HomeMy WebLinkAboutRS_2025_1013 Hyatt Regency TIRHyatt Regency – Lake Washington Splices
Stormwater Technical Information Report
October 13, 2025
Prepared for:
Hyatt Regency Lake Washington
1053 Lake Washington Boulevard N
Renton, Washington 98056
Prepared by:
Kevin Cline, CESCL
David Farr, P.E.
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TABLE OF CONTENTS
Figures (in text) ..................................................................................................................................... v
Appendices ........................................................................................................................................... v
Acronyms and Abbreviations .............................................................................................................. vi
Disclaimer ............................................................................................................................................ vii
1 Introduction .................................................................................................................................. 1
1.1 Project Overview .................................................................................................................. 1
2 Conditions and Requirements Summary .................................................................................... 7
2.1 Core Requirement #1 – Discharge at the Natural Location .............................................. 7
2.2 Core Requirement #2 – Offsite Analysis ............................................................................. 7
2.3 Core Requirement #3 – Flow Control Facilities ................................................................. 7
2.4 Core Requirement #4 – Conveyance System ..................................................................... 7
2.5 Core Requirement #5 – Construction Stormwater Pollution Prevention ......................... 7
2.6 Core Requirement #6 – Maintenance and Operations ..................................................... 7
2.7 Core Requirement #7 – Financial Guarantees and Liability .............................................. 7
2.8 Core Requirement #8 – Water Quality ............................................................................... 8
2.9 Special Requirement #1 – Other Adopted Area-Specific Requirements ......................... 8
2.10 Special Requirement #2 – Flood Hazard Area Delineation .............................................. 8
2.11 Special Requirement #3 – Flood Protection Facilities ....................................................... 9
2.12 Special Requirement #4 – Source Controls ........................................................................ 9
3 Offsite Analysis ............................................................................................................................. 9
4 Flow Control, Low Impact Development, and Water Quality Facility Analysis and Design . 10
4.1 Existing Site Hydrology ..................................................................................................... 10
4.2 Developed Site Hydrology ................................................................................................ 10
4.3 Performance Standards ..................................................................................................... 10
4.4 Flow Control System .......................................................................................................... 10
4.5 Water Quality System ........................................................................................................ 10
5 Conveyance System Analysis And Design ................................................................................ 10
6 Special Reports and Studies ...................................................................................................... 10
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7 Other Permits .............................................................................................................................. 11
8 Erosion and Sediment Control Analysis and Design ............................................................... 11
8.1 Erosion and Sediment Control .......................................................................................... 11
8.2 Stormwater Pollution Prevention and Spill Control ......................................................... 11
9 Bond Quantities, Facility Summaries, and Declaration of Covenant ..................................... 12
10 Operations and Maintenance Manual ...................................................................................... 12
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FIGURES (IN TEXT)
Figure 1 Site Location Map
Figure 2 Site Boundary Map
Figure 3 Site Characteristics Map
Figure 4 Soils Map
Figure 5 Downstream Analysis Map
APPENDICES
Appendix A TIR Worksheet
Appendix B Lake Study/No Net Loss Determination
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ACRONYMS AND ABBREVIATIONS
BMP Best Management Practice
CAR Critical Area Report
CWA Clean Water Act
ESC Erosion and Sediment Control
NRCS Natural Resources Conservation Service
O&M Operations and Maintenance
PGIS Pollution-Generating Impervious Surface
PGPS Pollution-Generating Pervious Surface
RSWDM Renton Surface Water Design Manual
SFR Single-Family Residence
TIR Technical Information Report
USDA United States Department of Agriculture
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DISCLAIMER
This Hyatt Regency – Lake Washington Splices Stormwater Technical Information Report was
prepared by Pacific Stormwater Solutions, LLC. (Pacific Stormwater) for the pier repair project at
the Hyatt Regency in Renton, Washington. The material presented reflects Pacific Stormwater’s
professional opinion and judgement in accordance with the scope, schedule and other limitations
stated in this report and in the contract between Pacific Stormwater and the Client. The opinions
in this report are based on conditions and information existing at the time the document was
prepared and do not take into account any subsequent changes. In preparing this document,
Pacific Stormwater did not verify information supplied to it by others. Any use which a third party
makes of this document is the responsibility of said third party. Such a third party agrees that
Pacific Stormwater shall not be responsible for costs or damages of any kind, if any, suffered by it
or any other third party as a result of decisions made or actions taken based on this document.
