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Home My WebLink AboutAppendix Q - Noise & Vibration DR I-405, Renton Nickel Improvement Project, I-5 to SR 169 NOISE AND VIBRATION DISCIPLINE REPORT October 2005 %&e( !"b$ AÉ !"`$ !"`$ Aæ %&e( Bothell Kirkland Bellevue Renton AÊ AÐ Aí Aô AÌ Aí Aç AÅ Lake Washington Arterial Road Freeway Municipality Lake Park M0 2 Miles I-405 Project Area Renton Nickel Improvement Project NOISE AND VIBRATION DISCIPLINE REPORT I-405, Renton Nickel Improvement Project Prepared for Washington State Department of Transportation Urban Corridors Office And Federal Highway Administration Prepared by Parsons Brinckerhoff October 25, 2005 Title VI WSDOT ensures full compliance with Title VI of the Civil Rights Act of 1964 by prohibiting discrimination against any person on the basis of race, color, national origin or sex in the provision of benefits and services resulting from its federally assisted programs and activities. For questions regarding WSDOT's Title VI Program, you may contact the Department's Title VI Coordinator at 360. 705.7098. Americans with Disabilities Act (ADA) Information If you would like copies of this document in an alternate format—large print, Braille, cassette tape, or on computer disk, please call 360.705.7097. Persons who are deaf or hard of hearing, please call the Washington State Telecommunications Relay Service, or Tele-Braille at 7-1-1, Voice 1.800.833.6384, and ask to be connected to 360.705.7097. Renton Nickel Improvement Project Noise and Vibration Discipline Report i T ABLE OF C ONTENTS Glossary..............................................................................................................................................................................v Acronyms and Abbreviations Used in this Report ........................................................................................................vi Introduction........................................................................................................................................................................1 What is the Renton Nickel Improvement Project? ...........................................................................................................1 What is the No Build Alternative?................................................................................................................................2 What is the Build Alternative?.....................................................................................................................................2 How will stormwater from the project be managed? .................................................................................................12 What environmental and utilities issues influenced the project design and what was done to avoid and minimize project effects?....................................................................................................................................13 What is planned for wetland and stream mitigation?.....................................................................................................16 What benefits will the project provide?......................................................................................................................17 How will the project incorporate community design preferences?.............................................................................17 How will the project be constructed?.........................................................................................................................18 Why do we consider noise as we plan this project? ......................................................................................................19 What are the key points of this report?..........................................................................................................................19 Noise Analysis Overview.................................................................................................................................................21 What are sound and noise?...........................................................................................................................................21 What are typical sound levels, and what affects them?.................................................................................................22 Sources of sound......................................................................................................................................................23 The effect of distance................................................................................................................................................23 The effect of terrain and shielding.............................................................................................................................23 How are sound levels described?..................................................................................................................................25 What are the effects of loud noises?..............................................................................................................................25 What project coordination was performed? ...................................................................................................................26 What criteria are used to evaluate the project’s potential effects on the acoustical environment?................................26 Operational noise standards.....................................................................................................................................26 Construction noise standards....................................................................................................................................28 How was the noise study performed?............................................................................................................................28 Traffic noise prediction..............................................................................................................................................29 Analysis of project effects..........................................................................................................................................30 Noise mitigation analysis...........................................................................................................................................30 How is construction noise analyzed?.............................................................................................................................31 Existing Conditions.........................................................................................................................................................32 What is the study area for the noise analysis? ..............................................................................................................32 Where are the modeled noise receptor locations? ........................................................................................................33 What are the modeled noise levels?..............................................................................................................................46 Potential Effects...............................................................................................................................................................47 Will the project affect noise levels in the study area?....................................................................................................47 How do the Existing Conditions, No Build, and Build Alternatives differ?......................................................................48 Will project construction temporarily affect noise levels?...............................................................................................48 What are the noise sources during construction?.....................................................................................................48 What is the range of noise from construction equipment?........................................................................................49 TABLE OF CONTENTS Renton Nickel Improvement Project ii Noise and Vibration Discipline Report Does the project have other indirect effects that could be delayed or distant from the project?.................................... 50 Measures to Avoid or Minimize Project Effects............................................................................................................ 51 How will effects from construction noise be minimized?................................................................................................ 51 How can effects from traffic noise be minimized?......................................................................................................... 52 Traffic Management Measures................................................................................................................................. 52 Land Acquisition for Noise Buffers or Barriers.......................................................................................................... 53 Roadway Realignment.............................................................................................................................................. 53 Noise Insulation of Buildings..................................................................................................................................... 53 Noise Barriers........................................................................................................................................................... 53 Vibration........................................................................................................................................................................... 63 What is vibration?.......................................................................................................................................................... 63 How is vibration analyzed?............................................................................................................................................ 63 What are the potential effects of vibration?................................................................................................................... 63 How can the potential effects be minimized?................................................................................................................ 64 References....................................................................................................................................................................... 65 I. Noise Measurement and Model Validation.................................................................................................................. 1 II. Description of Measurement Locations....................................................................................................................... 2 III. Validation Results....................................................................................................................................................... 4 Appendix A: Noise Measurement and Model Validation Data Appendix B: Noise Barrier Analysis TABLE OF CONTENTS Renton Nickel Improvement Project Noise and Vibration Discipline Report iii E XHIBITS Exhibit 1. Project Vicinity Map......................................................................................................................................... 1 Exhibit 2. Project Overview Section 1............................................................................................................................. 3 Exhibit 3. Project Overview Section 2............................................................................................................................. 4 Exhibit 4. Project Overview Section 3............................................................................................................................. 5 Exhibit 5. Project Overview Section 4............................................................................................................................. 6 Exhibit 6. Project Overview Section 5............................................................................................................................. 7 Exhibit 7. Project Overview Section 6............................................................................................................................. 8 Exhibit 8. Project Overview Section 7............................................................................................................................. 9 Exhibit 9. Project Overview Section 8............................................................................................................................10 Exhibit 10: Location of Recommended Noise Barrier.....................................................................................................20 Exhibit 11: Typical Noise Levels ....................................................................................................................................22 Exhibit 12: Noise Barrier Effectiveness...........................................................................................................................24 Exhibit 13: FHWA Noise Abatement Criteria..................................................................................................................27 Exhibit 14: Maximum Permissible Environmental Noise Levels.....................................................................................27 Exhibit 15: Allowed Exceedences of the Maximum Permissible Noise...........................................................................28 Exhibit 16: Modeled Noise Levels at Receptors..............................................................................................................34 Exhibit 17: Modeled Noise Receptor Locations...............................................................................................................35 Exhibit 18: Modeled Noise Levels at Receptors..............................................................................................................36 Exhibit 19: Modeled Noise Receptor Locations...............................................................................................................37 Exhibit 20: Modeled Noise Levels at Receptors..............................................................................................................38 Exhibit 21: Modeled Noise Receptor Locations...............................................................................................................39 Exhibit 22: Modeled Noise Levels at Receptors..............................................................................................................40 Exhibit 23: Modeled Noise Receptor Locations...............................................................................................................41 Exhibit 24: Modeled Noise Levels at Receptors..............................................................................................................42 Exhibit 25: Modeled Noise Receptor Locations...............................................................................................................43 Exhibit 26: Modeled Noise Levels at Receptors..............................................................................................................44 Exhibit 27: Modeled Noise Receptor Locations...............................................................................................................45 Exhibit 28: Typical Construction Noise Levels...............................................................................................................49 Exhibit 29: Evaluated Noise Barriers..............................................................................................................................55 Exhibit 30: Allowed Barrier Area for Noise Barrier West 3..............................................................................................56 Exhibit 31: Allowed Barrier Area for Noise Barrier East 1...............................................................................................57 Exhibit 32: Allowed Barrier Area for Noise Barrier East 3...............................................................................................59 Exhibit 33: Allowed Barrier Area for Noise Barrier East 4...............................................................................................60 Exhibit 34: Location of Noise Barrier East 5....................................................................................................................61 Exhibit 35: Allowed Barrier Area for Noise Barrier East 5...............................................................................................62 TABLE OF CONTENTS Renton Nickel Improvement Project iv Noise and Vibration Discipline Report This page intentionally blank. Renton Nickel Improvement Project Noise and Vibration Discipline Report v GLOSSARY A-weight A standard frequency weighting that simulates how humans perceive sound. Ambient Noise The all-encompassing noise associated with a given environment (usually a composite of sounds from many sources near and far). Calibration Adjustment of the noise measurement system so the measured sound level agrees with a reference sound source. Calibration Check A check for variations between the measured sound level and a reference level; no-adjustment is made to the system. Decibel Ten times the base 10 logarithm of sound pressure divided by the reference sound pressure of 20 microPascals. Duration The time a noise event lasts. Energy Average The energy average of two or more quantities expressed on a common decibel scale differs from those arithmetic averages of the quantities. For example, the energy average of 60 dB and 70 dB is 67.4 dB. The arithmetic average of 60 and 70 is 65. Equivalent Noise Level (Leq) The equivalent steady-state sound level in A-weighted decibels for a stated period of time, which contains the same acoustic energy as the actual time-varying sound level for the same period of time. Hertz (Hz) A unit of frequency measured in cycles per second. Lmax This symbol represents the maximum sound level, in decibels. This is the maximum value of the noise level that occurs during a single event. Lmin This symbol represents the minimum sound level, in decibels. This is the minimum value of the noise level that occurs during a single event. Ln The A-weighted sound level, in decibels, that is exceeded n percent of the time in a given interval. For example, L10 is the A-weighted sound level exceeded 10 percent of the time over the given interval (usually 1 hour). The default Ln percentages are 10, 30, 50, 70, and 90. L00 is the same as the maximum sound level because it is the level exceeded 0 percent of the time. Logarithm Also abbreviated to “log.” The log is the exponent that indicates the power to which a number must be