HomeMy WebLinkAboutOrd 2516 - EXHIBIT A - 2016 Surface Water Design ManualFollowing is
2016 Surface Water Design Manual
adopted April 2016
as Exhibit A
to Ordinance 2516
KING COUNTY, WASHINGTON
SURFACE WATER
DESIGN MANUAL
King County
Department of Natural Resources and Parks
April 24, 2016
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
King County Executive'
Dow Constantine
Metropolitan King County Council'
Rod Dembowski, District 1
Larry Gossett, District 2
Kathy Lambert, District 3
Jeanne Kohl - Welles, District 4
Dave Upthegrove, District 5
Claudia Balducci, District 6
Pete von Reichbauer, District 7
Joe McDermott, District 8
Reagan Dunn, District 9
Department of Permitting and Environmental Review
(DPER)
John Starbard, Director
Jim Chan, Assistant Director
Lisa Verner, Legislative Coordinator
Department of Natural Resources and Parks (DNRP)
Christie True, Director
Bob Burns, Deputy Director
Water and Land Resources Division (WLRD)
Mark Isaacson, Division Director
John Taylor, Assistant Division Director
Primary Contributing Staff (WLRD)
Curt Crawford, P.E, Stormwater Services Sec. Manager
Mark Wilgus, P.E., Engineer IV
Ken Krank, P.E., Former Supervising Engineer
David Batts, Senior WQ Engineer
Jeff Pray, P.E., Engineer
Dale Nelson, Engineer
Primary Contributing Staff (DPER)
Molly Johnson, P.E., Former Development Engineer
Primary Supporting Staff (WLRD)
Bob Gilland, Administrative Specialist
Other Contributing Staff (WLRD)
Jeff Burkey, Hydrologist
Lucy Traxinger, Engineer II
Lica Dulan, Engineer 1
http://www.kingcounty.gov/elected/executive/constantine.aspx
z http: / /www.kingcounty.gov /council/ councilmembers /find_district.aspx
Other Contributing Staff (Previous Editions)
Steve Foley, PE, Former Senior Engineer
Kate Rhoads, Former Senior WQ Engineer
Mary Lear, P.E., Former Engineer
Sue Clarke, Former Senior WQ Engineer
Kelly Whiting, P.E., Former Senior Engineer
Louise Kulzer, Former Senior Water Quality Specialist
Jeff Stern, Senior Water Quality Planner
Thor Tyson, Former Geologist
Bruce Johnson, P.E., Former Senior Engineer
Linda Holden, P.E., Former Senior Engineer
Rhett Jackson, P.E., Former Senior Hydrologist
David Hartley, P.E., Former Senior Hydrologist
Randall Parsons, P.E., Former Senior Engineer
Dave Hancock, Senior Engineer
John Koon, Engineer
Jeff Jacobson, P.E., Former Engineer
Amy Carlson, Former Engineer
Don Althauser, P.E., Managing Engineer
Jennifer Gaus, Former Engineer
Randy Brake, Former Engineer
Zahid Khan, P.E., Supervising Engineer
Jeff O'Neill, P.E., Former Supervising Engineer
Ann Bethel, Former Engineer
Richard Lowe, P.E., Senior Engineer
Rebecca Marcy, Project Program Manager
Consultants (Previous Editions)
Rick Schaefer, P.E., formerly RW Beck & Associates
Malcom Leytham, PhD, P.E., Northwest Hydraulic
Consultants
Gary Minton, PhD, P.E.
