HomeMy WebLinkAbout21. Final Mitigation_ Canopy PUD.pdfBUFFER
ENHANCEMENT
AREA A
6,788 SF WRI PROJECT #18158Date: 7/14/2021SHEET 1/2FINAL MITIGATION PLAN - STREAM SCANOPY - LINCOLN PL NERENTON, WASHINGTONPREPARED FOR: Blue Fern Development, LLCAttn: Michelle Branley1414 Market St, #200Kirkland, WA 980039505 19TH AVE SE, SUITE 106EVERETT, WA 98208TEL: 425.337.3174FAX: 425.337.3045Drawn by: A. RichardsonPROJECT MONITORING PROGRAM
Requirements for monitoring project:
1. Initial compliance/as-built report
2. Site inspection (twice per year) for five years
3. Annual reports (one report submitted during each monitored year)
Purpose for Monitoring
The purpose for monitoring this mitigation project shall be to evaluate its success.
Success will be determined if monitoring shows at the end of five years that the
definitions of success stated below are met. The property owner shall grant access to
the mitigation area for inspection and maintenance to the contracted landscape and/or
wetland specialist and City of Renton during the monitoring period or until the project is
evaluated as successful.
Monitoring
Monitoring shall be conducted twice annually for five years in accordance with the
approved Mitigation Plan. The monitoring period will begin once the City receives
written notification confirming the mitigation plan has been implemented and City staff
inspects the site and issues approval of the installation.
Vegetation Monitoring
Sampling points or transects will be established for vegetation monitoring and photo
points will be established from which photos will be taken throughout the monitoring
period. Permanent sampling points must be identified on the mitigation site plans in the
first monitoring report (they may be drawn on approved plans by hand). Each sampling
point shall detail herbaceous, shrub, and tree coverage. Monitoring of vegetation
sampling points shall occur once per monitored year.
Wetland Hydrology Monitoring
To ensure that wetland hydrology is not impacted by the development, the wetland
boundaries will be reviewed during the spring monitoring visit of each monitored year. If
it appears that any existing wetland areas are no longer saturated or inundated for
sufficient duration to support wetland conditions, those areas will be demarcated in the
field and depicted on a map. Additional mitigation may need to be provided, as
described in the contingency plan in Section 15, below.
Photo points
No less than four permanent photo points will be established within the mitigation
areas. Photographs will be taken from these points to visually record condition of the
mitigation areas. Photos shall be taken annually between May 15 and September 30
(prior to leaf drop), unless otherwise specified.
CONTINGENCY PLAN
If 20% of the plants are severely stressed during any of the inspections, or it appears
20 percent may not survive, additional plantings of the same species may be added to
the planting area. Elements of a contingency plan may include, but will not be limited
to: more aggressive weed control, pest control, mulching, replanting with larger plant
material, species substitution, fertilization, soil amendments, and/or irrigation.
PROJECT NOTES
Pre-Construction Meeting
Mitigation projects are typically more complex to install than to describe in plans.
Careful monitoring by a wetland professional for all portions of this project is strongly
recommended. Construction timing and sequencing is important to the success of this
type of project. There will be a pre-construction meeting on this site between the
Permittee, the consulting wetland professional, and laborers. The objective will be to
verify the location of erosion control facilities, verify the location of mitigation areas, and
to discuss project sequencing.
Inspections
A wetland professional shall be contracted to periodically inspect the mitigation
installation described in this plan. Minor adjustments to the original design may be
necessary prior to and during construction due to unusual or hidden site conditions. A
City of Renton representative and/or the consulting professional will make these
decisions during construction.
INTRODUCTION
The subject property is composed of five King County tax parcels (3345700015,
3345700016, 3345700017, 3345700018, 3345700020). The site is approximately
10.1-acres, located at and adjacent to 8314 110th Pl SE and 4130 Lincoln Ave NE in
the City of Renton, Washington (Section 32, Township 24N, Range 5E, W.M.). Access
is via a driveway from Lincoln Ave NE.
SITE DESCRIPTION
The subject property is located within the May Creek sub-basin of the Cedar
River/Lake Washington Watershed (WRIA 8). Lake Washington is approximately 3,000
feet west of the subject property. Surrounding land use is mixed, including residential,
commercial, and industrial uses; with I-405 approximately 1,100 feet to the west. The
site is partially developed; in the south, there are multiple single-family residences and
associated infrastructure, while the northern portion contains naturally vegetated
pasture and forested areas. Topography slopes steeply to the west, and, according to
King County iMap, is underlain by high erosion hazard areas, with slopes in excess of
20 percent.
Four wetlands (Wetlands A through D) and one stream (Stream S) were identified
within the investigation area.
Pursuant to Renton Municipal Code (RMC), on-site wetlands were classified under the
Washington State Wetland Rating System for Western Washington: 2014 Update
(Hruby 2014). Wetlands A through D are classified as Category IV wetlands. Per RMC
(7)(a) Stream S was classified based on the WAC 222-16-030. As such, Stream S is
classified as a Type Np Stream. Per 4-3-050(G)(2), Category IV wetlands typically
receive 50-foot buffers (when adjacent to non-low impact land uses) and Type Np
streams typically receive 75-foot buffers.
In addition, geological hazards were identified on-site by the geotechnical engineer,
Terra Associates, Inc. Geological hazards identified include protected slopes, high
erosion hazard area, and low seismic hazard area. Per RMC 4-3-050G(2), protected
slopes require a 15 foot structure setback.
MONITORING REPORT CONTENTS
Monitoring reports shall be submitted by December 31 of each year during the
monitoring period. As applicable, monitoring reports must include descriptions / data
for:
PROJECT SUCCESS & COMPLIANCE
Criteria for Success
Upon completion of the proposed mitigation project, an inspection by a qualified
biologist will be made to determine plan compliance. A compliance report will be
supplied to the City of Renton within 30 days after the completion of planting. A
landscape professional or wetland professional will perform condition monitoring of the
plantings in the spring and fall of each monitored year. A written report describing the
monitoring results will be submitted to the City after each site inspection of each
monitored year. Final inspection will occur five years after completion of this project.
The contracted consultant will prepare a report as to the success of the project.
Definition of Success
The planting areas shall meet the following performance standards:
*Volunteering native species may be included in the aerial cover calculations.
The species mix should resemble that proposed in the planting plans, but strict
adherence to obtaining all of the species shall not be a criterion for success.
a) End of Year 1
• 100 percent survival of newly planted species and
• Less than 10 percent cover of weedy/invasive species
b) End of Year 2
• 80 percent survival of newly planted species
• Less than 10 percent cover of weedy/invasive species
c) End of Year 3
• At least 50 percent native vegetation coverage within the mitigation areas*
• Less than 10 percent cover of weedy/invasive species
d) End of Year 5
• At least 80 percent aerial cover of native woody plant species*,
• Less than 10 percent cover of weedy/invasive species.
