FLOOD00285

• County: Statewide
• Community: State
• Stream Name: All
• Title: Floodplain Designation and Approval
• Date: 12/11/1987
• Prepared For: State of Colorado
• Prepared By: CWCB
• Floodplain - Doc Type: Miscellaneous

{: 1~8S THE PUBLIC RECORD CORPORATION
ALL RIGHTS RESERVED

IICRI.I.88

Paoe 11

R~le 6. Standards for Delineation cf A roxima1.e FloM lain inlormatid :
To qualify as approximate floodplain information, the standards .f
this rule with consideration of the effects of dams and levees
being subject to the criteria of rules 7 and 8, respectively, must
be met.

A. Topographic Bast Mapping.

I. Work Mali. The b,,;'; available tcpogr<iphic base map shall
be used to develor approximdte floodplain information.
Such work map shall, at a minimum, be t~e mcst recent
edition of a 7.~ nin~te quadrangle as published by the U.S.
Geolog~cal Survey {USGS}.

B.

Hydrologic ~nalysis

,~.-

I.

2. Other Reauirements. The hydrology for approximate
fl 000;:>1 ain information shall, at a m1n1mum, meet the
hydrology standards in rule 5.B.2 through 5.B.6. for
detailed floodplain information.

C. Hydraulic Analysis

I.

Floodolain Boundaries.
shall show, at a minimum,
IOO-year flood.

Approximate flooded area maps
the floodplain boundary for the

2. Methodolooy. Approximate flooded area maps shall be
based on the followin sim lified methods or an other
method approved by the Board, either indiVidually or in
combination, as appropriate:

a. Assumed Deoth Method. An assumed flood depth above
the channel may be used in conjunction with the best
available topographic map. The assumed depth may be
determined from a regional regression analysis of
depth-frequency relations or from the slope-area-
conveyance calculation at representative cross
sections. Where approximate floodplain boundaries have
been developed based on an assumed or representative

THE CODE OF COLORADO REGULATIONS

2 CCR 408-1