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1 INTRODUCTION
Pacific Stormwater has prepared this Technical Information Report (TIR) in support of the Hyatt
Regency – Lake Washington Splices (Project) in accordance with the 2022 City of Renton Surface
Water Design Manual (RSWDM) and as required by the pre-application meeting (PRE 25-000168)
memorandum by the City of Renton. As stated in the memorandum project is required to comply
with special requirements #1: Area Specific Requirements, #2: Flood Hazard Delineation, #3:
Flood Protection Facilities, and #4: Source Control. This report contains all technical information
and analysis necessary for Targeted Drainage Review, Category #1. The TIR worksheet from
Reference 8-A of the RSWDM is included in Appendix A of this report.
1.1 PROJECT OVERVIEW
The proposed Project is located at 1053 Lake Washington Boulevard N in a mixed use zone in
Renton, King County, Washington (Figure 1). The Project area is primarily on King County parcel
number 00523059075, but also includes a small portion of the property to the northeast (parcel
number 0322059124). The Project area, which may encompass up to approximately 0.45 acres and
is shown on Figure 2, will be referred to as the Site.
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Figure 1. Site Location Map
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Figure 2. Site Boundary Map
The Site is currently developed with a 334,335 square-foot multi-story hotel building constructed
in 2017, paved parking and drive areas, landscaping, lakeside promenade, and in-water dock.
(Figure 2). The proposed project consists of repairing the existing pier by splicing 11 existing
piles and removing 8 derelict piles. No upland demolition, removal, excavation, staging, material
import, or construction is proposed. All work will be conducted from a barge stationed in Lake
Washington. A September 2025 Lake Study conducted by Northwest Environmental Consulting
(Appendix B) determined as long as Best Management Practices (BMPs) and conservation
measures are used, the proposed project will result in No Net Loss of ecological functions at the
Site. Site characteristics are shown below on Figure 3.
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Figure 3. Site Characteristics Map (with legend)
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According to the United States Department of Agriculture (USDA) Natural Resources
Conservation Service (NRCS) Soil Survey, soil at the Site is categorized as Urban Land (Figure 4).
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Figure 4. Soils Map (with legends)
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2 CONDITIONS AND REQUIREMENTS SUMMARY
Per the pre-application meeting with the City of Renton held on July 3, 2024, the proposed Project
requires a Simplified Drainage Review with Targeted Drainage Review Category #1. The Project
will include repairing 11 existing pier piles by splicing and removing eight derelict piles. Core
Requirements #1 through #8 and Special Requirements #1 through #4 are discussed in the
following sections, in accordance with the Targeted Drainage Review Category #1 requirements
presented in the RSWDM.
2.1 CORE REQUIREMENT #1 – DISCHARGE AT THE NATURAL LOCATION
The Site is developed with an existing stormwater catchment system that discharges to Lake
Washington and will not be altered during the proposed project. Any natural discharge locations
for the Site will not be altered during the proposed project.
2.2 CORE REQUIREMENT #2 – OFFSITE ANALYSIS
The proposed Project will not add new impervious or pervious surface or change the rate, volume,
or duration of stormwater discharge from the Site.
2.3 CORE REQUIREMENT #3 – FLOW CONTROL FACILITIES
The proposed Project will not add new impervious surface or pervious surface. Storm and surface
water runoff generated from the existing impervious surfaces at the Site will be mitigated by the
existing stormwater facilities installed at the Site.
2.4 CORE REQUIREMENT #4 – CONVEYANCE SYSTEM
No new pipe systems, culverts, ditches, or channels or be constructed during this Project. There
will be no alterations to the existing onsite conveyance systems.
2.5 CORE REQUIREMENT #5 – CONSTRUCTION STORMWATER POLLUTION PREVENTION
Erosion and sediment controls will be implemented for the proposed Project per the measures
detailed in Section 8.
2.6 CORE REQUIREMENT #6 – MAINTENANCE AND OPERATIONS
No new drainage facilities will be installed at the Site for the proposed Project.
2.7 CORE REQUIREMENT #7 – FINANCIAL GUARANTEES AND LIABILITY
No new drainage facilities will be installed at the Site for the proposed Project.
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2.8 CORE REQUIREMENT #8 – WATER QUALITY
This Project will not create new or replace any pollution generating impervious surface (PGIS) or
pollution generating pervious surface (PGPS).
2.9 SPECIAL REQUIREMENT #1 – OTHER ADOPTED AREA-SPECIFIC REQUIREMENTS
The Joint Aquatic Resources Permit Application (JARPA) has been completed for the proposed
project. A September 2025 Lake Study conducted by Northwest Environmental Consulting
(Appendix B). The report details the following conservation measures:
• The proposed project will not affect the lake bed. All pile stubbing will be completed to
the upper 3 feet of the piling.