1. Site plan and vicinity map
2. Historic description of project, including date of installation, current year of
monitoring, restatement of mitigation/restoration goals, and performance
standards
3. Plant survival, vigor, and areal coverage for every plant community (transect
or sampling point data), and explanation of monitoring methodology in the
context of assessing performance standards
4. Wetland and buffer conditions, e.g., surrounding land use, use by humans,
and/or wild and domestic creatures
5. Observed wildlife, including amphibians, avians, and others
6. Assessment of nuisance / exotic biota and recommendations for management
7. Color photographs taken from permanent photo-points that shall be depicted
on the monitoring report map
PROJECT DESCRIPTION
The applicant is proposing to develop a 56-lot residential development and associated
infrastructure. To accommodate this development, the applicant will do a combination of
buffer width averaging and wetland/buffer impacts, to be mitigated for on-site. As a result
of required frontage improvements and stormwater infrastructure, the applicant will
permanently impact the entirety of Wetland A (and a portion of an associated ditch),
totaling 1,585 square feet, and a small portion (240 square feet) of Wetland B’s buffer. In
addition, the applicant will utilize buffer averaging to accommodate the proposed
development adjacent to Wetland B, Wetland D, and Stream S.
As mitigation for the impacts, the applicant is proposing a combination of on-site and
off-site mitigation. A portion of the compensation (meeting City of Renton requirements)
for Wetland A impacts will be provided by enhancing the entirety of the on-site portions
of Wetlands B and D (totaling 4,865 square feet). This exceeds the 3:1 (enhancement to
impact) ratio for Category IV wetlands, per RMC 4-3-050(J)(4)(c).
The aforementioned impact to the buffer of Wetland B will be mitigated for via
enhancement of 700 square feet of buffer located between Wetland B and Lincoln Ave
NE (exceeding the 1:1 mitigation to impact ratio required by RMC 4-3-050(J)(4)(d)). To
accommodate Stream S buffer width averaging, the applicant proposes to enhance a
6,788 square feet of stream buffer, per RMC 4-3-050(I)(2)(b)(v).
As part of the proposed development the City of Renton is requiring an on-site and
off-site trail to connect the development to the City of Newcastle’s pedestrian trail
located along the NE 43rd Street right-of-way, north of the subject property. The off-site
portion of the trail will be located within the unopened right-of-way of 112th Avenue SE,
that parallels the eastern property boundary. The trail shall be 5 feet wide, with the
majority consisting of wood chips underlain with filter fabric, and will be field fit to avoid
trees. The trail will cross portions of wetland, stream, and buffer. Per RMC 4-3-050C(3)
and RMC 4-3-050C(4), trails are exempt and allowed within critical areas and their
associated buffers as long as they meet certain requirements. The portion of trail
crossing the wetland will consist of a boardwalk and supported by pin piles. The slatted
decking of the boardwalk and grated top of the dock will allow precipitation to move
through the structure. This design minimizes impacts to the wetland and aquatic area
and avoids any fill or grading within the wetland. Disturbance within the wetland will be
limited to vegetation impacted for boardwalk installation. This portion of the trail will
impact approximately 134 square feet of vegetation associated with Wetland D. To
mitigate for any temporal loss of vegetation from installation of the boardwalk, buffer
enhancement of a portion of Wetland D’s on-site buffer is proposed at a 3:1
enhancement to impact ratio. The bridge proposed over Stream S will be approximately
6 feet wide and will consist of concrete slabs and metal railings. The crossing will be
consistent with WDFW stream crossing guidelines.
S
D
SDSD
SD
SDSD
SDSDSD 1098111345637545355504956(OPEN SPACE)TRACT B35363240333837393452474851(OPEN SPACE)TRACT Q2324251826192720(OPEN SPACE)TR. E2128222930(OPEN SPACE)TRACT F(OPEN SPACE)TR. D214117151614423112464544(STORM/ OPEN SPACE)TRACT H(OPEN SPACE)TRACT G(OPEN SPACE)TRACT I(STORM/OPEN SPACE)TRACT A43X
X
X
X
X
X X
X
X X
X
X
X
X
X
X
X
X
X X X
X X X X
X X X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X X
X
X
STEEP SLOPE
AREA 436 SF
STEEP SLOPE AREA
9,997 SF
WETLAND A
TO BE FILLED
1,585 SF
APPROXIMATE
BOUNDARY OF
STREAM S
EX. DITCH
UTILITY EASEMENT
WETLAND B
CATEGORY IV
50' BUFFER
WETLAND C
CATEGORY IV
50' BUFFER
WETLAND D
CATEGORY IV
50' BUFFER
STREAM S
TYPE NP
75' BUFFER
APPROXIMATE
LOCATION OF
TRAIL IMPACT
APPROXIMATE LOCATION
OF TRAIL TO CONNECT TO
CITY OF NEWCASTLES TRAIL
ALONG NE 43RD ST RIGHT-OF-WAY
APPROXIMATE
LOCATION OF
STREAM CROSSING
UNOPENED
RIGHT-OF-WAY
OF 112TH AVE SE
PROPOSED TRAIL
1050495247485146X
X
X
X
X X X
X X X X
X X X
X
X
X
X
X
X
X
WETLAND CSTREAM S
STREAM S
BUFFER REDUCTION
2,635 SF
STREAM S
BUFFER ADDITION
2,695 SF52'15'97'BUFFER IMPACT
380 SF
BUFFER IMPACT
401 SF
BUFFER
ENHANCEMENT
AREA B
781 SF
Scale 1" = 60'
6030 90 1200
LEGEND
WETLAND ENHANCEMENT
BUFFER IMPACT
BUFFER ENHANCEMENT
BUFFER AVERAGING
(REDUCTION)
BUFFER AVERAGING
(ADDITION)
WETLAND PROPERTY BOUNDARY
STREAM
STANDARD BUFFER
75% OF STANDARD BUFFER
15' BUFFER STRUCTURE
SETBACK
APPROX . STREAM
BOUNDARY
FINAL BUFFER/PERMANENT
FENCE/SIGNSXXWETLAND IMPACT
RIGHT-OF-WAY
Scale 1" = 100'
10050 150 2000TED-40-4179R-417981
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DEVELOPMENT ENGINEERING
msippo 05/10/2022
R-417986
WRI PROJECT #18158Date: 7/14/2021SHEET 2/2FINAL MITIGATION PLAN - STREAM SCANOPY - LINCOLN PL NERENTON, WASHINGTONPREPARED FOR: Blue Fern Development, LLCAttn: Michelle Branley1414 Market St, #200Kirkland, WA 980039505 19TH AVE SE, SUITE 106EVERETT, WA 98208TEL: 425.337.3174FAX: 425.337.3045Drawn by: A. RichardsonPLANT INSTALLATION GUIDELINES
SHRUB PLANTING DETAIL
No Scale
Compacted topsoil
water thoroughly
Water basin with
3-4" of mulch
Prune diseased and
broken branches
Planting hole min .
twice size of root ball
TREE PLANTING DETAIL
No Scale
Prune diseased and
broken branches
Lath stakes driven
securely in to the ground
Water basin with 3-4" mulch
Unglazed planting pit surface
1/2 topsoil , 1/2 native soil,
water thoroughly, fertilize
Planting pit min .
twice size of root
ball
6" min .
