Gwinnett Index

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: 235 | P a g e 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.