• Short-term risks include the potential for petroleum spills that can occur with any
equipment operation. The chance of impact to the aquatic environment is reduced
because a crew trained in using spill containment measures will be on site and employ
these measures should a spill occur.
• The work will be completed during the prescribed in-water work window for this area of
Lake Washington (July 16 to December 31). Operating within this time frame helps
protect Chinook salmon, steelhead, bull trout and other salmonid fish species.
• Applicable BMPs will be used such as a floating boom around the in-water work area to
contain any floating debris that may escape during construction. The barge will have a
perimeter containment sock to absorb oil and grease that may wash from the barge
during construction.
• Hazardous material containment materials such as spill absorbent pads and trained
personnel will be required onsite during any phase of construction where machinery is in
operation near surface waters.
Additionally, the owner has opted to pay the required in-lieu fee to King County to complete the
mitigation requirements as required by the National Marine Fisheries Service using the King
County Restoration and Permitting (RAP) process. The City of Renton has not codified in lieu
mitigation as an option for the project.
Project activities will not affect shoreline functions.
2.10 SPECIAL REQUIREMENT #2 – FLOOD HAZARD AREA DELINEATION
The proposed Project area is not within any mapped FEMA 100-year floodplain. Constructing a
new or modifying any existing flood protection facility is not included in the proposed Project.
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2.11 SPECIAL REQUIREMENT #3 – FLOOD PROTECTION FACILITIES
The Project does not propose to construct a new or modify any existing flood protection facilities.
2.12 SPECIAL REQUIREMENT #4 – SOURCE CONTROLS
This Project does not require a commercial building or site development permit.
3 OFFSITE ANALYSIS
Stormwater runoff from the existing hotel development is discharged to Lake Washington from
three separate outfalls. One outfall (central) is only served by the central portion of the Site. The
southern outfall is served by the adjoining industrial Boeing facility, commercial office buildings,
electrical sub-station, and associated right-of-way infrastructure. The northern outfall is served by
the adjoining commercial office building property, two multi-family residential properties and
associated right-of-way infrastructure. Lake Washington is a Clean Water Act (CWA) Section
303(d)-listed impaired water body for many contaminants including bacteria, metals, PCBs, and
pesticides.
A Level 1 Downstream Analysis was not conducted as there will be no addition or alteration of
the existing flow pattern at the Site.
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4 FLOW CONTROL, LOW IMPACT DEVELOPMENT, AND WATER QUALITY FACILITY
ANALYSIS AND DESIGN
4.1 EXISTING SITE HYDROLOGY
The Site is approximately 90 percent hardscape with storm and surface water discharging directly
to Lake Washington. There are no wetlands and/or streams located on the Site or within the
project area.
4.2 DEVELOPED SITE HYDROLOGY
The Project proposes to splice 11 existing piles and remove eight derelict piles from the existing
dock located within Lake Washington. All work will be conducted from a barge stationed in the
lake. No upland construction, staging, demolition, excavation, or hauling is proposed. No new
impervious or pervious surfaces will be constructed.
4.3 PERFORMANCE STANDARDS
Flow control best management practices (BMPs) per RSWDM Core Requirement #9 are not
required for this Project. No new conveyance systems will be constructed and the flow serving
the existing conveyance system will not be altered.
4.4 FLOW CONTROL SYSTEM
No new conveyance systems will be constructed and the flow serving the existing conveyance
system will not be altered.
4.5 WATER QUALITY SYSTEM
No new conveyance systems will be constructed and the flow serving the existing conveyance
system will not be altered.
5 CONVEYANCE SYSTEM ANALYSIS AND DESIGN
No new conveyance systems will be constructed for this Project.
6 SPECIAL REPORTS AND STUDIES
A Lake Study/No Net Loss Determination was prepared by Northwest Environmental Consulting,
LLC in September of 2024 (Appendix B).
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7 OTHER PERMITS
The site owner and their representatives have completed the JARPA process and obtained all
other applicable permits and approvals for this Project.
8 EROSION AND SEDIMENT CONTROL ANALYSIS AND DESIGN
8.1 EROSION AND SEDIMENT CONTROL
The proposed Project will occur in-water of Lake Washington. All work will be conducted from a
barge stationed in the lake. No upland construction, staging, demolition, excavation, or hauling
is proposed. No new impervious or pervious surfaces will be constructed. The following erosion
and sediment control (ESC) procedures will be implemented for this Project:
• Debris Boom – Floating debris booms will be installed around the perimeter of the in-
water work area to prevent migration of any water-born debris produced during the
project.