Carlos Herrera, P.E., Herrera Environmental Consultants
Beth Schmoyer, P.E., formerly Herrera Environmental
Mark Ewbank, P.E., Herrera Environmental Consultants
Mike Giseburt, P.E., R.W. Beck & Associates
Sarah Spear Cooke, Ph.D., Cooke Scientific Services
SvR Design Company
4/24/2016 2016 Surface Water Design Manual
INTRODUCTION
TABLE OF CONTENTS
AND OVERVIEW
KING COUNTY, WASHINGTON
SURFACE WATER
DESIGN MANUAL
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
4/24/2016 2016 Surface Water Design Manual
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TABLE OF CONTENTS
CHAPTER 1
DRAINAGE REVIEW AND
REQUIREMENTS
Section 1.1
Section
Section
Section
Section
Drainage Review
1.1.1 Projects Requiring Drainage
Review
1.1.2 Drainage Review Types and
Requirements
1.1.3 Drainage Review Required By
Other Agencies
1.1.4 Drainage Design Beyond
Minimum Compliance
Section 1.2 Core Requirements
Section 1.2.1 Core Reqmt #1: Discharge at the
Natural Location
Section 1.2.2 Core Reqmt #2: Offsite Analysis
Section 1.2.3 Core Regent #3: Flow Control
Section 1.2.4 Core Reqmt #4: Conveyance
System
Section 1.2.5 Core Reqmt #5: Erosion and
Sediment Control
Section 1.2.6 Core Reqmt #6: Maintenance and
Operations
Section 1.2.7 Core Reqmt #7: Financial
Guarantees and Liability
Section 1.2.8 Core Reqmt #8: Water Quality
Section 1.2.9 Core Reqmt #9: Flow Control
BMPs
Section 1.3 Special Requirements
Section 1.3.1 Special Reqmt #1: Other Adopted
Area - Specific Requirements
Section 1.3.2 Special Reqmt #2: Flood Hazard
Area Delineation
Section 1.3.3 Special Reqmt #3: Flood
Protection Facilities
Section 1.3.4 Special Reqmt #4: Source Control
Section 1.3.5 Special Reqmt #5: Oil Control
Section 1.4 Adjustment Process
Section 1.4.1 Adjustment Authority
Section 1.4.2 Criteria for Granting Adjustments
Section 1.4.3 Adjustment Application Process
Section 1.4.4 Adjustment Review Process
Section 1.4.5 Request for Reconsideration
Procedure
1 -24
1 -24
1 -25
1 -25
1 -27
1 -38
1 -55
1 -60
1 -65
CHAPTER 2
DRAINAGE PLAN
SUBMITTAL
Section 2.1
Section 2.1.1
Section 2.1.2
Section 2.2
Section 2.2.1
Section 2.2.2
Section 2.2.3
Section 2.2.4
Section 2.2.5
Section 2.3
Section 2.3.1
Section 2.3.2
1 -66 Section 2.4
1 -68
1 -82
1 -99
1 -99
1 -101
1 -102
1 -103
1 -105
1 -107
1 -108
1 -108
1 -110
1 -110
1 -112
Section 2.4.1
Section 2.4.2
Section 2.4.3
Plans for Permits and
Drainage Review
Plans Required for Permit
Submittal
Plans Required for Drainage
Review
Plans Required with Initial
Permit Application
Subdivision, UPD, and Binding 2 -5
Site Plans
Short Subdivisions 2 -6
Commercial Site Development 2 -6
Single family Residential 2 -6
Other Permits 2 -6
Drainage Review Plan 2 -7
Specifications
Engineering Plan Specifications 2 -8
Projects in Targeted Drainage 2 -37
Review
Plans Required After Drainage 2 -39
Review
Plan Changes After Permit 2 -39
Issuance
Final Corrected Plan Submittal 2 -39
Final Plat, Short Plat, and 2 -40
Binding Site Plan Submittals
2 -3
2 -3
2 -3
2 -5
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KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TABLE OF CONTENTS
CHAPTER 3
HYDROLOGIC
ANALYSIS & DESIGN
Section 3.1
Section 3.1.1
Section 3.1.2
Section 3.1.3
Section 3.2
Section 3.2.1
Section 3.2.2
Section 3.2.3
Section 3.2.4
Section 3.3
Section 3.3.1
Section 3.3.2
Section 3.3.3
Section 3.3.4
Section 3.3.5
Section 3.3.6
Section 3.3.7
Hydrologic Design Standards
and Principles
Hydrologic Impacts and
Mitigation
Flow Control Standards
Hydrologic Analysis Using
Continuous Models
Runoff Computation and
Analysis Methods
Rational Method
Continuous Models and the
Runoff Files Method
The Approved Model
The HSPF Model
Hydrologic Design
Procedures and
Considerations
CHAPTER 4
CONVEYANCE SYSTEM
ANALYSIS & DESIGN
3 -3 Section 4.1 Route Design and Easement 4 -3
Requirements
3 -3 Section 4.1.1 Route Design 4 -3
Section 4.1.2 Easement and Setback 4 -3
3 -5 Requirements
3 -7
3 -11
3 -13
Section 4.2
Section 4.2.1
Section 4.2.2
Section 4.2.3
Pipes, Outfalls, and Pumps
Pipe Systems
Outfall Systems
Pump Systems
3 -21 Section 4.3 Culverts and Bridges
Section 4.3.1 Culverts
3 -34
3 -34
3 -37
General Hydrologic Design 3 -37
Process