raised to produce a given number. For example: if B2 = N, the 2 is the logarithm of N (to the base B), or 102 =100 and the logarithm of 100 (to the base 10) = 2. Noise Level The weighted sound pressure level measured by using a metering characteristic with an “A” frequency weighting network and reported as dBA. Peak The maximum sound level during a given time interval when the normal frequency and time weighting is not used. The noise measurement instrument has a peak detector that responds rapidly to changing sound levels, unlike the normal time weighting of the instrument. Sound Exposure (SE) Sound Exposure is the total sound energy of the actual sound during a given time interval. Unlike the Sound Exposure Level, it is not expressed in dB, but in units of Pascal squared-seconds. Sound Exposure Level (SEL) Sound Exposure Level is the level of a steady one-second-long sound that contains the same energy as the actual (unsteady) sound over the total measurement duration (elapsed time). It is expressed in decibels. Sound Exposure Level is related to Leq, but all the energy is squeezed into a one-second period as opposed to being spread over a stated period of time. Sound pressure level or noise level (SPL) Sound pressure level, in decibels, is an A-weighted sound pressure level. The A-weighting characteristic modifies the frequency response of the measuring instrument to account approximately for the frequency characteristics of the human ear. The reference pressure is 20 micro-newtons/ square meter (2 x 10-4 microbar). Renton Nickel Improvement Project vi Noise and Vibration Discipline Report ACRONYMS AND ABBREVIATIONS USED IN THIS REPORT CAD Computer Aided Drafting dB Decibels dBA A-weighted decibels DOT U.S. Department of Transportation Ecology Washington State Department of Ecology EDNA Environmental designation for noise abatement EPA U.S. Environmental Protection Agency FHWA Federal Highway Administration Hz Hertz HOV High-Occupancy Vehicle I-405 Interstate 405 Ldn Day/Night sound level Leq Equivalent A-weighted sound level Leq (h) Equivalent A-weighted sound level averaged hourly Lmax Maximum sound level during a period of time Lmin Minimum sound level during a period of time Ln n represents the percentage of time the sound level is exceeded. NAC Noise abatement criteria RE Residential equivalency SEL Sound exposure level SR State Route TNM Traffic Noise Model WAC Washington Administrative Code WSDOT Washington State Department of Transportation Renton Nickel Improvement Project Noise and Vibration Discipline Report 1 INTRODUCTION What is the Renton Nickel Improvement Project? The Renton Nickel Improvement Project is a highway expansion project that will improve mobility and safety through Tukwila and Renton. On I-405, this project begins just east of the I-5/I-405 interchange in Tukwila and extends north past the Cedar River to the SR 169 (Maple Valley Highway) interchange. The project will build an additional lane both northbound and southbound between I-5 and SR 169. On SR 167, the project will extend the southbound high-occupancy vehicle (HOV) lane north to I-405 and add a southbound auxiliary lane from I-405 to the SW 41st Street off-ramp. These limits comprise the study area for the project. Prior to planning this specific project, WSDOT created the I-405 Corridor Program. This program provides a comprehensive strategy to reduce congestion and improve mobility throughout the I-405 corridor. The corridor begins at the I-5 interchange in the city of Tukwila and extends northward 30 miles to the I-5 interchange in the city of Lynnwood. The program’s purpose is to provide an efficient, integrated, and multimodal system of transportation solutions. Using the I-405 Corridor Program’s Selected Alternative as the Master Plan to improve I-405, WSDOT developed relatively low cost, congestion relief roadway improvements as an interim step in achieving the Master Plan. As part of this effort, WSDOT began to define the Renton Nickel Improvement Project. The Renton Nickel Improvement Project was developed as part of a first step in providing a focused strategy to improve I-405 between I-5 in Tukwila and SR 169 in Renton and SR 167 southbound from I-405 to SW 41st Street, see Exhibit 1. This discipline report analyzes two project alternatives: the No Build Alternative and the Build Alternative. Exhibit 1. Project Vicinity Map G r e en R i v e r C e d ar Riv er Interurban TrailCedar River Interpretive Trail Panther Creek Wetlands Green River TrailBlack River Riparian Forest Fort Dent Park Cedar River Park Liberty Park SW 41st St S W 3 4 t h S t S W 2 7 t h S t SW 16th St Southcenter ParkwayW Valley HwyI n t e r u r ban Ave SMa ple V alley H w yRainier Ave SS W Sun s e t B lvdS W 7 t h S t S W G r a d y W a y Lind Ave SWTUKWILA RENTON S pri n g br ook CreekBenson Rd SSW 23rd St Talbot Rd SBenson Dr SI-405 Northern Project Limit at SR 169 I-405 Southern Project Limit at I-5 !"`$ %&e( Aæ Aç Aí SR 167 Southern Project Limit at SW 41st St 0 0.25 0.5 Miles M AÅ Arterial Road Freeway Trail Stream Lake Park Municipality INTRODUCTION Renton Nickel Improvement Project 2 Noise and Vibration Discipline Report What is the No Build Alternative? The No Build Alternative assumes that only routine activities such as road maintenance, repair, and safety improvements would take place over the next 20 years. This alternative does not include improvements to increase roadway capacity or reduce congestion. For these reasons, it does not satisfy the project’s purpose—improve I-405 between I-5 in Tukwila and SR 169 in Renton and SR 167 southbound from I-405 to SW 41st Street. The No Build Alternative has been evaluated in this discipline report to establish a baseline for comparing the effects associated with the Build Alternative. What is the Build Alternative? The new lanes that will be built under this project are: An I-405 northbound general-purpose (GP) lane from I-5 to the SR 167 off-ramp. An I-405 northbound auxiliary lane from the SR 167 to I-405 on-ramp to the SR 169 off-ramp. An I-405 southbound auxiliary lane from the SR 169 to I-405 on-ramp to the SR 167 off-ramp. An I-405 southbound GP lane from the SR 167 to I-405 on-ramp to the I-5 off-ramp. A SR 167 southbound auxiliary lane from I-405 to the SW 41st Street off-ramp. Also, the existing inside HOV lane will be extended north to I-405 from its present starting point in the vicinity of SW 21st Street. See Exhibits 2 through 9 show the project features. In addition to adding lanes to I-405 and SR 167, this project will provide the following improvements. Improve Interchanges Minor modifications will be made to the ramps at the SR 167 interchange: The one-lane ramp from northbound I-405 to SR 167 will be widened to a 2-lane off connection, which provides a dedicated lane to southbound SR 167 and a dedicated lane to northbound Rainer Avenue. See Exhibit 5. Traffic from two consecutive single-lane on- ramps from southbound I-405 to SR 167 will be separated by a concrete barrier. This will provide a smoother transition to the mainline and reduce congestion on the on-ramps. What is an auxiliary lane? An auxiliary lane is a lane added between interchanges—from one on-ramp to the next off-ramp. It is dedicated to traffic entering and leaving the freeway and provides motorists with more time and extra room to accelerate or decelerate and merge when getting on and off the freeway. 89:P 89:T Existing On-ramp On-ramp with proposed auxiliary lane INTRODUCTION Renton Nickel Improvement Project Noise and Vibration Discipline Report 3 T u k w i l a P a r k w a y I-405 Southern Project Limit at I-5 Gilliam Creek Cottage Creek Westfield Shoppingtown MallSouthcenter ParkwaySouthcenter Blvd 65th Ave STUKWILA RENTON!"`$ %&e( Sec. 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí I-405 Northboundbound Improvements: A general-purpose lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. I-405 Southbound Improvements: A general-purpose lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. M0250500 Feet I-405 NORTHBOUND Existing Proposed I-405 SOUTHBOUND Existing Proposed Renton Renton Piped River/Creek Channel Open River/Creek Channel Ecology EmbankmentÃÃÃÃÃÃÃÃÃÃÃÃ Retaining Wall Stormwater Flow Control Facility New Pavement Easement Acquisition Parcel Acquisition Existing ROW Areas of Construction New ROW Exhibit 2. Project Overview Section 1 INTRODUCTION Renton Nickel Improvement Project 4 Noise and Vibration Discipline Report ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃInterurban TrailFort Dent Park W Valley HwyInterurban Ave S RENT ONT UKWI L AG r e en RiverSouthcenter B lv d65th Ave SAí %&e( %&e(UP RRBNSF RRBridge Restripe Only Bridge Rail Replacement Bridge Rail Replacement M o n s t e r R d S WTUKWILA RENTON!"`$ %&e( Sec. 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí I-405 Northbound Improvements: A general-purpose lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. I-405 Southbound Improvements: A general-purpose lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. M0250500 Feet I-405 SOUTHBOUND Existing Proposed Renton Renton I-405 NORTHBOUND Existing Proposed %&e( Retaining Wall Piped River/Creek Channel Open River/Creek Channel ÃÃÃÃÃÃÃÃÃÃÃÃ Ecology Embankment Stormwater Flow Control Facility New Pavement Areas of Construction Easement Acquisition Parcel Acquisition Existing ROW New ROW Exhibit 3. Project Overview Section 2 INTRODUCTION Renton Nickel Improvement Project Noise and Vibration Discipline Report 5 ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃ SW 16th St S W G r a d y W a y SW G ra d y W a y Oakesdale Ave SWSW 16th St %&e( Potential Staging Area Bridge Replacement S prin g br o o k Cr eekBridge Replacement TUKWILA RENTON!"`$ %&e( Sec. 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí I-405 Northbound Improvements: A general-purpose lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. The existing Springbrook Creek and Oakesdale Avenue bridges will be replaced and the existing culvert will be removed. I-405 Southbound Improvements: A general-purpose lane will be added by restriping the existing pavement and adding pavement up to 70 feet to the outside at some locations. The existing Springbrook Creek and Oakesdale Avenue bridges will be replaced and the existing culvert will be removed.M0250500 Feet I-405 SOUTHBOUND Existing Proposed Renton Renton I-405 NORTHBOUND Existing Proposed Piped River/Creek Channel Open River/Creek Channel ÃÃÃÃÃÃÃÃÃÃÃÃ Ecology Embankment Retaining Wall Stormwater Flow Control Facility New Pavement Areas of Construction Easement Acquisition Parcel Acquisition Existing ROW New ROW Exhibit 4. Project Overview Section 3 INTRODUCTION Renton Nickel Improvement Project 6 Noise and Vibration Discipline Report ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃ SW 19th StLind Ave SWS G r a d y W a y Aæ %&e( Potential Staging Area Noise Wall Renton CinemaRolling Hills Creek Panther Creek Wetlands SW 16th St Lake AveSouthRainier Ave STUKWILA RENTON!"`$ %&e( Sec. 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí I-405 Northbound Improvements: A general-purpose lane will be added up to the SR 167 interchange and an auxiliary lane will be added from the SR 167 to I-405 on-ramp north. These lanes will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. I-405 Southbound Improvements: An auxiliary lane will be added up to the I-405 to SR 167 on-ramp and a general-purpose lane will be added south of the interchange. These lanes will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. SR 167 Southbound Improvements: An auxiliary lane will be added by restriping existing pavement and adding up to 19 feet of pavement at the outside at some locations. The existing HOV lane will be extended north from SW 21st Street to the interchange with I-405.M0250500 Feet I-405 SOUTHBOUND Existing Proposed Renton Renton I-405 NORTHBOUND Existing Proposed SR 167 SOUTHBOUND Existing Proposed Renton ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃ ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃ Piped River/Creek Channel Open River/Creek Channel Proposed Noise Wall ÃÃÃÃÃÃÃÃÃÃÃÃ Ecology Embankment Retaining Wall Stormwater Flow Control Facility New Pavement Areas of Construction Easement Acquisition Parcel Acquisition Existing ROW New ROW Exhibit 5. Project Overview Section 4 INTRODUCTION Renton Nickel Improvement Project Noise and Vibration Discipline Report 7 ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃPanther Creek Wetlands S W 2 7 t h S t Talbot Rd SEast Valley RdTalbot Rd SPotential Staging Area SW 23rd St TUKWILA RENTON!"`$ %&e( Sec. 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí SR 167 Improvements: In addition to extending the HOV lane north from SW 21st Street, an auxiliary lane will be added by restriping the existing pavement and adding pavement up to 19 feet to the outside at some locations. M0250500 Feet SR 167 SOUTHBOUND Existing Proposed Renton RentonÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃ Piped River/Creek Channel Open River/Creek Channel ÃÃÃÃÃÃÃÃÃÃÃÃ Ecology Embankment Retaining Wall Stormwater Flow Control Facility New Pavement Areas of Construction Easement Acquisition Parcel Acquisition Existing ROW New ROW Exhibit 6. Project Overview Section 5 INTRODUCTION Renton Nickel Improvement Project 8 Noise and Vibration Discipline Report ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃSW 41st St S W 3 3 r d S t Panther CreekEast Valley RdTalbot Rd SLind Ave SWAæ SR 167 Southern Project Limit at SW 41st St TUKWILA RENTON!"`$ %&e( Sec. 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí SR 167 Improvements: An auxiliary lane will be added by restriping the existing pavement and adding pavement up to 19 feet to the outside at some locations. The new lane will tie into the existing ramp connection to SW 41st Street. M0250500 Feet SR 167 SOUTHBOUND Existing Proposed Renton Renton Piped River/Creek Channel Open River/Creek Channel ÃÃÃÃÃÃÃÃÃÃÃÃ Ecology Embankment Retaining Wall Stormwater Flow Control Facility New Pavement Areas of Construction Easement Acquisition Parcel Acquisition Existing ROW New ROW Exhibit 7. Project Overview Section 6 INTRODUCTION Renton Nickel Improvement Project Noise and Vibration Discipline Report 9 ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃS G rady W ayB e a c o n S 7 t h S tWilliams %&e( Potential Staging Area Replace Bridge Bridge Widening Existing Bridge to be Demolished Thunder Hills Creek Rolling Hills Creek Noise Wall Benson Rd STalbot Rd STUKWILA RENTON!"`$ %&e( Sec, 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí I-405 Northbound Improvements: An auxiliary lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. I-405 Southbound Improvements: An auxiliary lane will be added by restriping the existing pavement and adding pavement up to 24 feet to the outside at some locations. Benson Rd S Improvements: The Benson Rd S overpass will be replaced and realigned to the west of its current location. The new overpass will have 2 lanes with 5-foot bike lanes on both sides and a 6-foot sidewalk on the west side.M0250500 Feet I-405 NORTHBOUND Existing Proposed I-405 SOUTHBOUND Existing Proposed Renton Renton Parcel Acquisition New ROW Existing ROW Easement Acquisition Areas of Construction New Pavement Stormwater Flow Control Facility Retaining Wall ÃÃÃÃÃÃÃÃÃÃÃÃ Ecology Embankment Proposed Noise Wall Piped River/Creek Channel Open River/Creek Channel Exhibit 8. Project Overview Section 7 INTRODUCTION Renton Nickel Improvement Project 10 Noise and Vibration Discipline Report C edar River Cedar River Interpretive Trail Cedar River Park Liberty Park Ma p l e V a ll e y H w y H o u s e r W a y S N 3 r d S t Bronson Wa y N%&e( I-405 Northern Project Limit at SR 169 Aç Restripe Only Main AvenueCedar Ave SRenton Ave STUKWILA RENTON!"`$ %&e( Sec. 1 Sec. 2 Sec. 3 Sec. 4 Sec. 5 Sec. 6 Sec. 7 Aæ Aç Sec. 8 Aí I-405 Northbound Improvements: An auxiliary lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. I-405 Southbound Improvements: An auxiliary lane will be added by restriping the existing pavement and adding pavement up to 15 feet to the outside at some locations. M0250500 Feet I-405 NORTHBOUND Existing Proposed I-405 SOUTHBOUND Existing Proposed Renton Renton Piped River/Creek Channel Open River/Creek Channel ÃÃÃÃÃÃÃÃÃÃÃÃ Ecology Embankment Retaining Wall Stormwater Flow Control Facility New Pavement Areas of Construction Easement Acquisition Parcel Acquisition Existing ROW New ROW Exhibit 9. Project Overview Section 8 INTRODUCTION Renton Nickel Improvement Project Noise and Vibration Discipline Report 11 Improve Benson Road The Benson Road overpass will be replaced and realigned to accommodate the southbound auxiliary lane on I-405 as well as future improvements to I-405 as shown on Exhibit 8. Improvements on Benson Road include a 6-foot sidewalk on the west side and 5-foot bike lanes on both sides. Widen and replace bridges Several bridges within the study area will be widened or replaced based on present location, cost, and existing soil conditions. To construct the new lanes, the project will: Widen Talbot Road Bridge on both the northbound and the southbound sides. See Exhibit 8. Replace Springbrook Creek Side Channel Bridge and Oakesdale Avenue Bridge with new southbound and northbound structures and remove the Springbrook Creek box culvert. See Exhibit 4. Replace the rail on the I-405 bridges over SR 181 and the Union Pacific and Burlington Northern Santa Fe railroads. The project will not affect the I-405 bridges over the Green River, Lind Avenue, or the Cedar River. The project will also not affect the Cedar Avenue or Renton Avenue overpasses. The roadway will be restriped in these areas to accommodate the new lanes. Use retaining walls Widening I-405 and SR 167 will require retaining walls to minimize the construction footprint and right-of-way acquisition. Retaining walls will also help avoid and minimize effects to wetlands and other sensitive areas. Improve culverts WSDOT anticipates that construction will affect some existing stormwater cross culverts and one stream culvert. Associated culvert improvements include extending the existing structures due to widening the roadway and stabilizing culvert ends with rock or retaining walls. The I-405 Team will conduct a hydraulic analysis of the culverts to ensure that the modifications will have no effect on the base flood elevations. See the Fisheries and Aquatic Resources Discipline Report for detailed discussion on fish passage. Why rebuild Benson Road on a new alignment over I-405? By building the new overpass to the west on a new alignment, the new structure can be constructed while the existing structure remains open to traffic. Traffic can then be shifted onto the new structure, while the old overpass is demolished. What does a “rail” replacement involve? Typically, a bridge rail replacement project consists of making minor adjustments to the width of the bridge deck and replacing the guard rail or barrier. This type of project does not include adding new bridge columns or footings. INTRODUCTION Renton Nickel Improvement Project 12 Noise and Vibration Discipline Report