• Silt Curtain – Silt curtains will be installed in tandem with debris booms to contain any
bottom sediment that may be disturbed during project activities.
8.2 STORMWATER POLLUTION PREVENTION AND SPILL CONTROL
The following stormwater pollution prevention and spill control procedures will be implemented
for this Project, in accordance with the King County Stormwater Pollution Prevention Manual and
Appendix D of the RSWDM:
• Material Delivery, Storage, and Containment (Section D.2.2.4) – Materials will be properly
stored and covered to prevent stormwater contamination and reduce exposure of
surfaces to precipitation. Any waste and pollutants generated or encountered onsite will
be handled and disposed of in a manner that does not cause contamination of
stormwater. Spill prevention and containment measures will be implemented for any
equipment used during the Project.
• Maintain Protective BMPs (Section D.2.2.10) – All BMPs used for the duration of the Project
will be maintained and repaired or replaced as needed to assure continued performance
and provide effective pollutant protection. Wattles shall remain or be repositioned until
root establishment has been achieved.
• Manage the Project (Section D.2.2.11) – The Project will be phased to the maximum
degree practicable to account for seasonal work limits. Routine inspections and
monitoring will be conducted.
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No chemicals, including agricultural chemicals, are anticipated to be used during the Project. No
cement, cement-related products, or other pH-modifying sources are anticipated to be used and
now saw-cutting will occur during the Project.
9 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT
Bond quantities, facility summaries, and/or a declaration of covenant are not required for this
project.
10 OPERATIONS AND MAINTENANCE MANUAL
The Site does not have any existing flow control or water quality facilities and no new facilities will
be constructed for this Project, therefore an operations and maintenance manual is not required.
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APPENDICES
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2025 Stormwater TIR – Hyatt Splice
APPENDIX A – TIR WORKSHEET
CITY OF RENTON SURFACE WATER DESIGN MANUAL
2022 City of Renton Surface Water Design Manual 6/22/2022
8-A-1
REFERENCE 8-A
TECHNICAL INFORMATION REPORT (TIR)
WORKSHEET
Part 1 PROJECT OWNER AND
PROJECT ENGINEER
Part 2 PROJECT LOCATION AND
DESCRIPTION
Project Owner _____________________________
Phone ___________________________________
Address __________________________________
Project Engineer ___________________________
Company _________________________________
Phone ___________________________________
Project Name __________________________
CED Permit # ________________________
Location Township ________________
Range __________________
Section _________________
Site Address __________________________
Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS
Land Use (e.g., Subdivision / Short Subd.)
Building (e.g., M/F / Commercial / SFR)
Grading
Right-of-Way Use
Other _______________________
DFW HPA
COE 404
DOE Dam Safety
FEMA Floodplain
COE Wetlands
Other ________
Shoreline
Management
Structural
Rockery/Vault/_____
ESA Section 7
Part 5 PLAN AND REPORT INFORMATION
Technical Information Report Site Improvement Plan (Engr. Plans)
Type of Drainage Review
check one):
Date (include revision
dates):
Date of Final:
Full
Targeted
Simplified
Large Project
Directed
Plan Type (check
one):
Date (include revision
dates):
Date of Final:
Full
Modified
Simplified
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
6/22/2022 2022 City of Renton Surface Water Design Manual
8-A-2
Part 6 SWDM ADJUSTMENT APPROVALS
Type (circle one): Standard / Blanket
Description: (include conditions in TIR Section 2)
Approved Adjustment No. ______________________ Date of Approval: _______________________
Part 7 MONITORING REQUIREMENTS
Monitoring Required: Yes / No
Start Date: _______________________
Completion Date: _______________________
Describe: _________________________________
Re: SWDM Adjustment No. ________________
Part 8 SITE COMMUNITY AND DRAINAGE BASIN
Community Plan: ____________________________________________________________________
Special District Overlays: ______________________________________________________________
Drainage Basin: _____________________________________________________________________
Stormwater Requirements: _____________________________________________________________
Part 9 ONSITE AND ADJACENT SENSITIVE AREAS
River/Stream ________________________
Lake ______________________________
Wetlands ____________________________
Closed Depression ____________________
Floodplain ___________________________
Other _______________________________
Steep Slope __________________________
Erosion Hazard _______________________
Landslide Hazard ______________________
Coal Mine Hazard ______________________
Seismic Hazard _______________________
Habitat Protection ______________________
REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
2022 City of Renton Surface Water Design Manual 6/22/2022
Ref 8-A-3
Part 10 SOILS
Soil Type Slopes Erosion Potential
High Groundwater Table (within 5 feet)
Other ________________________________
Sole Source Aquifer
Seeps/Springs
Additional Sheets Attached
Part 11 DRAINAGE DESIGN LIMITATIONS
REFERENCE
Core 2 – Offsite Analysis_________________
Sensitive/Critical Areas__________________
SEPA________________________________
LID Infeasibility________________________
Other________________________________
LIMITATION / SITE CONSTRAINT
Additional Sheets Attached
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet
per Threshold Discharge Area)
Threshold Discharge Area:
name or description)
Core Requirements (all 9 apply):
Discharge at Natural Location Number of Natural Discharge Locations:
Offsite Analysis Level: 1 / 2 / 3 dated:__________________
Flow Control (include facility
summary sheet)
Standard: _______________________________
or Exemption Number: ____________
Conveyance System Spill containment located at: _____________________________
Erosion and Sediment Control /
Construction Stormwater Pollution
Prevention
CSWPP/CESCL/ESC Site Supervisor: _____________________
Contact Phone: _________________________
After Hours Phone: _________________________
Maintenance and Operation Responsibility (circle one): Private / Public
If Private, Maintenance Log Required: Yes / No
Financial Guarantees and Liability Provided: Yes / No
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
6/22/2022 2022 City of Renton Surface Water Design Manual
8-A-4
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet
per Threshold Discharge Area)
Water Quality (include facility
summary sheet)
Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog
or Exemption No. _______________________
On-site BMPs Describe:
Special Requirements (as applicable):
Area Specific Drainage
Requirements
Type: SDO / MDP / BP / Shared Fac. / None
Name: ________________________
Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None
100-year Base Flood Elevation (or range): _______________
Datum:
Flood Protection Facilities Describe:
Source Control
commercial / industrial land use)
Describe land use:
Describe any structural controls:
Oil Control High-Use Site: Yes / No
Treatment BMP: _________________________________
Maintenance Agreement: Yes / No
with whom? _____________________________________
Other Drainage Structures
Describe:
REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
2022 City of Renton Surface Water Design Manual 6/22/2022
Ref 8-A-5
Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS
MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION
Clearing Limits
Cover Measures
Perimeter Protection
Traffic Area Stabilization
Sediment Retention
Surface Water Collection
Dewatering Control
Dust Control
Flow Control
Control Pollutants
Protect Existing and Proposed
BMPs/Facilities
Maintain Protective BMPs / Manage
Project
MINIMUM ESC REQUIREMENTS
AFTER CONSTRUCTION
Stabilize exposed surfaces
Remove and restore Temporary ESC Facilities
Clean and remove all silt and debris, ensure
operation of Permanent BMPs/Facilities, restore
operation of BMPs/Facilities as necessary
Flag limits of sensitive areas and open space
preservation areas
Other _______________________
Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch)
Flow Control Description Water Quality Description On-site BMPs Description
Detention
Infiltration
Regional
Facility
Shared
Facility
Other
Vegetated
Flowpath
Wetpool
Filtration
Oil Control
Spill Control
Other
Full Dispersion
Full Infiltration
Limited Infiltration
Rain Gardens
Bioretention
Permeable
Pavement
Basic Dispersion
Soil Amendment
Perforated Pipe
Connection
Other
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
6/22/2022 2022 City of Renton Surface Water Design Manual
8-A-6
Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS
Drainage Easement
Covenant
Native Growth Protection Covenant
Tract
Other ____________________________
Cast in Place Vault
Retaining Wall
Rockery > 4 High
Structural on Steep Slope
Other _______________________________
Part 17 SIGNATURE OF PROFESSIONAL ENGINEER
I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were
incorporated into this worksheet and the attached Technical Information Report. To the best of my
knowledge the information provided here is accurate.
Signed/Date
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2025 Stormwater TIR – Hyatt Splice
APPENDIX B – LAKE STUDY/NO NET LOSS DETERMINATION
Hyatt Regency at Southport
Lake Study/No Net Loss Determination
Prepared for
Hyatt Regency
1053 Lake Washington Boulevard NW
Renton, WA 98056
Prepared by
Northwest Environmental Consulting, LLC
3639 Palatine Avenue North
Seattle, WA 98103
206-234-2520
September 2025
Hyatt Regency at Southport
Lake Study 1
Project Purpose
The project purpose is to repair 11 piles using bonnet splices at the hotel pier in Lake
Washington and remove an additional 8 derelict piles.
