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1. RECURRENCE INTERVAL <br />OFor drainage areas of 100 acres orless, <br />Tm (recurrence interval) = 10 years, unless <br />otherwise specified. <br />OFor drainage areas of 100 acres or less <br />with sump, or tailwater effect and for the <br />design of roadway culverts and bridgesuti — <br />Ilzing static head at entrance, Tim (recurrence <br />interval) = 50 years. <br />OFor' drainage areas greater than 100 <br />acres and all streams, design curves based <br />upon maximum recorded flood peaks. <br />IF <br />2. RUNOFF QUANTITY <br />OFor drainage areas of 100 acres or less, <br />the rational method shall be used. <br />0 For drainage areas greater than 100 <br />acres and all streams, refer to Plate 6 on <br />page 19 titled "Design Curves for Peak <br />Discharge vs. Drainage Area ". The rational <br />method and flood frequency analysis may be <br />used as a check. <br />