Minnesota

Minnesota Stormwater Manual

StateMinnesotahighNo

Open source PDF ↗Official agency page ↗

Other manuals in Minnesota: City of Minneapolis

Document Metadata

Jurisdiction level

state

“Published by the Minnesota Pollution Control Agency”
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State

Minnesota

“St. Paul, MN 55155-4194”
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Version / edition

Version 2, January 2008

“Version 2. January 2008”
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Adoption / effective date

2008-01-01

“Version 2. January 2008”
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Last revised date

2008-01-01

“Version 2. January 2008”
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Relationship to state manual

independent

“Created by the Minnesota Stormwater Steering Committee”
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Design Criteria

Design storm return periods (years)

1-year, 2-year, 5-year, 10-year, 25-year, 100-year

“1-Year design storm; 2-Year design storm; 5-Year design storm; 10-Year design storm; 25-Year design storm; 100-Year design storm”
Chapter 8, Section 3.1.1 Precipitation

Water quality volume method

Unified sizing water quality volume (Vwq) based on rainfall depth representing 90% of annual runoff-producing events statewide (1.09 inches ± 0.04 inches) or 95% (1.46 inches ± 0.08 inches), with separate snowmelt Vwq computed for cold-climate sites and BMPs sized for the larger of rainfall or snowmelt volumes; framework also includes recharge (Vre), channel protection (Vcp), 10-year overbank flood (Vp10), and 100-year extreme flood (Vp100) criteria.

“The rainfall depth which represents 90% and 95% of runoff producing events was 1.09 inches (+/- 0.04 inches) and 1.46 inches (+/- 0.08 inches), respectively.”
Chapter 8, Section 3.2.2 Water Quality Event

Peak flow calculation method(s)

Rational Method, NRCS Technical Release 55 (TR-55), NRCS Technical Release 20 (TR-20), SCS Type II 24-hour rainfall distribution

“The Rational Method is used to estimate peak runoff rates for very small sites. The simple equation for peak discharge is Q=CiA.”
Chapter 8, Section 3.2.4 Runoff Coefficient

Required hydrologic/hydraulic software

TR-55, TR-20, HEC-1, HEC-HMS, WinTR-55, HEC-RAS

“TR-55 (original or DOS) ... HEC-1 ... HEC-HMS ... WinTR-20 (or TR-20) ... WinTR-55 ... HEC-RAS”
Chapter 8, Table 8.1 Modeling Tool Selection

Approved BMP categories

Pollution Prevention, Better Site Design / Low Impact Development, Runoff Volume Minimization, Bioretention Practices, Filtration Practices, Infiltration Practices, Stormwater Ponds, Stormwater Wetlands, Temporary Construction Erosion and Sediment Control, Supplemental Pre- and Post-Treatment BMPs

“Pollution Prevention: Chapter 12-1 ... Better Site Design: Chapter 12-2 ... Bioretention Practices: Chapter 12-6 ... Filtration Practices: Chapter 12-7 ... Infiltration Practices: Chapter 12-8 ... Stormwater Ponds: Chapter 12-9 ... Stormwater Wetlands: Chapter 12-10”
Chapter 12 Table of Contents