17.30.651    D-2 CLASSIFICATION STANDARDS

(1) Waters classified D-2 are to be maintained suitable for agricultural purposes and secondary contact recreation. Because of conditions resulting from flow regulation, maintenance of the ditch or geomorphological and riparian habitat conditions, the quality of these waters is marginally suitable for aquatic life.

(2) No person may violate the following specific water quality standards for waters classified D-2:

(a) the aquatic life standards for priority pollutants listed in DEQ-7;

(b) the aquatic life standards for ammonia and other non-priority pollutants listed in DEQ-7, unless those standards are modified or removed based upon a use attainability analysis developed for a specific water body;

(c) the designated uses of a receiving water body under a different classification must be fully maintained;

(d) the geometric mean number of Escherichia coli bacteria may not exceed 630 colony forming units per 100 milliliters and 10 percent of the samples may not exceed 1,260 colony forming units per 100 milliliters during any 30-day period. Water quality criteria for Escherichia coli are expressed in colony forming units per 100 milliliters of water or as most probable number, which is a statistical representation of the number of organisms in a sample, as incorporated by reference in 40 CFR 136.3(b).

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History: 75-5-301, MCA; IMP, 75-5-301, MCA; NEW, 2002 MAR p. 2196, Eff. 8/16/02; AMD, 2004 MAR p. 725, Eff. 4/9/04; AMD, 2006 MAR p. 528, Eff. 2/24/06; AMD, 2017 MAR p. 602, Eff. 5/13/17.