Water Resources of Minnesota

Current Issues

A Whole System Approach to Understanding Agricultural Chemicals in the Environment

Surface runoff flows from a corn field in the Sugar Creek basin, Indiana.

The effects of the use of agricultural chemicals and other practices associated with agriculture on the quality of streams and groundwater is well known; however, less is known about how those effects may vary across different geographic regions of the Nation. Scientists at the U.S. Geological Survey (USGS) are conducting studies on the transport and fate of agricultural chemicals in diverse agricultural settings across the country using comparable and consistent methodology and study designs (fig. 1; Capel and others, 2004; Capel and others, 2008). Assessments in five study areas have been completed, and the results highlight how environmental processes and agricultural practices interact to affect the movement and transformation of agricultural chemicals in the environment. The studies address major environmental compartments, including surface water, groundwater, the unsaturated zone, the streambed, and the atmosphere, as well as the pathways that interconnect these compartments. The study areas represent major agricultural settings, such as irrigated diverse cropping in the West and corn and soybean row cropping in the Midwest and, therefore, findings are relevant throughout much of the Nation.

Full Fact Sheet

The USGS has released the national compilation of water use for 2005 (press release). The report is currently available at the USGS publications warehouse. The USGS also released Fact Sheet 2009-3098 entitled "Summary of Estimated Water Use in the United States in 2005".

Recent NAWQA Publications

We are pleased to announce the publication of two journal articles from the NAWQA Program. These articles examine effects of urbanization on stream ecosystems in 9 metropolitan areas across the United States. Full citations and brief summaries follow. Online versions of the papers are available at http://www.bioone.org/toc/jnbs/28/4. Additional information about the NAWQA EUSE study is available at http://water.usgs.gov/nawqa/urban/. If you have questions about the papers contact Larry Brown or Jerad Bales.

Urban Streams Across the USA: Lessons Learned from Studies in 9 Metropolitan Areas

Studies of the effects of urbanization on stream ecosystems have usually focused on single metropolitan areas. Synthesis of the results of such studies have been useful in developing general conceptual models of the effects of urbanization, but the strength of such generalizations is enhanced by applying consistent study designs and methods to multiple metropolitan areas across large geographic scales. Four major conclusions emerged from these studies. First, responses of hydrologic, physical habitat, water-quality, and biotic variables to urbanization varied among metropolitan areas, except that insecticide inputs consistently increased with urbanization. Second, prior land use, primarily forest and agriculture, appeared to be the most important determinant of the response of biota to urbanization in the areas we studied. Third, little evidence was found for resistance to the effects of urbanization by macroinvertebrate assemblages, even at low levels of urbanization. Fourth, benthic macroinvertebrates have important advantages for assessing the effects of urbanization on stream ecosystems relative to algae and fishes. Overall, our results demonstrate regional differences in the effects of urbanization on stream biota and suggest additional studies to elucidate the causes of these underlying differences.

Larry R. Brown, Thomas F. Cuffney, James F. Coles, Faith Fitzpatrick, Gerard McMahon, Jeffrey Steuer, Amanda H. Bell, and Jason T. May, 2009, Urban streams across the USA: lessons learned from studies in 9 metropolitan areas, J. N. Am. Benthol. Soc., 28(4):1051–1069, DOI: 10.1899/08-153.1, Published online: 27 October 2009

Relationship of Stream Ecological Conditions to Simulated Hydraulic Metrics Across a Gradient of Basin Urbanization

The relationships among urbanization, stream hydraulics, and aquatic biology were investigated across a gradient of urbanization in 30 small basins in eastern Wisconsin. Simulation of hydraulic metrics with 1-dimensional unsteady flow models was an effective means for mechanistically coupling the effects of urbanization with stream ecological conditions (i.e., algae, invertebrates, and fish). Urbanization, characterized by household, road, and urban land density, was positively correlated with the lowest shear stress for 2 adjacent transects in a reach for the low-flow summer (p , 0.001) and autumn (p , 0.01) periods. Urbanization also was positively correlated with Reynolds number and % exposed stream bed during months with moderate to low flows. Our study demonstrated the value of temporally and spatially explicit hydraulic models for providing mechanistic insight into the relationships between hydraulic variables and biological responses. For example, the positive correlation between filter-feeding invertebrate richness and minimum 2-transect shear stress observed in our study is consistent with a higher concentration of water-column particulates available for filtration. The strength of correlations between hydraulic and biological metrics is related to the time period (annual, seasonal, or monthly) considered. The hydraulic modeling approach, whether based on hourly or daily flow data, allowed documentation of the effects of a spatially variable response within a reach, and the results suggest that stream response to urbanization varies with hydraulic habitat type.

Jeffrey J. Steuer, Jerad D. Bales, and E. M. P. Giddings, 2009, Relationship of stream ecological conditions to simulated hydraulic metrics across a gradient of basin urbanization, J. N. Am. Benthol. Soc., 28(4):955–976 DOI: 10.1899/08-157.1, Published online: 27 October 2009

More Current Issues

Data via GoogleMaps

New Maps Deliver Current Streamflow Conditions

We recently added a Google-Map based Web page to deliver map-based current surface-water resources conditions in Minnesota.

The maps utilize zoom and pan to allow you to focus in on the water-monitoring sites that interest you. The maps show current streamflow as compared to historical records. By hovering your mouse over a site, a popup box shows the most recent stage and streamflow.