Minnesota River Research

The Minnesota River is one of America's the 20 Most Endangered Waterways. Most of the watershed is highly agricultural, with a significant urban influence in the lowest reaches. A major analysis in the early 1990s (MNRAP, the Minnesota River Assessment Project) documented frequent violations of water quality standards for bacteria, phosphorus, turbidity, and dissolved oxygen. The Governor of Minnesota asserted in 1992 that the river would be fishable and swimable by 2002, now a challenging if not impossible goal. The University of Minnesota has a long-term and widespread involvement in the Minnesota River (Minnesota River Home Page).

In a major NSF-funded Project, we addressed the scale discontinuity that exists between decision-making and scientific knowledge in the Minnesota River Basin. We see scientists continuing to stress the understanding of cumulative effects, and more coarse spatial scales such as watersheds and basins. However, political, social and economic forces are causing decision-makers to act at increasingly local scales.

Our explicit objective is to improve the understanding of how biophysical and socio-economic variables interact in agricultural watersheds of varying scales, landscape conditions and land-use management practices. We further ask how that interaction affects export of nutrients. We examine the resulting effects on in-stream biological communities, which in turn affect decision-making about land use.

The Water Quality group tested the hypothesis that the variance in the distribution of stream macrobenthic communities could best be modeled at a scale representing the intersection of agro-ecoregion and sub-watershed. We used a nested experimental design to ask if in-stream classification, aquatic habitat quality and biotic integrity were more homogenous within agroecoregions than within major watershed boundaries. We learned that stream habitat was best explained at the intersection level (i.e., sub-watershed and agroecoregion) but that benthos distribution was best explained more locally (i.e., by habitat).

To date, three papers have been published and several more are in progress relating to this area. We were recently granted a new project for $75,000, and a larger grant is pending.