Table S4.

Land use summary for full watersheds, reduced watersheds, and 60-m buffers

Scale parameterMinimumMeanMaximumSD
Full watershed
 Area, km22.881,37712,8542,431
 Estimated septic systems0.019,579246,03341,902
 Septic density, no. per km20.015.7113.719.5
 Population density, persons per km271311,597281
 Population density on WWTP0981,589279
 Population density on septic71141,567236
 Impervious surface, km20.415.1356.99.8
 Urban, %3.1616.799.70.21
 Agriculture, %0.02874.20.22
 Open, %0.06.9720.10.05
 Forest, %0.1931.470.70.18
 Water, %0.02.6823.70.04
 Wetland, %0.071448.30.1
 Barren, %0.00.312.450.0
Reduced watershed
 Area, km20.153664,065630
 Estimated septic systems0.022,299246,03345,592
 Septic density, no. per km20.016.111418.8
 Population density, persons per km271471,597306
 Population density on WWTP01151,589307
 Population density on septic71241,567259
 Impervious surface, km20.47.555.913.6
 Urban, %3.121.399.726.2
 Agriculture, %0.027.277.424
 Open, %0.06.1618.85.27
 Forest, %0.02971.219.5
 Water, %0.01.6115.43.32
 Wetland, %0.013.947.912.1
 Barren, %0.00.7731.13.87
60-m riparian buffer
 Area, km20.064649778.3
 Estimated septic systems0.02,67228,2565,596
 Septic density, no. per km20.01510421
 Population density, persons per km271241,567259
 Population density on WWTP0000
 Population density on septic03210524
 Impervious surface, km20.05.542.79.64
 Urban, %0.018.998.323
 Agriculture, %0.021.472.121.7
 Open, %0.03.6419.43.8
 Forest, %0.022.162.614.9
 Water, %0.06.0963.212
 Wetland, %0.027.376.317.9
 Barren, %0.00.5924.93.12
  • Entire upstream drainage area including lakes (n = 64).

  • Watersheds were defined as the total upstream area to the nearest lake draining to each respective river sampling point (n = 52).