optimum conditions for recreation based 

 upon utilization of fish, other aquatic life, 

 and wildlife should apply, with specific and 

 limited exceptions. The Subcommittee en- 

 dorses by reference the criteria for these 

 purposes recommended by the National 

 Technical Advisory Subcommittee on 

 Fish, Other Aquatic Life, and Wildlife. 



C. Primary Contact Recreation 



I. Criteria for mandatory factors. 



(a) Fecal coliform should be used as the 

 indicator organism for evaluating the 

 microbiological suitability of recrea- 

 tion waters. As determined by mul- 

 tiple-tube fermentation or membrane 

 filter procedures and based on a mini- 

 mum of not less than five samples for 

 any 30-day period of the recreation 

 season, the fecal coliform content of 

 primary contact recreation waters 

 shall not exceed a log mean of 200/ 

 100 ml, nor shall more than 10 per- 

 cent of total samples during any 30- 

 day period exceed 400/100 ml. 



(b) In primary contact recreation waters, 

 the pH should be within the range of 

 6.5-8.3 except when due to natural 

 causes and in no case shall be less 

 than 5.0 nor more than 9.0. When 

 the pH is less than 6.5 or more than 

 8.3, discharge of substances which 

 further increases unfavorable total 

 acidity or alkalinity should be limited. 



II. Criteria for desirable factors. 



(a) For primary contact waters, clarity 

 should be such that a Secchi disc is 

 visible at a minimum depth of 4 

 feet. In "learn to swim" areas, the 

 clarity should be such that a Secchi 

 disc on the bottom is visible. In div- 

 ing areas, the clarity shall equal the 

 minimum required by safety stand- 

 ards, depending on the height of the 

 diving platform or board. 



(b) In primary contact recreation waters, 

 except where caused by natural con- 

 ditions, maximum water temperature 

 should not exceed 85 F (30 C). 



III. Marine waters 



The Subcommittee suggests, as a gen- 

 eral practice, application of a single set of 

 criteria for fresh, estuarine, and marine 

 waters. 



aesthetics 