Build a noise wall One noise wall will be built on the northbound side of the freeway as shown on Exhibits 5 and 8. The wall will begin at the intersection of South 14th Street and South 15th Street and follow South 14th Street east to Talbot Road. This wall will be approximately 2,150 feet long and 18 feet tall. How will stormwater from the project be managed? Stormwater from the project will be managed for both quality and peak flows using currently accepted best management practices (BMPs). The I-405 Team has designed the stormwater management facilities to comply with the following guidelines and procedures: WSDOT Highway Runoff Manual M 31-16 WSDOT Hydraulics Manual M 23-03 Stormwater treatment facilities The project will add new impervious surface within the study area, most of which will be within the Springbrook Creek basin. This project will treat runoff for an area equal to 100 percent of these new surfaces. The project will use BMPs that the HRM lists as enhanced treatment facilities. The I-405 Team has proposed that stormwater be treated using a combination of these facilities. In most of the study area, ecology embankments will be used to capture runoff from the edge of the pavement and provide water quality treatment. Ecology embankments also serve to convey treated runoff to receiving waters or to flow control facilities as required. The project also includes a combined stormwater quality wetland and detention facility that addresses water quality and flow control in one facility. Exhibits 2 through 9 show the location of stormwater facilities that will be built for this project. Ecology Embankment Cross-Section What are the guidelines for stormwater management facilities? Water quality treatment will be provided for an area equal to the new impervious surfaces created on the project. Impervious surfaces, such as pavement, are those that do not allow water to penetrate into the ground. Stormwater from new impervious surfaces or an equal area will be controlled in detention facilities. This process allows water to be held (detained) and thus released at rates that are equal to existing conditions. INTRODUCTION Renton Nickel Improvement Project Noise and Vibration Discipline Report 13 Drainage Collection and Conveyance Some changes to existing drainage will be necessary to provide flow control and water quality treatment to address the new impervious area added by the project. However, existing storm drainage systems will be kept to the greatest extent possible and existing flow patterns will be maintained. Where roadway widening affects drainage ditches that convey water from adjacent private properties, the project design will assure that existing conveyance capacities are maintained. What environmental and utilities issues influenced the project design and what was done to avoid and minimize project effects? Throughout the development of the Renton Nickel Improvement Project design, environmental elements were reviewed and design features were modified to avoid or minimize negative effects to the environment. Influence on the project design came from: Soil Conditions: the soils in the project area are highly prone to accentuate earthquake shaking, which influences how bridges can be widened or replaced. Noise: highway noise in the project area already exceeds acceptable levels, which means that including noise walls as part of the project had to be considered. Wetland Locations: many wetlands are located along the edges of the highway, which influence whether the widened sections will use retaining walls or fill slopes. Historical Sites: some historic sites exist within the study area, so the project design was coordinated to avoid these properties. Because the I-405 Team planned for these environmental considerations, several design features have the benefit of avoiding or minimizing potential effects due to the project. These design features are described from south to north below. I-405, I-5 to SR 167 WSDOT will construct a retaining wall from west of the 68th Avenue structure over I-405 at Tukwila Parkway What are detention facilities? These facilities control stormwater runoff so that it can be released at a controlled rate. Two types are commonly used: Ponds. Vaults. Similar to a pond, but with a hard-sided construction. These concrete structures function like a pond but also provide detention storage. INTRODUCTION Renton Nickel Improvement Project 14 Noise and Vibration Discipline Report The proposed design modifications allow the additional lanes to be added over the Green River by restriping instead of bridge widening. This avoids effects on the river, stream habitat, floodplain, and Interurban Trail. to the Green River. This wall avoids the need to construct a fill slope that would extend into Gilliam Creek. See Exhibit 2. WSDOT will provide a narrower outside shoulder on northbound I-405 at the Green River Bridge. The shoulder will vary from 10 to just over 3 feet at the west abutment of the existing bridge. Narrowing the shoulder avoids modifications to the existing bridge. As a result, the design also avoids effects to the river, the 100-year floodplain, the ordinary high water level, and adjacent riparian zones. At the SR 181 interchange, the bridge and ramp will be restriped to provide the new general-purpose lane and ramp improvements. This approach minimizes the need to widen the existing SR 181 Bridge, reconstruct the SR 181 interchange, or modify the Southcenter Boulevard crossing of the Green River. This in turn avoids relocating or diverting the Interurban Trail, which goes under the bridge. See Exhibit 3. Near the Westfield Shoppingtown Mall, a large Seattle Public Utilities water transmission line parallels I-405. WSDOT will line this pipe so that is can support the loads from the new roadway embankment. This approach allows the line to stay in its present location. WSDOT will remove the existing I-405 bridges over the Springbrook Creek side channel and Oakesdale Avenue and replace them with a single northbound and a single southbound bridge. This approach will allow for the removal of the Springbrook Creek box culvert. Construction of the new bridges will be phased with the southbound bridge built slightly to the north of the existing roadway. This phasing minimizes the need to construct temporary roadway to maintain traffic operations. WSDOT also evaluated the location of the new bridge piers and selected locations that will minimize the effect on the existing stream, stream buffer, and trail that crosses under the bridge. WSDOT will construct a narrower exit gore from I-405 to the northbound ramp at the SR 167 interchange as shown in Exhibit 5. By building a narrower exit gore, the project can be constructed within the existing right- of-way. This has the benefit of avoiding right-of-way acquisition, avoiding effects to the wetland outside the right-of-way, and avoiding effects to the existing Lind Avenue Bridge. What is an exit gore? An exit gore is a roadway feature that separates an exiting lane from the main lanes. An exit gore can be defined either by paint stripes, raised buttons, physical barriers, or a combination of these. INTRODUCTION Renton Nickel Improvement Project Noise and Vibration Discipline Report 15 Retaining walls will help to avoid and minimize effects on the Panther Creek wetlands along SR 167 SR 167, southbound from I-405 to SW 41st Street WSDOT will build a retaining wall along a large portion of the west edge of SR 167 southbound instead of an earth fill slope. See Exhibits 6 and 7. The retaining wall minimizes effects on three wetlands. The retaining wall has the added benefit of minimizing right-of-way needs and reduces the effect on existing utility crossings, in particular, the City of Seattle’s 60- inch water line and Olympic Petroleum’s two high pressure pipelines, which all cross under SR 167. I-405, SR 167 to SR 169 WSDOT will add a lane by restriping I-405 northbound next to the Talbot Hill retaining wall immediately east of the SR 167 interchange. Restriping instead of widening avoids the need to reconstruct the existing Talbot Hill retaining wall and avoids effects on properties south of I-405 in this area. Between Talbot Road and the “S-Curves”, northbound I-405 will be widened to achieve standard lane and shoulder widths. Most of this length will be supported by retaining walls to minimize effects to Thunder Hills Creek, adjacent properties, and the existing cut slope south of I-405. To support the fill required to widen the roadway on the north side of I-405 next to the outfall for the original Rolling Hills Creek culvert, the design uses a retaining wall. By using the retaining wall, the project improvements at this location can be constructed without affecting the existing culvert. WSDOT will use a non-standard design for the I-405 to SR 167 exit ramp. The changes from the design standards include not providing a recovery lane, narrowing the distance between the through lane and ramp, and providing narrower shoulders. While these changes deviate from WSDOT design standards they are an improvement over existing conditions. These features will avoid effects to the existing Rolling Hills Creek/Thunder Hills Creek channel located between I-405 and the Renton Cinema complex as shown in Exhibit 5. Using retaining walls along the west side of Benson Road avoids effects to Rolling Hills Creek and the wetlands east of Talbot Road. WSDOT will use retaining walls to support widening southbound I-405 south of the Cedar Avenue overpass. Using retaining walls versus a fill slope, avoids encroaching on Cedar Avenue and Main Avenue in Renton. What is a recovery lane? A recovery lane is a paved area adjacent to an off-ramp. This area gives drivers, who find themselves exiting the freeway unintentionally, room to maneuver back onto the freeway. INTRODUCTION Renton Nickel Improvement Project 16 Noise and Vibration Discipline Report WSDOT also plans to replace the existing Benson Road overpass on a new alignment. The new bridge will be located slightly to the west of the existing bridge. This will allow traffic to continue to use the existing overpass until the new one is completed. This will minimize disruption for local traffic and to emergency response vehicles. Where northbound and southbound I-405 passes under the Renton Avenue and Cedar Avenue overpasses, WSDOT will add lanes by restriping. This design avoids replacing the two overpasses; however, the available area does not allow the standard shoulder and lane widths. WSDOT shifted a proposed stormwater facility to avoid effects to the existing Renton Coal Mine Hoist Foundation site south of Benson Road. This site is on the Washington Historic Register. What is planned for wetland and stream mitigation? WSDOT will compensate for unavoidable effects to wetlands with credits from the Springbrook Creek Wetland and Habitat Mitigation Bank. Mitigation is needed for 1.66 acres of wetlands. The Springbrook Creek Wetland and Habitat Mitigation Bank is being developed as a joint effort between WSDOT and the City of Renton. This ‘bank’ will construct a new high quality wetland complex that will serve to replace other wetlands that are filled in by projects such as the Renton Nickel Improvement Project. The location of the bank is shown to the left. In addition to wetland mitigation, the site will also provide flood storage mitigation. The Springbrook Creek Wetland and Habitat Mitigation Bank will be one of the first urban mitigation banks to be certified in Washington. To mitigate project effects on streams, WSDOT will remove the existing Springbrook Creek box culvert. With the new I-405 southbound and northbound bridges that will span both Springbrook Creek and Oakesdale Avenue, the box culvert is no longer needed. After the new bridges are in place, the box culvert will be removed and the streambed in that area will be restored. This will improve fish habitat within Springbrook Creek. Any additional stream mitigation required to offset project effects will be accommodated within the project vicinity. Renton Coal Mine Hoist Foundation site looking west r Interurban TrailPanther Creek Wetlands Green River TrailFort Dent Park SW 41st St S W 3 4 t h S t S W 2 7 t h S t SW 16th St W Valley HwyS W 7 t h S t S W G r a d y W a y Lind Ave SWS pri n g br ook CreekSW 23rd St Aæ Aí M 0 0.25 0.5 Miles 100 Year Floodplain 500 Year Floodplain Park Renton Tukwila Springbrook Creek Wetland & Habitat Mitigation Bank Wetlands Local Road Legend Trail Arterial Road Freeway River/Creek Channel Study Area Limits Springbrook Creek Wetland and Habitat Mitigation Bank INTRODUCTION Renton Nickel Improvement Project Noise and Vibration Discipline Report 17 What benefits will the project provide? The Build Alternative will benefit the area by reducing congestion at chokepoints, reducing the duration of congestion during peak commuter travel hours, and improving freight movement. This section of I-405, from the I-5 interchange to SR 169, is congested due to large traffic volumes and merging and diverging traffic. The new lanes will help relieve congestion by adding roadway capacity. This in turn will improve safety by providing drivers with more time and extra room to accelerate or decelerate and move into and out of the stream of traffic when getting on and off the freeway. This provides a smoother transition for motorists as they get on and off I-405 in Tukwila and Renton and helps decrease rear-end and sideswipe collisions. The project reduces congestion approaching the SR 167 interchange, and it complements the completed southbound I-405 to southbound SR 167 flyover ramp. This project will construct one noise wall along northbound I-405 from the intersection of South 14th Street and South 15th Street east to Talbot Road. This wall will benefit residents in that area by lowering the overall noise levels. Another benefit of this project is that it continues the application of the Context Sensitive Solutions (CSS) design choices made by the communities within the I-405 corridor. The Benson Road realignment will reflect the most comprehensive application of these design choices as explained further in the next section. How will the project incorporate community design preferences? The Renton Nickel Improvement Project is being planned, developed, and designed according to CSS guidelines. These guidelines establish the community design preferences used to design the project features. Working within the framework for the overall I-405 corridor, the Urban Design Guidelines will be adapted to incorporate the communities’ design preferences. These preferences will be included in the contract documents prepared for the Renton Nickel Improvement Project. The selected I-405 theme of “Culture, Nature, and Progress,” with nature being the dominant theme, will be carried into corridor-wide and local I-405 designs. The new Benson Road overpass is the main project feature that will receive CSS treatment. The new southbound and northbound bridges over Springbrook This rendering shows the new Benson Road overpass with the CSS Guidelines applied INTRODUCTION Renton Nickel Improvement Project 18 Noise and Vibration Discipline Report Creek and Oakesdale Avenue will also receive CSS treatments. The rest of the project elements will be designed to match in color and vegetation type only, as many of these elements will be affected by construction of future Master Plan projects. During future Master Plan phases for the overall I-405 corridor, the approved CSS guidelines will be applied throughout. How will the project be constructed? Construction of the entire Renton Nickel Improvement Project is expected to take two years, beginning in early 2008 and being completed in late 2010. However, construction activity will not be constant for the entire study area throughout this time, and in some locations, the work will take substantially less time than two years. Construction will pose some minor inconveniences because of localized travel delays due to temporary lane closures and narrowed lanes and shoulders. At-grade construction At-grade construction, which occurs on the same elevation as the existing lanes, will be staged to minimize traffic delays and detours. Typically, lanes are shifted toward the median. WSDOT then places a concrete barrier to close off the shoulder. Staging allows construction to occur safely without closing lanes for the duration of construction. Access to construction areas will occur from the roadway side to minimize property effects. Bridge construction Construction of the I-405 bridges will occur in multiple stages to minimize traffic delays and detours. The following describes typical staging for bridge construction. As the first stage, traffic is shifted toward the I-405 median and the existing lanes and shoulders are narrowed slightly to allow widening of the existing structure or construction of the new bridge depending on the design. In the next stage, traffic is shifted onto the new bridge area. If the bridge is being replaced rather than simply widened, the old structure is demolished after traffic is shifted to the new bridge. The new Benson Road overpass will also be staged. The new structure will be built to the west, while the existing overpass remains in service. After traffic has been shifted onto the new overpass, the existing structure will be demolished. At-grade construction for this project will likely be staged similar what is shown above. Here, the southbound lanes of I-5 were shifted toward the median and a concrete barrier closed off the shoulder to provide crews a safe work area. INTRODUCTION Renton Nickel Improvement Project Noise and Vibration Discipline Report 19 Staging areas Construction staging areas along I-405 and SR 167 will be within the WSDOT right-of-way. Potential staging areas have been identified as shown on Exhibits 2 through 9. Traffic control Detour agreements with the local agencies will be obtained after WSDOT awards the contract. A traffic control plan will be approved by WSDOT prior to starting construction. The plan’s primary objectives will be to provide a safe facility, to streamline the construction schedule, and to minimize reductions to existing traffic capacity. To lessen effects on traffic, the duration of activities will be minimized and reductions in capacity will be limited and will be targeted to a period when they will have the least effect. Why do we consider noise as we plan this project? Sound is an element of daily life that when perceived as unpleasant, unwanted, or disturbingly loud, is called noise. The effects of noise are considered by the I-405 Team in order to understand the potential effect of traffic and construction noise on public health and welfare. Federal regulations (23 CFR 772) and WSDOT NAC require a noise analysis for projects that add new through capacity to a highway or when a highway is realigned. Additional travel lanes on I-405 and higher speeds during peak hours from reduced congestion could increase perceived noise levels at sensitive receptors such as residential and park land in the study area. This noise analysis will determine if mitigation measures such as noise barriers are warranted to buffer the roadway from noise sensitive areas. What are the key points of this report? Some places in the study area already exceed the noise abatement criteria (NAC). These places include approximately 105 residences, 2 parks, 2 trails, and an aquatic center. Ten of these residences exceed the criteria because of noise from local traffic on Main Avenue South, Southwest Grady Way, and Southcenter Boulevard. Are you new to reading noise reports? Environmental disciplines generally have vocabularies all their own. We encourage readers who are new to noise related terminology to invest a few minutes now reviewing the Glossary and the list of Acronyms in the preceding sections. An understanding of the A-weighted decibel (dBA) and the Equivalent A-weighted sound level (Leq) will be especially helpful in following our analysis of this important environmental element. What is the Noise Abatement Criteria (NAC)? Noise regulations and guidelines are the basis for evaluating potential noise effects. For state and federally funded highway projects, traffic noise impacts occur when predicted noise levels approach or exceed the noise abatement criteria (NAC) established by the FHWA. The NAC is 67 decibels. INTRODUCTION Renton Nickel Improvement Project 20 Noise and Vibration Discipline Report If this project is not built, no additional residence(s) would approach or exceed the NAC up until at least the year 2030. The NAC is 67 dBA (decibels) Leq (equivalent sound level). If the project is built, noise levels will increase primarily at residences in the Renton Hill, Steeplechase, and Talbot Hill neighborhoods. Noise levels will grow over time with an increase of 0 to 3 dBA Leq by the year 2030. Thirty-nine residences would go from being below the NAC to being at or above the NAC, if this project is built. These 39 residences added to the existing 105 residences make a total of 144 future residences that are predicted to experience noise levels at or above the NAC in 2030. This study found that a noise wall was both reasonable and feasible in one location alone the study area. Exhibit 10 displays this location. This noise wall would reduce noise levels below the NAC at 43 residences. One hundred and one other residences, would still approach or exceed the NAC in 2030. Adverse effects may also result from construction noise levels from heavy equipment including heavy trucks, excavators, jackhammers, and pile drivers. However these noises would be temporary occurring only during the construction period. !!!! !! !!!!!!!!!!!! !! !! !! !!!!!!!!!!!!Lake Ave STalbot Rd SS 15th St %&e( 167 Legend Noise Levels Predicted to be Below the Noise Abatement Criteria (NAC)!! { Noise Levels Predicted to Approach or Exceed the NAC Due to I-405 and SR 167 Traffic!! 