FENCING & SIGNAGE
Per RMC 4-3-050(G)(3)(f)-(h) outlines fencing and signage requirements. Prior to
construction, the outer extent of the approved critical area buffer and areas not to be
disturbed shall be marked with high visibility orange construction fencing and silt
fencing. Subsequently, permanent fencing of the native growth protection area
containing critical area shall be installed, along with permanent signs (made of wood or
metal, adhered to treated or metal posts). Sign locations and size specifications shall
be approved by the city. RMC 4-3-050(G)(3)(h) recommends the following wording for
signs,
“Protection of this natural area is in your care. Alteration or
disturbance is prohibited by law.”
MAINTENANCE
The mitigation areas will require periodic maintenance to remove undesirable species
and replace vegetation mortality. Maintenance shall occur in accordance with the
approved plans. Chemical control, only if approved by City staff, shall be applied by a
licensed applicator following all label instructions.
Duration and Extent
In order to achieve performance standards, the permittee shall have the mitigation area
maintained for the duration of the five-year monitoring period. Maintenance will include:
watering, weeding around the base of installed plants, pruning, replacement,
re-staking, removal of all classes of noxious weeds (see Washington State Noxious
Weeds List, WAC 16-750-005) as well as Himalayan blackberry, and any other
measures needed to ensure plant survival. The landscape designer and/or wetland
professional shall direct all maintenance.
Survival
The permittee shall be responsible for the health of 100% of all newly installed plants
for one growing season after installation has been accepted by the City of Renton. A
growing season for these purposes is defined as occurring from spring to spring
(March 15 to March 15 of the following year). For fall installation (often required), the
growing season will begin the following spring. The permittee shall replace any plants
that are: failing, weak, defective in manner of growth, or dead during this growing
season, as directed by the landscape designer, wetland professional, and/or City of
Renton staff.
Installation Timing for Replacement Plants
Replacement plants shall be installed between September 15 and January 15, unless
otherwise determined by the landscape designer, wetland professional, and/or City of
Renton staff.
Standards for Replacement Plants
Replacement plants shall meet the same standards for size and type as those
specified for the original installation, unless otherwise directed by the landscape
designer, wetland professional, and/or City of Renton staff.
Replanting
Plants that have settled in their planting pits too deep, too shallow, loose, or crooked
shall be replanted as directed by the landscape designer, wetland professional, and/or
City of Renton staff.
Herbicides / Pesticides
In general, chemical controls shall not be used in the mitigation area, sensitive areas,
or their buffers. However, limited use of herbicides may be approved depending on
site-specific conditions, only if approved by City of Renton staff.
Irrigation / Watering
Water shall be provided during the dry season (July 1 through October 15) for the first
two years after installation to ensure plant survival and establishment. A temporary
above ground irrigation system shall be installed within the Stream S buffer
enhancement area and Wetland B buffer enhancement area to provide water. Water
shall be applied at a rate of 1” of water twice per week for year one and 1” per week
during year two. If the mitigation plantings meet 80 percent survival at the end of year
two, the system may be removed.
General
The permittee shall include in general maintenance activities the replacement of any
vandalized or damaged signs, habitat features, fences, or other structural components
of this mitigation site.
PLANTING NOTES
Plant in the early spring or late fall and obtain all plants from a reputable nursery. Care
and handling of all plant materials is extremely important to the overall success of the
project. The origin of all plant materials specified in this plan shall be native plants,
nursery grown in the Puget Sound region of Washington. Some limited species
substitution may be allowed, only with the agreement of the landscape designer,
wetland professional, and/or City staff.
Pre-Planting Meeting
Prior to control of invasive species or installation of mitigation plantings, a site meeting
between the contracted landscaper and the consulting wetland professional shall occur
to resolve any questions that may arise. During this meeting a discussion regarding
plant spacing and locations of plant species including wetland verses buffer species
shall occur between the landscape contractor and the consulting wetland professional.
Handling
Plants shall be handled so as to avoid all damage, including: breaking, bruising, root
damage, sunburn, drying, freezing or other injury. Plants must be covered during
transport. Plants shall not be bound with wire or rope in a manner that could damage
branches. Protect plant roots with shade and wet soil in the time period between
delivery and installation. Do not lift container stock by trunks, stems, or tops. Do not
remove from containers until ready to plant. Water all plants as necessary to keep
moisture levels appropriate to the species horticultural requirements. Plants shall not
be allowed to dry out. All plants shall be watered thoroughly immediately upon
installation. Soak all containerized plants thoroughly prior to installation.
PLANTING NOTES CONT'D
Storage
Plants stored by the Permittee for longer than one month prior to planting shall be
planted in nursery rows and treated in a manner suitable to those species’ horticultural
requirements. Plants must be re-inspected by the wetland professional and/or
landscape designer prior to installation.
Damaged plants
Damaged, dried out, or otherwise mishandled plants will be rejected at installation
inspection. All rejected plants shall be immediately removed from the site.
Plant Names
Plant names shall comply with those generally accepted in the native plant nursery
trade. Any question regarding plant species or variety shall be referred to the
landscape designer, wetland professional, or City staff. All plant materials shall be true
to species and variety and legibly tagged.
Quality and condition
Plants shall be normal in pattern of growth, healthy, well-branched, vigorous, with
well-developed root systems, and free of pests and diseases. Damaged, diseased,
pest-infested, scraped, bruised, dried out, burned, broken, or defective plants will be
rejected. Plants with pruning wounds over 1-inch in diameter will be rejected.
Roots
All plants shall be balled and burlapped (B &B) or containerized, unless explicitly
authorized by the landscape designer and/or wetland professional. Rootbound plants
or B&B plants with damaged, cracked, or loose rootballs (major damage) will be
rejected. Immediately before installation, plants with minor root damage (some broken
and/or twisted roots) must be root-pruned. Matted or circling roots of containerized
plantings must be pruned or straightened and the sides of the root ball must be
roughened from top to bottom to a depth of approximately half an inch in two to four
places. Bare root plantings of woody material are allowed only with permission from the
landscape designer, wetland professional and/or City staff.
Sizes
Plant sizes shall be the size indicated in the plant schedule in approved plans. Larger
stock may be acceptable provided that it has not been cut back to the size specified,
and that the root ball is proportionate to the size of the plant. Smaller stock may be
acceptable, and preferable under some circumstances, based on site-specific
conditions. Measurements, caliper, branching, and balling and burlapping shall conform
to the American Standard of Nursery Stock by the American Association of Nurserymen
(latest edition).
Form
Evergreen trees shall have single trunks and symmetrical, well-developed form.
Deciduous trees shall be single trunked unless specified as multi-stem in the plant
schedule. Shrubs shall have multiple stems and be well-branched.
Timing of Planting
Unless otherwise approved by City staff, all planting shall occur between November 1
and March 1. Overall, the earlier plants go into the ground during the dormant period,
the more time they have to adapt to the site and extend their root systems before the
water demands of spring and summer.
Weeding
Existing and exotic vegetation in the mitigation areas will be hand-weeded from around
all newly installed plants at the time of installation and on a routine basis throughout
the monitoring period. No chemical control of vegetation on any portion of the site is
recommended.
Site conditions
The contractor shall immediately notify the landscape designer and/or wetland
professional of drainage or soil conditions likely to be detrimental to the growth or
survival of plants. Planting operations shall not be conducted under the following
conditions: freezing weather, when the ground is frozen, excessively wet weather,
excessively windy weather, or in excessive heat.
