HomeMy WebLinkAboutD_Falcon_Ridge_Lift_Station_180531.pdfDEPARTMENT OF COMMUNITY
AND ECONOMIC DEVELOPMENT
PLANNING DIVISION
CERTIFICATE OF EXEMPTION
FROM CRITICAL AREAS REGULATIONS
EVALUATION FORM & DECISION
DATE:
PROJECT NUMBER:
PROJECT NAME:
PROJECT MANAGER:
May 31, 2018
LUA18-000336
Falcon Ridge Lift Station Replacement
Angelea Weihs, Assoicate Planner
CONTACT:Michael Benoit, City of Renton - Sewer
1055 S Grady Way
Renton, WA 98057
LOCATION:2471 SE 8TH PL
DESCRIPTION:Renton Wastewater Utility is requesting approval of a Critical Area Exemption in order to
replace the existing Falcon Ridge Lift Station currently located on Tract B (247520TR-B) of
Falcon Ridge (AKA Cedar Ridge) Development. The Falcon Ridge Lift Station, located at
the east end of SE 8th Place, is a duplex fiberglass-enclosed lift station that serves the
Falcon Ridge subdivision. The lift station was constructed in 1981 and has now reached
the end of its useful life. The City of Renton proposes to construct a replacement lift
station on abutting land currently owned by the City Parks Department, east of the
existing lift station. The parcel proposed for the new lift station (parcel 2123059003) is 30
acres and contains critical areas, including Ginger Creek, protected and sensitive slopes,
erosion hazards, landslide hazards, and coalmine hazards; however, the new lift station
will be more than 300 feet from Ginger Creek and more than 60 feet from all other geologic
hazardous areas, with the exception of moderate coalmine hazards. The proposed lift
station will be located on the far west side of the lot, along the street frontage of SE 8th
PL. The lift station will occupy approximately 1,990 square feet of land area. Construction
of the proposed lift station will occur while the existing station remains in service. The
proposed lift station will have the same capacity as the existing station, which has
adequate capacity to serve the area for the foreseeable future. The new lift station facility
will consist of:
• A 10-foot-diameter wet well completed to a depth of 13 feet;
• A 4-foot-diameter precast concrete manhole completed to a depth of 8 feet;
• An 8-foot by 8-foot valve vault completed to a depth of 9 feet; and
• A 10-foot by 9-foot electrical building and emergency generator, both supported on
separate, at-grade concrete slab foundations.
A Geological Evaluation prepared by RH 2 Engineering, Inc. (Exhibit 2; dated September 5,
2017) was submitted with the project application. The reports state that risks from
landslides, mass wasting, liquefaction and flooding is low/negligible. In addition, risk of
groundwater seepage from surrounding native soil during site development is negligible
unless construction occurs following a period of sustained rainfall, and risk of earthquakes
of a magnitude 5 to 6 during the next 50 years is high (80%). Staff recommends as a
condition of approval, that the applicant follow the recommendations provided the the
Page 1 of 4
DocuSign Envelope ID: 1FE3B99D-4498-460B-81D0-C89B9C24216C
City of Renton Department of Community & Economic Development Certificate of Exemption from Critical Areas Regulations
Falcon Ridge Lift Station Replacement LUA18-000336
Geotechnical Evaluation, which includes recommendations related to site excavation,
subgrade preparation, use of excavated earth materials, slope stability, seismic design
factors, and on-site infiltration capacity.
RH2 Engineering also provided a Coal Mine Hazard Evaluation (Exhibit 3; dated Mach 9,
2018) with the project application. The Coal Mine Hazard Evaluation states that, according
to mapping of the former Renton Coal Company Mine available on the Washington State
Department of Natural Resources website, underground coal mining extended no closer
than 1,300 feet west of the Site and at depths of at least 200 feet below the proposed
location. In addition, the report states that geologic investigations for the proposed lift
station conducted in May of 2017 encountered only dense glacial till, and no indication of
subsidence or weakness in the till was observed in the 14-foot-deep soil exploration
excavation. The Coal Mine Hazard Evaluation concludes that former coal mine activities
do not pose a significant risk of ground subsidence that could negatively impact the
construction and operation of the Falcon Ridge Lift Station.