Location
The subject property is located at 1053 Lake Washington Boulevard NW (King County parcel
number 0523059076) in the City of Renton, Washington (Sheet 1). The parcel is on the
waterfront of Lake Washington.
Project Description
The proposed work is to repair 11 piles using bonnet splices, under a 2,167-square-foot pier
that serves the Hyatt Regency hotel. All work will be completed in water 10 to 15 feet deep and
occur in the upper 5 feet of the water column. Bonnet splicing requires removal of up to 3 feet
of the tops of piles. A steel section is added to the top of the pile by placing plates around the
top of the remaining pile and though bolting. A 6-inch epoxy coated steel pile section is then
bolted to the steel plates and fastened to the cap beam. 8 derelict piles will also be permanently
removed.
The pier provides moorage for hotel guests, and a place for guests to enjoy shoreline access
while staying at the hotel.
During construction, a floating boom will surround the work barge, pier, and work area.
Project drawings are included in Appendix A – Project Drawings.
Approach
Northwest Environmental Consulting LLC (NWEC) biologist Brad Thiele conducted a site visit in
August 2025 to evaluate conditions on site and adjacent to the site. NWEC also consulted the
following sources for information on potential critical fish and wildlife habitat along this shoreline:
• City of Renton COR Maps online database
(https://rp.rentonwa.gov/HTML5Public/Index.HTML?viewer=CORMaps)
• Washington State DNR Natural Heritage Features database
(https://www.dnr.wa.gov/publications/amp_nh_trs.pdf?znn6z)
• Washington Department of Fish and Wildlife (WDFW): Priority Habitats and Species
online database (http://apps.wdfw.wa.gov/phsontheweb/)
• WDFW SalmonScape online database of fish distribution and ESA listing units
(https://apps.wdfw.wa.gov/salmonscape/)
Hyatt Regency at Southport
Lake Study 2
Site Description
The subject property is a shoreline tract in urban Renton, between the Boeing Renton Facility
and Gene Coulon Memorial Park. It has shoreline on its northern boundary with the hotel
landward, office buildings to the south, industrial buildings to the west, and condominiums to the
east.
The hotel property is fully built out, with a parking lot and adjacent buildings. The shoreline is
bulkheaded with concrete. Some mowed grass and ornamental shrubs exist on the hotel site.
The nearest shoreline vegetation is on Bird Island in Gene Coulon Memorial Park, east of the
site, and on the Boeing Facility shoreline west of the site.
The substrate of the lake is sand, gravel, and cobble. Euarasian milfoil (an invasive species)
was present at the time of the site visit. The Cedar River enters Lake Washington a half-mile
west of the hotel, along the western boundary of the Boeing facility.
Adjacent multi-family residential properties to the east and west have shared-use docks.
Lake and Stream Classifications
As a Shoreline of Statewide Significance (RMC 4-3-090B1) Lake Washington is defined as a
Shoreline of the State (RMC 4-11-190S). The Shoreline is designated as “Urban Center-2” (City
of Renton 2025) (Figure 1). No streams are present within 500 feet of the site.
Ordinary High Water Mark
The Ordinary High Water Mark (OHWM) for Lake Washington is the line of mean high water
(RMC 4-11-150 Definitions O). The Lake Washington water depth is controlled by the Army
Corps of Engineers at the Hiram M. Chittenden Locks and is at 21.8 feet above sea level (Corps
of Engineers Datum). The OHWM at the project site is shown in Appendix A – Project Drawings.
Vegetative Cover of the Site
There are no wetlands or floodplains mapped as occurring in the study area. There are no DNR
Natural Heritage Features listed in the study area (Figure 2). The site is maintained as a hotel
property with some street scaping. The site is generally paved and the water front is a paved
promenade.
Ecological Functions of Lake Washington at Site.
The site lacks native plantings that would provide habitat functions along the shoreline. There is
no plantable area along the shoreline. The nearest shoreline vegetation is on Bird Island at
Gene Coulon Memorial Park, and on the Boeing Facility’s shoreline to the west.
Hyatt Regency at Southport
Lake Study 3
Species Use
Birds
Birds observed near the site include raptors, herons, eagles, waterfowl, and songbirds. Bald
eagles, protected by the Bald and Golden Eagles Protection Act and the Migratory Bird Treaty
Act, are protected as a “sensitive species” within the state of Washington (WAC 232-12-011).
