Charlotte-Mecklenburg

Charlotte-Mecklenburg Stormwater Design Manual

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April 2026 public-comment draft (Certification of Adoption not yet published). Manual covers conveyance design (hydrology, channels, pipes, culverts, energy dissipators); post-construction water quality volume / SCM sizing is deferred to separate Post Construction Stormwater Ordinances/Regulations referenced in §1.7—not specified in this text. Software listed is City verification tooling; designers may use any method-based tools.

Fields not found in document: design_criteria.water_quality_volume_method

Other manuals in North Carolina: North Carolina Department of Environmental Quality (NCDEQ)

Document Metadata

Jurisdiction level

municipality

“This manual has been developed to assist in the design and evaluation of stormwater management facilities in the City of Charlotte, Charlotte ETJ, and Mecklenburg County.”
Chapter 1, Section 1.1, Page 6

State

North Carolina

“Figure 1-2. Stormwater conveyance structures in Charlotte, NC”
Chapter 1, Page 9

Version / edition

April 2026 (public comment draft)

“April 2026”
Title Page

Adoption / effective date

Not found in document

“A Certification of Adoption will be added when the final Design Manual is published.”
Certification of Adoption, Page 1

Last revised date

2026-04

“The goals of the 2026 update to this manual are to”
Chapter 1, Section 1.2, Page 7

Relationship to state manual

independent

“Streamline information by focusing on City of Charlotte, Charlotte ETJ, and Mecklenburg County requirements”
Chapter 1, Section 1.2, Page 7

Design Criteria

Design storm return periods (years)

2-year, 10-year, 25-year, 50-year, 100-year

“Table 2-1. Summary of design storm requirements... Channels ... 10-yr ... At sags on local streets 25-yr ... At sags on arterials and primary access streets 50-yr ... Primary access streets 100-yr ... Streets across regulated floodways 100-yr, 24-hr per FEMA”
Chapter 2, Table 2-1, Page 10

Water quality volume method

Not found in document

No evidence cited

Peak flow calculation method(s)

Rational Method (with frequency factor Cf, custom runoff coefficients, and custom rainfall intensities), NRCS Method / Curve Number (TR-55; Type II center-weighted 6-hour storm unless otherwise specified), Custom Charlotte-Mecklenburg precipitation tables (Appendix 2)

“Either the Rational Method or the NRCS Method may be applied, with watershed sizes, appropriate applications, and necessary adjustments detailed in the table below.”
Chapter 2, Section 2.4, Page 11

Required hydrologic/hydraulic software

HEC software (City verification), HydroCAD, StormCAD

“The City will typically use HEC software to verify designs submitted by the development community. In addition, the City may check designs using HydroCAD and StormCAD. Designers may use any software tools that are based on the methods described in this manual.”
Chapter 1, Section 1.3, Page 7

Approved BMP categories

Vegetated channels (turfgrass and native plant), Armored channels (when vegetated not feasible), Closed pipe systems, Culverts, Riprap aprons (energy dissipation), Plunge pools (energy dissipation)

“Use vegetated channels whenever feasible • Implement armored channels only when a vegetated channel is not feasible”
Chapter 3, Table 3-1, Page 20