HomeMy WebLinkAbout08 Response to Additional Informtion RequestDonna Frostholm
From: Richard Rathvon <rich@ rathvonconsulting.com >
Sent: Thursday, January 30, 2025 5:55 AM
To: Donna Frostholm
Cc: rrathvon@gmail.com; 'Terry McHugh'
Subject: Email 1 of 3
Attachments: JC_DCD reply_25_01_final.docx; Attachment A.pdf, Easement referenced in Dabob View
Tracts -Attachment B.pdf, SU V5 PG 165_Dabob Tracts -Attachment C.pdf, Attachment
D.pdf
ALERT: BE CAUTIOUS This email originated outside the organization. Do not open attachments or click on links if you are
not expecting them.
Donna,
I am providing our response to your November request in 3 separate emails due to the size of the 6
attachments.
Please let me know if you have any questions or require further information.
Thank you.
Regards,
Rich
Proprietary and confidential
Responses to questions and issues raised in email dated November 5 7024
1. Question 1 Issue 1: A number of the comments DCD received pertained to concerns about
Twana Way. The proposal submitted to DCD did not include alteration or expansion of the
primitive road nor was there any indication that vegetation would need to be cleared or limbed
for heavy equipment to access your parcel. It is my understanding from our meeting a few
weeks ago that you are not proposing any improvements or vegetation
clearing/trimming. Since then, I have discussed your proposal with building division and it is
their understanding that your contractor is expecting to improve the road. Clarify if road
improvements or vegetation/trimming is proposed.
Answer:
o. We are not proposing to alter or expand the road, including "cut and fill"
activities or removal of trees. However, road maintenance may be required during
and/or after the construction process due to the use of the road by construction vehicles.
By way of background, we have easement rights to use Twana Way for ingress and
egress generally. In addition, we have specific easement rights pursuant to at least two
recorded easements, which includes the authority to upkeep and maintain the road, as
follows: (i) Easement 203763 recorded on January 19, 1970, provides a 30 foot -wide
easement, and all permitted easement users "agree to share in the upkeep and
maintenance of the road ...'; and (ii) Easement 278885 recorded on July 24, 198Z
provides a 60 foot -wide easement for ingress and egress, together with the right to
install, maintain and repair the roadway.
See: (i) Attachment A — Easement 203763 (initial easement prior to the recording of the
Dabob View Tracts survey), (ii) Attachment B — Easement 203763 (easement
accompanying the recording of the Dabob View Tracts survey, and (iii) Attachment C —
Recorded survey relating to Easement 203763 (the Dabob View Tracts survey).
Additionally, any maintenance activities undertaken would not be inconsistent with prior
maintenance activities, which has been performed by: (i) Glomset (see comments
relating to our permit where he stated "I have been working on Twana Way for over 40
years (fixing the road)") (see Attachment D}; (ii) other owners in the past, including
Hawley and Walker; and (iii) Oliver during 2023 (filling in the severely worn -down grade
with rock and gravel on the landward side of the sharp corner just past their driveway).
Proprietary and confidential
Finally, we do not believe that such road maintenance activities would be inconsistent
with JCC rules.
We are not proposing to engage in clearing of vegetation along the road, including the
removal of trees. However, if limbs prevent the safe passage of vehicles, we intend to
remove only those limbs that impede safe passage. While we are not presently aware
of any such limbs, this necessary and limited activity is permitted under the maintenance
rights referenced in the Easements noted above. Additionally, we do not believe that
such limited trimming activities would be inconsistent with JCC rules.
2. Question_/ Issue 2: It is assumed that all materials to construct the house and install the
septic system will be trucked to the property and that no building materials will be transported
by barge. Confirm that this is correct.
Answer: We are not intending or proposing to barge building materials to the site.
3. Question 1 Issue 3: The Geologic Hazard Assessment prepared by Stratum Group was reviewed
by Crescent Environmental (Crescent). Stratum Group responded to comments from Crescent,
which you then forwarded on to me. Additional information is needed to show compliance with
Jefferson County Code (JCC) requirements and to fully address comments from
Crescent. Submit a revised geotechnical report or an addendum to the existing report that is
consistent with report requirements in JCC 18.22.905(2) and 18.22.945. This would include, but
is not limited to, the following:
a. Incorporate existing sources of information (such as documents, maps, photos) that
were reviewed and considered to evaluate geologically hazardous areas for your parcel;
b. Address the slope failure shown in the Ecology oblique photos in the report;
c. Discuss methods used to assess the rate of regression and tsunami hazard in more
detail;
d. Revise Figure 4 to include the extent of the geologically hazardous areas and buffers on
the property so it is clear if the suitable building area is within a geologically hazardous
area or a buffer.