Flow Control Design Using the 3 -39
Runoff Files Method
Conveyance System Design 3 -41
with the Runoff Files Method
Safety Factors in Hydrologic 3 -41
Design
Design Options for Addressing 3 -43
Downstream Drainage Problems
Point of Compliance Analysis 3 -46
Onsite Closed Depressions and 3 -47
Ponding Areas
4 -7
4 -7
4 -29
4 -36
4 -37
4 -37
Section 4.3.2 Culverts Providing for Fish 4 -51
Passage /Migration
Section 4.3.3 Bridges 4 -53
Section 4.4 Open Channels, Floodplains, 4 -55
and Floodways
Section 4.4.1 Open Channels 4 -55
Section 4.4.2 Floodplain /Floodway Analysis 4 -71
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KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TABLE OF CONTENTS
CHAPTER 5
FLOW CONTROL DESIGN
Section 5.1
Section 5.1.1
Section 5.1.2
Section 5.1.3
Section 5.1.4
Section 5.1.5
Section 5.1.6
Section 5.1.7
Section 5.2
Section 5.2.1
Section 5.2.2
Section 5.2.3
Section 5.2.4
Section 5.2.5
Section 5.2.6
Section 5.2.7
Detention Facilities
Detention Ponds
Detention Tanks
Detention Vaults
Control Structures
Parking Lot Detention
Roof Detention
Simple Detention Pond for
Cleared Areas
Infiltration Facilities
General Requirements for
Infiltration Facilities
Infiltration Ponds
Infiltration Tanks
Infiltration Vaults
Infiltration Trenches
Alternative Infiltration Systems
Small Infiltration Basins
5 -3
5 -3
5 -18
5 -22
5 -25
5 -35
5 -35
5 -36
5 -43
5 -44
5 -55
5 -58
5 -61
5 -63
5 -65
5 -67
CHAPTER 6
WATER QUALITY DESIGN
Section 6.1
Section 6.1.1
Section 6.1.2
Section 6.1.3
Section 6.1.4
Section 6.1.5
Section 6.2
Section 6.2.1
Section 6.2.2
Section 6.2.3
Section 6.2.4
Section 6.2.5
Section 6.2.6
Section 6.3
Section 6.3.1
Section 6.3.2
Section 6.3.3
Section 6.3.4
Section 6.3.5
Section 6.4
Section 6.4.1
Section 6.4.2
Section 6.4.3
Section 6.4.4
Section 6.5
Section 6.5.1
Section 6.5.2
Section 6.5.3
Section 6.5.4
Section 6.6
Section 6.6.1
Section 6.6.2
Section 6.7
Section 6.7.1
Section 6.7.2
Water Quality Menus
Basic Water Quality Menu
Enhanced Basic Water Quality
Menu
Sensitive Lake Protection Menu
Sphagnum Bog Protection Menu
High -Use Menu
General Requirements for WQ
Facilities
Water Quality Design Flows and
Treatment Volumes
Sequence of Facilities
Setbacks, Slopes, and
Embankments
Facility Liners
Flow Splitter Designs
Flow Spreading Options
Vegetated Flowpath Facility
Designs
Basic Bioswales
Wet Bioswales
Lateral Inflow Bioswales
Standard Filter Strips
Narrow Area Filter Strips
Wetpool Facility Designs
Wetponds — Basic and Large
Wetvaults
Stormwater Wetlands
Combined Detention and Wetpool
Facilities
Filtration Facility Designs
General Requirements For
Filtration Facilities
Sand Filters — Basic and Large
Sand Filter Vaults
Linear Sand Filters
Oil Control Facility Designs
Catch Basin Inserts
Oil /Water Separators
Proprietary Facility Designs
Ecology Requirements
King County Requirements
6 -3
6 -4
6 -7
6 -9
6 -13
6 -15
6 -17
6 -17
6 -20
6 -23
6 -27
6 -32
6 -36
6 -41
6 -41
6 -57
6 -60
6 -61
6 -69
6 -71
6 -71
6 -86
6 -92
6 -98
6 -105
6 -105
6 -106
6 -123
6 -128
6 -133
6 -133
6 -140
6 -153
6 -153
6 -154
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KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TABLE OF CONTENTS
DEFINITIONS
APPENDICES
APPENDIX A
Maintenance Requirements for Flow Control,
Conveyance, and WQ Facilities
APPENDIX B
Master Drainage Plan Objective, Criteria,
Components and Review Process
APPENDIX C (detached)
Simplified Drainage Requirements
APPENDIX D (detached)
Construction Stormwater Pollution Prevention
Standards
REFERENCE
1. KCC 9.04 — Surface Water Runoff Policy
2. Adopted Critical Drainage Areas
3. Other Adopted Area Specific Drainage
Requirements
A RA Zone Clearing Restrictions
4. Other Drainage Related Regulations and
Guidelines
A Grading Code Soil Amendment Standard
B Clearing & Grading Seasonal Limitations
C Landscape Management Plan Guidelines
D Shared Facility Maintenance
Responsibility Guidance
5. Wetland Hydrology Protection Guidelines
6. Hydrologic /Hydraulic Design Methods
A Infiltration Rate Test Methods
B Pond Geometry Equations
C Introduction to Level Pool Routing
D Supplemental Modeling Guidelines
REFERENCE (continued)
7. Engineering Plan Support