A total of eleven (11) trees are proposed for removal as part of the proposed lift station
development. City Arborist, Terry Flatley, reviewed the proposal and agrees that these
trees would not survive construction work and/or are in the way of facilities to be built (See
Exhibit 4). Terry Flatley observed that other surrounding trees could be impacted by the
project, and should be protected with construction fencing kept in place until the project is
completed, and that no equipment should go beyond the limits of construction shown on
the plan. Staff recommends as a condition of approval that the applicant install and
maintain six-foot (6') high chain link temporary construction fencing, which includes tree
protection signage, around the "limit of construction" as identified on the site plan (Exhibit
1).
CRITICAL AREA:Coalmine Hazard
EXEMPTION JUSTIFICATION:RMC 4-3-050C.3.e.ii: New trails, existing Parks, Trails, Roads, Facilities, and Utilities –
Maintenance, Operation, Repair, and the Construction of New Trails
Page 2 of 4
DocuSign Envelope ID: 1FE3B99D-4498-460B-81D0-C89B9C24216C
City of Renton Department of Community & Economic Development Certificate of Exemption from Critical Areas Regulations
Falcon Ridge Lift Station Replacement LUA18-000336
FINDINGS:The proposed development is consistent with the following findings pursuant to RMC
section 4-3-050C.2.d:
i. The activity is not prohibited by this or any other provision of the Renton Municipal Code
or State or Federal law or regulation;
ii. The activity will be conducted using best management practices as specified by
industry standards or applicable Federal agencies or scientific principles;
iii. Impacts are minimized and, where applicable, disturbed areas are immediately
restored;
iv. Where water body or buffer disturbance has occurred in accordance with an exemption
during construction or other activities, revegetation with native vegetation shall be required;
v. If a hazardous material, activity, and/or facility that is exempt pursuant to this Section
has a significant or substantial potential to degrade groundwater quality, then the
Administrator may require compliance with the Wellhead Protection Area requirements of
this Section otherwise relevant to that hazardous material, activity, and/or facility. Such
determinations will be based upon site and/or chemical-specific data.
DECISION: An exemption from the Critical Areas Regulations is hereby Approved with Conditions*.
CONDITIONS:1. The applicant shall follow the recommendations provided in the Falcon Ridge Lift
Station Engineering Geology Evaluation (dated September 5, 2017) prepared by RH2
Engineering, Inc.
2. The applicant shall install and maintain six-foot (6') high chain link temporary
construction fencing, which includes tree protection signage, around the "limit of
construction" as identified on the site plan (Exhibit 1), prior to any construction activities.
SIGNATURE & DATE OF DECISION:
DateJennifer Henning, Planning Director
May 31, 2018
The above land use decision will become final if the decision is not appealed within the 14-day appeal period
(RCW 43.21.C.075(3); WAC 197-11-680).
Page 3 of 4
DocuSign Envelope ID: 1FE3B99D-4498-460B-81D0-C89B9C24216C
5/31/2018 | 2:25 PM PDT
City of Renton Department of Community & Economic Development Certificate of Exemption from Critical Areas Regulations
Falcon Ridge Lift Station Replacement LUA18-000336
APPEALS: An appeal of this administrative land use decision must be filed in writing together with the
required fee to the City of Renton Hearing Examiner, City of Renton, 1055 South Grady Way, Renton, WA 98057,
on or before 5:00 p.m., on June 14, 2018. RMC 4-8-110 governs appeals to the Hearing Examiner and additional
information regarding the appeal process may be obtained from the Renton City Clerk's Office, (425) 430-6510.
RECONSIDERATION: Within 14 days of the decision date, any party may request that the decision be reopened by the
approval body. The approval body may modify his decision if material evidence not readily discoverable prior to the original
decision is found or if he finds there was misrepresentation of fact. After review of the reconsideration request, if the approval
body finds sufficient evidence to amend the original decision , there will be no further extension of the appeal period. Any
person wishing to take further action must file a formal appeal within the 14-day appeal time frame.
EXPIRATION: Five (5) years from the date of decision (date signed).
