Design Frequency. 10 The freeway that is part of the Project is designated as Class I route based on drainage 11 frequency classification by ADOT. Storm frequency and hydraulic requirements within Effective 12 FEMA Special Flood Hazard Zone must be in accordance with FEMA Code of Federal 13 Regulations (CFR) for the National Flood Insurance Program: 44 CFR Parts 60 and 65, EO 14 11988, and 23 CFR 650.
Design Frequency. Major river crossings, bridges, culverts and storm drain systems shall be designed for the design-year frequency corresponding to the functional classification of the associated roadway. The functional classification for each roadway is shown in Section 11 in Book 2. Developer shall evaluate bridges for contraction scour and pier scour concerns and incorporate protection in accordance with Good Industry Practice. For interstate highways, the minimum overtopping flood to be used in the detailed design shall be the 50- year frequency.