0250 Feet Exhibit 10: Location of Recommended Noise Barrier What is Equivalent Sound Level (Leq)? The equivalent sound level (Leq) is widely used to describe environmental noise. It measures the average sound energy during a specified period of time. What do the terms feasible and reasonable mean? WSDOT evaluates many factors to determine whether barriers will be feasible and/or reasonable. To be feasible, a barrier must be constructible in a location that achieves a noise reduction of a least 7 dBA at one or more receptors and a reduction of at least 5 dBA at most of the first row of receptors. Determination of reasonableness depends on the number of sensitive receptors benefited by a reduction in noise of at least 3 dBA, the cost- effectiveness of the barriers, and concerns such as aesthetics, safety, and the desires of nearby residents. !!!! !! !!!!!!!!!!!!Lake Ave STalbot Rd SNoise Wall S 15th St %&e( 167 Legend Noise Levels Predicted to be Below the Noise Abatement Criteria (NAC)!! {0250 Feet Project noise effects without noise wall Project noise effects with noise wall Renton Nickel Improvement Project Noise and Vibration Discipline Report 21 NOISE ANALYSIS OVERVIEW This section discusses the definitions of sound and noise, sound level descriptors, what affects sound levels, project coordination, and details of how the traffic noise study was performed. What are sound and noise? Sound is created when objects vibrate, resulting in a minute variation in surrounding atmospheric pressure called sound pressure. The human response to sound depends on the magnitude of a sound as a function of its frequency and time pattern.1 Magnitude is a measure of sound energy in the air. Noise is unwanted sound. The range of magnitude, from the faintest to the loudest sound the ear can hear, is very large. The sound pressure near an airport runway is approximately one-million times greater than a soft whisper. To accommodate this range, sound levels are expressed on a logarithmic scale in units called decibels (dB). Humans respond to a sound’s frequency or pitch. The human ear can very effectively perceive sounds with a frequency between approximately 500 and 5,000 Hertz (Hz). The ability of humans to perceive sounds decreases outside this range. Environmental sounds are composed of many frequencies, each occurring simultaneously at its own sound pressure level. Frequency weighting, which is applied electronically by a sound level meter, combines the overall sound frequency into one sound level that simulates how a typical person hears sounds. The commonly used frequency weighting for environmental sounds is A- weighting (dBA), which is most similar to how humans perceive sounds of low to moderate magnitude. Loudness, in contrast to sound level, refers to how people subjectively perceive a sound. This varies from person to person, but most people judge relative loudness between sound levels similarly. The human ear can barely 1 Information on Levels of Environmental Noise Requisite to Protect Public Health and Welfare with an Adequate Margin of Safety. Report Number 550/9-74-004. EPA 1974. A-weighted Frequency Curve -60 -40 -20 0 20 20 40 80 160 315 630 1,250 2,500 5,000 10,000 20,000 Frequency (Hz)Adjustment (dBA)What is the Logarithm Scale? Logarithm is the exponent that indicates the power to which a number must be raised to produce a given number. For example: if B2 = N, the 2 is the logarithm of N (to the base B), or 102 =100 and the logarithm of 100 (to the base 10) = 2. NOISE ANALYSIS OVERVIEW Renton Nickel Improvement Project 22 Noise and Vibration Discipline Report perceive a 3-dBA increase, but a 5- or 6-dBA increase is readily noticeable and appears as if the sound is about one and one-half times as loud. A 10-dBA increase appears to be a doubling in sound level to most listeners. What are typical sound levels, and what affects them? Exhibit 11 presents typical A-weighted sound levels from various sources. The sound environments described between a quiet whisper or light wind at 30 dBA to a jet takeoff at 120 dBA demonstrate the great range of the human ear. A typical conversation is in the range of 60 to 70 dBA. Exhibit 11: Typical Noise Levels NOISE ANALYSIS OVERVIEW Renton Nickel Improvement Project Noise and Vibration Discipline Report 23 Sources of sound Because of the logarithmic decibel scale, a doubling of the number of sound sources (such as the number of cars operating on a roadway) increases sound levels by 3 dBA. A ten-fold increase in the number of sound sources will add 10 dBA. As a result, a sound source emitting a sound level of 60 dBA combined with another sound source of 60 dBA yields a combined sound level of 63 dBA, not 120 dBA. Noise levels from traffic sources depend on volume, speed, and the type of vehicle. Generally, an increase in volume, speed, or vehicle size increases traffic noise levels. Vehicular noise is a combination of noises from the engine, exhaust, and tires. Other conditions affecting the generation of traffic noise include: defective mufflers, steep grades, and roadway surface material and condition. The effect of distance Sound levels decrease with distance from the source. For a line source such as a roadway, sound levels decrease 3 dBA over hard ground (concrete or asphalt, pavement) or 4.5 dBA over soft ground (grass) for every doubling of distance between the source and the receptor. For a point source such as construction sources, sound levels will decrease between 6 and 7.5 dBA for every doubling of distance from the source. The effect of terrain and shielding The propagation of sound can be greatly affected by terrain and the elevation of the receiver relative to the sound source shown in Exhibit 12. Depressed terrain predominantly dominates the vicinity of the project area. Level ground is the simplest scenario: sound travels in a straight line between the source and receiver. As shown in the bottom row of Exhibit 12, if the sound source is depressed or the receiver is elevated, sound will generally travel directly to the receiver; however, sound levels may be reduced if the terrain crests between the source and receiver, resulting in a partial sound wall near the receiver. If the sound source is elevated or the receiver is depressed, then sound may be reduced at the receiver by the edge of the roadway. Even a short wall, such as a solid concrete jersey-type safety barrier, can be effective at blocking sound transmission between the source and Traffic Noise generated by various types of vehicles at various speeds 60 65 70 75 80 85 90 25 30 35 40 45 50 55 60 65 Speed (mph)Reference Mean Energy at 50 feet (dBA)Automobiles Medium Trucks Heavy Trucks Automobiles Medium Trucks Heavy Trucks What is Terrain? Terrain is a term used to describe the features of the land. NOISE ANALYSIS OVERVIEW Renton Nickel Improvement Project 24 Noise and Vibration Discipline Report receiver in Exhibit 12, top row. Putting a barrier between the receiver and the highest elevation of sound source results in a noise reduction of approximately 5 dBA. Exhibit 12: Noise Barrier Effectiveness Parsons Brinckerhoff, 2003 NOISE ANALYSIS OVERVIEW Renton Nickel Improvement Project Noise and Vibration Discipline Report 25 How are sound levels described? The equivalent sound level (Leq) is widely used to describe noise in human environments. The Leq is a measure of the average sound energy during a specified period of time. It is defined as the constant level that, over a given period of time, transmits to the receiver the same amount of acoustical energy as the actual time-varying sound. For example, two sounds, one of which contains twice as much energy but lasts only half as long as the other, can have the same Leq sound levels. Leq measured over a 1- hour period is the hourly Leq [Leq (h)], which is used for highway noise impact and abatement analyses. Short-term sound levels, such as those from a single truck passing by, can be described by either the total sound energy, which is related to the Leq, or the highest instantaneous sound level that occurs during the event. The maximum sound level (Lmax) is the greatest short-duration sound level that occurs during a single event. Lmax is used to describe noise levels that cause speech interference and sleep disruption. In comparison, Lmin is the minimum sound level that occurs during a specified period of time. What are the effects of loud noises? Prolonged exposure to high-intensity environmental noise directly affects human health by causing hearing loss. The U.S. Environmental Protection Agency (EPA) has established a protective level of 70 dBA Leq (24), below which hearing is conserved for exposure over a 40-year period.2 Although scientific evidence is not currently conclusive, noise is suspected of causing or aggravating other diseases. Environmental noise indirectly affects human welfare by interfering with sleep, thought, and conversation. The FHWA noise abatement criteria (NAC) are based on speech interference, which is a well documented effect that is relatively reproducible in human response studies. Noise can also disturb wildlife by disrupting communication, interfering with mating, and reducing the ability to obtain sufficient food, water, and cover. 2 Information on Levels of Environmental Noise Requisite to Protect Public Health and Welfare with an Adequate Margin of Safety. Report Number 550/9-74-004. EPA 1974. Example of two sound patterns with the same Leq (1 minute interval) 40 45 50 55 60 65 70 0 102030405060 Time (seconds)Sound Level (dB)Leq = 57 dBA Parsons Brinckerhoff, 2003 What does Leq (24) refer to? Leq (24) is the equivalent sound level measured over a period of 24 hours. NOISE ANALYSIS OVERVIEW Renton Nickel Improvement Project 26 Noise and Vibration Discipline Report What project coordination was performed? The I-405 noise team worked with federal, state, and local agencies and community members. This coordination included consultation with FHWA and the City of Renton, and participation in several community meetings with local residents. The residents received project information and provided input on the project and potential noise monitoring locations. What criteria are used to evaluate the project’s potential effects on the acoustical environment? Operational noise standards Noise regulations and guidelines are the basis for evaluating potential noise effects. For state and federally funded highway projects, traffic noise impacts occur when predicted Leq (h) noise levels approach or exceed the NAC established by the FHWA, or substantially exceed existing noise levels.3 Although “substantially exceed” is not defined by FHWA, WSDOT considers an increase of 10 dBA or more to be a substantial increase.4 The FHWA noise abatement criteria specify exterior and interior Leq (h) noise levels for various land activity categories as shown in Exhibit 13. All exterior noise sensitive uses within the Renton Nickel Improvement Project study area are Category B uses. WSDOT considers a noise impact to occur if predicted Leq (h) noise levels approach within 1 dBA of the noise abatement criteria in Exhibit 13. Thus, if a noise level is 66 dBA or higher, it will approach or exceed the FHWA noise abatement criterion of 67 dBA for residences. WSDOT defines severe traffic noise impacts as levels that exceed 75 dBA outdoors in Category B areas or 60 dBA indoors at Category E uses. Severe noise impacts also occur if predicted future noise levels exceed existing levels by 15 dBA or more at noise- sensitive locations as a result of the project. 3 Procedures for Abatement of Highway Traffic Noise and Construction Noise. Federal-Aid Highway Program Manual. Volume 7, Chapter 7, Section 3. Washington, D.C. U.S. Department of Transportation, 1982, Noise Abatement Council. 4 Traffic Noise Analysis and Abatement Policy and Procedures. Olympia, Washington. WSDOT, 1999. NOISE ANALYSIS OVERVIEW Renton Nickel Improvement Project Noise and Vibration Discipline Report 27 Exhibit 13: FHWA Noise Abatement Criteria Activity Category Leq(h) (dBA) Description of Activity Category A 57 (exterior) Lands on which serenity and quiet are of extraordinary significance and serve an important public need and where the preservation of those qualities is essential if the area is to continue to serve its intended purpose. B 67 (exterior) Picnic areas, recreation areas, playgrounds, active sports areas, parks, residences, motels, hotels, schools, churches, libraries, and hospitals. C 72 (exterior) Developed lands, properties, or activities not included in Categories A or B above. D – Undeveloped lands. E 52 (interior) Residences, motels, hotels, public meeting rooms, schools, churches, libraries, hospitals, and auditoriums. Source: US DOT, 1982. The Washington State Department of Ecology (Ecology) regulates noise levels at property lines of neighboring properties (WAC Chapter 173-60-040). Traffic noise is exempt from the property line noise limits, but the limits apply to construction noise during certain hours. The maximum permissible noise levels depend on the land uses of both the source noise and receiving property as shown in Exhibit 14. King County, the City of Renton, and the City of Tukwila have adopted the State of Washington’s property line standards with King County Code 12.88.020; Renton Municipal Code, Title 8, Chapter 7, Section 8-7-2; and Tukwila Municipal Code, Chapter 8.22. Exhibit 14: Maximum Permissible Environmental Noise Levels EDNA of Receiving Property EDNA1 of Noise Source Residential Commercial Industrial Residential 55 57 60 Commercial 57 60 65 Industrial 60 65 70 1 Environmental designation for noise abatement Source: WAC 173-60-040. The maximum permissible environmental noise level at residential receiving properties is reduced by 10 dBA between 10 p.m. and 7 am. Short-term NOISE ANALYSIS OVERVIEW Renton Nickel Improvement Project 28 Noise and Vibration Discipline Report exceedences above the permissible sound level are allowed. The maximum level may be exceeded by 5 dBA for a total of 15 minutes, by 10 dBA for a total of 5 minutes, or by 15 dBA for a total of 1.5 minutes during any 1 hour period as shown in Exhibit 15. Exhibit 15: Allowed Exceedences of the Maximum Permissible Noise Considering the allowed short-term exceedences in Exhibit 15, the permissible hourly Leq is approximately 2 dBA higher than the values in Exhibit 14. For example, a noise level of 57 dBA for 45 minutes and 62 dBA for 15 minutes (57 dBA + 5 dBA exceedence) is permissible for noise from a commercial activity received by a residential property; this sound pattern has an Leq (h) of 59 dBA. Construction noise standards Construction noise from projects within the State of Washington is exempt from Ecology property line regulations during daytime hours, but regulations apply to construction noise during nighttime hours (10 p.m. to 7 a.m. on weekdays and 10 p.m. to 8 a.m. on weekends). Performance of construction activities during nighttime hours would require noise variances from the City of Renton and the City of Tukwila. How was the noise study performed? Ambient noise levels were measured for 15-minute periods at 19 locations near the study area to describe the existing noise environment, identify major noise sources in the study area, validate the noise model, and characterize the weekday background environmental noise levels. Results of the noise measurements can be found in Appendix A. Measurement locations characterize the variety of noise conditions and represent other sensitive Duration of Exceedence Allowed Exceedence Statistical Descriptor Equivalent Leq(h) Increase 15 minutes 5 dBA L25 2 dBA 5 minutes 10 dBA L8 2 dBA 1.5 minutes 15 dBA L2.5 2 dBA Source: WAC 173-60-040. NOISE ANALYSIS OVERVIEW Renton Nickel Improvement Project Noise and Vibration Discipline Report 29 receptors near the proposed project. Existing (year 2002) and future noise levels for the No Build Alternative (year 2030) and the Build Alternative (design year 2030) were modeled at all of the 15- minute noise measurement locations and at 41 additional locations that may potentially be affected by the project. 