A King County Standard Map Symbols
B Standard Plan Notes and Example Construction
Sequence
C Stormfilter Facility Access and Cartridge
Configuration
8. Forms and Worksheets
A Technical Information Report (TIR) Worksheet
B Offsite Analysis Drainage System Table
C Water Quality Facility Sizing Worksheets
D Flow Control and Water Quality Facility Summary
Sheet and Sketch
E CSWPP Worksheet Forms
F Adjustment Application Form and Process
Guidelines
G Dedication and Indemnification Clause -
Final Recording
H Bond Quantities Worksheet
I Maintenance and Defect Agreement
J Drainage Facility Covenant
K Drainage Release Covenant
L Drainage Easement
M Flow Control BMP Covenant and BMP
Maintenance Instructions (Recordable format)
N Impervious Surface Limit Covenant
O Clearing Limit Covenant
P River Protection Easement
Q Leachable Metals Covenant
9. Interim Changes to Requirements
A Blanket Adjustments
B Administrative Changes
10. King County- Identified Water Quality Problems
11. Materials
A (VACANT)
B (VACANT)
C Bioretention Soil Media Standard Specifications
D (VACANT)
E Roofing Erodible or Leachable Materials
12. (VACANT)
13. (VACANT)
14. Supplemental Approved Facilities
A Approved Proprietary Facilities
B Approved Public Domain Facilities
4/24/2016 2016 Surface Water Design Manual
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
INTRODUCTION
OVERVIEW
King County's surface water features -- the rivers, lakes, wetlands, streams, and Puget Sound -- are a significant part of
our natural beauty and rich heritage. Spawning salmon, meandering rivers, and clean water are important natural
resources which must be managed wisely to protect their values.
As development of the County's landscape occurs and changes the quantity and quality of surface and storm water
runoff, great care must taken to minimize the impacts of these changes to natural resources, public safety, and property.
This necessitates the provision of surface and storm water management systems that not only mitigate such impacts but
must comply with the County's National Pollutant Discharge Elimination System (NPDES) General Municipal
Stormwater Permit issued by the Washington State Department of Ecology pursuant to the Clean Water Act.
This manual contains the requirements and standards for designing such surface and storm water management systems
in King County. As part of the permit approval process for certain types of permits for proposed development projects,
King County requires the construction of surface and storm water management systems to mitigate the impacts of new
development and redevelopment on natural and existing man -made drainage systems.
This manual regulates proposed projects through a mixture of requirements, performance standards, and design
standards. These requirements and standards are primarily enforced by the King County Department of Permitting and
Environmental Review (DPER), which is responsible for the drainage review and approval of engineering plans and
inspection of development projects during construction. This responsibility and how it is carried out is governed not
only by King County Code but to some extent by the County's NPDES municipal stormwater permit, which contains
specific requirements for drainage review and inspection of development projects. In addition to the Surface Water
Design Manual, DPER is also responsible for enforcement of all other King County regulations governing
development.
The Water and Land Resources (WLR) Division of the King County Depai tment of Natural Resources is responsible
for developing the requirements and standards, which includes publishing, updating and providing the technical support
for the Surface Water Design Manual. The WLR Division also reviews requests for experimental design adjustments
and blanket adjustments as described in Chapter 1, Section 1.4.
The chapters of this manual are organized as follows:
Chapter 1
DRAINAGE REVIEW AND REQUIREMENTS
Describes the basic drainage requirements that implement King County adopted surface water runoff
policies and explains how these requirements are applied to proposed projects through the drainage
review process.
