4824 stream reconnaissance.doc.pdfAltmann Oliver Associates, LLc AOA
PO Box 578 Carnation, WA 98014 Office (425) 333-4535 Fax (425) 33"509 Environmentai
Planning &
Landscape
Architecture
September 11, 2019
AOA-4824
Kernen Lien, Environmental Programs Manager
City of Edmonds
Development Services Department
Via email: kernen. lien A edmondswa.3zov
SUBJECT: Stream Buffer Enhancement — Critical Areas Report
718 Hindley Lane, Edmonds, WA
Parcel 27032400213300
Dear Kernen:
The purpose of this letter is to respond to the City's request for an environmental analysis
of the landscape work that was completed in the buffer of Hindley Creek on the above -
referenced site and the potential for approval of sediment dredging of the pond. We
conducted a site review on 5/24/19 to evaluate the landscape work and to determine if
any restoration would be necessary. We met again with Jamie Bails of WDFW on 7/1/19
to come up with a plan for potential dredging of the pond in addition to the restoration
plantings required of the City.
1.0 PROJECT SUMMARY
Hindley Creek flows from east to west through the southern portion of the site. Hindley
Creek is a tributary to Shell Creek. A large concrete dam is located in the central portion
of Hindley Creek on the property and creates an effective barrier to any upstream fish
migration.
Hindley Creek has been identified as a known anadromous fish -bearing stream by the
City of Edmonds and therefore meets the criteria for a Type F stream per EMC
23.90.010A.I.b. The reach of Hindley Creek located below the dam is presumed to have
anadromous fish access and therefore requires a standard 100-foot buffer from the stream
edge per EMC 23.90.040.D.I.b. The reach of Hindley Creek located above the dam is
inaccessible to anadromous fish and therefore requires a standard 75-foot buffer per EMC
23.90.040.D.I.c.
The on -site portion of Hindley Creek located above the dam consists primarily of a small
pond filled to within 24" of the surface with fine sediments, with a defined stream
channel north and upstream of the pond. There are a few scattered large trees located
amongst the lawn and planting beds on both sides of the pond and creek.
Kernen Lien
September 11, 2019
Page 2
The stream channel below the dam is well-defined and flows through a riparian corridor
that consists of a maintained yard area and scattered western red cedar (Thuja pficata)
trees and various ornamental plantings.
From our previous site review back in March of 2015 as part of the building permit for
the remodel of the house, it is apparent that the old lawn area located west of the pond
and creek was replaced with sod lawn and a small cobble swale to direct road drainage
from the driveway into the pond. Additionally, some ivy and other invasive plants were
removed from the cedar area located below the dam and planted with sword fern. This
was corroborated by the new owner, Don Ross.
All the stream buffers on the project site have been historically landscaped and not in
native condition. A side channel of the stream above the dam was filled due to debris
accumulation. During our onsite meeting on 7/1/19 it was decided that the stream should
remain as is and enhancement should occur along the OHWL to add more shade to the
creek. Additionally, we discussed excavating the sediments in the pond to allow for more
sediment storage during high flow events. The attached plan depicts restoration plantings
along the perimeter of the OHWL in addition to temporary bypass plans during exaction
of sediments within the pond area. We would like permission to remove the sediments
up to once yearly for a duration of 5 years at a time.
2.0 PROPOSED RESTORATION
To mitigate for the sod installation in the upper lawn area and for filling of the side
channel, we recommend removing the west 3' of sod adjacent the pond and planting
with slough sedge (Carex obnupta) clump divisions at 18" spacing. We also recommend
adding slough sedge to the cobble swale at 12" spacing to filter the road runoff and
absorb some of the potential contaminants prior to entering the open water. Some rocks
would need to be removed for the installation of the sedge in this area.
On the north end of the site, to provide more woody cover over the stream channel, we
recommend planting vine maple, Pacific ninebark, salmonberry and Indian plum with an
understory of slough sedge along either side of the stream channel. The plants should be
1-2 gallon in size, installed 18" from the stream ordinary -high-water line in one row.
These plants will provide shade overtime to reduce water temperature in this very
exposed run.
We also recommend planting coast strawberry in the upland berm between the lawn and
the creek to provide erosion control.
Below the dam, there are a few areas in the SW riparian corridor where ivy was removed
but not replanted. In these areas, we recommend planting 1-2 gallon sword fern
(Polystichum munitum) at 3' on -center. We recommend mulching all bare ground above
and below the dam with 2-3" of wood chips, wood chip mulch or medium course bark
mulch for weed control and water retention.
