Evaluating a Great Lakes scale landscape stressor index to assess water quality in the St. Louis River Area of ConcernJournal of Great Lakes Research


Will M. Bartsch, Richard P. Axler, George E. Host
Aquatic Science / Ecology, Evolution, Behavior and Systematics / Ecology


tre rn neso


Great Lakes

Lake Superior are , wa is o acte nt-s ity s iple flow regimes in 2010–2011. Additional data were analyzed from 34 upper wa9–2010. Stressor scores were significantly (p b 0.1) and positively correlated with eat Lak ation d eas of t


Journal of Great Lakes Research xxx (2014) xxx–xxx

JGLR-00826; No. of pages: 12; 4C: 4, 5

Contents lists available at ScienceDirect

Journal of Great Lakes Re j ourna l homepage: www.e lsev ie r .cotion severe enough to impair the beneficial uses of those water resources (SLRAC, 1992). The St. Louis River, which drains to the western arm of Lake Superior, is the second largest tributary to the lake and includes the westernmost headwater of the Laurentian Great

Lakes system. The lower portion of the river was designated as an AOC in 1989. It includes the watershed of the lower 63 km of the river and the far western arm of Lake Superior (Fig. 1). The St. Louis River AOC currently has nine Beneficial Use Impairments (BUI; LimnoTech, 2013) of the 14 possible IJC BUIs. BUI #6, the excessive loading of sediments also been found to be associated with poor water quality, including increased levels of nutrients and suspended sediment (Johnson et al., 1997; Crosbie and Chow-Fraser, 1999; Reavie et al., 2006; Trebitz et al., 2007; Morrice et al., 2008).

Terrestrial impacts to aquatic systems have been quantified by assessing individual or aggregate stressors summarized at the watershed scale (Danz et al., 2005, 2007; Host et al., 2005, 2011; King et al., 2005; Allan et al., 2013). Stressor indices can be as simple as rankingwatersheds along a single component such as percent impervious surface,and nutrients, is directly connected to develop the watershed. ⁎ Corresponding author: Tel.: +1 218 720 4316.

E-mail address: raxler@nrri.umn.edu (R.P. Axler). 1 Present address of the senior author: Environm

Midcontinent Ecology Division, 6201 Congdon Boulevard, http://dx.doi.org/10.1016/j.jglr.2014.11.031 0380-1330/© 2014 International Association for Great Lak

Please cite this article as: Bartsch,W.M., et al

Area of Concern, J Great Lakes Res (2014), htional Joint Commission oss the Great Lakes with ther sources of degradamany contaminants, including nutrients, sediments, heavy metals, petroleum products, salts, fecal indicator bacteria, organic contaminants and others (Paul and Meyer, 2001). High levels of agriculture have(IJC) identified 43 Areas of Concern (AOC) acr water quality, habitat, fish and wildlife, and oSt. Louis River AOC


Thewatersheds of the Laurentian Gr ulation growth and heavy industrializ centuries. As a result of this, many ar from extensive pollution. In 1987 theand E. coli in the upperwatershed. In the estuary, the indexwas significantly and positively correlatedwith NO2−/

NO3−-N, NH4+-N, and chloride atmultiple flow regime and location combinations. Soil K factor (an erosivity index from recent NRCS SSURGO soil surveys) was found to have stronger relationships with sediment related parameters than the stressor gradient. Although originally designed to help stratify sampling across a gradient of landscape stress and identify reference areas for restoration projects, the stressor index was shown to have substantial predictive power for multiple water quality parameters. © 2014 International Association for Great Lakes Research. Published by Elsevier B.V. All rights reserved. es underwent rapid popuring the 19th and 20th he Great Lakes suffered

Human development of watersheds, particularly urbanization and agriculture, has a strong impact on the quality and ecological functions of aquatic systems (Booth and Jackson, 1997; King et al., 2005; Galster et al., 2006; Brown et al., 2009; Johnson and Host, 2010). Urbanization is typically positively correlated with the concentrations and loads ofLandscape stressor index

Water quality TSS, turbidity, TP, NO2 −/NO3 −-N, dissolved oxygen saturation, pH, specific electrical conductivity, chloride, sulfate,Index words: nearshore areas during mult tershed sites sampled in 200Evaluating a Great Lakes scale landscape s quality in the St. Louis River Area of Conce

Will M. Bartsch 1, Richard P. Axler ⁎, George E. Host

Center for Water and the Environment, Natural Resources Research Institute, University of Min a b s t r a c ta r t i c l e i n f o

Article history:

Received 27 June 2014

Accepted 31 October 2014

Available online xxxx

Communicated by Craig Stow

The St. Louis River drains an including a 48.5 km2 estuary activities. Part of the estuary previously developed to char indexwere road density, poi developed land. Water qualment and land usewithin ental Protection Agency —

Duluth, MN 55804, USA. es Research. Published by Elsevier B ., Evaluating a Great Lakes scal ttp://dx.doi.org/10.1016/j.jglrssor index to assess water ta, 5013 Miller Trunk Highway, Duluth, MN 55811-1442, USA a of 9412 km2 into the western arm of Lake Superior. The river's lower section, s designated as a Great Lakes Area of Concern due to degradation from industrial ccupied by the largest port in the Great Lakes. A GIS-based stressor index was rize anthropogenic stress within thewatershed. The components of the stressor ource pollution permit density, population density, and percent agricultural and ampling was conducted at 27 sites in the estuary in tributaries and associated search m/locate / jg l ror as complex as summarizing dozens to hundreds of components as metrics or indices (Brabec et al., 2002; Danz et al., 2005, 2007). Spatial data from components that are believed to impact water quality can be compiled and organized within a Geographic Information System (GIS), and sampling units in a specific study area can be ranked relative to each other based on the level/intensity of individual or combined components. These stressor indices can provide an indicator of water .V. All rights reserved. e landscape stressor index to assesswater quality in the St. Louis River .2014.11.031 quality at a specific site without having to physically sample the site.