City of Boise

2019 Boise Stormwater Design Manual

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Open source PDF ↗Official agency page ↗

Fields not found in document: design_criteria.required_hydrologic_hydraulic_software

Other manuals in Idaho: Idaho, Idaho

Document Metadata

Jurisdiction level

City

“within the jurisdiction of the city of Boise (City)”
Section 1.1, Page 1-1

State

Idaho

“Idaho Department of Water Resources (IDWR)”
Section 2.5.C, Page 2-8

Version / edition

December 2019

“DECEMBER 2019”
Cover

Adoption / effective date

2019-12

“DECEMBER 2019”
Cover

Last revised date

2019-12

“This MANUAL replaces the 2018 version of the MANUAL.”
Section 1.1, Page 1-1

Relationship to state manual

independent

“The Stormwater Design Manual (MANUAL) defines minimum standards, requirements, and procedures for the design, permitting, construction,and maintenance of drainage systems within the jurisdiction of the city of Boise (City) in accordance withthe City's Stormwater Management and Discharge Control Ordinance (ORDINANCE), Title 10, Chapter 6”
Section 1.1, Page 1-1

Design Criteria

Design storm return periods (years)

2-year, 5-year, 10-year, 50-year, 100-year

“pre- and post-development flow rate calculations for the 2, 5, 10, and 50-year storm events at sites less than10 acres... the 2, 5, 10, 50, and 100-year storm event are required at hillside development areas and sites greater than 10 acres”
Section 2.5.B, Page 2-6

Water quality volume method

Treat storms up to 0.34-inch depth (City goal to fully treat at least 80% of annual storms); offsite discharges require 80% TSS removal; onsite infiltration systems retain the peak water quantity design volume.

“Water quality treatment depth is based on the City's goal to fully treat at least 80% of the storms annually (i.e. 80% of daily storm events are estimated to have a depth of 0.34" or less)... offsite stormwater discharges... require water quality treatment prior to discharge into the receiving drainage system to achieve an 80% reduction of Total Suspended Solids (TSS)”
Table 2-1 and Section 2.5.C, Pages 2-6 to 2-8

Peak flow calculation method(s)

Rational Method, NRCS TR-55

“Calculation methodologies to determine the storm criteria include the Rational Method and the Natural Resources Conservation Service (NRCS) TR-55 method with a 24-hour design storm.”
Section 2.5, Page 2-5

Hydrologic/hydraulic software

Not found in document

No evidence cited

Approved BMP categories

Sand Filters, Biofiltration Swales and Grass Buffer Strips, Oil Separators, Catch Basin Inserts, Infiltration Swales, Infiltration Basins, Seepage Beds, Dry Detention Ponds, Wet Extended Detention Ponds, Evaporation Ponds, Permeable Interlocking Concrete Pavers (PICP), Hydrodynamic Separators

“infiltration of water quality volume Biofiltration Swale 80% Pretreatment for offsite discharges; sediment forebay included or flow path lengthened for additional sediment removal Grass Buffer (Filter) Strip 85% Pretreatment for offsite discharges; removal rate based on 150’ b”
p. 19