Kernen Lien
September 11, 2019
Page 3
3.0 PERFORMANCE MONITORING
As part of the restoration project, maintenance and monitoring is required for a period of
5 years. The primary goal of the enhancement plan is to increase the habitat functions of
the stream buffer over current conditions.
3.1 Goals and Objectives
To meet this goal, the following objectives and performance standards have been
incorporated into the design of the plan:
3.1a Objective A: Increase the structural and plant species diversity within the mitigation
area.
Performance Standard- There will be 10096 survival of afl woody planted species
throughout the mitigation area at the end of the first year of planting. Following each
monitoring event after the first year of planting, there will be at least an 85910 survival
rate of afl planted tree and shrub species or equivalent replacement of a combination of
planted and re -colonized native species. In addition, following the first year after
planting, a combination of native or naturalized woody vegetation will cover at least
75910 of the mitigation area. The areal coverage will increase to at least 25910 following
the second year after planting, 30910 following the third year after planting, 40910
following the fourth year after planting, and 50910 following the fifth year after planting.
3.1b Objective B: Limit the amount of invasive and exotic species within the mitigation
area.
Performance Standard- After construction and following every monitoring event for a
period of 5 years, exotic and invasive plant species will be maintained at levels below
10'Xo total cover in afl planted areas. These species include, but are not limited to,
Himalayan and evergreen blackberry, reed canatygrass, morning glory, Japanese
knotweed, English Ivy, thistle, periwinkle, and creeping nightshade.
3.2 Monitoring Methodology
The monitoring program will be conducted for a period 5 years, with annual reports
submitted to the City of Edmonds & WDFW. The reports will detail if the site is meeting
performance standards and provide photos from established photo -points.
3.3 Maintenance
Maintenance will be conducted on a routine, year-round basis. Remedial action on the
site shall be implemented on an as -needed basis at the direction of the consultant or the
owner.
3.4 Weed Control
Routine removal and control of non-native and other invasive plants (e.g., Himalayan
and evergreen blackberry, Japanese knotweed, English ivy, morning glory, thistle and
creeping nightshade) shall be performed only by manual means, unless specifically
authorized by the consulting biologist. No spraying will be conducted adjacent the
Kernen Lien
September 11, 2019
Page 4
stream. Undesirable and weedy exotic plant species shall be maintained at levels below
10% total cover within any given stratum at any time during the five-year monitoring
period.
3.5 Contingency Plan
All dead plants will be replaced with the same species or an approved substitute species
that meets the goal of the enhancement plan. Plant material shall meet the same
specifications as originally installed material. Replanting will not occur until after reason
for failure has been identified (e.g., moisture regime, poor plant stock, disease, shade/sun
conditions, wildlife damage, etc.). Replanting shall be completed under the direction of
the consultant, City of Edmonds & WDFW, or the owner.
3.6 As -Built Plan
Following installation of the plant material, an as -built plan for the enhancement area will
be provided to the City of Edmonds & WDFW. The as -built plan will identify and
describe any changes in relation to the original approved plan and will provide a baseline
for subsequent monitoring of the site to ensure compliance with the plan during the
monitoring period.
These recommendations have been approved by the owner, Don. We hope to receive your
approval so the owner can get this work completed as soon as possible. We hope this
addresses your concerns and if you have any questions, please contact me a
simone(@,altoliver.com .
Sincerely,
ALTMANN OLIVER ASSOCIATES, LLC
Simone Oliver, PLA
Principal
Attachment
cc: Don Ross & Jamie Bails via email
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ON SOLID OROUND OR ON COMPACTED BAG<FILL.
BA6KFILL FLANTINO HOLE 1/2 FULL HITH
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ROOTBALL. 00 NOT DISTURB FOOTBALL.
BA6KFILL REMAININO PLANTINO HOLE PER
SPECIFICATIONS. AMEND BAGKFILL AS NOTED
IN THE INSTALLATION NOTES.
FINAL ORADE.
SCARIFY SIDES OF PLANTINO HOLE. MAKE SURE
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A PRE-GONSTRUGTION MEETINO SHALL BE HELD HITH THE OHNER'S REPRESENTATIVE, GONTRAGTOR, DESION CONSULTANTS, AND AoENGY
REPRESENTATIVES. THE PURPOSE OF THE MEETINO HILL BE TO REVIEN SEOUENGIN0, ROLES AND RESPONSIBILITIES AND THE GONSTRUGTION PLANS.
INSTALL SANDBAO GOFFFERDAM AND PIPE BY-FASS. SHOC,< REMAININO POOL AREAS AND REMOVE FISH.