Planting Pits
Planting pits shall be circular or square with vertical sides, and shall be 6” deeper and
12” larger in diameter than the root ball of the plant. Break up the sides of the pit in
compacted soils. Set plants upright in pits. Burlap shall be removed from the planting
pit. Backfill shall be worked back into holes such that air pockets are removed without
adversely compacting down soils.
Fertilizer
Slow release fertilizer may be used if pre-approved by City of Renton staff. Fertilizers
shall be applied only at the base of plantings underneath the required covering of
mulch (that does not make contact with stems of the plants). No soil amendment or
fertilizers will be placed in planting holes.
Staking
Most shrubs and many trees DO NOT require any staking. If the plant can stand alone
without staking in a moderate wind, do not use a stake. If the plant needs support, then
strapping or webbing should be used as low as possible on the trunk to loosely brace
the tree with two stakes. Do not brace the tree tightly or too high on the trunk. If the
tree is unable to sway, it will further lose the ability to support itself. Do not use wire in a
rubber hose for strapping as it exerts too much pressure on the bark. As soon as
supporting the plant becomes unnecessary, remove the stakes. All stakes must be
removed within two (2) years of installation.
Plant Location
Colored surveyors ribbon or other appropriate marking shall be attached to the
installed plants to assist in locating the plants while removing the competing non-native
vegetation and during the monitoring period.
Arrangement and Spacing
The plants shall be arranged in a pattern with the appropriate numbers, sizes, species,
and distribution that are required in accordance with the approved plans. The actual
placement of individual plants shall mimic natural, asymmetric vegetation patterns
found on similar undisturbed sites in the area. Spacing of the plantings may be
adjusted to maintain existing vegetation with the agreement of the landscape designer,
wetland professional, and/or City staff.
Inspection(s)
A wetland professional shall be present on site to inspect the plants prior to planting.
Minor adjustments to the original design may be required prior to and during
construction.
Woodchip Mulch
All landscaped areas denuded of vegetation and soil surface surrounding all planting
pit areas shall receive no less than 2 to 4 inches of certified woodchip mulch after
planting. A layer of woodchip mulch will be placed around the base of each plant in a
3-foot radius and at a depth of 2 to 4 inches. The woodchip mulch shall not be allowed
to contact plant stems in order to avoid plant decay and rot.
SPLIT RAIL FENCE
NOTES:
1. Sign placement shall be subject to the approval of the
City of Renton. Alternative sign designs may be submitted
to the City of Renton for approval.
3. All signs must be secure and permanent.
CRITICAL AREA PROTECTION AREA
SIGN INSTALLATION GUIDELINES
NOT TO SCALE
CRITICAL AREA
PROTECTION AREA
12"x 18" Aluminum sign with white
reflective background.
Install one per protected feature
in a conspicuous place .
Minimum of two galvanized or stainless
steel wood lag bolts to firmly secure sign.5 ft.
2 ft.
min.
4' X 4' pressure treated wooden
post with 1/2" chamfer at top.
Magnetic locator pin (e.g., pipe, rebar,
20 penny nail, etc.) placed 8-12" from
post along CAPA line.
Quick-set concrete
Compacted native material6"
THIS AREA IS PROTECTED
TO PROVIDE WILDLIFE HABITAT
AND MAINTAIN CRITICAL
AREA(S) FUNCTIONS/VALUES .
PROTECTION OF THIS
NATURAL AREA IS IN YOUR CARE.
ALTERATION OR
DISTURBANCE IS PROHIBITED
BY LAW
STREAM S BUFFER ENHANCEMENT PLAN
If soils associated with the old road grade are compacted, site preparation including soil
decompaction and amendment will occur prior to planting. If necessary, soils will be
decompacted and 3 inches of premium topsoil shall be tilled into the top 6 inches of
existing soil. The topsoil amendment shall have at least 15 percent organic content.
Prior to planting, invasive woody species including (but not limited to) Himalayan
blackberry (Rubus armeniacus) will be removed from the buffer enhancement area. Any
existing native plants within the buffer shall be retained and protected. The following
native trees and shrubs will be planted in the buffer enhancement area and any
disturbed areas will be seeded with the buffer grass seed mix specified below:
TYPICAL LARGE WOODY DEBRIS PLACEMENT
NOTES:
1) LOGS TO BE AT LEAST 10" IN DIAMETER, AND ≥ 8' LENGTH
CONIFER SPECIES (CEDAR, HEMLOCK, FIR).
2) PLACEMENT OF HABITAT LOGS TO BE DETERMINED IN THE FIELD.
NOTES:
1) LOGS TO BE A MINIMUM OF 4" IN DIAMETER AND MINIMUM 15' LENGTH
2) EACH CLUSTER SHALL INCLUDE 2-3 LOGS OF DIFFERING DIAMETERS
3) LOGS WITH ROOTWADS SHALL BE SET IN A SLIGHT DEPRESSION
WITHIN BUFFER ENHANCEMENT AREAS
CEDAR, HEMLOCK, OR FIR
WITH INTACT ROOTWAD,
BURIED ≥2/3 LENGTH
INTO STREAMBED
LWD CROSS-SECTION
No Scale
STREAM BED
ROOTWAD IN CONTACT
WITH STREAM,
FACING UPSTREAM
IN-STREAM
LARGE WOODY DEBRIS
In addition to the enhancement plantings, any trees measuring four or more inches in
diameter that are removed within 200-feet of Stream S, during the clearing and grading
process, will be added to the Stream S buffer enhancement area. A minimum of one (1)
piece of large woody debris (LWD) will be placed within the stream channel. Minimum
size of this LWD will be 10-inch diameter and at least 8-feet in length. This LWD should
be an evergreen species preferably cedar, hemlock, or fir, as they have relatively
slower decay rates than deciduous species and have complex root systems.
In-channel LWD shall be buried with a minimum of two-thirds of its length into the
graded stream bank at an approximate 60-degree angle with its root-wad in contact
with the stream and facing upstream.
TWO-LOG FEATURE DETAIL
No Scale
THREE-LOG FEATURE DETAIL
No ScaleTED-40-4179R-417982
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DEVELOPMENT ENGINEERING
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R-417987
37.5' 15'
37 .5'50'Scale 1" = 100'
10050 150 2000 WRI PROJECT #18158Date: 7/14/2021SHEET 1/2FINAL MITIGATION PLAN - WETLANDS B AND DCANOPY - LINCOLN PL NERENTON, WASHINGTONPREPARED FOR: Blue Fern Development, LLCAttn: Michelle Branley1414 Market St, #200Kirkland, WA 980039505 19TH AVE SE, SUITE 106EVERETT, WA 98208TEL: 425.337.3174FAX: 425.337.3045Drawn by: A. RichardsonINTRODUCTION
The subject property is composed of five King County tax parcels (3345700015,
3345700016, 3345700017, 3345700018, 3345700020). The site is approximately
10.1-acres, located at and adjacent to 8314 110th Pl SE and 4130 Lincoln Ave NE in
the City of Renton, Washington (Section 32, Township 24N, Range 5E, W.M.). Access
is via a driveway from Lincoln Ave NE.
