Sec. 1. 38 MRSA §465, sub-§4, ¶B, as amended by PL 2003, c. 664, §1, is further amended to read:

B. The dissolved oxygen content of Class C water may be not less than 5 parts per million or 60% of saturation, whichever is higher, and not less than 6.5 parts per million as a 30-day average whenever the daily water temperature is equal to or less than 24 degrees centigrade or the ambient temperature of the water body, whichever is lower, except that in identified salmonid spawning areas where water quality is sufficient to ensure spawning, egg incubation and survival of early life stages, that water quality sufficient for these purposes must be maintained. In addition, in order to provide additional protection for growth of indigenous fish, dischargers that were issued final discharge licenses or water quality certificates prior to March 16, 2004 that are based on a 6.5 parts per million dissolved oxygen criterion must continue to be licensed using a temperature of 24 degrees centigrade or the ambient temperature of the water body, whichever is lower. Final discharge licenses and water quality certificates not based on a 6.5 parts per million dissolved oxygen criterion prior to March 16, 2004 must be based on a 6.5 parts per million dissolved oxygen criterion at a temperature of 22 degrees centigrade or the ambient temperature of the water body, whichever is lower. Between May 15th and September 30th, the number of Escherichia coli bacteria of human origin in these waters may not exceed a geometric mean of 142 per 100 milliliters or an instantaneous level of 949 per 100 milliliters. The board shall adopt rules governing the procedure for designation of spawning areas. Those rules must include provision for periodic review of designated spawning areas and consultation with affected persons prior to designation of a stretch of water as a spawning area.

SUMMARY

The bill requires all Class C waters to meet a 6.5 parts per million dissolved oxygen 30-day average standard whenever the daily water temperature is equal to or less than 24 degrees centigrade or the ambient temperature of the water body, whichever is lower.