HomeMy WebLinkAboutC_On-Hold_Canopy_200128January 28, 2020
Jordan Salisbury
Blue Fern Development, LLC
11232 120th Ave NE, Suite 204
Kirkland, WA 98033
SUBJECT: "On Hold" Notice
Canopy PUD Preliminary Plat / LUA19-000223
Dear Mr. Salisbury,
The Planning Division of the City of Renton accepted the above master application for review on October 31, 2019.
During our review staff has determined that additional information is necessary in order to proceed. The following
information will need to be submitted before April 27, 2020 so that we may continue the review of the above
subject application:
1.Home variations – Additional varieties of exterior elevations, roof forms, and cladding will be needed for the
55-lot subdivision. A minimum of eight (8) differing varieties for the entire plat with the following variations
per row of lots:
a.Lots 1-6 minimum of three (3) different exterior elevations;
b.Lots 7-16 minimum of four (4) different exterior elevations;
c.Lots 17-29 minimum of four (4) different exterior elevations;
d.Lots 30-40 minimum of four (4) different exterior elevations;
e.Lots 41-47 minimum of two (2) different exterior elevations; and
f.Lots 48-55 minimum of three (3) different exterior elevations.
2.Residential Design Standards – The applicant is encouraged to review the residential design standards. Special
attention should be paid to the following:
a.Lot configuration – Variations to the lot widths would help break up the repetitive layout of the future
homes.
b.Front entries – Several of the floor plans do not indicate a porch to provide a focal point or space for
social interaction. Porches are intended to have a minimum depth of five (5) feet and can extend into
the front yard setback.
c.Windows and Doors – Several of the elevations do not appear to contain adequate window and door
coverage along the street. The minimum coverage is 25-percent for those facades facing street
frontage.
3.Setbacks – Reevaluate the front yard setbacks along Road A for all alley loaded homes. There appears to be
opportunity for meeting the 15-foot setback by adjusting the setbacks along the alleys. Additionally, Alley 3 is
shown at 20-feet and does not appear to be an emergency vehicle access. The street standards only require
a 16-foot width with 12-feet paved for residential alleys.
4.Sideyards for Lots 30-39 – Reevaluate side yard setbacks along these lots where the shared driveway is located.
By reducing the setback to three (3) feet on the shared driveway side, the flare of the driveways can be
reduced. This reduction would on the shared driveway side would result in a greater setback on the opposite
sideyard that could be designed with a “zipper” type setback and create usable space for the homeowners.
5.Lot 40 – Staff was amenable to modifying the alley load requirements for lots 30-40 if the lots contained R-6
lot widths of 60-feet or utilized shared driveways. Due to the location of the retaining wall along the north
side of the lot it is effectively a 35-foot wide lot similar to Lots 30-39. Relocate the wall and building footprint
to meet the intent of staff’s front load limitation.
6.Lots 15 and 16 – These lots should be rear loaded. There appears to be width to extend a driveway from Alley
1 to Lots 15 and 16 for rear load.
7.Lots 1-6 – These homes should be oriented to Lincoln Ave NE with front doors and primary entry features on
the west façade.
8.Retaining wall setback – The retaining walls along the northern portion of Road A need to be setback a
minimum of three (3) feet from the ROW.
9.Critical Area Tract Boundaries – Critical Areas along with their buffers and setbacks must be wholly within a
tract. It appears that portions of Lots 6, 42, and 43 are within reduced buffer setbacks. Resubmitted plans will
need to address this issue.
10.Stream Buffer Averaging – It does not appear the proposal is eligible for stream buffer averaging as indicated
on page 9 of the Critical Area Study and Conceptual Mitigation Plan prepared by Wetland Resources. RMC 4-
3-050I.2.b.i clearly states that buffer width averaging may be allowed only where, in part, there are existing
physical improvements in or near the water body and associated riparian area. The Critical Areas Study does
not provide an applicable response to this criterion. Reevaluation of this method will be necessary.
11.Wetland Buffer Averaging – Similar to the above reference stream buffer averaging eligibility, wetland buffer
averaging requires an existing physical improvement in or near the wetland pursuant to RMC 4-3-050I.3.b.i.
