Stormwater Atlas

King County

Surface Water Design Manual

CountyWashingtonhighNeeds reviewCitations verified

This extraction is flagged for quality review.

Compare each cited field to the official PDF before relying on it. What this means

King County SWDM 2021/2024; text extract truncated but core requirements and WQ/flow-control structure clear. Pipeline excerpt repair removed 2 unlocated citation(s).

Fields not found in document: document_metadata.jurisdiction_level, document_metadata.state_code

Document Metadata

Jurisdiction level
Not found in document

No evidence cited

State
Not found in document

No evidence cited

Version / edition
2021 Amended November 14, 2024

“July 23, 2021 Amended November 14, 2024”

Title

Adoption / effective date
2021-07-23

“July 23, 2021”

Title

Last revised date
2024-11-14

“Amended November 14, 2024”

Title

Relationship to state manual
independent

“King County Code (KCC) Chapter 9.04”

Chapter 1

Design Criteria

Design storm return periods (years)
2-year, 10-year, 25-year, 100-year

“Flow Control / design standards”

Chapter 3

Water quality volume method
Core Requirement #8: Water Quality. Water quality menus (Basic Water Quality Menu and others) in Chapter 6. Continuous simulation / WWHM-based sizing typical for flow control and WQ facilities.

“Core Reqmt #8: Water Quality”

Section 1.2.8

Peak flow calculation method(s)
Core Requirement #3: Flow Control, Flow Control Design standards (Chapter 3), Flow control design using continuous hydrologic modeling (WWHM), Core Requirement #9: Flow Control BMPs (dispersal/infiltration LID BMPs)

“Core Reqmt #3: Flow Control”

Section 1.2.3

Hydrologic/hydraulic software
Western Washington Hydrology Model (WWHM) / continuous simulation tools as specified

“Flow Control Design Using the”

Section 3.3.2

Approved BMP categories
Flow control facilities, Water quality treatment facilities (Basic WQ menu and others), Flow control BMPs / LID, Infiltration facilities

“Basic Water Quality Menu”

Section 6.1.1