2002 was evaluated as the existing year to be consistent with the transportation analysis for the Renton Nickel Improvement Project. Traffic noise prediction The FHWA Traffic Noise Model (TNM) Version 2.5 computer model5 was used to predict Leq(h) traffic noise levels. TNM provides precise estimates of noise levels at discrete points by considering interactions between different noise sources and topographical features. The model estimates the acoustic intensity at a receiver location calculated from a series of straight-line roadway sections. The noise emissions from each roadway section is calculated based on the number of automobiles, medium trucks, and heavy trucks per hour; vehicular speed; and reference noise emission levels of an individual vehicle. TNM also considers effects of intervening walls, topography, trees, and atmospheric absorption. Noise from sources other than traffic is not included. Therefore, when non-traffic noise such as aircraft noise is considerable in an area, TNM under-predicts the actual noise level. Because project impacts only depend on traffic noise levels, under-predicting the total environmental noise level does not affect the findings of the study. Noise monitoring results were used to validate the Existing Conditions TNM model. The project team noise specialists imported base maps and design files into the TNM package. Major roadways, topographical features, building rows, and sensitive receptors were digitized into the model. Elevations were added from the 2-foot contour data. Elevations for planned improvements were taken from design profiles, proposed cross sections, and proposed cut and fill limits. 5 FHWA, 2005. What effects traffic noise? Small changes in vehicle speed have a greater effect on noise than small changes in traffic volume. Therefore, the loudest traffic noise levels are often not experienced during rush hour. During rush hour traffic, traffic volumes increase and vehicle speeds decrease, resulting in lower traffic noise levels. NOISE ANALYSIS OVERVIEW Renton Nickel Improvement Project 30 Noise and Vibration Discipline Report Analysis of project effects Predicted noise levels were based on the loudest traffic hour of the day, when volumes are high but not congested, to estimate worst-case noise levels. The loudest hour is also called the peak hour. Existing peak-hour traffic analysis for the year 2002 shows that the traffic volumes on this portion of I-405 are at capacity part of the day. Congestion on I-405 in 2030 is expected to increase substantially and exceed the roadway’s capacity for both the Build and No Build alternatives. Predicted peak-hour congested traffic volumes for I-405 were predicted to decrease for both the Build and No Build alternatives. For use in TNM, the No Build Alternative assumed the same traffic volume on I-405 as the existing conditions model during the loudest hour. The Build Alternative added 1,750 vehicles to existing conditions loudest hour traffic volumes on I-405 in areas where an extra lane would be built. For other roadways in the study area, predicted future traffic volumes were used. This approach ensures that the loudest traffic hour is represented in the model because small changes in vehicle speed have a greater effect on noise than small changes in traffic volume. The traffic volumes and vehicle mix were based on the Renton Nickel Improvement Project Transportation Discipline Report and documented in Appendix A. The modeled sites represented similar receptors in the area, although noise levels at adjacent receptors may be different because of terrain or distance. Noise mitigation analysis Project team noise specialists then compared predicted noise levels to the FHWA NAC and counted the receptors affected by the Build Alternative. At receptors where noise levels were modeled to approach or exceed the NAC, noise specialists evaluated mitigation measures to determine if the reduction in traffic noise would be substantial enough to warrant the cost of barrier construction, using WSDOT feasibility and reasonableness criteria. A detailed discussion of WSDOT feasibility and reasonableness criteria is provided in the Mitigation section of this report. Noise barriers were evaluated using TNM in areas where noise impacts were predicted as a result of this project. What is WSDOT’s Noise Abatement Criteria level? Noise levels approach or exceed the noise abatement criteria (NAC) at 66 dBA. NOISE ANALYSIS OVERVIEW Renton Nickel Improvement Project Noise and Vibration Discipline Report 31 Project noise specialists evaluated the effectiveness of noise barriers at the outermost boundary of the right- of-way to minimize the potential for future corridor roadway projects to require their removal or relocation. How is construction noise analyzed? Construction noise was assessed using EPA reference levels. The analysis was based on noise levels from construction equipment typically used on this type of project. Noise levels were assessed at various distances from the construction site. Potential measures to reduce disturbance caused by construction noise were evaluated and are described in the Measures to Avoid or Minimize Project Effects section. Renton Nickel Improvement Project 32 Noise and Vibration Discipline Report EXISTING CONDITIONS What is the study area for the noise analysis? The I-405 Renton Nickel Improvement Project extends from the vicinity of the I-405/I-5 interchange north to the I-405/SR 169 interchange and south from the I-405/SR 167 interchange to the SR 167/SW 41st Street interchange. The study area for the noise analysis extends approximately 1,000 feet from roadway improvements associated with the project. There are a variety of land uses in the study area. The area is primarily residential with pockets of multi- family, park land, commercial, and industrial development. Terrain varies throughout the study area. The Renton Hill neighborhood consisting primarily of single family residences with limited multi-family units is located well above the elevation of I-405. The hillside and I-405 retaining walls shield a portion of the I-405 noise. Most residents in the Talbot Hill neighborhood are located above the elevation of the I-405/SR 167 interchange. In some places, however, residents are located at or below the I-405 elevation. Single family residences are the primary land use throughout this community. The closest residences are located approximately 100 feet from I-405, near Talbot Road. Several multi-family residential buildings are also located above I-405 north and east of the I-405/I-5 interchange. Residences west of I-405, west of Main Avenue South, fall below the elevation of I-405. Park and recreation land located within the study area include Liberty Park, Veterans Park, Cedar River Park and Trail, Renton Hill Park (also known as Freeway Park), Renton’s Narco Property, Ikawa Park, Tukwila Park, Springbrook Trail, Interurban Trail, and Green River Trail. Additional information on these resources can be found in the I-405 Renton Nickel Improvement Project Social Discipline Report and Section 4(f) Evaluation. No existing noise barriers are located parallel to I-405 within the project limits. Existing retaining walls, limited jersey barriers, and topography shield some residential areas. EXISTING CONDITIONS Renton Nickel Improvement Project Noise and Vibration Discipline Report 33 The portion of the study area between the Cedar River and SR 169 was analyzed as a part of the I-405 Renton to Bellevue Project. The previous analysis is included in this report. Where are the modeled noise receptor locations? Existing noise levels were modeled at 60 locations that represent 310 residences, six parks, four trails, Renton’s Narco Property, an aquatic center, and a library. Traffic noise is the dominant noise source in the study area with periodic air and rail noise. Predicted future traffic noise levels at most modeled sites increase between 1 and 3 dBA due to the increase in future traffic volumes. Noise levels at sites 8, 9, and N are predicted to be lower with the Renton Nickel Improvement Project than without the project due to the realigned Benson Road overpass and shielding from I-405. Future traffic noise levels at sites O, P, 1*, 2*, AB*, and AC* are also predicted to be lower with the Renton Nickel Improvement Project and the adjacent Renton to Bellevue Improvement Project due to shielding from I-405. The locations of all 60 modeled sensitive receptors are shown on Exhibits 16 through 27. Discussion and descriptions of noise measurements taken in the study area are included in Appendix A. EXISTING CONDITIONS Renton Nickel Improvement Project 34 Noise and Vibration Discipline Report Exhibit 16: Modeled Noise Levels at Receptors Future Modeled Noise Levels (dBA) without additional abatement Noise Receptor Number Activity Description Total Residences Represented Modeled Existing Noise Level (dBA) 2030 No Build 2030 Renton Nickel 1 Renton Public Library Library 64 64 65 2 Renton Hill Park 1 74 74 76 3 Residence at 412 Mill Ave. S. 7 64 64 67 4 Residence at 509 S. Main St. 3 71 71 73 5 Residence at 522 Well Ave. S. 7 62 62 64 6 Residence at 520 Mill Ave. S. 5 68 68 73 7 Residence at 518 Cedar Ave. S. 10 59 59 60 8 Berkshire Apartments Bldg P 7 68 68 65 9 Residence at 1114 Benson Rd. S. 4 69 69 64 A Veterans Park 1 67 67 69 B Residence at Mill Ave. S. 6 63 63 64 C Residence at Renton Ave. S. 6 64 64 66 D Residence at Beacon Way S. 2 62 62 63 E Residence at Beacon Way S. 10 58 58 60 F Residence at Cedar Ave. S. 9 56 56 59 G Residence at Cedar Ave. S. 7 61 61 64 H Residence at Mill Ave. S. 5 65 65 69 I Residence at Cedar Ave. S. 9 63 63 68 J Residence at Cedar Ave. S. 7 65 65 68 K Residence at Renton Ave. S. 9 65 65 67 L Berkshire Apartments Bldg. Q 4 64 64 65 N Residence at Benson Rd. S. 5 74 74 65 1* Liberty Park – furthest baseball field in outfield and tennis court Park 65 65 64 2* Liberty Park – baseball field, stands, and basketball court Park 69 70 69 3* Cedar River Park – soccer field and baseball field Park 68 68 71 AA* Cedar River Park – trail, picnic, recreational open space, beach area Park 62 62 63 AB* Liberty Park – skateboard facility Trail 69 69 67 AC* Aquatic Center Aquatic Center 67 67 63 Values in BOLD approach or exceed the NAC * I-405 Renton to Bellevue Project receptors analyzed EXISTING CONDITIONS Renton Nickel Improvement Project Noise and Vibration Discipline Report 35 Exhibit 17: Modeled Noise Receptor Locations EXISTING CONDITIONS Renton Nickel Improvement Project 36 Noise and Vibration Discipline Report Exhibit 18: Modeled Noise Levels at Receptors Future Modeled Noise Levels (dBA) without additional abatement Noise Receptor Number Activity Description Total Residences Represented Modeled Existing Noise Level (dBA) 2030 No Build 2030 Renton Nickel 10 Residence at 1306 Smithers Ave. S. 2 71 71 72 11 Residence at 301 South 14th St. 8 68 68 71 13 Residence at 1503 Lake Ave. S. 5 67 67 67 14 Residence at 1514 Lake Ave. S. 3 62 62 64 M Residence at SW 13th St. 3 67 67 68 O Residence at S. 14th St. 3 73 73 72 P Residence at Whitworth Ave. S. 5 70 70 69 Q Residence at Shattuck Ave. S. 6 67 67 67 R Residence at Morris Ave. S. 8 66 66 67 S Residence at Smithers Ave. S. 7 63 63 65 T Residence at S. 15th St. 5 66 66 66 U Residence at Whitworth Ave. S. 6 65 65 66 X Residence at Lake Ave. S. 5 66 66 67 Y Residence at Lake Ave. S. 4 62 62 63 AB Residence at Lake Ave. S. 6 64 64 66 AC Residence at Lake Ave. S. 6 63 63 64 AF Residence at Davis Ave. S. 8 63 63 65 AG Residence at Davis Ave. S. 6 58 58 59 AH Residence at Talbot Crest Dr. S. 14 62 62 63 AI Residence at Talbot Crest Dr. S. 14 55 55 56 Values in BOLD approach or exceed the NAC EXISTING CONDITIONS Renton Nickel Improvement Project Noise and Vibration Discipline Report 37 Exhibit 19: Modeled Noise Receptor Locations EXISTING CONDITIONS Renton Nickel Improvement Project 38 Noise and Vibration Discipline Report Exhibit 20: Modeled Noise Levels at Receptors Future Modeled Noise Levels (dBA) without additional abatement Noise Receptor Number Activity Description Total Residences Represented Modeled Existing Noise Level (dBA) 2030 No Build 2030 Renton Nickel 15 Residence at 3521 Shattuck Ave. S. 10 64 64 65 16 Residence at 402 South 36th St. 9 59 59 60 AJ Residence at Talbot Rd. S. 5 62 62 63 AK Residence at Talbot Rd. S. 3 63 63 65 Values in BOLD approach or exceed the NAC EXISTING CONDITIONS Renton Nickel Improvement Project Noise and Vibration Discipline Report 39 Exhibit 21: Modeled Noise Receptor Locations EXISTING CONDITIONS Renton Nickel Improvement Project 40 Noise and Vibration Discipline Report Exhibit 22: Modeled Noise Levels at Receptors Future Modeled Noise Levels (dBA) without additional abatement Noise Receptor Number Activity Description Total Residences Represented Modeled Existing Noise Level (dBA) 2030 No Build 2030 Renton Nickel V Springbrook Trail 1* 73 73 74 Values in BOLD approach or exceed the NAC * Table B-3 in Appendix B describes residential equivalency of users at Receptor V, Springbrook Trail. EXISTING CONDITIONS Renton Nickel Improvement Project Noise and Vibration Discipline Report 41 Exhibit 23: Modeled Noise Receptor Locations EXISTING CONDITIONS Renton Nickel Improvement Project 42 Noise and Vibration Discipline Report Exhibit 24: Modeled Noise Levels at Receptors Future Modeled Noise Levels (dBA) without additional abatement Noise Receptor Number Activity Description Total Residences Represented Modeled Existing Noise Level (dBA) 2030 No Build 2030 Renton Nickel W Family Fun Center 10 69 69 70 Z Tukwila Park 3 64 64 65 AA Interurban Trail 3 72 72 73 AE Green River Trail 1 71 71 71 Values in BOLD approach or exceed the NAC EXISTING CONDITIONS Renton Nickel Improvement Project Noise and Vibration Discipline Report 43 Exhibit 25: Modeled Noise Receptor Locations EXISTING CONDITIONS Renton Nickel Improvement Project 44 Noise and Vibration Discipline Report Exhibit 26: Modeled Noise Levels at Receptors Future Modeled Noise Levels (dBA) without additional abatement Noise Receptor Number Activity Description Total Residences Represented Modeled Existing Noise Level (dBA) 2030 No Build 2030 Renton Nickel 12 Outdoor Use at Southcenter View Condos 6 69 69 69 AD Ikawa Park 1 69 69 70 Values in BOLD approach or exceed the NAC EXISTING CONDITIONS Renton Nickel Improvement Project Noise and Vibration Discipline Report 45 Exhibit 27: Modeled Noise Receptor Locations EXISTING CONDITIONS Renton Nickel Improvement Project 46 Noise and Vibration Discipline Report What are the modeled noise levels? Existing conditions noise levels in the study area were modeled using TNM and levels ranged between 55 and 74 dBA. These levels range from typical suburban outdoor sound levels, between 50 to 60 dBA6, to very noisy levels, above 70 dBA, that are typical of locations within 100 feet of a busy freeway. Noise levels at 28 of the 60 sites representing an equivalent of 105 residences, 2 parks, 2 trails, and an aquatic center were modeled to currently approach or exceed the FHWA criteria of 67 dBA for existing conditions. These modeling results represent the loudest traffic hour of the day, when volumes are high but not congested, so traffic speeds remain high. 6 Information on Levels of Environmental Noise Requisite to Protect Public Health and Welfare with an Adequate Margin of Safety. Report Number 550/9-74-004. EPA 1974. Renton Nickel Improvement Project Noise and Vibration Discipline Report 47 POTENTIAL EFFECTS Will the project affect noise levels in the study area? Currently, noise levels at 28 of the 60 locations modeled approach or exceed the FHWA criteria. With the Build Alternative, modeling indicates that without the proposed noise barrier, noise levels will approach or exceed the NAC at 33 locations representing an equivalent of 144 residences, two parks, and two trails. With the noise abatement measures proposed as part of the Renton Nickel Improvement Project, noise levels at 25 sites will continue to approach or exceed the criteria. Severe noise impacts are predicted at one location in the study area, Receptor 2, Renton Hill Park. Noise levels at this location are predicted to reach 76 dBA Leq under the Renton Nickel Improvement Project. As shown on Exhibit 17, Receptor 4, noise levels adjacent to Main Avenue South will exceed the noise abatement criteria because of noise contributed by local traffic on Main Avenue South. Traffic noise from Main Avenue South was modeled separately from I-405 noise at Receptor 4. With the Build Alternative including traffic noise from I-405, traffic noise at Receptor 4 will be 73 dBA Leq(h). Traffic on Main Avenue South contributes 71 dBA, while traffic from I-405 contributes approximately 68 dBA at this location. Noise levels were measured at an outdoor swimming pool area at the South Center View Condos located northeast of the I-405/I-5 interchange along Macadam Road South. This is shown as Receptor 12 on Exhibit 27. This outdoor area will exceed the noise abatement criteria because of noise caused by the overall traffic noise within the I-405/I-5 interchange and from local traffic on Macadam Road South. Traffic noise from I-405 was modeled separately from local street noise at Receptor 12. With the Build Alternative, traffic noise at Receptor 12 is modeled to be 69 dBA Leq(h) with or without including traffic noise from I-405. POTENTIAL EFFECTS Renton Nickel Improvement Project 48 Noise and Vibration Discipline Report How do the Existing Conditions, No Build, and Build Alternatives differ? Noise levels for the No Build Alternative were predicted to increase by 0 to 2 dBA. Noise levels at 28 locations would approach or exceed the noise abatement criteria. All of these sites currently approach or exceed the noise abatement criteria as a result of the contribution of traffic on local streets. Noise levels for the Build Alternative were predicted to increase by 0 to 2 dBA at the majority of residences with a 5 dBA Leq increase at five first row residences along Mill Avenue South and nine second row residences along Cedar Avenue South. Will project construction temporarily affect noise levels? Construction activities will generate noise during the construction period. Construction usually will be carried out in several reasonably discrete steps, each of which having its own mix of equipment and, consequently, its own noise characteristics. Roadway construction will involve clearing, cut-and-fill (grading) activities, removing old roadways, importing and compacting fill, paving, and pile driving. What are the noise sources during construction? The most prevalent noise source at construction sites will be the internal combustion engine. Engine- powered equipment includes earth-moving and compaction equipment, material-handling equipment, and stationary equipment. Mobile equipment operates intermittently, with periods of high and low noise, while stationary equipment, such as generators and compressors, operates at sound levels fairly constant over time. Because trucks will be present during most phases and will not be confined to the active construction area, noise from trucks could affect more area residents. Other construction noise sources will include impact equipment and tools such as pile drivers. Impact tools could be pneumatically powered, hydraulic, or electric. Construction noise will be intermittent. Construction noise levels will depend on the type, amount, and location of construction activities. The type of POTENTIAL EFFECTS Renton Nickel Improvement Project Noise and Vibration Discipline Report 49 construction methods will establish the maximum noise levels of construction equipment used. The amount of construction activity will define how often construction noise will occur. The proximity of construction equipment to adjacent properties will affect the noise levels of the receptor. Maximum noise levels of construction equipment for the Build Alternative will be similar to typical maximum levels presented in Exhibit 28. 