Table 2

Pearson's r correlations between log10 E. coli concentrations and explanatory variables at inland lake sites for daily sampling, 2010-2011a

VariablePearson's r correlation for beach site% of sites for which variable was significantNo. of sites used in models
Alum CampersAlum NorthAlum CentralAtwood MainBuckeye BrooksBuckeye CrystalBuckeye FairfieldBuck Cr NorthBuck Cr SouthGLSM CampersGLSM WestGLSM EastTappan Main
Field measurements
    Day of yr0.450.110.00−0.040.060.220.300.270.260.270.140.110.01462
    Turbidity0.410.110.160.470.14−0.08−0.08−0.150.000.290.120.240.23386
    Water temp0.240.150.070.360.20−0.030.120.150.25−0.100.080.180.24316
    Birds0.150.010.00−0.010.140.250.310.150.370.100.030.190.10232
    Swimmers0.220.010.010.390.090.070.280.040.110.000.000.000.20311
    Wave height0.02−0.090.000.360.10−0.180.260.13−0.050.32−0.010.230.11311
Weather data from NWS
    Rainfall, Rd−1a0.300.190.340.130.270.360.310.060.240.160.250.180.09541
    Rainfall, Rw48e0.350.210.340.120.310.390.340.060.210.160.230.130.12621
    Wind alongshore, 8 a.m.0.08−0.080.020.01−0.040.060.37−0.17−0.140.060.260.08−0.14232
    Wind alongshore, 24 h−0.050.060.14−0.010.270.290.520.31−0.11−0.080.21−0.020.29312
    Wind offshore, 8 a.m.0.00−0.13−0.090.12−0.04−0.110.220.100.080.36−0.060.140.11151
    Wind offshore, 24 h−0.12−0.14−0.050.130.040.25−0.060.00−0.050.280.030.160.22231
    Wind code × wind speed, 8 a.m.0.200.150.420.260.35234
Radar rainfall
    Radarxcell-av-Rd−1b,g0.340.160.330.180.320.330.350.150.200.200.400.300.16692
    Radarxcell-av-Rd−2c,g0.400.130.110.070.200.100.280.060.050.030.13−0.070.06151
    Radarxcell-av-Rd−3d,g0.090.310.18−0.080.01−0.06−0.070.000.000.010.230.040.08152
    Radarxcell-av-Rw48e.g0.460.200.350.190.330.390.420.140.190.180.390.210.17621
    Radarxcell-av-Rw72f,g0.500.270.380.160.360.330.420.120.170.170.420.190.21691
    Radarxcell-sum-Rd−1b,h0.360.240.380.120.260.370.350.120.170.220.400.290.19771
    Radarxcell-sum-Rw48e,h0.520.300.400.140.260.400.400.120.170.200.370.200.20621
    Radarxcell-sum-Rw72f,h0.560.360.420.120.310.330.400.110.160.200.410.180.23621
USGS or USACE gauge
    Rain gauge, Rd−1b0.410.330.450.180.270.270.200.080.180.230.290.130.19691
    Rain gauge, Rd−3d0.150.150.12−0.02−0.09−0.05−0.08−0.12−0.100.150.230.190.1382
    Rain gauge, Rw48e0.550.370.460.210.260.280.200.100.140.270.330.120.21692
    Rain gauge, Rw72f0.580.390.450.180.230.260.180.080.100.290.360.140.23692
    Discharge or stage, 24 h, lagged 1 day0.18−0.16−0.170.000.320.310.200.000.14−0.02152
    Water surface elevation, 8 a.m.0.510.210.230.290.160.310.040.07381
    Water surface elevation, change in 24 h0.460.300.380.240.300.150.060.18381
  • a Relations that were significant at P < 0.05 are in italics and bold. —, not determined. Variables used in selected models are shaded.

  • b Rd1 is the amount of rainfall in the 24-h period before sampling.

  • c Rd2 is the amount of rainfall in the 24-h period 2 days before sampling.

  • d Rd3 is the amount of rainfall in the 24-h period 3 days before sampling.

  • e Rw48 is the amount of rainfall in the 48-h period before sampling, with the most recent rainfall receiving the most weight and calculated as (2 * Rd1) + Rd2.

  • f Rw72 is the amount of rainfall in the 72-h period before sampling, with the most recent rainfall receiving the most weight and calculated as (3 * Rd1) + (2 * Rd2) + Rd1.

  • g Radarxcell-av is the hourly maximum value among multiple 4-km cells divided by the number of cells for the time period specified.

  • h Radarxcell-sum is the sum from multiple 4-km cells for the time period specified.