Attachments:Site Plan, Geotech Report, Coal Mine Evaluation, Arborist Comments
Page 4 of 4
DocuSign Envelope ID: 1FE3B99D-4498-460B-81D0-C89B9C24216C
SE 8TH PL
TP1
CONSTRUCTION LIMIT
N: 175512.43
E: 1306016.27
CONSTRUCTION LIMIT
N: 175442.57
E: 1305988.19
CONSTRUCTION LIMIT
N:175429.30
E: 1306010.31
CONSTRUCTION LIMIT
N: 175434.36
E: 1306029.03
CONSTRUCTION LIMIT
N: 175449.56
E: 1306039.08
CONSTRUCTION LIMIT
N: 175459.53
E: 1306030.04
CONSTRUCTION LIMIT
N: 175483.43
E: 1306034.92
CONSTRUCTION LIMIT
N: 175506.37
E: 1306031.63
CONSTRUCTION LIMIT
N: 175507.20
E: 1306008.25
CONSTRUCTION LIMIT
N: 175504.57
E: 1305988.11
REBAR CAP
BENCHMARK
BOLLARD
BOLLARD TO BE REMOVED
WATER METER
FIRE HYDRANT (2 PORT)
WATER GATE VALVE
STORM DRAIN MANHOLE
CULVERT DAYLIGHT
SANITARY SEWER MANHOLE
IRRIGATION VALVE
POWER VAULT
TELEVISION PEDESTAL
POWER PAD MOUNT TRANSFORMER
TEST PIT
DECIDUOUS TREE
CONIFEROUS TREE
DECIDUOUS TREE TO BE REMOVED
CONIFEROUS TREE TO BE REMOVED
FENCE (AS NOTED)
FENCE TO BE REMOVED
UNDERGROUND TELEPHONE
NATURAL GAS
UNDERGROUND POWER
SANITARY SEWER
SEWER FORCEMAIN
STORM DRAIN MAIN
WATER MAIN
RIGHT OF WAY LINE
CENTER RIGHT OF WAY LINE
PROPERTY LINE
PROPERTY SECTION BOUNDARY
ASPHALT ROAD
CONCRETE DRIVEWAY
AHFJDHApr 9, 2018Apr 9, 2018REN117-038FCLS-D-CIV01.DWGSHOWN
C01 3 32
DWG NO.:DATEDESCRIPTIONREVISIONSBYREVIEWENGINEER:SAVE DATE:REVIEWED:PLOT DATE:CLIENT:FILENAME:SHEET NO.:JOB NO.:NO.0"1"2"
DRAWING IS FULL SCALE WHEN
BAR MEASURES 2"
SCALE:PRELIMINARYwww.rh2.comRH2 ENGINEERING, INC.Bothell, Wa22722 29th Drive SE, Suite 2101.800.720.8052EXISTING SITE PLANCITY OF RENTONFALCON RIDGE LIFT STATIONCITY OF RENTONFALCON RIDGE LIFT STATIONEXISTING SITE PLAN
EXISTING LEGEND
EXISTING LIFT STATION1 EXISTING POWER UTILITIES2
2
1
SILT FENCE TO BE INSTALLED
PRIOR TO CONSTRUCTION
207
TAKE ALL NECESSARY MEASURES TO
PROTECT TREES NOT MARKED FOR REMOVAL
BOLLARD, TO
BE REMOVED
ELECTRICAL PANEL,
TO BE REMOVED
TELEMETRY PANEL,
TO BE REMOVED
VACUUM-PRIMED PUMPS AND
PIPING, TO BE REMOVED
EXISTING SITE3
EXISTING GAS MONITORING
STATION. DO NOT DISTURB
EXISTING PARK BOUNDARY STAKE
AND PROPERTY CORNER TO BE
REPLACED WITH SURVEY PINS
3
1 CITY AND FIRE DEPARTMENT MUST HAVE ACCESS TO FIRE HYDRANT
AT ALL TIMES. UNDER NO CIRCUMSTANCES SHALL HYDRANT ACCESS
BE BLOCKED OR LIMITED.
DO NOT BLOCK SWING GATE. PRIVATE ACCESS TO SOUTHERN
PROPERTY THROUGH GATE SHALL BE MAINTAINED AT ALL TIMES.
DO NOT BLOCK GATE. WHILE LIFT STATION IS IN OPERATION, CITY
MUST HAVE FULL ACCESS TO EXISTING LIFT STATION AT ALL TIMES.
DO NOT BLOCK ACCESS TO HOUSE AND DRIVEWAY FROM SE 8TH PL.
2
3
1
2
3
NTC: MAY THE CONTRACTOR USE
SOME/ALL OF THE PARKING SPACES
WEST OF THE EXISTING WET WELL?
CONSTRUCTION LIMITS. NO WORK
MAY TAKE PLACE BEYOND THIS
BOUNDARY ON THE PARKS PARCEL.