60 70 80 90 100 110 Compactors (rollers) Front-end loaders Backhoes Tractors Scrapers, graders Pavers Trucks Concrete mixers Concrete pumps Cranes (movable) Cranes (derrick) Pumps Generators Compressors Pneumatic wrenches Jack hammers, rock drills Pile drivers (peaks) Vibrator SawsEquipment TypeNoise Level (dBA) at 15 meters (50 ft.)Earth MovingMaterials HandlingStationaryImpactOtherSource: EPA, 1971 and WSDOT, 1991. Exhibit 28: Typical Construction Noise Levels What is the range of noise from construction equipment? As shown in Exhibit 28, maximum noise levels from construction equipment will range from 69 to 106 dBA at 50 feet. Construction noise at residences farther POTENTIAL EFFECTS Renton Nickel Improvement Project 50 Noise and Vibration Discipline Report away will decrease at a rate of 6 dBA per doubling of distance from the source. The number of occurrences of the Lmax noise peaks will increase during construction, particularly during pile-driving activities. Because some equipment will be turned off, idling, or operating at less than full power at any time and because construction machinery is typically used to complete short-term tasks at any given location, average Leq noise levels during the day will be less than the maximum noise levels presented in Exhibit 28. Construction noise levels could be reduced by the construction practices identified in the Measures to Avoid or Minimize Project Effects section. Does the project have other indirect effects that could be delayed or distant from the project? An effect is considered indirect when it occurs later in time or farther removed from an original project action. Indirect effects may include effects related to changes in the pattern of land use, population density or growth rate and related effects on other natural systems. The noise analysis for this project is based on the transportation demand forecasting model, including the effects of unmet demand on the transportation system. By including unmet demand, the indirect effects of increased transportation capacity are included in the analysis. Were cumulative effects looked at for this discipline? The team did not evaluate cumulative effects for this discipline report. A report of cumulative effects is not needed for every discipline studied for NEPA and SEPA documentation. The disciplines that were studied for cumulative effects are Air Quality, Surface Water and Water Quality, Fisheries and Aquatic Habitat, and Wetlands. The cumulative effects for these disciplines are presented in the Cumulative Effects Analysis Discipline Report. Renton Nickel Improvement Project Noise and Vibration Discipline Report 51 MEASURES TO AVOID OR MINIMIZE PROJECT EFFECTS Noise can be controlled at three locations: (1) at the source, such as with mufflers and quieter engines; (2) along the noise path, with barriers; and (3) at the receptor, with insulation. Noise abatement is necessary only where frequent human use occurs and where a lower noise level would provide benefits.7 How will effects from construction noise be minimized? Construction noise will be reduced by using enclosures or walls to surround noisy equipment, installing mufflers on engines, using quieter equipment or construction methods, minimizing operation time, and locating equipment far from sensitive receptors. To reduce construction noise at nearby receptors, the following activities will be incorporated by WSDOT where practicable: Require early construction of permanent noise barriers to provide noise shielding. Limit noisiest construction activities, such as pile driving, to between 7 a.m. and 10 p.m. to reduce construction noise levels during sensitive nighttime hours. Equip construction equipment engines with adequate mufflers, intake silencers, and engine enclosures to reduce their noise. Turn off construction equipment during prolonged periods of nonuse to eliminate noise. Require WSDOT to maintain all equipment and train their equipment operators in good practices to reduce noise levels. Locate stationary equipment away from residences to decrease noise. 7 Procedures for Abatement of Highway Traffic Noise and Construction Noise. Federal-Aid Highway Program Manual. Volume 7, Chapter 7, Section 3. Washington, D.C. U.S. DOT, 1982. MEASURES TO AVOID OR MINIMIZE PROJECT EFFECTS Renton Nickel Improvement Project 52 Noise and Vibration Discipline Report Construct temporary noise barriers or curtains around stationary equipment that must be located close to residences, to decrease noise levels at nearby sensitive receptors. Require resilient bed liners in trucks being loaded on-site. Prohibit banging of dump truck tailgates. Require WSDOT to use OSHA-approved ambient sound sensing backup alarms to reduce disturbances from backup alarms during quieter periods. How can effects from traffic noise be minimized? FHWA regulations in 23 CFR 772 specify that when noise impacts are identified, abatement (mitigation) measures to reduce the noise must be evaluated. All noise abatement measures that are determined to be feasible and reasonable, including local resident support, must be incorporated into the project design prior to project approval by FHWA. A variety of mitigation methods can effectively reduce traffic noise levels. For example, noise generated from long-term operation of the project can be reduced by implementing traffic management measures, acquiring land as buffer zones or for constructing noise barriers or berms, realigning the roadway, providing noise insulating of public use or nonprofit institutional structures, and constructing noise barriers or berms. These measures were evaluated for their potential to reduce noise impacts from the proposed project. The results of this evaluation are summarized in this section. Final determination of the size and placement of noise barriers or berms and implementation of other noise attenuating methods will take place during detailed project design, after an opportunity for additional public involvement, and after approval at the local, state, and federal levels. Traffic Management Measures Several traffic management measures were considered to reduce noise in the study area. Traffic management measures include time restrictions or traffic control devices and signing to prohibit certain vehicle types (i.e., motorcycles and heavy trucks), modify speed limits, and implement exclusive lane designations. MEASURES TO AVOID OR MINIMIZE PROJECT EFFECTS Renton Nickel Improvement Project Noise and Vibration Discipline Report 53 Restricting vehicle types or lowering speed limits on I-405 could worsen congestion and is contrary to the purpose of the facility. Land use controls could help reduce noise impacts throughout the study area; the area, however, is largely built out. These measures, therefore, are not recommended for the Renton Nickel Improvement Project. A transportation system management plan combined with increased transit facilities to encourage the use of carpools and public transit, however, would reduce vehicle trips and subsequently traffic noise. Land Acquisition for Noise Buffers or Barriers I-405 in the study area is bordered by residential properties. Acquiring land in this area would require relocating residents and would be unreasonably expensive for the purpose of noise mitigation. Roadway Realignment The project’s horizontal alignment is defined by the existing alignment and available right-of-way. The vertical alignment is constrained by the need to provide clearance above and below crossing roadways, streams, pedestrian trails, and railways. Lowering the I-405 mainline to provide noise reduction to some receptors would be prohibitively expensive, provide only marginal improvement and could increase noise levels at other receptors. Noise Insulation of Buildings Although insulation of buildings could be feasible, this remedy does not apply to commercial and residential structures, which constitute most uses within the study area. Noise Barriers Noise barriers include noise barriers, berms, and buildings that are not sensitive to noise. A noise barrier’s effectiveness is determined by its height and length and by project site topography. WSDOT evaluates many factors to determine whether barriers will be feasible and/or reasonable. To be feasible, a barrier must be constructible in a location that achieves a noise reduction of at least 7 dBA at MEASURES TO AVOID OR MINIMIZE PROJECT EFFECTS Renton Nickel Improvement Project 54 Noise and Vibration Discipline Report one or more receptors and provides a reduction of at least 5 dBA at most of the first row of receptors. Determination of reasonableness depends on the number of sensitive receptors benefited by a reduction in noise of at least 3 dBA, the cost-effectiveness of the barriers, and concerns such as aesthetics, safety, and the desires of nearby residents. Noise barriers were evaluated in areas where noise levels were predicted to approach or exceed the NAC where a large number of noise sensitive receptors were closely grouped together to allow for a reasonable evaluation. Noise sensitive areas that approach or exceed the NAC were evaluated for noise barriers except for Renton Hill Park, Veterans Park, Springbrook Trail, Family Fun Center, Interurban Trail, Ikawa Park, Green River Trail, and the outdoor use area at the South Center View Condos at Macadam Road. These noise sensitive areas are located in areas where noise mitigation from I-405 is not feasible based on their physical location in relation to I-405. Receptor locations and noise levels are shown in Exhibits 16 through 27. Also, the absence of a large number of noise sensitive receptors in the immediate area of each space listed above would prevent them from meeting WSDOT’s reasonableness criteria. Noise modeling results for the Build Alternative predict a severe noise effect at Renton Hill Park. Existing noise levels at Renton Hill Park are 74 dBA and are predicted to reach 76 dBA under the Build Alternative. The park is located approximately 20 feet north of I-405 southbound lanes. Renton Hill Park does not have a large number of users as it is removed from most commonly used pedestrian areas. A noise barrier analysis at Renton Hill Park was not performed because the park’s limited use makes constructing a noise barrier not reasonable. Reasonableness is directly related to the number of users a park land regularly receives. Nine noise barriers were evaluated for the Renton Nickel Improvement Project. Evaluated noise barrier locations are shown in Exhibit 29. One noise barrier is planned as a part of the Renton Nickel Improvement Project and is labeled Noise Barrier East 5. Noise Barrier East 5 will be in a location where no barrier currently exists. The evaluation of each noise barrier is summarized in this section. For more detailed information regarding the noise barrier evaluation, refer to Appendix B. At what noise level do severe effects occur? Severe noise effects as described by WSDOT occur at or above 75 dBA. MEASURES TO AVOID OR MINIMIZE PROJECT EFFECTS Renton Nickel Improvement Project Noise and Vibration Discipline Report 55 Exhibit 29: Evaluated Noise Barriers The portion of the study area between the Cedar River and SR 169 was analyzed for the Master Plan as a part of the I-405 Renton to Bellevue Project. The analysis completed for the I-405 Renton to Bellevue Project included the analysis of Noise Barrier West 1 and Noise Barrier East 1. Analysis for both noise barriers is repeated in this section. Noise Barrier West 1 – (Not Feasible) The Liberty Park area was evaluated for a noise barrier along the I-405 southbound on-ramp between the I-405 Cedar River Bridge and SR 169. Noise levels in this area ranges from between 64 and 69 dBA without a barrier. The maximum noise reduction was 7 dBA at the nearest baseball field next to I-405. The other receptors (skateboard park and basketball/tennis courts) were able to receive a 3 to 4 dBA reduction. The barrier would not provide a 5 dBA reduction at the majority of the first row receivers in the park. Noise Barrier West 1 is not feasible because it is not able to achieve the necessary 5 dBA reduction at the majority of the first row receivers. R iv e r Cedar River Interpretive Trail Panther Creek Wetlands k River r ian Forest Cedar River Park Liberty Park SW 16th St Ma p l e V alley H w y S W Sun s e t B lvdS W 7 t h S t S W G r a d y W a y Lind Ave SWRENTON S pri n g brook CreekBenson Rd SSW 23rd St Talbot Rd SB%&e( Aç Noise Barrier East 6 Noise Barrier East 4 Noise Barrier East 3 Noise Barrier East 2 Noise Barrier East 1 Noise Barrier East 5 Noise Barrier West 1 Noise Barrier West 2 Noise Barrier West 3 MEASURES TO AVOID OR MINIMIZE PROJECT EFFECTS Renton Nickel Improvement Project 56 Noise and Vibration Discipline Report Noise Barrier West 2 – (Not Feasible) A noise barrier was evaluated along the right-of-way west of I-405 from the Cedar Avenue South overpass at I-405 to South Grady Way. The modeled receptors along Main Avenue South and Well Avenue South (Receptors 4 and 5) are below the elevation of I-405. Noise levels in the vicinity of Noise Barrier West 2 were predicted to be 64 to 73 dBA without a barrier. This area was found to not be feasible because it is not possible to provide a 7 dBA reduction with a 24- foot-tall wall at either of the modeled receptors. The majority of the traffic noise in the area is generated by traffic on Main Avenue South. Traffic noise from Main Avenue South was modeled separately from I-405 at Receptor 4. With the Build Alternative including traffic noise from I-405, traffic noise at Receptor 4 is 73 dBA Leq(h). Traffic on Main Avenue South contributed 71 dBA of the total traffic noise generated in the model; therefore, mitigation to eliminate noise from I-405 will not substantially reduce total traffic noise levels at this location. Noise Barrier West 3 – (Feasible, Not Reasonable) The single-family residences along the I-405 southbound on-ramp from SR 167 were evaluated for a noise barrier. The noise barrier was evaluated along the north edge of the I-405 on-ramp, between I-405 Mainline and SR 167 mainline. Noise levels in this area were predicted to be 68 dBA with the project. The maximum noise reduction was 7 dBA at the three residences represented by Receptor M shown in Exhibit 30. No additional receptors are located in this area. To provide a 7 dBA reduction, Noise Barrier West 3 would have an area of 25,821 square feet and a height of 24 feet. Exhibit 30: Allowed Barrier Area for Noise Barrier West 3 Modeled Site Residences Represented Leq (dBA) Allowed Barrier Area (ft2) Noise Level with Barrier (dBA) Reduction (dBA) M 3 67 2,310 60 7 TOTAL Barrier Area (ft2) 2,310 25,821 Planning Level Cost($) $74,636 $834,276 MEASURES TO AVOID OR MINIMIZE PROJECT EFFECTS Renton Nickel Improvement Project Noise and Vibration Discipline Report 57 Based on WSDOT’s mitigation allowance, the allowable area for the benefited residential equivalency of Noise Barrier West 3 is 2,310 square feet as shown in Exhibit 30. WSDOT’s mitigation allowance can be found in Table B-1 of Appendix B. Based on these results, a noise barrier is not reasonable in the vicinity of Noise Barrier East 1. Noise Barrier East 1 – (Feasible, Not Reasonable) The Cedar River Park area was evaluated for a noise barrier. The noise barrier was evaluated along the east edge of I-405, between I-405 Cedar River Bridge and SR 169. Noise levels in this area would range between 63 and 73. The maximum noise reduction was 7 dBA at the nearest baseball field next to I-405 as shown in Exhibit 31. The second receptor near the Cedar River would receive a 3- dBA reduction. Noise Barrier East 1 would have an area of 14,240 square feet and a height of 16 feet. Exhibit 31: Allowed Barrier Area for Noise Barrier East 1 Modeled Site Residences Represented Leq (dBA) Allowed Barrier Area (ft2) Noise Level with Barrier (dBA) Reduction (dBA) 3* 6 71 6,246 64 7 AA* 3 63 0 63 0 AC* 10 63 0 62 1 TOTAL Barrier Area (ft2) 6,246 14,240 Planning Level Cost($) $201,808 $460,094 * site analyzed in I-405 Renton to Bellevue Project Based on WSDOT’s mitigation allowance, the allowable area for the benefited residential equivalency of Noise Barrier East 1 is 6,246 square feet as shown in Exhibit 31. Based on these results, a noise barrier is not reasonable in the vicinity of Noise Barrier East 1. Noise Barrier East 2 – (Not Feasible) The area along the east right-of-way of I-405, above the retaining wall separating I-405 from Renton Hill was evaluated for a noise barrier. Noise levels in the area of Noise Barrier East 2 were predicted to range between 64 and 66 dBA without a noise barrier. MEASURES TO AVOID OR MINIMIZE PROJECT EFFECTS Renton Nickel Improvement Project 58 Noise and Vibration Discipline Report This barrier was found to not be feasible because it would not be possible to provide a 7 dBA reduction in I-405 traffic noise levels for any of the residences represented by modeled sites B, C, D, and E with a wall of 24 feet in height. This barrier was included in the evaluation of the Noise Barrier East 3 evaluation as shown in Appendix B, but again was found not to provide the necessary 3 dBA reduction at enough residences located behind the barrier to meet WSDOT’s reasonableness criteria. A longer barrier was not evaluated in this area due to space limitations resulting from the Cedar Avenue South and Renton Avenue South overpasses. Noise Barrier East 3 – (Feasible, Not Reasonable) The area along the east right-of-way of I-405, above the retaining wall separating I-405 from Renton Hill was evaluated for a noise barrier. Noise levels in the area of Noise Barrier East 3 were predicted to range between 59 and 73 dBA without a noise barrier. With a 12- to 16-foot-tall barrier, the maximum noise reduction would be 9 dBA at modeled site 6, which represents 5 residences. Modeled sites 3, F, G, H, I, and J represent a total of 44 residences and will receive a 3 to 7 dBA reduction with a 12- to 16-foot-tall barrier. A 12- to 16-foot-tall barrier will also provide at least a 5 dBA noise reduction at the majority of first row residences. Ten residences from Receptors 6 and H receive at least a 6 dBA reduction in noise. Receptor 3, representing 7 first row residences, will receive just under a 5 dBA reduction and Receptor D, representing 2 first row residences, will receive a 2 dBA reduction from Noise Barrier East 3. Additional barrier heights were evaluated including barrier analyses which incorporated a nearby barrier (Noise Barrier East 2). The results of each evaluation is presented in Appendix B. The 12- to 16-foot-tall barrier will have an area of approximately 40,323 square feet and a length of 2,654 feet. Based on WSDOT’s mitigation allowance, the allowable area that the residences in the vicinity of Noise Barrier East 3 can receive is 40,387 square feet as shown in Exhibit 32. Based on these results, a noise barrier was initially thought to be reasonable in the vicinity of Noise Barrier East 3. MEASURES TO AVOID OR MINIMIZE PROJECT EFFECTS Renton Nickel Improvement Project Noise and Vibration Discipline Report 59 Exhibit 32: Allowed Barrier Area for Noise Barrier East 3 Modeled Site Residences Represented Leq (dBA) Allowed Barrier Area (ft2) Noise Level with Barrier (dBA) Reduction (dBA) 3 7 67 5,390 63 4 6 5 73 5,880 64 9 F 9 59 6,300 56 3 G 7 64 4,900 58 6 H 5 69 4,525 62 7 I 9 68 7,533 61 7 J 7 68 5,859 65 3 TOTAL Barrier Area (ft2) 40,387 40,323 Planning Level Cost($) $1,305,000 $1,303,000 + $1,150,000 Because Noise Barrier East 3 would be located above the retaining wall separating I-405 from Renton Hill, construction techniques were further evaluated. The I-405 Team identified that the retaining wall above which Noise Barrier East 3 would be located would require additional engineering to support the noise barrier. The additional costs to construct Noise Barrier East 3 were estimated to be $1,150,000 which makes Noise Barrier East 3 unreasonable for all of the designs options considered. Noise Barrier East 4 – (Feasible, Not Reasonable) The area along the east right-of-way of I-405, above Renton Hill was evaluated for a noise barrier. Noise levels in the area of Noise Barrier East 4 were predicted to range between 64 and 65 dBA without a noise barrier. While noise levels below the NAC are normally not considered for noise barrier placement, this area currently exceeds the NAC and is predicted to exceed the NAC without the Renton Nickel Improvement Project. Existing and future No Build noise levels in this area range from 68 to 74 dBA; however, the Renton Nickel Improvement Project will redesign the Benson Road overpass and add a cul-de- sac at first row residences along Benson Road. Noise levels at residences in the area are predicted to range from 64 to 65 dBA due to shielding from the new cul- de-sac and reconstruction of the Benson Road overpass further away from these residences. MEASURES TO AVOID OR MINIMIZE PROJECT EFFECTS Renton Nickel Improvement Project 60 Noise and Vibration Discipline Report A 12- to 16-foot-tall barrier was evaluated for placement following WSDOT right-of-way along Renton Hill north of Benson Road and around the new cul-de-sac to the south. The maximum noise reduction would be 7 dBA at modeled site 8, which represents 7 residences. A 12- to 16-foot-tall barrier would also provide at least a 5 dBA noise reduction at the majority of first row residences as Receptor N and Receptor 8 account for all the first row residences behind Noise Barrier East 4. As shown in Exhibit 33, the 12- to 16-foot-tall barrier does not meet WSDOT’s criteria for reasonableness as the 12- to 16-foot-tall barrier design has an area of approximately 14,086 square feet while WSDOT’s mitigation allowance is 7,700 square feet . Exhibit 33: Allowed Barrier Area for Noise Barrier East 4 Modeled Site Residences Represented Leq (dBA) Allowed Barrier Area (ft2) Noise Level with Barrier (dBA) Reduction (dBA) 8 7 65 4,200 58 7 9 4 64 0 63 1 N 5 65 3,500 60 5 TOTAL Barrier Area (ft2) 7,700 14,086 Planning Level Cost($) $249,000 $455,000 Additional barrier heights were evaluated which did not meet WSDOT’s criteria for reasonableness. The results of each barrier height evaluated are provided in Appendix B. Noise Barrier East 5 – Feasible, Reasonable (2,153 feet long, 18 feet tall, located along South 14th Street) A noise barrier was evaluated along the southern right- of-way of I-405 along South 14th Street beginning at Talbot Road South to the east and ending west of the South 14th Street/South 15th Street intersection atop Talbot Hill. The location of Noise Barrier East 5 is shown in Exhibit 34. Noise levels in the vicinity of Noise Barrier East 5 were predicted to range between 66 and 72 dBA without a wall. MEASURES TO AVOID OR MINIMIZE PROJECT EFFECTS Renton Nickel Improvement Project Noise and Vibration Discipline Report 61 LakeAve Talbot Rd S!! !! !!!! !!!!!!!!!!!!!! %&e( 167 S 15th St Noise Barrier East 5 14 13 11 10 UT S RQ P O Exhibit 34: Location of Noise Barrier East 5 With an 18-foot-tall barrier, the maximum noise reduction will be 9 dBA at modeled sites 10, 11, and O which represent all 13 first row residences. Receptors P, Q, R, T, and U, which represent residences further from Noise Barrier East 5, will receive 3 to 7 dBA reductions in noise levels. Additional barrier heights were evaluated and the results of each are provided in Appendix B. The 18- foot-tall barrier will have an area of approximately 36,848 square feet and a length of 2,153 feet. Based on WSDOT’s mitigation allowance, the allowable area that the residences in the vicinity of Noise Barrier East 5 can receive is 36,878 square feet as shown in Exhibit 35. Based on these results, a noise barrier would be reasonable in the vicinity of Noise Barrier East 5. Noise Barrier East 5 will be located along the southern right-of-way of I-405, adjacent to South 14th Street primarily. This area should be evaluated further to determine if any non-typical construction techniques are required as this area is located along the edge of Talbot Hill. Additional cost considerations may be necessary if it is determined that typical noise barrier construction techniques do not apply at this area. MEASURES TO AVOID OR MINIMIZE PROJECT EFFECTS Renton Nickel Improvement Project 62 Noise and Vibration Discipline Report Exhibit 35: Allowed Barrier Area for Noise Barrier East 5 Modeled Site Residences Represented Leq (dBA) Allowed Barrier Area (ft2) Noise Level with Barrier (dBA) Reduction (dBA) 10 2 72 2,218 63 9 11 8 71 8,328 62 9 O 3 72 3,327 63 9 P 5 69 4,525 62 7 Q 6 67 4,620 63 4 R 8 67 6,160 64 3 T 5 66 3,500 63 3 U 6 66 4,200 63 3 TOTAL Barrier Area (ft2) 36,878 36,848 Planning Level Cost($) $1,192,000 $1,191,000 Noise Barrier East 6 – (Not Feasible) The area along the southeast right-of-way of the SR 167 off-ramp to I-405 northbound was evaluated for a noise barrier. Noise levels in the area of Noise Barrier East 6 were predicted to range between 63 and 67 dBA without a noise barrier. Noise Barrier East 6 was found not to be feasible because it would not be possible to provide a 7 dBA reduction in I-405 and SR 167 traffic noise levels for any of the residences represented by modeled sites 13, 14, X, Y, AB, and AC with a wall of 24 feet in height. The primary reason Noise Barrier East 6 did not reduce traffic noise at the modeled sites in this area is because the WSDOT right-of-way line is located alongside SR 167, approximately 50 below the elevation of the modeled sites. Renton Nickel Improvement Project Noise and Vibration Discipline Report 63 VIBRATION What is vibration? Vibration is generated by an object moving in an oscillatory motion, or back and forth between two points. The characteristics of vibration are described in terms of displacement (how far it moves), velocity (how fast it moves), and acceleration (how fast it gains speed). Humans respond to vibrations by feeling the average amplitude of the vibration velocity in there bodies. The vibration velocity level is reported in decibels relative to a level of 1x10-6 inches per second and denoted VdB. In contrast to airborne noise, ground-borne vibration is not a phenomenon that most people experience every day. The background vibration velocity level in residential areas is usually 50 VdB or lower, well below the threshold of perception for humans, which is around 65 VdB. Most perceptible indoor vibration is caused by sources within buildings such as operation of mechanical equipment, movement of people or slamming of doors. Although the perceptibility threshold is about 65 VdB, human response to vibration is not usually severe unless the vibration exceeds 70 VdB. This is a typical level 25 feet from a truck or bus lane unless there are bumps in the road. There is potential for minor damage to fragile historic buildings at vibration levels greater than 100 VdB. How is vibration analyzed? Because roadway traffic with rubber tires generate low levels of vibration, construction activities are the most likely cause of noticeable vibration. Typical vibration levels for various construction activities are evaluated to determine if they have any potential to cause damage to structures along I-405. What are the potential effects of vibration? During operation, vibration levels would continue to be similar to those currently occurring in the study area. No substantial vibration effects will occur. VIBRATION Renton Nickel Improvement Project 64 Noise and Vibration Discipline Report During construction, various activities would create vibrations. Heavy construction equipment, such as large bulldozers and loaded trucks, frequently generate between 85 and 87 VdB at 25 feet. Pile driving may generate between 104 and 112 VdB at 25 feet. The vibration energy from pile driving decreases to between 92 and 100 VdB at 100 feet. Vibratory compaction equipment may also be used during construction. Depending on the size of machinery, compaction equipment may generate similar vibration levels as pile driving equipment. The potential for minor damage to fragile structures is limited to approximately 25 feet from most construction activities and 100 feet from pile driving. People will feel minor ground movement at greater distances, but because the construction activities are temporary, and there is negligible potential for damage to fragile structures, this will not constitute a negative effect. How can the potential effects be minimized? In order to minimize potential effects of vibration, pile driving is not recommended within 100 feet of fragile structures. No structures sensitive to vibration are located within 100 feet of the Renton Nickel Improvement Project. Use of large bulldozers and vibratory rollers should be limited to beyond 25 feet from fragile structures. Renton Nickel Improvement Project Noise and Vibration Discipline Report 65 REFERENCES King County 1999 King County Code Title 12, Chapters 12.86-12.100. Noise. Seattle, Washington. Renton, City of 1999 Renton City Code, Chapter 7, Section 8-7-2. Noise. City of Renton, Washington. Tukwila, City of 1999 Tukwila Municipal Code, Chapters 8.22. Noise. City of Tukwila, Washington. U.S. Environmental Protection Agency (EPA) 1974 Information on Levels of Environmental Noise Requisite to Protect Public Health and Welfare with an Adequate Margin of Safety. Report Number 550/9-74-004. 1971 Noise from Construction Equipment and Operations, Building Equipment, and Home Appliances. Washington, D.C. U.S. Department of Transportation (USDOT) Federal Highway Administration 1998 FHWA Traffic Noise Model User’s Guide. Washington D.C. 1996 Measurement of Highway Related Noise. Washington D.C. 1995 Transit Noise and Vibration Impact Assessment. Washington D.C. 1995 Transit Noise and Vibration Impact Assessment. Washington D.C. 1982 Procedures for Abatement of Highway Traffic Noise and Construction Noise. Federal-Aid Highway Program Manual. Volume 7, Chapter 7, Section 3. Washington, D.C. 1973 Fundamentals and Abatement of Highway Traffic Noise. Washington D.C. Washington Administrative Code (WAC) 1999 Chapter 173-60. Maximum Environmental Noise Levels. Olympia, Washington. Washington State Department of Transportation (WSDOT) 2003 Environmental Procedures Manual. Olympia, Washington. 1999 Traffic Noise Analysis and Abatement Policy and Procedures. Olympia, Washington. 1987 Directive D22-22. Noise Evaluation Procedures for Existing Highways. Olympia, Washington. APPENDIX A Noise Measurement and Model Validation Data Renton Nickel Improvement Project Noise and Vibration Discipline Report A-1 NOISE MEASUREMENT AND MODEL VALIDATION DATA I. Noise Measurement and Model Validation Ambient noise levels were measured for 15-minute periods at 16 locations near the study area to describe the existing noise environment, identify major noise sources in the study area, validate the noise model, and characterize the weekday background environmental noise levels. Measurement locations characterize the variety of noise conditions and represent other sensitive receptors near the proposed project. The FHWA Traffic Noise Model (TNM) Version 2.5 computer model (FHWA, 2004) was used to predict Leq(h) traffic noise levels. TNM is used to obtain precise estimates of noise levels at discrete points by considering interactions between different noise sources and the effects of topographical features on the noise level. The model estimates the acoustic intensity at a receiver location calculated from a series of straight-line roadway sections. Noise emissions from free- flowing traffic depend on the number of automobiles, medium trucks, and heavy trucks per hour; vehicular speed; and reference noise emission levels of an individual vehicle. TNM also considers effects of intervening barriers, topography, trees, and atmospheric absorption. Noise from sources other than traffic is not included. Therefore, when non-traffic noise such as aircraft noise is considerable in an area, TNM under-predicts the actual noise level. Because project impacts only depend on traffic noise levels, under-predicting the total environmental noise level does not affect the findings of the study. Noise monitoring results were used to validate the Existing Conditions TNM model. The project team noise specialists exported base maps and design files from MicroStation as DXF files and imported them into the TNM package. Major roadways, topographical features, building rows, and sensitive receptors from the MicroStation files were digitized into the model. Elevations were added from the 2-foot contour data. Elevations for planned improvements were taken from design profiles, proposed cross sections, and proposed cut and fill limits. Sixteen measured sites were chosen to represent noise-sensitive sites in the study area. Fifteen- minute noise measurements were taken at each of these 16 sites to estimate the Leq (h). The measured sites represent approximately 80 single family residences, multi-family units, a park, and a library. For noise model calibration, traffic volumes were adjusted to match field counts during the time of day of the noise measurement. Additional topographical and geometrical detail was added to the TNM model until the model results at each of the 16 measurement sites were within 2 dBA of the measured levels for the validation run of the model. Hotels not considered in the noise analysis due to the lack of ground floor outdoor uses are: the Renton Travel Lodge, the Springhill Suites Marriot, Hilton Garden Hotel, and the Larkspur Landing all located west of SR 167; and the Hampton Inn and the Homestead Studio Suites Hotel located south of I-405 at SR 181. The Holiday Inn located northeast of the I-405/SR 167 interchange has an outdoor use area in the center of the building, but this area was not considered in the noise analysis as traffic noise levels from I-405 were observed well below the NAC. The Nelson House and Best Western Inn South Center are located further than 1,000 feet from the project study area. The Valley Medical Center was visited during field activities. Traffic noise levels at Valley Medical Center were observed well below the NAC during field reconnaissance activities. APPENDIX A Renton Nickel Improvement Project A-2 Noise and Vibration Discipline Report Exhibit A-1. Summary of Noise Measurements Receptor Number Location Date Time Leq 1 Renton Public Library March 22, 2005 10:40 AM 63.8 2 Renton Hill Park March 22, 2005 10:15 AM 73.9 3 412 Mill Avenue South March 8, 2005 3:25 PM 65.9 4 509 South Main Street March 8, 2005 11:35 AM 72.0 5 522 Well Avenue South March 22, 2005 11:15 AM 60.7 6 520 Mill Avenue South March 8, 2005 11:15 AM 67.7 7 518 Cedar Avenue South March 8, 2005 2:30 PM 59.4 8 Berkshire Apartments (Bldg. P) March 22, 2005 12:10 PM 68.0 9 1114 Benson Road South March 22, 2005 12:45 PM 69.7 10 1306 Smithers Avenue South March 8, 2005 2:00 PM 70.4 11 301 South 14th Street March 8, 2005 10:05 AM 68.8 12 Outdoor Use at South Center View Condos March 22, 2005 1:10 PM 69.0 13 1503 Lake Avenue South March 10, 2005 2:10 PM 68.1 14 1514 Lake Avenue South March 10, 2005 2:10 PM 61.5 15 3521 Shattuck Avenue South March 10, 2005 1:25 PM 66.8 16 402 South 36th Street March 10, 2005 1:25 PM 58.7 1* Liberty Park November 3, 2003 11:30 AM 65.0 2* Liberty Park November 3, 2003 11:30 AM 68.0 3* Cedar River Park November 3, 2003 12:09 PM 68.0 * Sites were analyzed as a part of the I-405 Renton the Bellevue Project II. Description of Measurement Locations The measurement represented by Receptor 1 is located at Renton Public Library at 100 Mill Avenue South. The measurement was taken approximately 500 feet from the western edge of I-405, on the Cedar River Bridge just outside the library entrance. Receptor 1 is representative of 10 residential equivalent units (Exhibit B-3 in Appendix B). The measurement represented by Receptor 2 is located at Renton Hill Park just west of I-405 between the Renton Avenue South overpass at I-405 and the Cedar Avenue South overpass at I-405. The measurement was taken approximately 30 feet from the western edge of I-405, in the center of the benched area facing I-405. Receptor 2 is representative of 1 residential equivalent unit (Exhibit B-3 in Appendix B). The measurement represented by Receptor 3 is located in the front yard of the property facing I-405 at 412 Mill Avenue South. The measurement was taken approximately 75 feet from the eastern edge of I-405. This receptor is located approximately 30 feet above I-405 and is partially shielded by the retaining wall separating the Renton Hill Neighborhood from I-405. Receptor 3 is representative of 7 residences. The measurement represented by Receptor 4 is located in front of the property at 509 Main Avenue South. The measurement was taken approximately 150 feet from the western edge of I-405. Receptor 4 is representative of 3 residences. APPENDIX A Renton Nickel Improvement Project Noise and Vibration Discipline Report A-3 The measurement represented by Receptor 5 is located in the backyard of the property at 522 Well Avenue South. The measurement was taken approximately 300 feet from the western edge of I-405. Receptor 5 is representative of 7 residences. The measurement represented by Receptor 6 is located in an elevated front yard on the first floor ground level of a single family residence facing I-405 of the property at 520 Mill Avenue South. The measurement was taken approximately 100 feet from the eastern edge of I-405. This receptor is located approximately 30 feet above I-405 and is partially shielded by the retaining wall alongside I-405. Receptor 6 is representative of 5 residences. The measurement represented by