Water Quality Flagging Program ( )


The following predicted concentrations of Fecal Indicator Bacteria (FIB) are based on modeled correlations between FIB and weather or water conditions. Flagging is based on safety thresholds for boating. The weather and water data is sourced from the CESN weather station at Community Boating and the USGS Waltham river flow gauge. Currently the predictions are only based on one year of historical statistics. An ideal model would include 2-3 years of history. New models will be developed in future years as more data is collected. Click here for a full description of this bacteria forecasting project.

Water quality flags, with forecasted E.coli concentrations and probabilities (updated hourly):
As of: 09/23/17 17:59 Modeled Concentration Probability of Exceedance Flag
Model Reach 2
   Newton Yacht Club - cfu49% Blue (safe for boating)
   Watertown Yacht Club - cfu49% Blue (safe for boating)
   Community Rowing, Inc. - cfu49% Blue (safe for boating)
Model Reach 3
   CRCK at Herter Park - cfu48% Blue (safe for boating)
   Harvard's Weld Boathouse - cfu48% Blue (safe for boating)
Model Reach 4
   Riverside Boat Club - cfu43% Blue (safe for boating)
Model Reach 5
   Charles River Yacht Club34 cfu1% Blue (safe for boating)
   Union Boat Club34 cfu1% Blue (safe for boating)
   Community Boating34 cfu1% Blue (safe for boating)
   CRCK at Kendall Square34 cfu1% Blue (safe for boating)






Model formulas:

Reach 2 logistic model

ln(p/(1-p)) = 0.26 + 0.044*WtmpD1 - 0.036*AtmpD1 + 0.0014*Hours - 0.23*log(Hours+0.0001)

p = probability of exceeding safety threshold;

WtmpD1 = Previous 24hr average water temp (F); AtmpD1 = previous 24hr average air temp (F); Hours = Hours since last rain


Reach 3 logistic model

ln(p/(1-p)) = 1.41 + 0.026*WtmpD1 - 0.0007*PARD2 + 0.0009*Hours - 0.302*log(Hours+0.0001) + 0.0015*FlowD2 - log(FlowD2)

p = probability of exceeding safety threshold;

WtmpD1 = Previous 24hr average water temp (F); PARD2 = previous 48hr average PAR; Hours = Hours since last rain; FlowD2 = previous 48hr average flow


Reach 4 logistic model

ln(p/(1-p)) = 3.65 + 0.025*WtmpD1 - 0.664*PARD2 + 0.0014*Hours - 0.343*log(Hours+0.0001)

p = probability of exceeding safety threshold;

WtmpD1 = Previous 24hr average water temp (F); PARD2 = previous 48hr average PAR; Hours = Hours since last rain


Reach 5 logistic model

ln(p/(1-p)) = -3.18 + 3.94*RainD2 - 1.62*RainD7 + 1.28*log(FlowD1) - 0.34*WindD1 - 0.21*WtmpD1

p = probability of exceeding safety threshold;

RainD2 = Previous 48hr total rainfall; RainD7 = previous 7-day total rainfall

FlowD1 = Previous 24hr average riverflow; WindD1 = previous 24hr average windspeed

WtmpD1 = previous 24hr average water temp