4
4
EXISTING FENCE
TO BE REMOVED
EXHIBIT 1
DocuSign Envelope ID: 1FE3B99D-4498-460B-81D0-C89B9C24216C
SE 8TH PL
00 B0
64 B0
00 A066 A0-2.68%
-
1
.
3
7%-2.74%371
372
373
374
375376
377 375375-10 C-000 C050 C0EAST-WEST (A) PROFILE
360'
370'
380'
390'
360'
370'
380'
390'
0+000+66
2
1
NORTH-SOUTH (B) PROFILE
360'
370'
380'
390'
360'
370'
380'
390'
0+00 0+64
2
1
PROPOSED LIFT STATION LOCATION
AHFJDHApr 9, 2018Apr 9, 2018REN117-038FCLS-D-CIV02.DWGSHOWN
C02 4 32
DWG NO.:DATEDESCRIPTIONREVISIONSBYREVIEWENGINEER:SAVE DATE:REVIEWED:PLOT DATE:CLIENT:FILENAME:SHEET NO.:JOB NO.:NO.0"1"2"
DRAWING IS FULL SCALE WHEN
BAR MEASURES 2"
SCALE:PRELIMINARYwww.rh2.comRH2 ENGINEERING, INC.Bothell, Wa22722 29th Drive SE, Suite 2101.800.720.8052PROPOSED OVERALL SITE PLANCITY OF RENTONFALCON RIDGE LIFT STATIONCITY OF RENTONFALCON RIDGE LIFT STATIONELECTRICAL BUILDING, SEE DWG NO.
S01 FOR ADDITIONAL INFORMATION
EG
WETWELL, SEE DWG NOS. S03 AND
M01 FOR ADDITIONAL INFORMATION
VALVE VAULT, SEE MECHANICAL
DRAWINGS FOR ADDITIONAL INFORMATION
PROPOSED LEGEND
PROPOSED OVERALL SITE PLAN
1
1
20'
GATE
JUNCTION BOX ENCLOSURE,
SEE ELECTRICAL DRAWINGS
FOR ADDITIONAL INFORMATION
ELECTRICAL BUILDING
EG SLAB
WETWELL
VALVE VAULT
GRAVEL PATH, 3' WIDE
UNLESS OTHERWISE NOTED
6' WIDTH x 6' LENGTH x 1.5' DEPTH ROCK
PROTECTION OUTFALL SHALL BE QUARRY
SPALLS IN ACCORDANCE WITH SECTION
9-13.6 OF THE STANDARD SPECIFICATIONS.
PROVIDE 1' COVER OVER TOP OF PIPE.
8" PVC STORM PIPE,
APPROX. LENGTH 23'
25-SA OIL-WATER SEPARATOR
VAULT OR APPROVED EQUAL.
IE IN = 374.05'
IE OUT = 373.95'
THICKENED
ASPHALT CURB
IE OUT = 370.0'
TYPE 1 CATCH BASIN.
RIM EL = 374.85'
IE OUT = 372.33'
4" DI TEE WITH THRUST BLOCK. INSTALL (2) 4" GATE
VALVES AND (3) PVC FLANGE ADAPTERS ON TEE
8" PVC PIPE, APPROX.
LENGTH 25'-0"
PROPOSED CHAIN
LINK FENCE
4" PVC RJ PIPE, APPROX. LENGTH 24'.
SEE ABANDONMENT NOTES ON DWG
NO. G01 FOR ADDITIONAL PHASING
AND CONSTRUCTION INFORMATION.
PROPOSED PAVEMENT RESTORATION
SHALL MATCH GRADE ON NORTH AND WEST
SIDES. SEE DWG NO. C05 FOR DETAILS
PROPOSED PAVEMENT, SEE DWG NOS. C03
AND C05 FOR ADDITIONAL INFORMATION
PROPOSED FENCE
EXISTING GRADE
PROPOSED GRADE
EXISTING GRADE
PROPOSED GRADE
EXCAVATED MATERIAL MAY BE REUSED FOR SITE FILL PROVIDED THAT
6" AND LARGER OBJECTS AND ORGANIC DEBRIS ARE REMOVED PRIOR
TO PLACEMENT. PROTECT EXCAVATED MATERIAL FROM EXCESS
MOISTURE. DURING PLACEMENT, BACKFILL SHOULD BE PLACED AT
OPTIMAL MOISTURE IN 6" LOOSE LIFTS AND COMPACTED TO A FIRM
AND UNYIELDING CONDITION AT LEAST 95% OF MAXIMUM DRY DENSITY
AS DETERMINED BY THE MODIFIED PROCTOR TEST (ASTM D 1557).
