thomas, the University of Minnesota, and the Minnesota Pollution Control Agency to determine the fate and effects of endocrine active chemicals and pharmaceutical compounds in streams, lakes, and groundwater. Samples are being obtained from streams and lakes with varying degrees of wastewater, on-site septic tank density, or nonpoint-source influences from urban and agricultural sources.
Contact: Melinda Erickson, Richard Kiesling, and Kathy Lee