FLOOD08620

• Designation Number: 463
• County: Boulder
• Community: Longmont
• Basin: South Platte
• Title: FIS - Longmont, CO, Boulder County
• Date: 9/1/1987
• Designation Date: 5/1/1998
• Floodplain - Doc Type: Floodplain Report/Masterplan

1.0 INTRODUCTION

1.1

Purpose of study

.

This Flood Insurance Study report revises and updates a previous
Flood Insurance Study/Flood Insurance Rate Map for the City of
Longmont, Boulder County, Colorado. This information will be used
by the City of Longmont to update existing flood plain regulations
as part of the regular phase of the National Flood Insurance
Program (NFIP). The information will also be used by local and
regional planners to further promote sound land use and flood
plain development.

.

In some states or communities, flood plain management criteria or
regulations may exist that are more restrictive or comprehensive
than the minimum Federal requirements. In such cases, the more
restrictive criteria take precedence and the State (or other
jurisdictional agency) will be able to explain them.

1.2 Authority and Acknowledgments

The sources of authority for this Flood Insurance Study are the
National Flood Insurance Act of 1968 and the Flood Disaster
Protection Act of 1973.

The hydrologic and hydraulic analyses for the initial study were
performed by Gingery Associates, Inc., for the Federal Emergency
Management Agency (FEMA), under Contract No. H-3716. That work
was completed in March 1976.

The additional hydrologic and hydraulic analyses for this revised
study were performed by Gingery Associates, Inc., Simons, Lee and
Associates, and Water Resources Consultants, Inc. for the Colorado
Water Conservation Board (CWCB), as reported in flood plain infor-
mation reports for Lefthand Creek (References 1 and 2), and for
Dry Dreek No.1 and St. Vrain Creek (References 3 and 4, respect-
ively).

1.3

Coordination

.

The City of Longmont Engineering Department supplied zoning and
corporate boundary maps for use in the initial study, as well as
various detailed drawings for channel improvements, such as final
construction plans for the spring Gulch Linear Park and storm
drainage facilities, dated January 1973, and the structural plans
for the Pratt Street bridge, over the St. Vrain Creek, The City
of Longmont Planning Department has supplied a copy of the st,
Vrain Comprehensive plan (Reference 5), which describes the
comprehensive plan for what is called the prime Urbanized Area
(PMA) of Longmont. The Planning Department also provided a copy