Answer: See Attachment E.
Proprietary and confidential
4. Question Issue 4: JCC 18.25.270(3) and JCC 18.25.590(3) require a cumulative impact
assessment. Submit an addendum to the Peninsula Environmental report that addresses
cumulative impacts.
Answer: See Attachment F.
Attachment A
h�.
JAN 11576
y gown am 1 MR
MIS AGUMM bads and sotsred into 014 Sal day e!
December, 1969, by and betwaon Darold Pederson and !Ruby A.
husband and rife, Walter A. Padersoa and Janet Pederaam
'husband and rite, and Lorall ft. Dar and Edith Day, husband and
rifi, hareiaafter known as tba party of the first part, and
Maria Workman, R widow, hereinafter known at party et the second
• eery.
'The first partlao are the a.sers of the following described
coal estate, to -wits.
Who Rest halt of the southwest quarter*ee s■atla► is,
*orAship 37 north, Ungs 1 Kest. V.pj., Jefferson County,
WashiavM1
The Enema party is the Omar eft
The 18orthwast carterof the Aouthwast quarter of
said auction JI
Each party i■ desirous of roaurinq an eaaeaent over and
ae:coss the land of the other party as hereinafter set tom ,.spa'
In eoneideratiea of each party 9rsatinp to the other respeat4q
aaaelA,apta, the parties grant an follows
!arty of the fleet pert hereby granta to party of the asonnd
part ass sassmest roc load puncia■ by the most t■e-Lb ia wouta to
aasnaact with existing road which runs In a general Yortherly quad
Southerly direction acmes the east half of the southwest
quasur of said aactioa, also an anaslant to me the astiating
•r • read.
Party of the aeeond part grarita unto party of the tint. Dart
in aaaaayut for road pugmsas over end lams• the northwet quext r
Of tbG southwest quarter of said section, following the *se Val
MUSING of an ■xiatiAg road. {
The road aaeasents herein granted are thirty (3a) fast is r
al Width# and permanent and perpetual.
l 32 she road easanenta bareis granted will be cued jointly by
• � M7 M'3AL l'37'ATk
: sALIM TAX RVQ` •.�U •
.� 16.:�5l ��Tr .,.bR�tison
tie
= both the party of the first port and party of the second part.
2 and will connect with each other.
.all parties making usa of the ■aeeRaat &gran to share in the
4 aPhear and saintenance of the road in proportion to their use
• � tharael.-
8 Both grantore and granteeep ehels saQpssOrs and assigns
7 ,sneer" the right to use the said road, MP Eaeernents for ingress
8 and egreu to all Such properties as may be owned by the
I respectIva parties in either section 15 or 22, Towmehip 27 North,
10 Range 10 Nest N.R., Jefferson Ceun
tY. Washington.
11 IN NlTNE88 WUP80d, the parties hareto hava hareunte
12 •effLued their signaturathie
13 3rJ dart' of December, 1969.
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28 a rCught pick of the granted easements, not drawn to seals,
29 ie wtt"b4d tO ehw the general course of the reapeetive
eaaes.ente herein convelyao.