SITE DESCRIPTION
The subject property is located within the May Creek sub-basin of the Cedar
River/Lake Washington Watershed (WRIA 8). Lake Washington is approximately 3,000
feet west of the subject property. Surrounding land use is mixed, including residential,
commercial, and industrial uses; with I-405 approximately 1,100 feet to the west. The
site is partially developed; in the south, there are multiple single-family residences and
associated infrastructure, while the northern portion contains naturally vegetated
pasture and forested areas. Topography slopes steeply to the west, and, according to
King County iMap, is underlain by high erosion hazard areas, with slopes in excess of
20 percent.
Four wetlands (Wetlands A through D) and one stream (Stream S) were identified
within the investigation area.
Pursuant to Renton Municipal Code (RMC), on-site wetlands were classified under the
Washington State Wetland Rating System for Western Washington: 2014 Update
(Hruby 2014). Wetlands A through D are classified as Category IV wetlands. Per RMC
(7)(a) Stream S was classified based on the WAC 222-16-030. As such, Stream S is
classified as a Type Np Stream. Per 4-3-050(G)(2), Category IV wetlands typically
receive 50-foot buffers (when adjacent to non-low impact land uses) and Type Np
streams typically receive 75-foot buffers.
In addition, geological hazards were identified on-site by the geotechnical engineer,
Terra Associates, Inc. Geological hazards identified include protected slopes, high
erosion hazard area, and low seismic hazard area. Per RMC 4-3-050G(2), protected
slopes require a 15 foot structure setback.
PROJECT MONITORING PROGRAM
Requirements for monitoring project:
1. Initial compliance/as-built report
2. Site inspection (twice per year) for five years
3. Annual reports (one report submitted during each monitored year)
Purpose for Monitoring
The purpose for monitoring this mitigation project shall be to evaluate its success.
Success will be determined if monitoring shows at the end of five years that the
definitions of success stated below are met. The property owner shall grant access to
the mitigation area for inspection and maintenance to the contracted landscape and/or
wetland specialist and City of Renton during the monitoring period or until the project is
evaluated as successful.
Monitoring
Monitoring shall be conducted twice annually for five years in accordance with the
approved Mitigation Plan. The monitoring period will begin once the City receives
written notification confirming the mitigation plan has been implemented and City staff
inspects the site and issues approval of the installation.
Vegetation Monitoring
Sampling points or transects will be established for vegetation monitoring and photo
points will be established from which photos will be taken throughout the monitoring
period. Permanent sampling points must be identified on the mitigation site plans in the
first monitoring report (they may be drawn on approved plans by hand). Each sampling
point shall detail herbaceous, shrub, and tree coverage. Monitoring of vegetation
sampling points shall occur once per monitored year.
Wetland Hydrology Monitoring
To ensure that wetland hydrology is not impacted by the development, the wetland
boundaries will be reviewed during the spring monitoring visit of each monitored year. If
it appears that any existing wetland areas are no longer saturated or inundated for
sufficient duration to support wetland conditions, those areas will be demarcated in the
field and depicted on a map. Additional mitigation may need to be provided, as
described in the contingency plan in Section 15, below.
Photo points
No less than four permanent photo points will be established within the mitigation
areas. Photographs will be taken from these points to visually record condition of the
mitigation areas. Photos shall be taken annually between May 15 and September 30
(prior to leaf drop), unless otherwise specified.
PROJECT NOTES
Pre-Construction Meeting
Mitigation projects are typically more complex to install than to describe in plans.
Careful monitoring by a wetland professional for all portions of this project is strongly
recommended. Construction timing and sequencing is important to the success of this
type of project. There will be a pre-construction meeting on this site between the
Permittee, the consulting wetland professional, and laborers. The objective will be to
verify the location of erosion control facilities, verify the location of mitigation areas, and
to discuss project sequencing.
Inspections
A wetland professional shall be contracted to periodically inspect the mitigation
installation described in this plan. Minor adjustments to the original design may be
necessary prior to and during construction due to unusual or hidden site conditions. A
City of Renton representative and/or the consulting professional will make these
decisions during construction.
CONTINGENCY PLAN
If 20% of the plants are severely stressed during any of the inspections, or it appears
20 percent may not survive, additional plantings of the same species may be added to
the planting area. Elements of a contingency plan may include, but will not be limited
to: more aggressive weed control, pest control, mulching, replanting with larger plant
material, species substitution, fertilization, soil amendments, and/or irrigation.
S
D
SDSD
SD
SDSD
SDSDSD 1098111345637545355504956(OPEN SPACE)TRACT B35363240333837393452474851(OPEN SPACE)TRACT Q2324251826192720(OPEN SPACE)TR. E2128222930(OPEN SPACE)TRACT F(OPEN SPACE)TR. D214117151614423112464544(STORM/ OPEN SPACE)TRACT H(OPEN SPACE)TRACT G(OPEN SPACE)TRACT I(STORM/OPEN SPACE)TRACT A43X
X
X
X
X
X X
X
X X
X
X
X
X
X
X
X
X
X X X
X X X X
X X X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X X
X
X
STEEP SLOPE
AREA 436 SF
STEEP SLOPE AREA
9,997 SF
WETLAND A
TO BE FILLED
1,585 SF
APPROXIMATE
BOUNDARY OF
STREAM S
EX. DITCH
INSET 2 SHT 2:
UTILITY EASEMENT
WETLAND B
CATEGORY IV
50' BUFFER
WETLAND C
CATEGORY IV
50' BUFFER
WETLAND D
CATEGORY IV
50' BUFFER
STREAM S
TYPE NP
75' BUFFER
APPROXIMATE
LOCATION OF
TRAIL IMPACT
APPROXIMATE LOCATION
OF TRAIL TO CONNECT TO
CITY OF NEWCASTLES TRAIL
ALONG NE 43RD ST RIGHT-OF-WAY
APPROXIMATE
LOCATION OF
STREAM CROSSING
UNOPENED
RIGHT-OF-WAY
OF 112TH AVE SE
PROPOSED TRAIL
SDSD
SD 67(OPEN SPACE)TRACT QX
X
X
X
X
X X
X
X X
X
X
X
X474246454443 X
X
X
X
X
X
X
X
X
X
X
X
X
X X
WETLAND D
TO BE ENHANCED
3,100 SF
BUFFER REDUCTION
2,095 SF
BUFFER ADDITION
645 SF
BUFFER ADDITION
1,660 SF
WETLAND B
TO BE ENHANCED
1,765 SF
BUFFER REDUCTION
1,032 SF
BUFFER ADDITION
1,092 SF
BUFFER IMPACT
240 SF
BUFFER
ENHANCEMENT
700 SF
15'
BUFFER
ENHANCEMENT
1,356 SF
WETLAND IMPACT
134 SF
BUFFER IMPACT
274 SF
BUFFER IMPACT
680 SF
TWO-LOG FEATURE DETAIL
No Scale
THREE-LOG FEATURE DETAIL
No Scale
TYPICAL LARGE WOODY DEBRIS PLACEMENT
NOTES:
1) LOGS TO BE A MINIMUM OF 10" IN DIAMETER AND MINIMUM 15' LENGTH
2) EACH CLUSTER SHALL INCLUDE 2-3 LOGS OF DIFFERING DIAMETERS
3) LOGS WITH ROOTWADS SHALL BE SET IN A SLIGHT DEPRESSION
LARGE WOODY DEBRIS
In addition to the enhancement plantings, a minimum of two (2) pieces of woody debris
(per wetland) will be added to Wetlands B and D. If possible, material removed from
the site for development will be salvaged for use as woody debris within the buffer
enhancement area. Woody debris shall consist of coniferous logs or root wads.