Eagles were not observed in the area during the site study and no nest or adequate nesting
trees were visible along the shoreline. Bald eagles and other raptors are common on along the
shoreline of Lake Washington. Bird Island, less than a half mile to the east, supports many
native birds.
Mammals
No wild mammals were observed during the site visit, but Lake Washington is known to have
river otters, beavers, nutrias, and muskrats. Deer and coyotes are known to be present in the
vicinity; however, the hotel is in a highly urbanized area and presence of any mammals is
unlikely outside the park.
Fish
WDFW’s PHS mapping and SalmonScape mapping tools show the following salmonid species
using Lake Washington for migration and/or rearing: residential coastal cutthroat (Oncorhynchus
clarki), winter steelhead (O. mykiss), Dolly Varden/bull trout (Salvelinus malma), sockeye
salmon (O. nerka), fall Chinook (O. tshawytscha), coho salmon (O. kisutch), and kokanee (O.
nerka). The Salmonscape database maps the site as critical habitat to the Evolutionarily
Significant Unit (ESU) of Threatened Chinook and steelhead (Figure 3). Fall Chinook salmon
and winter steelhead are mapped as rearing in the first mile of the Cedar River, and spawning
upriver. Coho salmon are mapped as rearing in the first few hundred feet of the Cedar River,
and spawning upriver. Sockeye and kokanee are mapped as present in the first few miles of the
river, then spawning upriver. Bull trout are mapped as present in the river, and rearing in Lake
Washington.
The nearest salmon stream is the Cedar River, which enters the lake a half mile west of the
project area on the western edge of the Boeing facility. The project site is accessible to any fish
migrating or rearing in the lake, and Lake Washington is designated as critical habitat for
Endangered Fall Chinook salmon. A small stream enters the lake in Gene Coulon Memorial
Park. City mapping designates this as a Fish stream, but SalmonScape does not show
presence of salmonids.
There is wetland mapped west of the site, on the Boeing property shoreline (Figure 4).
Measures to Protect Trees and Vegetation
No trees will be disturbed during construction as all work will occur in-water and from the work
barge. No vegetation will be removed.
Hyatt Regency at Southport
Lake Study 4
Project Impacts and Conservation Measures
Direct Impacts:
Sediments: Sediment disturbance will occur below the OHWM and along the shoreline of Lake
Washington. Additionally, the tug and barge propwash may disturb sediments temporarily when
making trips to/from the site. Juvenile salmonids could be temporarily displaced or stressed by
increased turbidity. Impacts to sediments should be minimal from pile work and the project
actions are not expected to exceed State Water Quality Standards.
Pile stub repairs are minimally invasive and do not require any disturbance of sediments. All
work is completed in the upper portion of the water column.
Lakebed: The proposed project will not affect the lake bed. All pile stubbing will be completed
to the upper 3 feet of the piling.
Noise: Construction equipment will create noise audible to neighbors and in-water. Noise
disturbance from the underwater chain saw will be short-term, and similar to that of vessel
motors. This noise will have negligible effects on fish and wildlife in the area. Work will be
completed during the in-water work window when juvenile fish are not expected to be present.
Potential spills: Short-term risks include the potential for petroleum spills that can occur with
any equipment operation. The chance of impact to the aquatic environment is reduced because
a crew trained in using spill containment measures will be on site and employ these measures
should a spill occur.
Indirect Impacts:
Recreational Boating: The project supports continued recreational boating, which has been
identified as a limiting factor for salmonid populations in Lake Washington. The pile repairs will
preserve existing moorage capacity in Lake Washington.
Other Conservation measures:
Work window: The work will be completed during the prescribed in-water work window for this
area of Lake Washington (July 16 to December 31). Operating within this time frame helps
protect Chinook salmon, steelhead, bull trout and other salmonid fish species.
Best Management Practices: Applicable BMPs will be used such as a floating boom around
the in-water work area to contain any floating debris that may escape during construction. The
barge will have a perimeter containment sock to absorb oil and grease that may wash from the
barge during construction.
Hazardous material containment materials such as spill absorbent pads and trained personnel
will be required onsite during any phase of construction where machinery is in operation near
surface waters.
Mitigation Strategy
Avoidance and Minimization
Impacts to Lake Washington cannot be avoided. The project has been designed to reduce
impacts by using BMPs to reduce potential impacts from construction. The repairs minimize
impacts by pile splicing, which does not require driving of new piles, and no new overwater
Hyatt Regency at Southport
Lake Study 5
coverage is proposed. The maintenance repairs are the minimum necessary to complete the
work.