Page 11 of the Critical Areas Study does not provide an applicable response to this criterion. Reevaluation of
this method will be necessary.
12.Wetland B Buffer Impacts – Page 14 of the Critical Areas Study asserts the proposed 240 square foot wetland
buffer impacts are exempt for frontage improvements. The identified exemption in the report is intended for
utilities, traffic control, walkways, bikeways within existing improved right-of-way or easements. Please
provide clarification that the area of proposed impacts is within existing improved right-of-way.
13.Common Open Space – Tracts D and E do not appear to meet the common open space standard of
“concentrated in large usable areas.” These tracts appear to be remnants and in the case of Tract E
significantly encumbered by a retaining wall. Remove these tracts from the common open space total and
reconfigure to comply with the 10-percent minimum. Additionally, these remnants can be integrated into
abutting lots to assist in lot width variation.
14.Private Open Space – Compliance with the PUD private open space standards (RMC 4-9-150E.2) could not be
confirmed. Please provide sheets that confirm dimensional and minimum space standards are met for each
lot.
15.Survey - the topographic map does not appear to match City aerials. The neighboring home is represented to
be over the property line and in the aerials there is a deck that is not shown on the map. There is also a shed
shown straddling the two property lines, but it is unclear to whom the shed belongs. These encroachments
should be addressed with the neighboring property owner.
If there are easements of record that will no longer be needed, provide proof of extinguishing the private
easements such as ingress, egress and utilities easements listed in title report.
Title reports are dated 2017 and 2018. Be advised that an updated title report for final platting process to
confirm ownership and encumbrances will be required.
16.Fire Comments – The Renton Regional Fire Authority has indicated the proposed water improvements will not
be sufficient as applicant is showing dwellings exceeding 3,600 square feet. Applicant can redesign proposed
water systems for higher flow rates or propose to lower fire flows through use of approved fire sprinkler
systems.
17.Water Main Improvements – The following items related to the new water mains need to be addressed:
a.The water main extension within Lincoln Avenue shall be 12-inch diameter connecting to the
existing City’s 12-inch water line near the south property line of parcel 3345700015 to the north
property line of Parcel #3345700015.
b.The internal water main shall be increased from an 8-inch diameter main to a 10-inch water main in
order to provide a minimum fire flow of 1,500 gpm.
c.The dead end water main within Alley 1 shall have a fire hydrant located at the end of the main.
d.The City of Renton Water System and Coal Creek Utility District Water System shall not be
connected.
18.Secondary Geotechnical Comments – Please find the enclosed comments prepared by GeoEngineers and
prepare responses and if needed corrections to reports/plans based on those comments. Specifically, written
responses to items 1 through 12 and a response to the MSE vegetated wall system are needed with the
resubmittal package.
19.Muckleshoot Tribe Comments – Please find the enclosed comments prepared by the Muckleshoot Indian Tribe
Fisheries Division. Reevaluation of the stream typing based on the Tribe’s comments will be necessary. Please
provide responses and clarifications regarding the stream and stormwater treatment methods indicated in
the comment letter.
At this time, your project has been placed “on hold” pending receipt of the requested information. Please provide
written responses to each of the correction items noted above and provide cross-reference to sheet and/or
reports to confirm compliance. The maximum time for resubmittal shall be within ninety (90) days of this notice.
Please contact me at (425) 430-6593 or mherrera@rentonwa.gov should you have any questions.
Sincerely,
Matt Herrera, AICP
Senior Planner
enc: Secondary Geotechnical Review Letter prepared by GeoEngineers, dated December 19, 2019
Muckleshoot Indian Tribe emailed comments dated November 14, 2019
cc: Earlington 60 Inc / Owner(s)
Glacial Ventures II LLC/ Applicant
1101 South Fawcett Avenue, Suite 200
Tacoma, Washington 98402
253.383.4940
December 19, 2019
City of Renton
Community and Economic Development
1055 South Grady Way
Renton, Washington 98057-3232
Attention: Matt Herrera
Subject: Geotechnical Engineering Review Services
Canopy Subdivision
Renton, Washington
File No. 0693-084-00
INTRODUCTION
This report presents comments from our review of geotechnical engineering analyses of the proposed
Canopy Subdivision located at 4196 Lincoln Avenue NE in Renton, Washington. Our services are being
provided to the City of Renton Department of Community and Economic Development in accordance with
our agreement dated November 19, 2019 and executed December 3, 2019.
