Vermont

The Vermont Stormwater Management Manual Volume I – Stormwater Treatment Standards

StateDEP / DEQVermonthighNoCitations verified

Open source PDF ↗Official agency page ↗

Other manuals in Vermont: City of Burlington, City of Montpelier

Document Metadata

Jurisdiction level

State

“Vermont Agency of Natural Resources”
Title Page

State

Vermont

“Natural Resource Conservation Service (NRCS) methods for calculating runoff have been found to underestimate the volume and rate of runoff for rainfall events less than 2". In order to adapt NRCS methods for the water quality storm, a modified Curve Number (CN) shall be”
p. 17

Version / edition

DRAFT March 1, 2016

“DRAFT March 1, 2016”
Title Page

Adoption / effective date

Not found in document

No evidence cited

Last revised date

2016-03-01

“DRAFT March 1, 2016”
Title Page

Relationship to state manual

independent

“This manual was produced to provide technical analysis and design guidance for the Vermont Agency of Natural Resources Stormwater Management Program.”
1-1

Design Criteria

Design storm return periods (years)

1-year, 10-year, 100-year

“1-year 24 hour storm... 10-year storm... 100-year storm”
2-2

Water quality volume method

WQv = (P)(Rv)(A) / 12, where P = 1.0 inch, Rv = 0.05 + 0.009(I), I = percent impervious, A = site area in acres.

“WQTS in acre- feet of storage: WQv = (P)(Rv)(A) 12 where: WQv = water quality treatment volume (acre-feet) P = 1.0 inch across Vermont Rv = volumetric runoff coefficient, equal to: [0.05 + 0.009(I)] I = whole number percent impervious of the site A = site area (in acres) In as”
p. 16

Peak flow calculation method(s)

NRCS Runoff methods, Watershed Lag Method, TR-55, TR-20

“The Watershed Lag Method shall be used for determination of peak rates”
2-13

Hydrologic/hydraulic software

TR-55, TR-20, HECRAS

“The models TR-55 and TR-20 (or approved equivalent) will be used for determining peak discharge rates”
2-14

Approved BMP categories

Pre-Treatment Practices, Non-Structural Practices, Structural Stormwater Treatment Practices, Alternative Stormwater Treatment Practices

“Pre-Treatment Practices, Non-Structural Practices, Structural Stormwater Treatment Practices”
Table of Contents