Mitigation Approach
The proposal will remove 8 derelict piles from the area. All wood piles under the pier are
untreated.
The owner has opted to pay the required in-lieu fee to King County to complete the mitigation
requirements as required by the National Marine Fisheries Service using the RAP process. The
City of Renton has not codified in lieu mitigation as an option for the project.
Shoreline Function and Values
Project activities will not affect shoreline functions. The proposal is for a maintenance of an
existing structure.
Conclusion
Juvenile Chinook salmon, and other salmonids, rear and migrate along the Lake Washington
shoreline.
There will be temporary impacts from noise and disturbed sediments during installation of the
pilings to construct the new docks.
The project will minimize construction effects on the environment by following the prescribed in
water work window and use applicable BMPs to prevent construction spills and debris from
escaping the area.
The long-term effects of the repair consist of removing 8 derelict untreated piles from the water
column.
This project has been designed to meet current residential dock standards and will use Best
Management Practices to reduce project impacts. The conservation measures are designed to
preserve ecological functions or prevent further degradation of habitat and will result in No Net
Loss of ecological functions at the site.
Document Preparers
Brad Thiele Biologist 31 years of experience NWEC
Kristin Noreen Permit Specialist 26 years of experience NWEC
The conclusions and findings in this report are based on field observations and measurements
and represent our best professional judgment and to some extent rely on other professional
service firms and available site information. Within the limitations of project scope, budget,
and seasonal variations, we believe the information provided herein is accurate and true to
the best of our knowledge. Northwest Environmental Consulting does not warrant any
assumptions or conclusions not expressly made in this repo rt, or based on information or
analyses other than what is included herein.
Hyatt Regency at Southport
Lake Study 6
REFERENCES
City of Renton. 2025. COR Maps. Accessed August 2025 at
https://maps.rentonwa.gov/Html5viewer/Index.html?viewer=CORMaps.
City of Renton Municipal Code (RMC). 2021. RMC Section 4-8-120. Code Publishing. Accessed
August 2025 at
https://www.codepublishing.com/WA/Renton/#!/Renton04/Renton0408/Renton0408120.
html
Washington Department of Fish and Wildlife (WDFW). 2025. Priority Habitats and Species.
Online database. Accessed August 2025 at http://apps.wdfw.wa.gov/phsontheweb/
WDFW. 2021. SalmonScape. Online database. Accessed August 2025 at
http://apps.wdfw.wa.gov/salmonscape/
Washington State Department of Natural Resources. 2025. Sections that Contain Natural
Heritage Features. Accessed August 2025 at
https://www.dnr.wa.gov/publications/amp_nh_trs.pdf?znn6z
Appendix A:
Project Drawings
Waterfront Construction Inc.
NWS-2025-437
Waterfront Construction Inc.
NWS-2025-437
Waterfront Construction Inc.
NWS-2025-437
Waterfront Construction Inc.
NWS-2025-437
Waterfront Construction Inc.
NWS-2025-437
Waterfront Construction Inc.
NWS-2025-437
Appendix B:
Figures
Figure 1 City of Renton Critical Areas Map
Figure 2 DNR Natural Heritage Map
Figure 3 SalmonScape Map
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PHS Species/Habitats Overview:
Occurence Name Federal Status State Status Sensitive Location
Freshwater Forested/Shrub
Wetland N/A N/A No
Freshwater Forested/Shrub Wetland
Priority Area Aquatic Habitat
Site Name N/A
Accuracy NA
Notes Wetland System: Freshwater Forested/Shrub Wetland - NWI Code:
PSS1/FO1Ch
Source Dataset NWIWetlands
Source Name Not Given
Source Entity US Fish and Wildlife Service
Federal Status N/A
State Status N/A
PHS Listing Status PHS Listed Occurrence
Sensitive N
SGCN N
Display Resolution AS MAPPED
ManagementRecommendations http://www.ecy.wa.gov/programs/sea/wetlands/bas/index.html
Geometry Type Polygons
DISCLAIMER. This report includes information that the Washington Department of Fish and Wildlife (WDFW) maintains in a central computer database. It is not an attempt to provide you
with an official agency response as to the impacts of your project on fish and wildlife. This information only documents the location of fish and wildlife resources to the best of our knowledge.
Report Date: 08/19/2025
PHS Species/Habitats Details:
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Appendix C:
Site Photographs