The proposed development will include encroachment into a protected slope set back. Rockeries and
mechanically stabilize earth (MSE) retaining walls will be constructed as part of the development.
We understand that the main road and utilities will be transferred to the City at the completion of the
project. Alleys will remain as property of the future Homeowner’s Association. We understand that a
variance will be required for the setback encroachment and for proposed MSE retaining walls that exceed
6 feet in height.
DOCUMENTS REVIEWED AND REVIEW APPROACH
We reviewed a geotechnical report prepared for the project by Terra Associates dated March 19, 2019 and
revised August 22, 2019. We also reviewed the Canopy site development plans dated September 11, 2019
and a retaining wall exhibit that includes a manufacturer’s brochure for the Flex MSE retaining wall system.
We provide comments on the geotechnical aspects of these documents below.
City of Renton | December 19, 2019 Page 2
File No. 0693-084-00
GEOTECHNICAL REVIEW
Plan and Geotechnical Report Review
The following presents our review comments on the report and project plans. Our review only addresses
geotechnical aspects of retaining walls and slopes.
1. The soil parameters selected for the slope stability analysis and reported in the text appear appropriate
for the soils described and interpreted geologic conditions.
2. The report states that a horizontal acceleration of 0.2g was used in the pseudo-static analysis. It’s not
clear what seismic design level (i.e., return period) this is based on or if a reduction was included. A
seismic event with a 2 percent probability of exceedance in 50 years (about 2,475-year return period
in accordance with the IBC) is typically used to analyze slopes and potential failures that will impact
inhabited structures. A seismic event with a 7 percent probability of exceedance in 75 years (about
1,000-year return period in accordance with American Association of State Highway and Transportation
Officials [AASHTO] and Washington State Department of Transportation [WSDOT]) is typically used to
analyze slopes and potential failures that will impact structures such as retaining walls surrounding or
supporting roadways. For a pseudo-static analysis, one-half of the Peak Ground Acceleration (PGA) is
typically used based on the assumption that some permanent slope movement is acceptable.
3. Groundwater, perched or regional, is not included in the stability analysis. The reported critical failure
surfaces do occur at the contact between the upper weathered glacial till or fill and the lower
unweathered glacial till. This contact is where perched groundwater is indicated in the report. In our
opinion the perched groundwater should be included in the stability analyses at the locations indicated
in the logs and as described in the text. If this perched groundwater condition is expected to be transient
and is only expected to appear in response to recent rains, it would be appropriate in our opinion, to
reduce the extent or omit the perched groundwater from the seismic analysis.
4. The analysis of section B-B’, at the protected slope, models the rockery as having “infinite strength”
and the failure surface search feature limits the failure surface to an area above and below the rockery.
Failure surfaces through the rockery were apparently not considered or not reported. In our opinion the
analysis should either consider a failure surface through a rockery (modeled with an appropriate friction
angle) or a separate calculation should be provided indicating that the internal stability of the rockery
or other retaining system is not the critical failure mechanism. Additionally, both analyses might be
prudent given the proximity to an inhabited structure. As noted in the report Section 4.9 “a rockery is
not intended to function as an engineered structure.”
5. We generally concur with the conclusion in Section 3.4.3 that slopes “are not at risk of a deep-seated
failure in their current state.” However, proposed modifications in the Landslide Hazard Area consist of
cutting into the toe of the slope and leaving the above slope unmodified. In our opinion this increases
the risk that shallow surficial sloughs or even erosion could impact adjacent structures. We suggest
that either the standard minimum setbacks be maintained or that additional details be considered to
mitigate risk of run out damage to the adjacent structures. For example, increasing the height of the
retaining wall above the ground surface to provide a catchment for surface sloughs and erosion.
