Mark,
 
At the last meeting you asked the group to email you questions to address designated uses of lakes.  I'm not sure what that means, but I do have some questions for development/implementation of the draft lake nutrient criteria rule:
 
Protection of Aquatic Life

• What is the minimum sample number required for determining whether the annual geometric mean TP exceeds the advisory level or action level?
• What, if any, statistical tests will be used?  (I ask this because of the lengthy discussion at the June Clean Water Commission meeting regarding statistical tests and confidence levels for the 303(d) listing methodology.)
• How will algae blooms be determined to be "excessive" with respect to aquatic life protection?
• Where Secchi depth or turbidity are used as indications of impairment, how will turbidity due to inorganic suspended solids be distinguished from turbidity due to algae growth?  (Nutrient criteria won't correct turbidity caused by inorganic suspended solids.)
• Will reference lakes be used; and if so, how?

• What frequency and duration of exceedence of the chlorophyll-a advisory level or action level will be allowed before it is determined that numerical criteria for TN or TP must be promulgated for a drinking water supply reservoir?
• What is the minimum sample number required to determine that a criterion violation has occurred?
• What averaging period will be used for combining samples?
• What statistics will be used? (Arithmetic or geometric mean, statistical tests, confidence levels, etc.)
• How will impairment of drinking water use be determined? (See discussion in MDNR MOA with EPA re ACA TMDL Settlement Agreement, Appendix B)
• Will reference lakes be used; and if so, how?