PROPOSED IMPERVIOUS AREA: 1,990 SF
INCLUDING PAVEMENT AT EXISTING LIFT STATION
DO NOT DISTURB
EXISTING APPURTENANCE
SITE LIGHTING, TYP. SEE
ELECTRICAL DRAWINGS FOR
ADDITIONAL INFORMATION.
CORE DRILL PENETRATION FOR PROPOSED
PIPE. PIPE IE SHALL MATCH EXISTING
FLOOR ELEVATION, APPROXIMATELY
360.74' CONTRACTOR TO VERIFY.
PROPOSED FLAT TOP FOR
EXISTING MANHOLE
8" PVC STORM PIPE,
APPROX. LENGTH 2.5'
VENT PIPING AND CONCRETE PAD TO BE
INSTALLED OUTSIDE FENCE. PROVIDE FINE
GRADING TO ACCOMMODATE PAD.204
208
CONNECTION TO EXISTING SYSTEM
1
THE EXISTING STATION MUST REMAIN ONLINE AND OPERATIONAL UNTIL WRITTEN CONSENT HAS BEEN ISSUED BY THE
OWNER TO THE CONTRACTOR TO ABANDON THE EXISTING FACILITY. IN ORDER TO CONNECT THE DISCHARGE PIPE FROM
THE EXISTING WET WELL AND THE PROPOSED FORCEMAIN TO THE EXISTING FORCE MAIN, THE CONTRACTOR WILL PLUG
THE DISCHARGE PIPE OF MANHOLE #10040 AND UTILIZE VACTOR TRUCKING AS NECESSARY TO REMOVE INCOMING FLOWS
WHILE PROPOSED CONNECTIONS ARE INSTALLED. AT NO TIME SHALL THE LEVEL IN MANHOLE #10040 EXCEED 366.0'.
PROPOSED DISCHARGE PIPE FROM EXISTING WET WELL SHALL BE CORED. SEE CITY OF RENTON STANDARD
MANHOLE DETAIL FOR CONNECTION DETAIL. INSTALL PLUG AT UPSTREAM END TO PREVENT FLOW UNTIL
PROPOSED STATION IS APPROVED IN WRITING FOR OPERATION WITH WASTE WATER.
TEE CLUSTER WILL BE INSTALLED WITH EAST GATE VALVE NORMALLY CLOSED WITH A TEMPORARY BLIND FLANGE
UNTIL FINAL CONNECTION IS APPROVED. SEE CONNECTION DETAIL THIS SHEET.
SEE ABANDONMENT NOTES ON DWG NO. G01 FOR ADDITIONAL INFORMATION.
2
FITTINGS PER PLAN
CONNECTION DETAIL
1
2
PROTECT EXPOSED DISTURBED EARTH FROM
EROSION VIA MULCH OR HYDROSEEDING.
MAN ACCESS
GATE
210
200
DocuSign Envelope ID: 1FE3B99D-4498-460B-81D0-C89B9C24216C
101
111
106
105
103
102
00 B0
64 B0
00 A066 A0-2.68%
-
1
.
3
7%-2.74%371
372
373
374
375376
377 375375203
204
205
206
207
210
109
108
107
110
112
113
114
117
116
115
202
302 303
304
305
306
307
308
309
208
209
-10 C-000 C050 C0310
104
311
EAST-WEST (C) PROFILE
350'
360'
370'
380'
390'
350'
360'
370'
380'
390'
-0+10 0+00 0+50
POINT TABLE
POINT NO.
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
202
ELEV.
375.18
375.41
375.30
375.51
375.30
375.30
375.00
375.30
375.10
374.95
375.10
375.00
375.10
375.15
375.15
375.10
375.10
375.26
NORTHING
175483.83
175464.32
175462.09
175452.35
175448.22
175450.34
175472.76
175471.86
175471.19
175492.08
175489.11
175490.58
175488.49
175490.33
175488.64
175486.80
175486.43
175453.98
EASTING
1305975.30
1305981.69
1305989.56
1305982.54
1306008.80
1306024.40
1306028.08
1306021.47
1306016.52
1306025.45
1306014.08
1306014.39
1306009.58
1306009.33
1305996.86
1305997.11
1305994.43
1306010.34
DESC.