6. Subsurface explorations are limited in the vicinity of the Landslide Hazard Area and Protected Slope.
The geotechnical report states in Section 5 that Terra Associates, Inc. “should also provide geotechnical
service during construction to observe compliance with our design concepts, specifications, and
recommendations. This will allow for design changes if subsurface conditions differ from those
City of Renton | December 19, 2019 Page 3
File No. 0693-084-00
anticipated prior to the start of construction.” In our opinion, the geotechnical engineer of record should
confirm that the soil and groundwater conditions in the Protected Slope area are consistent with those
assumed in the analysis and should provide appropriate documentation to the City at the completion
of the project.
7. In Section 4.7, lateral earth pressures do not include pressures for the condition with slopes above the
wall. This condition is shown in multiple locations in the plans. It is also not clear what seismic design
level was used to develop the seismic loading. Different seismic loadings might be appropriate based
on the location of the retaining walls and risks as described in comment No. 2, above.
8. The plans indicate many tall retaining walls close to structures. In our opinion, if the collapse of a
retaining wall can significantly damage an inhabited structure, the wall must be designed to the same
seismic design standards as the adjacent structure. Alternatively, analysis can be provided indicating
that significant movement of the wall in the design seismic event will not impact the adjacent structure
or that the structure would not be damaged if it is impacted. In our opinion, any retaining wall and
structure that are closer horizontally than the vertical exposed height of the retaining wall should be
evaluated with these criteria.
9. The plans indicate a tiered retaining wall system located at Tract C. A global slope stability analysis
should be performed for this condition.
10. In Alley 3, a storm drain and a sanitary sewer are shown behind the proposed MSE retaining wall.
Utilities can be placed close to these walls or even incorporated into the reinforced section. However,
replacing or connecting to these utilities can require demolishing and reconstructing the wall, in whole
or in part. Wall details, once developed, should confirm that utility installation or replacement (including
space for trenching) will not encroach on the reinforced soil section of the wall. Alternatively, if utilities
must encroach on the reinforced zone, there could be a clear written understanding of how costs will
be shared between whomever is responsible for maintaining or replacing the utilities and whomever is
responsible for maintaining the retaining wall.
11. Sheet C3.32 is not sealed by an engineer and does not contain all the information required for
construction. Specifically, soil reinforcement schedule appears to be missing.
12. There are multiple locations, specifically Alley 3 and at the turn around on Alley 1, where a traffic barrier
or guardrail will likely be required above a retaining wall. In these cases, the walls must be designed to
withstand the design impact load from the guardrail and detailed to accommodate the guardrail.
Review of Proposed Flex MSE Vegetated Wall System
In our opinion, MSE walls and retaining systems, also referred to as structural earth walls (SEWs), can be a
very robust systems provided they are properly designed and constructed. The strength of the system
comes from the geosynthetic placed horizontally within the fill. The facing is secondary and prevents surface
sloughing and erosion. Planted faces are often used with MSE wall systems and can be successfully
maintained if appropriate plants are selected. The proposed Flex MSE wall consists of both a geosynthetic
soil reinforcing (geogrid) and a geosynthetic facing (Flex MSE Bag). Although we do not have direct
experience with this specific product, it is a proven concept.
There are some details, however, that should be considered regarding durability of these systems.
The facing, while not critical to the overall stability of the system, is important because it prevents localized
erosion of the face. Facings that only consist of geosynthetics, can be susceptible to damage, especially in
From: Karen Walter <KWalter@muckleshoot.nsn.us>
Sent: Thursday, November 14, 2019 10:12 AM
To: Matthew Herrera
Subject: FW: City of Renton LUA Complete Application: Canopy Preliminary Plat &
PUD, LUA19-000223
Attachments: NOA_Mailer_Canopy_Preliminary_Plat_PUD_191112.pdf;
ECF_Environmental_Checklist_190917_V1.pdf;
P_Site_Plan_190917_V1.pdf; WDFW barrier map for Lincoln Ave area of
Renton.pdf
Matt,
We have reviewed the NOA/proposed MDNS and other project documents for the Canopy Plat project
referenced above. We offer the following comments in the interest of protecting and restoring the Tribe’s
treaty-protected fisheries resources:
Stream Typing for on and offsite streams
According to the Preliminary Technical Information Report (TIR), there is a stream onsite and a stream
offsite. Both streams are shown as Type F (fishbearing) waters based on Renton’s stream classification
map (see the Downstream Exhibit in TIR). We agree. Also, based on WDFW’s fish passage barrier
map, they have identified fish passage barriers on these streams which means that the stream sections
above these barriers meets the physical criteria for presumed fish habitat or Type F waters under WAC
222-16-031. See https://geodataservices.wdfw.wa.gov/hp/fishpassage/index.html and the attached
map (Attachment 4).