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Attachment B
I
DZCLARATION OF RASRMM
IBIS DECLARATION OF EASEMENT ma is 7 - day of
19 U-, by HAROLD T d CAROL STEINKE,
his wife. WITNESSETH:
WHEREAS, the above mentio dividuals are owners of the
following described property, to w
Goverment Lot 1, Sec 7 1 T aship 27 North,
Range 1 West, V. rl
situate in the Cc �e arson, State of
Washington;
WHEREAS, the Owner �ei n end to sell portions of said
Goverment Lot 1 t� is? A ties and have them share a
common easements = ur 4i os f ingress, egress and utilities;
I�
and owners al ►teA to of it appurtenant lands,
NOW THER re do hereby declare and impose the
following eat a
1. a en for ingress, egress and utilities over
under, acro s and rough, together with the right to install,
maintain both the roadways and utilities, 60 feet in
width, in t 0 eet on each side of the following described
er lying in said Goverment Lot 1. section 15, Township
27 rt Pa ge 1 West, W.M., Jefferson County, Washington, the
c�nterl of which are described as follows, to wit:
Page I of 3
-1
Jun 24,1182 — —
'' +'o.= _ .. ''e=:• .'Q, .dfC�7e✓+rc .. "ARE;. •..T,,p„ JM.r%A .1A:T1.�- . '.e."r
Aeginning at the West-1/4 corner of Section 15,
Township 27 North, Range 1 West, Willamette
Meridian (from which the Northwest corner of said
section 15 lies a distance of 2640.00 feet, North
thereafl; thence, South 890--40'-30- EaSt along
the East -hest Centerline of said Section 1S, a
distance of 1334.39 feet to the Northeas� corner
of said Government Lot 1; thence South 0-12'-56-
West■ along the Easterly limits of said GoverA-
■ent Lot I, a distance of hence N feet, to the
TRBE POINT OF BEGINNING; thence North 68 '
Nest, a distance of 117.76 feet to a poinjr -e
irs%fter referred to as Point -A'; thence 4eth
21-3I'-08' Eaet, a distance of 219.29 feet;
thence North 0 -12'-T East, a distance of •44.4
feet? thence North 89-55'-56' nest, a-di�Cat�e1
of 13$.84 feet; thence North it -36' 8j Bssa
distance of 296.68 feet; thence South 2-31'744'
We$t, a distance of Z18.52 feet, thence",South
73-46'-56, West, a distance of 9 {4•..feetr
thence North 45-00'-00' Wst// istarlC of
83.31 Peet= thence North is -x5! 57" 89st., a dis-
tance of 162.58 feet to a Pa nt hereia3,s�ker re-
ferred to as Point -8-; tben a South 5.6-46'-11'
Weft, a distance of 278.42 fepk; thence,5outh
26-24'-44' West, a distance of 342.07 feet;
thence North 18-34'-28" West, a distance of
106.89 feet to a Pointr'hei nafter referred to as
Point 'C'; thence North`-"-41'-34- West a
distance of 160.19 feet, th'er�ce-Aortb 52a-461-28-
West, a distance of 193.22 €ettk,ihence North, a
distance of 28.66 feetzN ,thenbe orth 180-57--52'
East, a distance of 112t9§;�eet'to a Point here-
insfter referred o a$.,Fdipt!4b'; thence North
If -54'-23" Wes dsk nee of 73.33 feet, to a
Point on the Westeriy 2-unite• of said Government
Lot 1, {being a diskdnce of 580.10 feet South of
the West 1/4 corner of 6aid Section 151 end
terminus of thi* described centerline.
Also; begi-nninq',*t_-Point -4-B- as hereinabove de-
scribed; tlerfce 9or.th-8V-42- West, a distance
Of 194.34 fee tQ a Point hereinafter referred
to as #taint 78 �c jthe terminus of this center-
line. JJ
2. nt�ae� r ingress, egress and utilities, over,
under, across 19h, together with the right to install,
maintain a'd Din
both the roadway and utilities, being 20 feet
in width, 1e3eet on each side of the following described
centerline, said Government Lot 1, Section 15, Township
27 Nc - "_ ge 1 West, W.M., Jefferson County, Washington, the
tern. nne f which are described as follows, to wit:
Beginning at Pont 'A' as hereinabove described;
thence North 68-25'-19- West, a distance of
0.73 feet to the terminus of this described
(centerline.
Also; beginning at Point '$' as hereinabove
described; thence North 63-46'-20" East, a
distance of 127.40 feet to the terminus of this
described centerline.
3 Page 2 of 3
va 1.64 -;..273
un 24,1982 -
Allot beginning at Paint 'E' as bereinabove
described; thence North 8°-46'-42" west a
distance of 98.19 feet; thence North 156-22'-55'
Neste a distance of 161.93 feet; thence North, a
distance of 77.80 feed thence South 89°-40'-30'
Va t, a distance of 74.10 feet; thence south
43-06'-53" EmB�, a distance of 253.72 feet;
thence North 7$-47'-14' Eas�, a distance of
225.22 feet, thence North 52-3l'-47' EaSt, a
distance of 180.75 feet, thence South 79-08'-17
Nest, a distance of 142.34 feet to the termi�tus
of this described centerline.
Seginning at Pont 'B" as hereinabove des ibe
thtl*e North 8$-34'-03' WSst, a distance
40.00 feet; thence South 1 25'-57' wee
distance of 179.74 feet; thence South
Past, a distance of 59.01 feet, to the us�
of this described centerline.