EOP
EOP
EOP
EOP
EOP
EOP
EOG
EOP
EOP
EOG
EOP
EOP
EOP
EOP
EOP
EOP
EOP
WETWELL
POINT TABLE
POINT NO.
203
204
205
206
207
208
209
210
302
303
304
305
306
307
308
309
310
311
ELEV.
375.30
375.24
375.18
375.17
375.10
374.85
374.96
375.10
375.33
375.55
375.57
375.65
375.28
375.13
374.75
375.22
375.14
375.30
NORTHING
175452.49
175457.44
175461.79
175463.89
175476.97
175477.39
175482.43
175487.54
175464.62
175461.68
175447.70
175449.92
175471.93
175472.36
175499.93
175496.47
175484.61
175474.61
EASTING
1306017.13
1306016.46
1305999.39
1306014.84
1306015.74
1306005.12
1306008.10
1306014.30
1305986.93
1305989.26
1306008.67
1306024.97
1306021.97
1306025.11
1306013.12
1305987.72
1305987.53
1305987.23
DESC.
PANEL
PANEL
VAULT
VAULT
BLDG
CB
OWS
BLDG
FENCE
FENCE
FENCE
FENCE
FENCE
FENCE
FENCE
FENCE
FENCE
FENCE
AHFEHApr 9, 2018Apr 9, 2018REN117-038FCLS-D-CIV02.DWGSHOWN
C03 5 32
DWG NO.:DATEDESCRIPTIONREVISIONSBYREVIEWENGINEER:SAVE DATE:REVIEWED:PLOT DATE:CLIENT:FILENAME:SHEET NO.:JOB NO.:NO.0"1"2"
DRAWING IS FULL SCALE WHEN
BAR MEASURES 2"
SCALE:PRELIMINARYwww.rh2.comRH2 ENGINEERING, INC.Bothell, Wa22722 29th Drive SE, Suite 2101.800.720.8052PROPOSED SITE PLANCITY OF RENTONFALCON RIDGE LIFT STATIONCITY OF RENTONFALCON RIDGE LIFT STATIONPROPOSED SITE PLAN
EG
WETWELL, SEE DWG NOS. S03 AND
M01 FOR ADDITIONAL INFORMATION
VALVE VAULT, SEE MECHANICAL
DRAWINGS FOR ADDITIONAL INFORMATION
ROOF
OUTLINE
12' PAVEMENT
RADIUS
EXISTING
WET WELL
PROPOSED INFLUENT
GRAVITY PIPE
PROPOSED
WET WELL
PROPOSED MANHOLE TOP SHALL BE 108" DIAMETER
FLAT TOP FOR EXISTING 6' DIAMETER STRUCTURE
WITH MANHOLE FRAME AND COVER. CENTER OF
COVER SHALL BE 33" FROM EDGE OF SLAB.
EXISTING GRADE
PROPOSED GRADE
PROPOSED TOP SLAB
EXISTING MANHOLE
ASPHALT PAVEMENT201
6" CRUSHED ROCK,
COMPACTED TO A FIRM AND
UNYIELDING CONDITION
EXISTING NATIVE MATERIAL,
COMPACTED PRIOR TO
GRAVEL PLACEMENT
PROPOSED SLAB ON EXISTING MANHOLE 200
200
ELECTRICAL BUILDING, SEE DWG NO.
S01 FOR ADDITIONAL INFORMATION
SLOPE EXISTING
PAVEMENT AS SHOWN
DocuSign Envelope ID: 1FE3B99D-4498-460B-81D0-C89B9C24216C
9/5/2017 3:59 PM \\rh2.com\dfs\Bothell\Data\REN\117-038\Geo\Tech Memo re Falcon Ridge LS.docx
Signed: 9/5/17 Signed: 9/5/17
TECHNICAL
MEMORANDUM
Client: City of Renton
Project: Falcon Ridge Lift Station Replacement and Force Main Improvements
Project File: REN 117.038.01.101 Project Manager: Edwin Halim, PE
Composed by: Steve Nelson, LEG
Reviewed by: Tony Pardi, PE
Subject: Falcon Ridge Lift Station Engineering Geology Evaluation
Date: September 5, 2017
INTRODUCTION
The Falcon Ridge Lift Station, located at the east end of SE 8th Place east of Lake Youngs Way
SE in Renton WA, is a duplex fiberglass-enclosed lift station that serves the Falcon Ridge
subdivision. The lift station was constructed in 1981 and has now reached the end of its useful
life. The City of Renton (City) intends to construct a replacement lift station on land currently
owned by the City Parks Department east of the existing lift station. Construction of the
proposed lift station will occur while the existing station remains in service. The proposed lift
station will have the same capacity as the existing station, which has adequate capacity to serve
the area for the foreseeable future. The lift station facility will consist of:
• A 10-foot-diameter wet well completed to a depth of 13 feet;
• A 4-foot-diameter precast concrete manhole completed to a depth of 8 feet;
• An 8-foot by 8-foot valve vault completed to a depth of 9 feet; and
• A 10-foot by 9-foot electrical building and emergency generator, both supported on
separate, at-grade concrete slab foundations.
