Ecological Archives A025-057-A1

Emily K. Read, Vijay P. Patil, Samantha K. Oliver, Amy L. Hetherington, Jennifer A. Brentrup, Jacob A. Zwart, Kirsten M. Winters, Jessica R. Corman, Emily R. Nodine, R. Iestynwoolway, Hilary A. Dugan, Aline Jaimes, Arianto B. Santoso, Grace S. Hong, Luke A. Winslow, Paul C. Hanson, and Kathleen C. Weathers. 2015. The importance of lake-specific characteristics for water quality across the continental United States. Ecological Applications 25:943955. http://dx.doi.org/10.1890/14-0935.1

Appendix A. Model and predictor variable descriptions. Combined, regional, basin, buffer, and lake-specific scale models and categories of predictor variables included and complete list of predictor variables used, ordered by category, and data sources.

Table A1. Description of spatial models and sub-models, and the variables included in each model.

Model

Predictor variable category

Combined (all scales)

Percent cover basin and buffer

Lake-specific variables

Road variables basin and buffer

Regional variables

Topography basin and buffer

Regional

Regional variables

Basin

Percent cover basin

Road variables basin

Topography basin

Buffer

Percent cover buffer

Road variables buffer

Topography buffer

Lake-specific

Lake-specific variables

 

Table A2. Description of predictor variables, ordered by spatial scale, and relevant data sources.

Predictor variable category

Predictor variable

Data source

Percent cover basin and buffer

Percent open water

EPA NLA 2007

Percent perennial ice or snow

EPA NLA 2007

Percent open water + perennial ice or snow

EPA NLA 2007

Percent developed open space

EPA NLA 2007

Percent developed low intensity

EPA NLA 2007

Percent developed medium intensity

EPA NLA 2007

Percent developed high intensity

EPA NLA 2007

 

Percent total developed

EPA NLA 2007

 

Percent barren land

EPA NLA 2007

Percent deciduous forest

EPA NLA 2007

Percent coniferous forest

EPA NLA 2007

 

Percent mixed forest

EPA NLA 2007

Percent total forest

EPA NLA 2007

Percent shrub or scrub

EPA NLA 2007

Percent grassland

EPA NLA 2007

Percent pasture or hay

EPA NLA 2007

Percent cultivated crops

EPA NLA 2007

Percent agriculture (pasture + crops)

EPA NLA 2007

Percent woody wetland

EPA NLA 2007

Percent emergent herbaceous wetland

EPA NLA 2007

Percent wetland (woody + herbaceous)

EPA NLA 2007

Lake-specific variables

Lake area

EPA NLA 2007

Lake perimeter

EPA NLA 2007

Maximum depth (m)

EPA NLA 2007

Sediment to epilimnetic volume ratio

Derived from EPA NLA 2007 and Carpenter 1989

Watershed area

EPA NLA 20007

Ratio of watershed area to lake area

Derived from EPA NLA 2007

Shoreline development index (lake perimeter / 2 * sqrt(lake area * pi))

EPA NLA 2007

Elevation (m)

EPA NLA 2007

 

Lake perimeter to lake area ratio

Derived from EPA NLA 2007

X-coordinate from Albers projection (m)

EPA NLA 2007

Y-coordinate from Albers projection (m)

EPA NLA 2007

Residence time (days)

McDonald et al. 2013

Road variables basin and buffer

Mean percent impervious

National Land Cover Dataset 2006

Road length (km)

After Pechenick et al. 2014 and with TIGER/Line (2012) data set

 

Road density (road length / area)

After Pechenick et al. 2014 and with TIGER/Line (2012) data set

Mean minimum distance between lake edge and nearest road (m)

After Pechenick et al. 2014 and with TIGER/Line (2012) data set

Regional variables

Omernik Level II

EPA NLA 2007

Nutrient ecoregions

EPA NLA 2007

Topography basin and buffer

Elevation standard deviation (m)

Digital Elevation Model (1 arc-second resolution)

Elevation range (maximum elevation - minimum elevation) (m)

Digital Elevation Model (1 arc-second resolution)


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