FLOOD00275

• County: Adams
• Community: Westminster
• Title: Bruchez Farms Property - Big Dry Creek at Wadsworth Parkway
• Date: 1/1/1998
• Prepared For: Bruchez Farm
• Prepared By: Wright Water Engineers Inc
• Floodplain - Doc Type: Floodplain Report/Masterplan

Rule 6. Standards for Delineation of Aooroximate Floodolain Information:
To qualify as approximate floodplain information, the standards of
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 Base Mapping.

1. Work Mao. The best available topographic base map shall
be used to develop approximate floodplain information.
Such work map shall, at a minimum, be the most recent
edition of a 7.5 minute quadrangle as published by the U.S.
Geological Survey (USGS).

B. Hydrologic Analysis

1. Freauency. The hydrologic analysis for the preparation
of approximate floodplain information shall include, at a
minimum, calculation of the 100-year frequency flood peak
discharge.

2. Other Reauirements. The hydrology for approximate
floodplain information shall, at a minimum, meet the
hydrology standards in rule 5.B.2 through 5.B.6. for
detailed floodplain information.

C. Hydraulic Analysis

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

2. Methodoloay. Approximate flooded area maps shall be
based on the following simplified methods, or any other
method approved by the Board, either individually or in
combination, as appropriate:

1.

Approximate flooded area maps
the floodplain boundary for the

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

-17-