INSTALL SUMP PUMP IN OUITE HATER POOL, AND ASSOGIATED PIPINO.
PUMP OUT EXISTINO FOND.
REMOVE COFFER DAM AND BY-PASS.
THE BUFFER RESTORATION AREAS SHALL BE SOD -STRIPPED. ALL ORUBBED VEOETATION SHALL BE EXPORTED FROM THE SITE.
ALL PLANTS SHOULD BE INSTALLED BETHEEN DEGEMBER IST AND MARGH 15TH.
ALL PLANTSSHALL BE PIT -PLANTED IN PLANTING? PITS EXCAVATED 2X THE DIAMETER OF THE PLANT. PITS SHALL BE BAGKFILLED AITH A 50/10
MIX OF STEERGO TO NATIVE SOIL. PLANTS SHALL BE INSTALLED 2" HI G7H AND SURFAGED MULGHED TO A DEPTH OF 2" HITH MEDIUM-GOURSE BAR<
MULGH, ARE30RIST GHIPS OR GOMPOSTED HOO FUEL PLAGED CONTINUOUSLY THROUOHOUT THE ENTIRE BUFFER.
ALL PLANTS SHALL BE NURSERY OROHN (IN H. HA OR OR.) FOP, AT LEAST I YEAR FROM PURGHASE DATE, FREE FROM DISEASE OR PESTS,
HELL -ROOTED, BUT NOT ROOT -BOUND AND TRUE TO SPEGIES.
PLANT LAYOUTSHALL BE APPROVED BY AOA PRIOR TO INSTALLATION AND APPROVED UPON COMPLETION OF FLANTINO.
UPON COMPLETION OF PLANTINO, ALL PLANTSSHALL BE THOROUOHLY HATERED.
PERFORMANGESTANDARDS FOR RESTORED AREAS INGLUDE: 1) YEAR I - THERE HILL BE 100%SURVIVAL OF ALL PLANTED SPEC'IES. FOLLOV41NO
YEARS 2-5, THERE V41LL BE bO% SURVIVAL RATE OF ALL PLANTED SPEGIES OR EOUIVALENT REPLAGEMENT OF A GOMBINATION OF PLANTED AND
RE-GOLONIZED NATIVE SPEGIES. 2) FOLLONINO THE FIRST YEAR AFTER FLANTINO, A COMBINATION OF NATIVE OR NATURALIZED HOODY
VEOETATION HILL COVER AT LEAST 15% OF THE MITIOATION AREA. THE AERIAL GOVERAOE HILL INCREASE TO AT LEAST 25% FOLLONINO THE
SEGOND YEAR AFTER PLANTINO, 30% FOLLONINO THE THIRD YEAR AFTER PLANTINO, 40% FOLLONINO THE FOURTH YEAR AFTER PLANTINO AND
50% FOLLOHINO THE FIFTH YEAR AFTER PLANTINO. 3) AFTER GONSTRUGTION AND FOLLONINO EVERY MONITORINO EVENT FOR A PERIOD OF AT
LEAST FIVE YEARS, EXOTIC, AND INVASIVE PLANTSPEGIES HILL BE MAINTAINED AT LEVELS BELOH 10% TOTAL GOVERA6E IN ALL PLANTED AREAS.
THESE SPEGIES INGLUDE BUT ARE NOT LIMITED TO; HIMALAYAN AND EVEROREEN BLAC,<BERRY-, REED GANARY6RASS, MORNIN6 6LORY, -JAPANESE
<NOTAEED, ENGLISH IVY, THISTLE, PERIHIN<LE, AND GREEPING, NIOHTSHADE.
ANNUAL MONITORING7 REPORTS HILL BE PREPARED ANDSUBMITTED TO GITY OF EDMONDS HDFN EAGH OF THE FIVE YEARS OF THE MONITORINO
PERIOD. THE REPORTS HILL DETAIL IF THE SITE IS MEETING7 THE PERFORMANGESTANDARDS AND PROVIDE PHOTOS FROM ESTABLISHED PHOTO
POINTS.
UPON APPROVAL OF PLANTIN6 INSTALLATION BY AOA, GITY OF EDMONDS HILL BE NOTIFIED TO GONDUGT ASITE REVIEN FOR FINAL APPROVAL OF
GONSTRUGTION.
MAINTENANGESHALL BE IMPLEMENTED IN MARGH, MAY, -JULY AND OGTOBER FOR THE DURATION OF THE MONITORINO PERIOD AGGORDIN6 TO THE
SGHEDULE BELON.
ANNUAL MAINTENANGE SGHEDULE
MAINTENANGE ITEM
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