3. An Pasesent for walkway purpose nly,tibeing 10 feet
in width, lying in said Government Lots- Se !ae' , Township 27
North, Range 1 West, Willamette Merisdianj def �rs n County,
Washington, the centerline of which`i deseripeH as follows, to
wits
Beginning at Pont 'C' as herei bow described;
thence South 66 -10'-4 ' Wes, a distance of
234.20 feett thence Sdgtb-4,2 _33'-26' West, a
distance of 140.70 feet; �to" int lying 5 feet
Past of the Westerly limik�•QQf�g id Government
Lot 1; thence South, an a1-d .line lying 5 feet
laaterly of said Wes cly 1 s and parallel to
the said Westerly li;i d Government Lot
1, a distance o 70' ty�a� re or less to the
Past Shore of a Bav
4. All of the hesg1is�j�a; described Easements are as
graphically depicted v�)recorded under Auditor's Fee
Number , at Volt I of surveys Page
This declarat o eas ent and all rights of way hereby
created and depli ha be appurtenant to and run with said
Government 4s,
ffi N1 0 the parties have executed this
Instrument t1j diy,_and�ear first above written.
�-V CiGsrQ .�tsrxjt
moo• of t i� Ake
+ �
i Carol Steinke
twpr�qP! f
YS'1$' OFT1i ING EiN
Ot- SS.
at� { RSON
.'.�a is o certify that on this lep-IL day of <j
1 � 7 Onally appeared before me Harold Steinke and Carol
8t ilk his wife, to me known to be the individuals described in
wand wh)o xecuted the within and foregoing instrument, and ac-
kn�wlad�id that they signed the same as their free and voluntary
t aid deed, for the uses and purposes therein *e'n,t�ioned.
G under ay band an official seal this #2'day of
,19
imbi�ngtonirr
Pinaesidin
Page 3 of 3 va 164 !;., 74
Doc ld: 1642667
Attachment C RECORD OF
,S'URVEY
V/C/N/TY MAP I
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AUDITORS CERTIFICATE
SURVEYOR'S CERTIFICATE:
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Attachment E
PO Box 2546, Bellingham, Washington 98227
Phone: (360) 714-9409
November 14, 2024
Richard Rathvon
20 Liberty Knoll
Colts Neck, NJ 07722
rrathvon@gmail.com
Re: Geologic Hazard Assessment Update
660 Twana Way
Jefferson County Parcel 701164005
Quilcene, WA 98376
This geologic hazard assessment is an update of our previous geology hazard assessment report
dated February 15, 2022. Jefferson County has requested additional information based on
comments they received per the email below in italics. The additional information that is
applicable to the geology hazard assessment and our recommendations are incorporated into this
updated report.
Summary of response to County Request
The County request is present in italics below and our summarized response follows and then is
incorporated into the report.
3. The Geologic Hazard Assessment prepared by Stratum Group was reviewed by
Crescent Environmental (Crescent). Stratum Group responded to comments from
Crescent, which you then forwarded on to me. Additional information is needed to show
compliance with Jefferson County Code (JCC) requirements and to fully address
comments from Crescent. Submit a revised geotechnical report or an addendum to the
existing report that is consistent with report requirements in JCC 18.22.905(2) and
18.22.945. This would include, but is not limited to, the following:
a. Incorporate existing sources of information (such as documents, maps, photos)
that were reviewed and considered to evaluate geologically hazardous areas for your
parcel;
This updated report includes the Washington State Department of Ecology oblique aerial
photographs dating back to 1977 and aerial photographs dating back to the 1940s.
Stratum Group
Project: 1.31.22
November 14, 2022
Jefferson County Parcel 701164005
Geologic Hazard Assessment
Crescent indicated that we should have included in our evaluation NTI reports done on
"relatively nearby properties" and the groundwater study of eastern Jefferson County. The two
NTI reports are not near the site and are located in areas with markedly different geology and
shoreline conditions. There is no relevant information regarding the site slope stability or
geology processes in Grimstad and Carson (1981).
It has been our experience that doing our own assessment of site soils is a much more
appropriate way to assess soil conditions on a given site than simply relying on the USDA soils
maps. That said, our finding that the soils are well drained is consistent with the soil map and we
have added that to the soil description.
b. Address the slope failure shown in the Ecology oblique photos in the report;
We provide a more detailed description of the area on the north portion of the bluff slope that has
no trees. This location is an old erosion location and is as we noted in our report a site of soil
ravel. This feature appears at least as far back as 1977 and may be older per the lower resolution
photographs from the 1940s and 1950s.
