The score for each lake is based on the geometric mean number of Escherichia coli (E. coli) collected by the beach monitoring program (Table 1-1). Lakes with more than one beach were averaged together. EPA and Minnesota guidelines state that beaches should not exceed a geometric mean of 126 organisms per 100 mL during a 30-day time period. Lower numbers of organisms indicate less risk of illnesses for lake users.
Table 1-1. Scoring for the public health portion of LAURI.
|E. coli, (CFU/100mL)*||Score|
* The value used is the running geometric mean for the year, averaged for all the beaches on a lake.