Minimum size of the woody debris will be 10-inch diameter and 15 feet in length, or
10-foot diameter root-wads.
LEGEND
WETLAND ENHANCEMENT
BUFFER IMPACT
BUFFER ENHANCEMENT
BUFFER AVERAGING
(REDUCTION)
BUFFER AVERAGING
(ADDITION)
WETLAND PROPERTY BOUNDARY
STREAM
STANDARD BUFFER
75% OF STANDARD BUFFER
15' BUFFER STRUCTURE
SETBACK
APPROX . STREAM
BOUNDARY
FINAL BUFFER/PERMANENT
FENCE/SIGNSXXWETLAND IMPACT
RIGHT-OF-WAY
Scale 1" = 40'
4020 60 800
Scale 1" = 40'
4020 60 800
PROJECT DESCRIPTION
The applicant is proposing to develop a 56-lot residential development and associated
infrastructure. To accommodate this development, the applicant will do a combination of
buffer width averaging and wetland/buffer impacts, to be mitigated for on-site. As a result
of required frontage improvements and stormwater infrastructure, the applicant will
permanently impact the entirety of Wetland A (and a portion of an associated ditch),
totaling 1,585 square feet, and a small portion (240 square feet) of Wetland B’s buffer. In
addition, the applicant will utilize buffer averaging to accommodate the proposed
development adjacent to Wetland B, Wetland D, and Stream S.
As mitigation for the impacts, the applicant is proposing a combination of on-site and
off-site mitigation. A portion of the compensation (meeting City of Renton requirements)
for Wetland A impacts will be provided by enhancing the entirety of the on-site portions
of Wetlands B and D (totaling 4,865 square feet). This exceeds the 3:1 (enhancement to
impact) ratio for Category IV wetlands, per RMC 4-3-050(J)(4)(c).
The aforementioned impact to the buffer of Wetland B will be mitigated for via
enhancement of 700 square feet of buffer located between Wetland B and Lincoln Ave
NE (exceeding the 1:1 mitigation to impact ratio required by RMC 4-3-050(J)(4)(d)). To
accommodate Stream S buffer width averaging, the applicant proposes to enhance a
6,788 square feet of stream buffer, per RMC 4-3-050(I)(2)(b)(v).
As part of the proposed development the City of Renton is requiring an on-site and
off-site trail to connect the development to the City of Newcastle’s pedestrian trail
located along the NE 43rd Street right-of-way, north of the subject property. The off-site
portion of the trail will be located within the unopened right-of-way of 112th Avenue SE,
that parallels the eastern property boundary. The trail shall be 5 feet wide, with the
majority consisting of wood chips underlain with filter fabric, and will be field fit to avoid
trees. The trail will cross portions of wetland, stream, and buffer. Per RMC 4-3-050C(3)
and RMC 4-3-050C(4), trails are exempt and allowed within critical areas and their
associated buffers as long as they meet certain requirements. The portion of trail
crossing the wetland will consist of a boardwalk and supported by pin piles. The slatted
decking of the boardwalk and grated top of the dock will allow precipitation to move
through the structure. This design minimizes impacts to the wetland and aquatic area
and avoids any fill or grading within the wetland. Disturbance within the wetland will be
limited to vegetation impacted for boardwalk installation. This portion of the trail will
impact approximately 134 square feet of vegetation associated with Wetland D. To
mitigate for any temporal loss of vegetation from installation of the boardwalk, buffer
enhancement of a portion of Wetland D’s on-site buffer is proposed at a 3:1
enhancement to impact ratio. The bridge proposed over Stream S will be approximately
6 feet wide and will consist of concrete slabs and metal railings. The crossing will be
consistent with WDFW stream crossing guidelines.
MONITORING REPORT CONTENTS
Monitoring reports shall be submitted by December 31 of each year during the
monitoring period. As applicable, monitoring reports must include descriptions / data
for:
PROJECT SUCCESS & COMPLIANCE
Criteria for Success
Upon completion of the proposed mitigation project, an inspection by a qualified
biologist will be made to determine plan compliance. A compliance report will be
supplied to the City of Renton within 30 days after the completion of planting. A
landscape professional or wetland professional will perform condition monitoring of the
plantings in the spring and fall of each monitored year. A written report describing the
monitoring results will be submitted to the City after each site inspection of each
monitored year. Final inspection will occur five years after completion of this project.
The contracted consultant will prepare a report as to the success of the project.
Definition of Success
The planting areas shall meet the following performance standards:
*Volunteering native species may be included in the aerial cover calculations.
The species mix should resemble that proposed in the planting plans, but strict
adherence to obtaining all of the species shall not be a criterion for success.
a) End of Year 1
• 100 percent survival of newly planted species and
• Less than 10 percent cover of weedy/invasive species
b) End of Year 2
• 80 percent survival of newly planted species
• Less than 10 percent cover of weedy/invasive species
c) End of Year 3
• At least 50 percent native vegetation coverage within the mitigation areas*
• Less than 10 percent cover of weedy/invasive species
d) End of Year 5
• At least 80 percent aerial cover of native woody plant species*,
• Less than 10 percent cover of weedy/invasive species.
1. Site plan and vicinity map
2. Historic description of project, including date of installation, current year of
monitoring, restatement of mitigation/restoration goals, and performance
standards
3. Plant survival, vigor, and areal coverage for every plant community (transect
or sampling point data), and explanation of monitoring methodology in the context
of assessing performance standards
4. Wetland and buffer conditions, e.g., surrounding land use, use by humans,
and/or wild and domestic creatures
5. Observed wildlife, including amphibians, avians, and others
6. Assessment of nuisance / exotic biota and recommendations for management
7. Color photographs taken from permanent photo-points that shall be depicted
on the monitoring report mapTED-40-4179R-417983
100 of 107
DEVELOPMENT ENGINEERING
msippo 05/10/2022 R-417988
WRI PROJECT #18158Date: 7/14/2021SHEET 2/2FINAL MITIGATION PLAN - WETLANDS B AND DCANOPY - LINCOLN PL NERENTON, WASHINGTONPREPARED FOR: Blue Fern Development, LLCAttn: Michelle Branley1414 Market St, #200Kirkland, WA 980039505 19TH AVE SE, SUITE 106EVERETT, WA 98208TEL: 425.337.3174FAX: 425.337.3045Drawn by: A. RichardsonPLANT INSTALLATION GUIDELINES
SHRUB PLANTING DETAIL
No Scale
Compacted topsoil
water thoroughly
Water basin with
3-4" of mulch
Prune diseased and
broken branches
Planting hole min .
twice size of root ball
TREE PLANTING DETAIL
No Scale
Prune diseased and
broken branches
Lath stakes driven
securely in to the ground
Water basin with 3-4" mulch
Unglazed planting pit surface
1/2 topsoil , 1/2 native soil,
water thoroughly, fertilize
Planting pit min .
twice size of root
ball
6" min .