Entire Document
Available Upon
Request
EXHIBIT 2
DocuSign Envelope ID: 1FE3B99D-4498-460B-81D0-C89B9C24216C
3/9/2018 3:47 PM J:\DATA\REN\117-038\GEO\TECH MEMO RE FALCON RIDGE LS ADDENDUM.DOCX
TECHNICAL
MEMORANDUM
Client: City of Renton
Project: Falcon Ridge Lift Station Replacement and Force Main Improvements
Project File: REN 117.038.01.101 Project Manager: Edwin Halim, PE
Composed by: Steve Nelson, LEG
Reviewed by: Tony Pardi, PE
Subject: Coal Mine Hazard Evaluation
Date: March 9, 2018
INTRODUCTION
The Falcon Ridge Lift Station, located at the east end of SE 8th Place east of Lake Youngs
Way SE in Renton, Washington, is a duplex fiberglass-enclosed lift station that serves the Falcon
Ridge subdivision. The lift station was constructed in 1981 and has now reached the end of its
useful service life. The City of Renton (City) intends to construct a replacement lift station on
land currently owned by the City Parks Department adjacent to and east of the existing lift
station. Construction of the proposed lift station will occur while the existing station remains in
service. The proposed lift station will have the same capacity as the existing station, which has
adequate capacity to serve the area for the foreseeable future. The replacement lift station facility
will consist of a 10-foot-diameter wet well completed at a depth of approximately 13 feet.
SITE CONDITIONS
The lift station site (the Site) is located within an area designated by the City as a Coal Mine
Hazard Area. Surficial geologic units at the Site encountered during a previous site investigation
consist of very dense sandy silt with gravel identified as unweathered glacial till
(RH2 Engineering, Inc., Technical Memorandum Falcon Ridge Lift Station Engineering Geology
Evaluation, September 5, 2017). Mapping by Washington State Department of Natural
3/09/18 3/09/18
Entire Document
Available Upon
Request
EXHIBIT 3
DocuSign Envelope ID: 1FE3B99D-4498-460B-81D0-C89B9C24216C
From: Terrence J. Flatley
Sent: Monday, April 09, 2018 1:56 PM
To: Angelea Weihs
Cc: Michael A Benoit
Subject: Falcon Ridge Lift Station - Tree Review
Hi Angelea,
I have reviewed the Falcon Ridge Lift Station project (attachments) and there are several trees shown in
red indicated for removal. Those trees would not survive construction work and/or are in the way of
facilities to be built and should be removed.
There are two additional trees not shown in red that are almost on the silt fence line (red dot/dash line).
One is a 24-inch diameter Western redcedar tree (yellow highlight) and the other is an 18-inch diameter
Western redcedar tree (yellow highlight). The trees have metal tags on them: the 24” tree is #10196 and
the other is #10194.
These two trees should be included in the tree removal because they will be too close to the
construction (limits of construction shown to be even closer to these trees) and would suffer significant
damage to their root systems (Western redcedar has a medium tolerance to development impacts).
The 24 inch tree will be about 7 feet from the finished facility and the 18 inch tree will be 10 feet. Under
ideal tree protection, these trees would require 18 to 24 feet of tree protection over the root systems in
order to not significantly impact tree health.
There are other surrounding trees that could be impacted by this project and should be protected with a
combination of construction fencing kept in place for the life of the project until completed and signage
on the fencing. No equipment should go beyond the limits of construction shown on the plan.
Terry Flatley, Urban Forestry and Natural Resources Manager
Community Services Department – 6th Floor
1055 South Grady Way
Renton, WA 98057
425-430-6601
ISA Certified Arborist - Municipal Specialist
EXHIBIT 4
DocuSign Envelope ID: 1FE3B99D-4498-460B-81D0-C89B9C24216C