The Wetland and Stream report for this project is incorrect as it describes the onsite stream (“Stream S”)
as a Type N, non-fishbearing stream. The project needs to be reevaluated for potential impacts to a larger
stream buffer based on the Type F classification. Any native tree that is greater than 4 inches in
diameter and within 200 feet of Stream S needs to be placed into the stream (at/below OHWM) as partial
mitigation for the permanent and temporal impacts to future wood recruitment functions that occur from
the tree removal.
Stormwater treatment
The project also needs to treat its stormwater using enhanced treatment methods to minimize impacts to
salmon (i.e. coho) from exposure to pollutants in the stormwater that will be discharged to the on and
offsite streams. The TIR notes that only “basic” treatment will be used.
We appreciate the opportunity to comment on this proposal and look forward to the City of Renton’s
responses.
Thank you,
Karen Walter
Watersheds and Land Use Team Leader
Muckleshoot Indian Tribe Fisheries Division
Habitat Program
39015-A 172nd Ave SE
Auburn, WA 98092
253-876-3116
From: Jennifer Cisneros [mailto:JCisneros@Rentonwa.gov]
Sent: Tuesday, November 12, 2019 11:28 AM
To: Karen Walter; Laura Murphy; 'separegister@ecy.wa.gov'; 'sepaunit@ecy.wa.gov';
'misty.blair@ecy.wa.gov'; 'Sepadesk@dfw.wa.gov'; 'sepacenter@dnr.wa.gov';
'Minnie.Dhaliwal@TukwilaWA.gov'; 'jgreene@kingcounty.gov'; 'steveo@newcastlewa.gov';
'andy.swayne@pse.com'; 'sepa@pscleanair.org'
Cc: Matthew Herrera
Subject: City of Renton LUA Complete Application: Canopy Preliminary Plat & PUD, LUA19-000223
Hello,
Please see attached documents for City of Renton LUA complete application for the following project:
Canopy Preliminary Plat & PUD
LUA19-000223
Attached are the Notice of Application, the Site Plan, and the Environmental Checklist.
Below are additional linked reports for your consideration.
Stormwater Report
Wetland and Stream Assessment
As the project progresses, more information will be available by request and through our online Public
Notice of Land Use Applications Map.
Regards,
Jenny Cisneros | Planning Technician
City of Renton | CED | Planning Division
1055 South Grady Way | 6th Floor | Renton, WA 98057
Phone: (425) 430-6583 | Fax: (425) 430-7300 | jcisneros@rentonwa.gov
Work Schedule: Tuesday – Friday
0 0.07 0.14 0.2 1 0.2 80.0 35 mi
No t a b arrier
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Di v ers ion
Na tu ra l B a rri e r -Verifi ed
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Un k no wn
Co rrecte dBarriers
NH D C o as tl i ne
NH D R iv e rsStream /Pe re nn ia lIntermittent /Ep h em e ral
Ca na l, D it ch
Pip elin e
Co nn ect or
NH D W a ter bod yLake, P on d,Re s erv o ir
Sw a mp , Ma rsh
Ice Ma ss
NH D A re a
La rge R iv e rs
Ca na l, D it ch
Fore s ho re
Ra pids
Exp o rt ed : 11 /14 /20 19 9 :48 :5 3 AM
Wa sh ingt on St ate Fish Pas sa ge m ap for Lin co ln
http://app s.wdfw.wa.gov/fish passage/?ex tent=-1 22.2021,47.5265,-122.1803,47.53 54