SPLIT RAIL FENCE
FENCING & SIGNAGE
Per RMC 4-3-050(G)(3)(f)-(h) outlines fencing and signage requirements .
Prior to construction , the outer extent of the approved critical area buffer
and areas not to be disturbed shall be marked with high visibility orange
construction fencing and silt fencing. Subsequently, permanent fencing of
the native growth protection area containing critical area shall be installed,
along with permanent signs (made of wood or metal, adhered to treated or
metal posts). Sign locations and size specifications shall be approved by
the city. RMC 4-3-050(G)(3)(h) recommends the following wording for
signs,
“Protection of this natural area is in your care.
Alteration or disturbance is prohibited by law.”
PLANTING NOTES CONT'D
Arrangement and Spacing
The plants shall be arranged in a pattern with the appropriate numbers, sizes, species,
and distribution that are required in accordance with the approved plans. The actual
placement of individual plants shall mimic natural, asymmetric vegetation patterns
found on similar undisturbed sites in the area. Spacing of the plantings may be
adjusted to maintain existing vegetation with the agreement of the landscape designer,
wetland professional, and/or City staff.
Inspection(s)
A wetland professional shall be present on site to inspect the plants prior to planting.
Minor adjustments to the original design may be required prior to and during
construction.
Woodchip Mulch
All landscaped areas denuded of vegetation and soil surface surrounding all planting
pit areas shall receive no less than 2 to 4 inches of certified woodchip mulch after
planting. A layer of woodchip mulch will be placed around the base of each plant in a
3-foot radius and at a depth of 2 to 4 inches. The woodchip mulch shall not be allowed
to contact plant stems in order to avoid plant decay and rot.
PLANTING NOTES
Plant in the early spring or late fall and obtain all plants from a reputable nursery. Care
and handling of all plant materials is extremely important to the overall success of the
project. The origin of all plant materials specified in this plan shall be native plants,
nursery grown in the Puget Sound region of Washington. Some limited species
substitution may be allowed, only with the agreement of the landscape designer,
wetland professional, and/or City staff.
Pre-Planting Meeting
Prior to control of invasive species or installation of mitigation plantings, a site meeting
between the contracted landscaper and the consulting wetland professional shall occur
to resolve any questions that may arise. During this meeting a discussion regarding
plant spacing and locations of plant species including wetland verses buffer species
shall occur between the landscape contractor and the consulting wetland professional.
Handling
Plants shall be handled so as to avoid all damage, including: breaking, bruising, root
damage, sunburn, drying, freezing or other injury. Plants must be covered during
transport. Plants shall not be bound with wire or rope in a manner that could damage
branches. Protect plant roots with shade and wet soil in the time period between
delivery and installation. Do not lift container stock by trunks, stems, or tops. Do not
remove from containers until ready to plant. Water all plants as necessary to keep
moisture levels appropriate to the species horticultural requirements. Plants shall not
be allowed to dry out. All plants shall be watered thoroughly immediately upon
installation. Soak all containerized plants thoroughly prior to installation.
Storage
Plants stored by the Permittee for longer than one month prior to planting shall be
planted in nursery rows and treated in a manner suitable to those species’ horticultural
requirements. Plants must be re-inspected by the wetland professional and/or
landscape designer prior to installation.
Damaged plants
Damaged, dried out, or otherwise mishandled plants will be rejected at installation
inspection. All rejected plants shall be immediately removed from the site.
Plant Names
Plant names shall comply with those generally accepted in the native plant nursery
trade. Any question regarding plant species or variety shall be referred to the
landscape designer, wetland professional, or City staff. All plant materials shall be true
to species and variety and legibly tagged.
Quality and condition
Plants shall be normal in pattern of growth, healthy, well-branched, vigorous, with
well-developed root systems, and free of pests and diseases. Damaged, diseased,
pest-infested, scraped, bruised, dried out, burned, broken, or defective plants will be
rejected. Plants with pruning wounds over 1-inch in diameter will be rejected.
Roots
All plants shall be balled and burlapped (B &B) or containerized, unless explicitly
authorized by the landscape designer and/or wetland professional. Rootbound plants
or B&B plants with damaged, cracked, or loose rootballs (major damage) will be
rejected. Immediately before installation, plants with minor root damage (some broken
and/or twisted roots) must be root-pruned. Matted or circling roots of containerized
plantings must be pruned or straightened and the sides of the root ball must be
roughened from top to bottom to a depth of approximately half an inch in two to four
places. Bare root plantings of woody material are allowed only with permission from the
landscape designer, wetland professional and/or City staff.
Sizes
Plant sizes shall be the size indicated in the plant schedule in approved plans. Larger
stock may be acceptable provided that it has not been cut back to the size specified,
and that the root ball is proportionate to the size of the plant. Smaller stock may be
acceptable, and preferable under some circumstances, based on site-specific
conditions. Measurements, caliper, branching, and balling and burlapping shall conform
to the American Standard of Nursery Stock by the American Association of Nurserymen
(latest edition).
Form
Evergreen trees shall have single trunks and symmetrical, well-developed form.
Deciduous trees shall be single trunked unless specified as multi-stem in the plant
schedule. Shrubs shall have multiple stems and be well-branched.
Timing of Planting
Unless otherwise approved by City staff, all planting shall occur between November 1
and March 1. Overall, the earlier plants go into the ground during the dormant period,
the more time they have to adapt to the site and extend their root systems before the
water demands of spring and summer.
Weeding
Existing and exotic vegetation in the mitigation areas will be hand-weeded from around
all newly installed plants at the time of installation and on a routine basis throughout
the monitoring period. No chemical control of vegetation on any portion of the site is
recommended.
Site conditions
The contractor shall immediately notify the landscape designer and/or wetland
professional of drainage or soil conditions likely to be detrimental to the growth or
survival of plants. Planting operations shall not be conducted under the following
conditions: freezing weather, when the ground is frozen, excessively wet weather,
excessively windy weather, or in excessive heat.
Planting Pits
Planting pits shall be circular or square with vertical sides, and shall be 6” deeper and
12” larger in diameter than the root ball of the plant. Break up the sides of the pit in
compacted soils. Set plants upright in pits. Burlap shall be removed from the planting
pit. Backfill shall be worked back into holes such that air pockets are removed without
adversely compacting down soils.
Fertilizer
Slow release fertilizer may be used if pre-approved by City of Renton staff. Fertilizers
shall be applied only at the base of plantings underneath the required covering of
mulch (that does not make contact with stems of the plants). No soil amendment or
fertilizers will be placed in planting holes.
Staking
Most shrubs and many trees DO NOT require any staking. If the plant can stand alone
without staking in a moderate wind, do not use a stake. If the plant needs support, then
strapping or webbing should be used as low as possible on the trunk to loosely brace
the tree with two stakes. Do not brace the tree tightly or too high on the trunk. If the
tree is unable to sway, it will further lose the ability to support itself. Do not use wire in a
rubber hose for strapping as it exerts too much pressure on the bark. As soon as
supporting the plant becomes unnecessary, remove the stakes. All stakes must be
removed within two (2) years of installation.
