WSP03580

• File Number: 8030
• Description: Section D General Correspondence-Other Organizations/Agencies
• State: CO
• Date: 5/1/1972
• Author: USWRC
• Title: US Water Resources Council-1972-1977-Flood Hazard Evaluation Guidelines for Federal Executive Agencies
• Water Supply Pro - Doc Type: Report/Study

8

Evaluation of Flood Hazard

There are two basic approaches to the evaluation of flood hazard,
either of which is suitable for all three types of floodplains. The
approaches are presented below in sunrmary form. Further details
about the two basic approaches or about their use are given in the
later section titled "Guidelines".

The Use of Rules and Regulations With A Floodplain Development Plan,
hereafter called the Plan Approach, is an approach in which specifica-
tions regarding flood hazard, based on these guidelines, are first
incorporated in an agency's administrative rules and regulations. Then,
for each floodplain to be considered, a long-range plan of land use
regulations for the area is made. The rules and regulations, and the
plan and related maps for a particular area indicate in detail what
uses under what conditions are suitable in that area. A potential
user can determine in advance the particular hazard by examining those
documents. Thus, he is likely to be discouraged from applying for
uses that would not be compatible with the plan.

The flood hazard evaluation is a process of reviewing an application and
of fully or conditionally approving useS allowed by express terms of
the rules and regulations. This approach requires detailed planning
studies of an entire floodplain for the delineation of whatever hydraulic
and topographic base lines are necessary for determination of degrees
of hazard and for preparation of the plan and related maps. When an
agency has developed information to use the plan approach for adminis-
tering E. O. 11296 a copy of the plan should be furnished to other
concerned agencies and to the community.

The Use of General Standards for Application to Case-by-Case
Development, hereafter called the Case Approach, is an approach in
which an agency first adopts general standards, based on these guidelines,
and subsequently detertnines on a case-by-case basis the suitability
of a proposed use in a particular floodplain.

Suitable photographs, topographic maps, floodplain information reports,
soils maps, or other maps useful in the Case Approach may be avail.
able', from Federal agencies such as the Agricultural Stabilization
& Conservation Service, Army Map Service, Bureau of Land Management,
Bureau of Outdoor Recreation, Bureau of Reclamation, National Ocean