[Code of Federal Regulations]
[Title 23, Volume 1]
[Revised as of April 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 23CFR650.117]

[Page 229]
 
                           TITLE 23--HIGHWAYS
 
 CHAPTER I--FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION
 
PART 650--BRIDGES, STRUCTURES, AND HYDRAULICS--Table of Contents
 
   Subpart A--Location and Hydraulic Design of Encroachments on Flood 
                                 Plains
 
Sec. 650.117  Content of design studies.

    (a) The detail of studies shall be commensurate with the risk 
associated with the encroachment and with other economic, engineering, 
social or environmental concerns.
    (b) Studies by highway agencies shall contain:
    (1) The hydrologic and hydraulic data and design computations,
    (2) The analysis required by Sec. 650.115(a), and
    (3) For proposed direct Federal highway actions, the reasons, when 
applicable, why FEMA criteria (44 CFR 60.3, formerly 24 CFR 1910.3) are 
demonstrably inappropriate.
    (c) For encroachment locations, project plans shall show:
    (1) The magnitude, approximate probability of exceedance and, at 
appropriate locations, the water surface elevations associated with the 
overtopping flood or the flood of Sec. 650.115(a)(1)(ii), and
    (2) The magnitude and water surface elevation of the base flood, if 
larger than the overtopping flood.