Discuss methods used to assess the rate of regression and tsunami hazard in more
detail;
A detailed analysis of the shoreline bluff retreat history and shoreline processes was utilized to
estimate the past long term shoreline bluff retreat as being less than one inch per year and was
included in the report. Contrary to the Crescent comment, we did not measure the bluff retreat
rate. The value we estimated is based on the evidence that we presented. Likewise our estimated
future long term shoreline bluff retreat of 2 inches per year is based on including a consideration
of relative sea level rise resulting in an increase of erosion and also considers the shoreline
processes along the entire shore reach. Crescent ignored the evidence and rationale we presented
and the comment was not applicable to our estimate. That said, we modified the language in the
report in hopes of clarifying our rationale for our estimated top of bluff retreat.
Regarding tsunami hazard, our assessment of the risk of the site being impacted by a tsunami has
not been changed, but we will included the Washington State Geologic Survey maps of tsunami
inundation in the area for the Cascadia Fault and the Seattle Fault and we added some further
discussion regarding the Dabob Bay Fault which has no tsunami modeling and the potential
wave risk from large landslides. In all cases, it is our opinion that the tsunami waves or landslide
generated waves do not pose a risk to the proposed building area.
SSRATIFl4 GRgl1p
Project: 1.31.22
November 14, 2022
Jefferson County Parcel 701164005
Geologic Hazard Assessment
d. Revise Figure 4 to include the extent of the geologically hazardous areas and
buffers on the property so it is clear if the suitable building area is within a geologically
hazardous area or a buffer.
We made a new Figure, Figure 9, to clarify the area of the property that is outside of any
potential landslide or shoreline bluff retreat area or buffer.
Introduction
This geologic hazard evaluation was conducted to assess the risk of landslide and erosion
hazards at 660 Twana Way to determine the feasibility and appropriate locations for the
construction of a new home and septic system on the property.
The Jefferson County Public Land Records landslide hazard map indicates that part of the
subject property is located in a moderate landslide hazard area and part of the property is located
in a high landslide hazard area. The shoreline stability map indicates that part of the subject
property has unstable slopes and an unstable recent slide is mapped as extending onto the north
portion of the shoreline bluff on the property. The shoreline area of the property is mapped as an
erosion hazard area and the lower portions of the property are mapped as a potential seismic
hazard area.
Based on our geologic hazard assessment, construction of a home and septic system can be
located on the site outside of any landslide hazards or shoreline bluff retreat from erosion for the
next 100 years as long as the home and septic system are located at least 30 feet from the top
edge of the shoreline bluff. Furthermore, such construction will not increase the risk of landslides
or erosion on or off the subject property as long as the recommendations in this report are
followed.
This geologic hazard assessment included a field inspection of the subject property and vicinity
including the shoreline area and slopes on and in the vicinity of the site. The evaluation also
included review of available geologic mapping, historical aerial photographs, historical land
surveys, lidar (light detecting and ranging) imagery, and our own notes, photographs, and
observations made in the vicinity of the site and at locations with similar geologic conditions.
GENERAL GEOLOGY
The Geologic Ma of the Quilcene 7.5 Minute Quadrangle, Jefferson Coun1y, Washington
(Contreras and others, 2014) indicates that subject property is underlain primarily by Whidbey
Formation sediments with the lower western third of the property mapped as being underlain by
Vashon ice contact deposits, which mantle older glacial and non -glacial formations such as the
Whidbey Formation in the area (Figure 1). The map also indicates Double Bluff drift glacial
deposits may be present at exposures at the southwest corner of the property. Landslides and
landslide scarps are indicated just to the south of the subject property.
STAATum GROUP
Project: 1.31.22
November 14, 2022
Jefferson County Parcel 701164005
Geologic Hazard Assessment
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Figure 1. Clipped and annotated geologic map showing the subject property. Qb = beach deposits, Qaf = alluvial
fan, Qgic = ice contact deposits, Qcw = Whidbey Formation, Qgdp = Possession glacial rift, Qco = Olympia non -
glacial deposits, Qgdd = Double Bluff glacial drift, Qc = Pre -Fraser non -glacial deposits, Qls = landslide. Hachures
are landslide scarps. Heavy dotted line with query is a surmised potential fault.
The Whidbey Formation is a non -glacial deposit that is between 125,000 and 80,000 years old.
The Whidbey Formation in the vicinity of the property consists predominantly of sand but also
includes units of silt and clay. The formation is dense and hard having been overridden by glacial
ice over two separate glacial periods.
The Vashon ice contact deposits (Qgic) are a mix of poorly sorted sediments deposited directly
by glacial ice during the late stages of the last glacial period between about 14,000 years ago.
