Duluth UDC § 836.04
Engineering Study Requirements for Floodplain Encroachments
Governing jurisdiction
Duluth
Land inside these city limits is governed by Duluth's own code and boards. A "Duluth, GA" mailing address is not proof of being inside them — most such addresses fall in unincorporated Gwinnett.
Boundary: US Census TIGERweb (Incorporated Places, ACS 2025 vintage), vintage 2025.
- Article
- 8 — Environmental Protection
- Pages in source
- 236–237
- Adopted
- 2025-09-08
- Amended through
- 2026-07-13
- Source
- Adopted PDF
Text
An engineering study is required, as appropriate to the proposed development activities on the site, whenever a
development proposes to disturb any land within the future-conditions floodplain, except for a residential single-
lot development on streams without established base flood elevations and/or floodways for which the provisions
of 836.04 apply. This study shall be prepared by a currently registered professional engineer in the State of Georgia
and made a part of the application for a permit. This information shall be submitted to and approved by the
Planning and Development Department prior to the approval of any permit which would authorize the disturbance
of land located within the future-conditions floodplain. Such study shall include:
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Article Eight. Environmental Protection
1. Description of the extent to which any watercourse or floodplain will be altered or relocated as a result of
the proposed development;
2. Step-backwater analysis, using a FEMA-approved methodology approved by the Planning and
Development Department. Cross-sections (which may be supplemented by the applicant) and flow
information will be obtained whenever available. Computations will be shown duplicating FIS results and
will then be rerun with the proposed modifications to determine the new base flood profiles, and future-
conditions flood profiles;
3. Floodplain storage calculations based on cross-sections (at least one every 100 feet) showing existing and
proposed floodplain conditions to show that base flood floodplain and future-conditions floodplain
storage capacity would not be diminished by the development;
4. The study shall include a preliminary plat, grading plan, or site plan, as appropriate, which shall clearly
define all future-conditions floodplain encroachments.