Plant Location
Colored surveyors ribbon or other appropriate marking shall be attached to the
installed plants to assist in locating the plants while removing the competing non-native
vegetation and during the monitoring period.
MAINTENANCE
The mitigation areas will require periodic maintenance to remove undesirable species
and replace vegetation mortality. Maintenance shall occur in accordance with the
approved plans. Chemical control, only if approved by City staff, shall be applied by a
licensed applicator following all label instructions.
Duration and Extent
In order to achieve performance standards, the permittee shall have the mitigation area
maintained for the duration of the five-year monitoring period. Maintenance will include:
watering, weeding around the base of installed plants, pruning, replacement,
re-staking, removal of all classes of noxious weeds (see Washington State Noxious
Weeds List, WAC 16-750-005) as well as Himalayan blackberry, and any other
measures needed to ensure plant survival. The landscape designer and/or wetland
professional shall direct all maintenance.
Survival
The permittee shall be responsible for the health of 100% of all newly installed plants
for one growing season after installation has been accepted by the City of Renton. A
growing season for these purposes is defined as occurring from spring to spring
(March 15 to March 15 of the following year). For fall installation (often required), the
growing season will begin the following spring. The permittee shall replace any plants
that are: failing, weak, defective in manner of growth, or dead during this growing
season, as directed by the landscape designer, wetland professional, and/or City of
Renton staff.
Installation Timing for Replacement Plants
Replacement plants shall be installed between September 15 and January 15, unless
otherwise determined by the landscape designer, wetland professional, and/or City of
Renton staff.
Standards for Replacement Plants
Replacement plants shall meet the same standards for size and type as those
specified for the original installation, unless otherwise directed by the landscape
designer, wetland professional, and/or City of Renton staff.
Replanting
Plants that have settled in their planting pits too deep, too shallow, loose, or crooked
shall be replanted as directed by the landscape designer, wetland professional, and/or
City of Renton staff.
Herbicides / Pesticides
In general, chemical controls shall not be used in the mitigation area, sensitive areas,
or their buffers. However, limited use of herbicides may be approved depending on
site-specific conditions, only if approved by City of Renton staff.
Irrigation / Watering
Water shall be provided during the dry season (July 1 through October 15) for the first
two years after installation to ensure plant survival and establishment. A temporary
above ground irrigation system shall be installed within the Stream S buffer
enhancement area and Wetland B buffer enhancement area to provide water. Water
shall be applied at a rate of 1” of water twice per week for year one and 1” per week
during year two. If the mitigation plantings meet 80 percent survival at the end of year
two, the system may be removed.
General
The permittee shall include in general maintenance activities the replacement of any
vandalized or damaged signs, habitat features, fences, or other structural components
of this mitigation site.
NOTES:
1. Sign placement shall be subject to the approval of the
City of Renton. Alternative sign designs may be submitted
to the City of Renton for approval.
3. All signs must be secure and permanent.
CRITICAL AREA PROTECTION AREA
SIGN INSTALLATION GUIDELINES
NOT TO SCALE
CRITICAL AREA
PROTECTION AREA
12"x 18" Aluminum sign with white
reflective background.
Install one per protected feature
in a conspicuous place .
Minimum of two galvanized or stainless
steel wood lag bolts to firmly secure sign.5 ft.
2 ft.
min.
4' X 4' pressure treated wooden
post with 1/2" chamfer at top.
Magnetic locator pin (e.g., pipe, rebar,
20 penny nail, etc.) placed 8-12" from
post along CAPA line.
Quick-set concrete
Compacted native material6"
THIS AREA IS PROTECTED
TO PROVIDE WILDLIFE HABITAT
AND MAINTAIN CRITICAL
AREA(S) FUNCTIONS/VALUES .
PROTECTION OF THIS
NATURAL AREA IS IN YOUR CARE.
ALTERATION OR
DISTURBANCE IS PROHIBITED
BY LAW
MITIGATION PLAN
Wetland Enhancement
Due to required frontage improvements and stormwater infrastructure, the applicant is
proposing to fill the entirety of Wetland A (1,585 square feet). Mitigation for the fill of
Wetland A will be provided through on-site wetland enhancement of Wetlands B and D,
totaling 4,865 square feet. The proposed wetland enhancement plantings and large
woody debris will increase diversity and density of native plants within Wetlands B and
D, while providing increased opportunities for wildlife habitat.
Wetland B Enhancement Plan
Prior to planting, invasive woody species including (but not limited to) Himalayan
blackberry (Rubus armeniacus), English holly (Ilex aquifolium), and English ivy (Hedera
helix) will be removed from the wetland. Any existing native plants within the wetlands
shall be retained and protected. Only shrubs will be planted within Wetland B, as a
dense native overstory and moderate native understory currently exist. In order to
provide dense vegetative cover to compete with potentially encroaching Himalayan
blackberry (Rubus armeniacus), spacing of shrubs is at 5 feet on-center. This will allow
the thicket forming species (twinberry, rose, and salmonberry) to outcompete
non-native species.
Wetland D Enhancement Plan
Prior to planting, invasive woody species including (but not limited to) Himalayan
blackberry (Rubus armeniacus) will be removed from the wetland. Any existing native
plants within the wetlands shall be retained and protected. In order to provide dense
vegetative cover to compete with potentially encroaching Himalayan blackberry (Rubus
armeniacus), spacing trees at 10 feet on-center and shrubs at 5 feet on-center. This
will allow the thicket forming species (twinberry, rose, and salmonberry) to outcompete
non-native species.
Buffer Enhancement
To compensate for minor impacts (240 square feet) to the buffer of Wetland B
associated with frontage improvements, a total of 700 square feet of buffer located
between Lincoln Ave NE and Wetland B will be enhanced with a variety of native
vegetation and large woody debris.
To compensate for minor impacts to Wetland D (134 square feet) and Wetland D’s
buffer (954 square feet) for installation of the pedestrian trail, a total of 1,536 square
feet of buffer will be enhanced. The proposed buffer enhancement plantings and large
woody debris will increase diversity and density of native plants within Wetlands B and
D, while providing increased opportunities for wildlife habitat.
Wetland B Buffer Enhancement
Prior to planting, invasive woody species including (but not limited to) Himalayan
blackberry (Rubus armeniacus) and English holly (Ilex aquifolium) will be removed from
the buffer enhancement area. Any existing native plants within the buffer shall be
retained and protected. As the overstory of Wetland B and surrounding buffer is dense
with red alder and black cottonwood, a variety of native shrubs and herbaceous
species will be planted in the understory. The following native shrubs and groundcover
will be planted in the buffer enhancement area:
Wetland D Buffer Enhancement
Prior to planting, invasive woody species including (but not limited to) Himalayan
blackberry (Rubus armeniacus) and English holly (Ilex aquifolium) will be removed from
the buffer enhancement area. Any existing native plants within the buffer shall be
retained and protected. The following native trees, shrubs, and groundcover will be
planted in the buffer enhancement area and any disturbed areas will be seeded with
the buffer grass seed mix specified below:
Any disturbed areas within the buffer enhancement areas will be seeded with the buffer
grass seed mix specified below:TED-40-4179R-417984
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DEVELOPMENT ENGINEERING
msippo 05/10/2022
R-417989