Chapter 2 - DRAINAGE PLAN SUBMITTAL
Describes the requirements and specifications for submittal of design plans for drainage review,
including report and plan formats, and scopes.
Chapter 3 - HYDROLOGIC ANALYSIS AND DESIGN
Presents the acceptable methods of hydrologic analysis used to estimate runoff and design flow
control, conveyance, and water quality facilities.
Chapter 4 - CONVEYANCE SYSTEM ANALYSIS AND DESIGN
Presents the acceptable methods, details, and criteria for analysis and design of conveyance systems.
2016 Surface Water Design Manual 4/24/2016
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
Chapter 5 - FLOW CONTROL DESIGN
Presents the acceptable methods, details, and criteria for analysis and design of flow control facilities.
Chapter 6 - WATER QUALITY DESIGN
Presents the acceptable methods, details, and criteria for analysis and design of water quality facilities.
DEFINITIONS - A comprehensive list of the words, terms, and abbreviations accompanied by their meaning as
applied in this manual.
APPENDICES:
• APPENDIX A - MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND
WQ FACILITIES
Contains the thresholds and standards for maintenance of all flow control facilities and
BMPs, conveyance systems, and water quality facilities required in this manual.
• APPENDIX B - MASTER DRAINAGE PLAN OBJECTIVES, CRITERIA AND COMPONENTS AND
REVIEW PROCESS
Describes in a general outline, the objectives, criteria, components and review process for
Master Drainage Plans prepared for Urban Planned Developments and very large projects.
• APPENDIX C - SIMPLIFIED DRAINAGE REQUIREMENTS (Separate Detached Publication)
Describes, the simplified drainage requirements for smaller projects that qualify for
Simplified Drainage Review.
• APPENDIX D - CONSTRUCTION STORMWATER POLLUTION PREVENTION STANDARDS
(Separate Detached Publication)
Describes, the required measures to be implemented during construction to prevent
discharges of sediment -laden runoff from the project site. It also describes effective
management practices for spill control and chemical pollutants used during construction that
may be needed to supplement the required erosion and sedimentation control measures,.
REFERENCE
Includes materials that are strictly for reference only and have not been adopted by the
public rule adopting this manual. The applicant is responsible to insure that the most current
materials are used in preparing a permit application.
4/24/2016 2016 Surface Water Design Manual
CHAPTER 1
DRAINAGE REVIEW
AND REQUIREMENTS
KING COUNTY, WASHINGTON
SURFACE WATER
DESIGN MANUAL
Section 1.1
Section 1.1.1
Section 1.1.2
Section 1.1.3
Section 1.1.4
Section 1.2
Section 1.2.1
Section 1.2.2
Section 1.2.3
Section 1.2.4
Section 1.2.5
Section 1.2.6
Section 1.2.7
Section 1.2.8
Section 1.2.9
Section 1.3
Section 1.3.1
Section 1.3.2
Section 1.3.3
Section 1.3.4
Section 1.3.5
Section 1.4
Section 1.4.1
Section 1.4.2
Section 1.4.3
Section 1.4.4
Section 1.4.5
Drainage Review
Projects Requiring Drainage Review
Drainage Review Types and
Requirements
Drainage Review Required By Other 1 -24
Agencies
Drainage Design Beyond Minimum 1 -24
Compliance
Core Requirements
Core Reqmt #1: Discharge at the
Natural Location
Core Reqmt #2: Offsite Analysis
Core Reqmt #3: Flow Control
Core Reqmt #4: Conveyance
System
Core Reqmt #5: Construction
Stormwater Pollution Prevention
Core Reqmt #6: Maintenance and
Operations
Core Reqmt #7: Financial
Guarantees and Liability
Core Reqmt #8: Water Quality
Core Reqmt #9: Flow Control BMPs
1 -25
1 -25
1 -27
1 -38
1 -55
1 -60
1 -65
1 -66
1 -68
1 -82
Special Requirements 1 -99
Special Reqmt #1: Other Adopted 1 -99
Area - Specific Requirements
Special Reqmt #2: Flood Hazard 1 -101
Area Delineation
Special Reqmt #3: Flood Protection 1 -102
Facilities
Special Reqmt #4: Source Control 1 -103
Special Reqmt #5: Oil Control 1 -105
Adjustment Process
Adjustment Authority
Criteria for Granting Adjustments
Adjustment Application Process
Adjustment Review Process
Request for Reconsideration
Procedure
1 -107
1 -108
1 -108
1 -110
1 -110
1 -112
2016 Surface Water Design Manual 4/24/2016