Receptor 7 is located in an elevated front yard and swimming pool area on the first floor ground level of a single family residence facing I-405 of the property at 518 Cedar Avenue South. The measurement was taken approximately 400 feet from the eastern edge of I-405. This receptor is located approximately 45 feet above I-405 and is partially shielded by the retaining wall alongside I-405. Receptor 7 is representative of 10 residences. The measurement represented by Receptor 8 is located at a ground floor outdoor use area at building P of the Berkshire Apartments at 1300 Eagle Ridge Drive South. The measurement was taken approximately 200 feet from the eastern edge of I-405, in the grassy lawn west of the building facing I-405. Receptor 8 is representative of 6 ground floor apartment units and an adjacent single family residence. The measurement represented by Receptor 9 is located in the side yard facing I-405 of the property at 1114 Benson Road South. The measurement was taken approximately 400 feet from the southeastern edge of I-405. Receptor 9 is representative of 4 residences. The measurement represented by Receptor 10 is located in the front yard facing I-405 of the property at 1306 Smithers Avenue South. The measurement was taken approximately 50 feet from the southern edge of I-405 and is one of the nearest properties to I-405 along the study area. Receptor 10 is representative of 2 residences. The measurement represented by Receptor 11 is located in the front yard facing I-405 of the property at 301 South 14th Street. The measurement was taken approximately 100 feet from the southern edge of I-405 and approximately 45 feet above two I-405 northbound on-ramps. Receptor 11 is representative of 8 residences. The measurement represented by Receptor 12 is located at the South Center View Condos located at 15210 Macadam Road South. The measurement was taken approximately 1,000 feet northeast from the northern edge of I-405 and the western project limit, alongside an outdoor swimming pool south of the building facing I-405. Receptor 12 is representative of 3 residential equivalent units (Exhibit B-3 in Appendix B). The measurement represented by Receptor 13 is located in the backyard facing SR 167 of the property at 1503 Lake Avenue South. The measurement was taken approximately 300 feet from the eastern edge of the SR 167 off-ramp to I-405 northbound. Receptor 13 is located approximately 50 feet above the elevation of the nearest SR 167/I-405 interchange roadways. Receptor 13 is representative of 5 residences. The measurement represented by Receptor 14 is located in the front yard facing SR 167 of the property at 1514 Lake Avenue South. The measurement was taken approximately 500 feet from the eastern edge of SR 167 and approximately 60 feet higher than the nearest SR 167/I-405 interchange roadways. Receptor 14 is representative of 3 residences. The measurement represented by Receptor 15 is located in the backyard facing SR 167 of the property at 3521 Shattuck Avenue South. The measurement was taken approximately 500 feet from the eastern edge of SR 167. Receptor 15 is representative of 10 residences. APPENDIX A Renton Nickel Improvement Project A-4 Noise and Vibration Discipline Report The measurement represented by Receptor 16 is located in the front yard facing SR 167 of the property at 402 South 36th Street. The measurement was taken approximately 650 feet from the eastern edge of SR 167. Receptor 16 is representative of 9 residences. III. Validation Results Exhibit A-2. Measured Noise Levels and Validation Traffic Noise Model (TNM) Outputs Receptor Number Address Measured Leq Modeled Leq 1 Renton Public Library 63.8 64 2 Renton Hill Park 73.9 74 3 412 Mill Avenue South 65.9 66 4 509 South Main Street 72.0 71 5 522 Well Avenue South 60.7 62 6 520 Mill Avenue South 67.7 68 7 518 Cedar Avenue South 59.4 59 8 Berkshire Apartments (Bldg. P) 68.0 68 9 1114 Benson Road South 69.7 69 10 1306 Smithers Avenue South 70.4 71 11 301 South 14th Street 68.8 68 12 Outdoor Use at South Center View Condos 69.0 69 13 1503 Lake Avenue South 68.1 69 14 1514 Lake Avenue South 61.5 63 15 3521 Shattuck Avenue South 66.8 67 16 402 South 36th Street 58.7 59 1* Liberty Park 65.0 65 2* Liberty Park 68.0 69 3* Cedar River Park 68.0 68 * Sites were analyzed as a part of the I-405 Renton to Bellevue Project APPENDIX B Noise Barrier Analysis Renton Nickel Improvement Project Noise and Vibration Discipline Report B-1 NOISE BARRIER ANALYSIS WSDOT evaluates many factors to determine whether barriers will be feasible and/or reasonable. To be feasible, a barrier must be constructible in a location that achieves a noise reduction of at least 7 dBA at one or more receptors, and have a reduction of at least 5 dBA at most of the first row receptors. Once a noise barrier is found to be feasible, WSDOT evaluates whether the noise barrier is reasonable. To be reasonable, the noise barrier surface area may not exceed the sum of the allowed barrier surface area per household. Exhibit B-1 summarizes the allowed area per each receptor benefited by a reduction of at least 3 dBA. For noise levels above 74 dBA, the allowed barrier-surface-area per household increases by 70 square feet per dBA increase. Exhibit B-1: Noise Mitigation Allowance Design Year Traffic Noise Decibel Level Allowed Barrier Surface Area Per Household In Square Meters (square feet)* 66 dBA 65.0 (700) 67 dBA 71.5 (770) 68 dBA 77.7 (837) 69 dBA 84.0 (905) 70 dBA 90.5 (973) 71 dBA 96.7 (1,041) 72 dBA 103.0 (1,109) 73 dBA 109.2 (1,176) 74 dBA 115.5 (1,244) Source: WSDOT, 1999. *For receptors that experience a reduction of at least 3 dBA The cost applied to all noise barriers per WSDOT guidelines is $32.31 per square foot. These costs represent a planning-level estimate. Once preliminary engineering of the noise barriers is completed, WSDOT’s opinion of cost may differ considerable from the planning level estimate, depending on soil conditions, wall height, and integration into other structures. Residential Equivalency WSDOT calculates reasonableness based on the number of residences that benefit from a noise barrier. For noise-sensitive uses other than residences, a residential equivalency (RE) of the users is calculated, based on the usage factor and number of users (WSDOT, 1987). Residences may be in use at all times, but many other facilities such as schools have specific hours of operation. The usage factor accounts for the times of operation. Exhibit B-2 shows typical usage factors. In Washington, the average household has three members, so for sites with other than residential uses the number of users is divided by three to convert to households. Exhibit B-3 presents the APPENDIX B Renton Nickel Improvement Project B-2 Noise and Vibration Discipline Report residential equivalency for receptors in the I-405 Renton Nickel study area that include sensitive uses (other than single-family residences) that approached or exceeded the NAC. Exhibit B-2: WSDOT Established Usage Factors Site Hours/Day Days/Week Months/Year Usage Factor Homes 24 7 12 1 Apartments 24 7 12 1 Hospitals 24 7 12 1 Churches 6 3 12 0.11 Schools 10 5 9 0.22 Parks 10 5 5 0.17 APPENDIX B Renton Nickel Improvement Project Noise and Vibration Discipline Report B-3 Exhibit B-3: Residential Equivalency Noise Receptor Activity Description Number of Users Usage Factor Users to Households Factor Residential Equivalency (RE) 1 Renton Public Library 2102 0.22 0.33 15 2 Renton Hill Park 101 0.17 0.33 1 12 Outdoor pool at Condos 292 0.17 0.33 2 V Springbrook Trail 101 0.17 0.33 1 W Family Fun Center 1802 0.17 0.33 10 Z Tukwila Park 501 0.17 0.33 3 AA Interurban Trail 501 0.17 0.33 3 AD Ikawa Park 101 0.17 0.33 1 AE Green River Trail 101 0.17 0.33 1 A Veterans Park 101 0.17 0.33 1 1* Liberty Park – furthest baseball field in outfield and tennis court 101 0.17 0.33 1 2* Liberty Park – baseball field, stands, and basketball court 1081 0.17 0.33 6 3* Cedar River Park – soccer field and baseball field 1081 0.17 0.33 6 AA* Cedar River Park – trail, picnic, recreational open space, beach area 501 0.17 0.33 3 AB* Liberty Park – skateboard facility 201 0.17 0.33 1 AC* Aquatic Center 1802 0.17 0.33 10 1 Number of users was estimated at because user data were not available from Renton Parks Department. 2 Estimated average number of users at any one time while facility is open. * Sites analyzed in I-405 Renton to Bellevue Project The remainder of this section describes noise barriers where multiple barrier heights were evaluated. Each one is presented from north to south and east to west and identified by which side of I-405 it is located on. The titles include either a summary of the barriers feasibility and reasonableness, or the size of the proposed barrier. APPENDIX B Renton Nickel Improvement Project B-4 Noise and Vibration Discipline Report Noise Barrier East 2 Noise Barrier East 2 was found to not be feasible because it would not be possible to provide a 7 dBA reduction in I-405 traffic noise levels for any of the residences represented by modeled sites B, C, D and E with a wall of 24 feet in height. Noise Barrier East 2 was included in the barrier analysis of Noise Barrier East 3, which is feasible and reasonable. The barrier analysis with both the feasible and reasonable Noise Barrier East 3 wall height at 12 to 16 feet tall and a 24-foot-tall Noise Barrier East 2, was found not to provide the required 7 dBA reduction behind East Wall 2 as show in Exhibit B-4 below. Modeled sites B, C, D, and E are located behind or near Noise Barrier East 2. Exhibit B-4. Noise Barrier East 2 – 12 to 16 feet tall and Noise Barrier East 3 – 24 feet tall Modeled Site Residences Represented Leq (dBA) Allowed Barrier Area (ft2) Noise Level with Barrier Reduction (dBA) 3 7 67 5,390 63 4 6 5 73 5,880 64 9 F 9 59 6,300 56 3 G 7 64 4,900 58 6 H 5 69 4,525 62 7 I 9 68 7,533 61 7 J 7 68 5,859 65 3 B 6 64 0 63 1 C 6 66 0 66 0 D 2 63 0 61 2 E 10 60 0 58 2 Total Barrier Area (ft2) 18,606 49,674 Planning Level Cost($) $601,000 $1,605,000 Noise Barrier East 3 Noise Barrier East 3 is located along the east right-of-way of I-405, above the retaining wall separating I-405 from Renton Hill, adjacent to Mill Avenue South. The minimum height of Noise Barrier East 3 is the proposed height presented in the main body of this report and presented here for comparison purposes in Exhibit B-5 below. Exhibit B-6 shows the results of Noise Barrier East 3 at 20 to 24 feet tall. By increasing the barrier height to 20 to 24 feet, nine additional residences receive a 3 dBA reduction in noise; however, WSDOT’s mitigation allowance is 18,606 square feet which is far less than the total barrier area of 61,302 for Noise Barrier East 2 at 12 to 16 feet tall and Noise Barrier East 3 at 24 feet tall. Because Noise Barrier East 3 would be located above the retaining wall separating I-405 from Renton Hill, construction techniques were further evaluated. The I-405 Team identified that the retaining wall in which Noise Barrier East 3 would located above would require additional engineering to support the noise barrier. The additional costs to construct Noise Barrier East 3 were estimated to be $1,150,000 which makes Noise Barrier East 3 unreasonable for all of the designs options considered. APPENDIX B Renton Nickel Improvement Project Noise and Vibration Discipline Report B-5 Exhibit B-5. Noise Barrier East 3 Height 1 – 12 to 16 feet tall Modeled Site Residences Represented Leq (dBA) Allowed Barrier Area (ft2) Noise Level with Barrier Reduction (dBA) 3 7 67 5,390 63 4 6 5 73 5,880 64 9 F 9 59 6,300 56 3 G 7 64 4,900 58 6 H 5 69 4,525 62 7 I 9 68 7,533 61 7 J 7 68 5,859 65 3 Total Barrier Area (ft2) 40,387 40,323 Planning Level Cost($) $1,305,000 $1,303,000 + $1,150,000 Exhibit B-6. Noise Barrier East 3 Height 2 – 20 to 24 feet tall Modeled Site Residences Represented Leq (dBA) Allowed Barrier Area (ft2) Noise Level with Barrier Reduction (dBA) 3 7 67 5,390 63 4 6 5 73 5,880 64 9 F 9 59 6,300 56 3 G 7 64 4,900 58 6 H 5 69 4,525 62 7 I 9 68 7,533 61 7 J 7 68 5,859 65 3 K 9 67 6,930 64 3 Total Barrier Area (ft2) 47,317 61,302 Planning Level Cost($) $1,529,000 $1,981,000 + $1,150,000 Noise Barrier East 4 The area along the east right-of-way of I-405, above Renton Hill was evaluated for a noise barrier. Noise levels in the area of Noise Barrier East 4 were predicted to range between 64 and 65 dBA without a noise barrier (Exhibit B-7). While noise levels below the NAC are normally not considered for noise barrier placement, this area currently exceeds the NAC and is predicted to exceed the NAC without the Renton Nickel Improvement Project. Existing and future No Build noise levels in this area range from 68 to 74 dBA; however, the Renton Nickel Improvement Project will redesign the Benson Road overpass and add a cul-de-sac at first row residences along Benson Road. Noise levels at residences in the area are predicted to range from 64 to 65 dBA due to shielding from the new cul-de-sac and reconstruction of the Benson Road overpass further away from these residences. A 12- to 16-foot-tall barrier was evaluated for placement following WSDOT right-of-way along Renton Hill north of Benson Road and around the new cul-de-sac to the south. The maximum noise reduction would be 7 dBA at modeled site 8, which represents 7 residences. A 12- to 16- foot-tall barrier would also provide at least a 5 dBA noise reduction at the majority of first row APPENDIX B Renton Nickel Improvement Project B-6 Noise and Vibration Discipline Report residences as Receptor N and Receptor 8 account for all the first row residences behind Noise Barrier East 4. As shown in Exhibit 35, the 12- to 16-foot-tall barrier does not meet WSDOT’s criteria for reasonableness as the 12- to 16-foot-tall barrier design would have an area of approximately 14,086 while WSDOT’s mitigation allowance is 7,700. Additional barrier heights and designs were evaluated (Exhibit B-8 and Exhibit B-9) with barrier heights of 10 to 16 feet and 14 to 20 feet with separate horizontal alignments in an attempt to meet WSDOT’s reasonableness criteria. The 10- to 16-foot-tall barrier was placed along the western boundary of the new cul-de-sac. This barrier design would reduce noise levels by 7 dBA at the same 7 residences represented by receptor N as in the 12 to 16 feet tall design. The 10- to 16- foot-tall barrier design also reduces noise levels by at least 5 dBA at the majority of first row residences, so this design meets the feasibility criteria. As shown in Exhibit B-8, the 12- to 16-foot- tall barrier design does not meet WSDOT’s reasonableness criteria. A third barrier design was evaluated at 14 to 20 feet tall located along the western boundary of the new cul-de-sac, but the noise barrier would not continue northward to shield residences further northeast from Benson Road. This design achieved feasibility by reducing traffic noise levels at least 7 dBA at the first row receptor represented by Receptor N. This design also did not meet WSDOT’s reasonableness criteria as shown in Exhibit B-9. While both of the additional barriers analyzed were feasible, neither met WSDOT’s reasonable allowance. The 10- to 16-foot-tall barrier will have an area of approximately 12,586 square feet and the 14 to 20-foot-tall barrier will have an area of 8,927 square feet. Exhibit B-7. Noise Barrier East 4 Height 1 – 12 to 16 feet tall (located along Benson Road) Modeled Site Residences Represented Leq (dBA) Allowed Barrier Area (ft2) Noise Level with Barrier Reduction (dBA) 8 7 65 4,200 58 7 9 4 64 0 63 1 N 5 65 3,500 60 5 Total Barrier Area (ft2) 7,700 14,086 Planning Level Cost($) $249,000 $455,000 Exhibit B-8. Noise Barrier East 4 Height 2 – 10 to 16 feet tall (located along new cul-de-sac) Modeled Site Residences Represented Leq (dBA) Allowed Barrier Area (ft2) Noise Level with Barrier Reduction (dBA) 8 7 65 4,200 58 7 9 4 65 0 64 1 N 5 67 3,850 62 5 Total Barrier Area (ft2) 8,050 12,586 Planning Level Cost($) $260,000 $407,000 APPENDIX B Renton Nickel Improvement Project Noise and Vibration Discipline Report B-7 Exhibit B-9. Noise Barrier East 4 Height 3 – 14 to 20 feet tall (shields only residences along Benson Road) Modeled Site Residences Represented Leq (dBA) Allowed Barrier Area (ft2) Noise Level with Barrier Reduction (dBA) 8 7 65 0 65 0 9 4 65 0 65 0 N 5 67 3,850 60 7 Total Barrier Area (ft2) 3,850 8,927 Planning Level Cost($) $124,000 $288,000 Noise Barrier East 5 A noise barrier was evaluated along the southern right-of-way of I-405 along South 14th Street beginning at Talbot Road South to the east and ending west of the South 14th Street/South 15th Street intersection atop Talbot Hill. The location of Noise Barrier East 5 is shown in Exhibit 36. Noise levels in the vicinity of Noise Barrier East 5 were predicted to range between 66 and 72 dBA without a wall. With an 18-foot-tall barrier, the maximum noise reduction would be 9 dBA at modeled sites 10, 11 and O which represent 5 residences. Modeled site 8 representing all 14 first row residences. Receptors P, Q, R, T, and U which represent residences further from Noise Barrier East 5 would receive 3 to 7 dBA reductions in noise levels (Exhibit B-10). A second barrier height was evaluated at 12 feet (Exhibit B-11). The 14 foot wall has a maximum noise reduction of 7 dBA, 2 dBA less than the 18 foot barrier and not perceivable to most humans. The shorter barrier will not provide a dBA benefit to 25 of the residences which receive a 3 dBA reduction with the 18 foot barrier. The 12 foot barrier will have an area of approximately 25,835 square feet and will not meet the reasonableness criteria because an area of up to 18,398 square feet would be allowed. A 24-foot-tall noise barrier was also evaluated (Exhibit B-12), but would not meet reasonableness criteria. Based on the results, an 18 foot Noise Barrier East 5 will be feasible and reasonable. Exhibit B-10. Noise Barrier East 5 Height 1 – 18 feet tall Modeled Site Residences Represented Leq (dBA) Allowed Barrier Area (ft2) Noise Level with Barrier Reduction (dBA) 10 2 72 2,218 63 9 11 8 71 8,328 62 9 O 3 72 3,327 63 9 P 5 69 4,525 62 7 Q 6 67 4,620 63 4 R 8 67 6,160 64 3 T 5 66 3,500 63 3 U 6 66 4,200 63 3 Total Barrier Area (ft2) 36,878 36,848 Planning Level Cost($) $1,192,000 $1,191,000 APPENDIX B Renton Nickel Improvement Project B-8 Noise and Vibration Discipline Report Exhibit B-11. Noise Barrier East 5 Height 2 – 12 feet tall Modeled Site Residences Represented Leq (dBA) Allowed Barrier Area (ft2) Noise Level with Barrier Reduction (dBA) 10 2 72 2,218 67 5 11 8 71 8,328 64 7 O 3 72 3,327 66 6 P 5 69 4,525 64 5 Q 6 67 0 65 2 R 8 67 0 65 2 T 5 66 0 65 1 U 6 66 0 65 1 Total Barrier Area (ft2) 18,398 25,835 Planning Level Cost($) $594,000 $835,000 Exhibit B-12. Noise Barrier East 5 Height 3 – 24 feet tall Modeled Site Residences Represented Leq (dBA) Allowed Barrier Area (ft2) Noise Level with Barrier Reduction (dBA) 10 2 72 2,218 63 9 11 8 71 8,328 62 9 O 3 72 3,327 63 9 P 5 69 4,525 62 7 Q 6 67 4,620 63 4 R 8 67 6,160 64 3 S 7 65 4,900 62 3 T 5 66 3,500 63 3 U 6 66 4,200 63 3 Total Barrier Area (ft2) 41,778 48,707 Planning Level Cost($) $1,350,000 $1,574,000