Contreras and others (2014) mapped the unit where deposits appeared to be associated with ice
wasting and the surface area of the deposits lacked streamlines associated with ice movement.
The Double Bluff drift (Qgdd) consists of sediment deposited during a glacial period that is
estimated to have taken place between 190,000 and 125,000 years ago. This formation represents
a glacial period that occurred three ice ages ago. The basis of the interpretation is from age
estimates and map relationships in the larger vicinity than shown on the map; however, this area
is geologically complex due to the presence of a fault zone and local offsets and folding.
STRATUM GROUP
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Geologic Hazard Assessment
Our observations are generally consistent with the above -described mapping. Soils observed on
the property upland and exposed along the shoreline bluff primarily consist of very dense,
stratified, sand and gravel with lesser silt lenses (Figure 2). These dense deposits are commonly
overlain by a surficial cap of medium dense, poorly sorted, and unstratified, sand, silt, and gravel
interpreted to represent Vashon ice contact deposits (Figure 3). A very dense, poorly sorted, and
unstratified sand, silt, and gravel unit exposed at the base of the shoreline bluff on the subject
property and to the south is consistent with Contreras and others (2014) interpretation of the unit
being the Double Bluff drift mapped in the vicinity (Figure 2).
&Z
Figure 2. Whidbey Formation sand and gravel with Double Bluff drift at the base of the bluff a few hundred feet
south of the subject property.
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- rt-,
Figure 3. Medium dense, poorly sorted sediment consistent with Vashon ice contact deposits on the site upland.
STRATUM GROUP
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SITE SPECIFIC OBSERVATIONS
An annotated lidar hillshade image of the subject property and vicinity is provided in Figure 4.
The property is accessed by Twana Way, a gravel/dirt road, which crosses through the subject
property from the southeast corner to the northwestern portion of the property.
W.
Figure 4. Annotated lidar hillshade map of the subject property showing key site features.
outside of any landslide or erosion hazards is outlined with green dashed line.
Potential building area
The west edge of the property consists of a shoreline bluff (Figure 5). The bluff is nonexistent to
very low at the northwest corner of the property where the bluff descends down to an accretion
shore area and steadily rises to the south before dipping down somewhat near the southwest
corner where the bluff intersects a valley. The bluff at the property is approximately 40 feet high
at its maximum height. The bluff face slopes at approximately 10 degrees on the low, north end
and slopes up to approximately 30 degrees toward the south end of the bluff.
The bluff is underlain by primarily by compact sand and gravel consistent with pre glacial
alluvial sediment but the lower part of the southern portion of the bluff is underlain by very hard,
poorly sorted silt with sand, gravel and cobbles that is consistent with glacial till. The bluff face
is vegetated primarily with Douglas fir trees with an understory of mostly grass with some other
shrubs. Limited portions of the bluff are brush and grass covered. We observed no concentration
of hydrophilic vegetation or evidence of springs or groundwater seeps on the bluff face.
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Figure 5. View of the beach and shoreline bluff on the subject property, looking northwest.
The beach at the base of the bluff is a gravel and sand beach. Minor past erosion of the toe of the
bluff is evident at or very near the southwest corner of the property where the very hard, likely
Double Bluff, glacial drift deposits are exposed at the base of the bluff (see Figure 5 above).
The upper part of the beach consists of sand and gravel with driftwood. It appears that water did
reach the base of the bluff recently, likely during the recent high tide/storm surge event on
January 11, 2022. However, no significant erosion was evident and it appears that erosion occurs
on an infrequent basis. A grass -covered accretion beach fronts the northwest end of the property
and extends as a long shoreline spit for over a mile to the north of the subject property. No
erosion was evident on the accretion shore area and water did not reach the slope area fronted by
the accretion shore reach.
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Geologic Hazard Assessment
The shoreline at the property is located in a transition zone between areas of bluff erosion (feeder
bluffs) south of the subject property and shoreline accretion to the north. These observations are
consistent with shoreline type designations on the Washington Coastal Atlas (Figure 6) and
Jefferson County Public Lands Records Coastal Gealo is Services, 2015).
n Coastal Lendtorrns
v Feeder duff exceptional
v Feeder duff
Trenspoc zone
Feeder bluff - Talus
Accretion shoreform
v Pocket beach
Pocket beach - artificial
No appreciable drlR
Artificial
Bedrock
Figure 6. Coastal landforms map from the Coastal Atlas.
The upland area above the shoreline bluff slopes up at approximately 10 degrees or less (Figure
7). This gentle slope area is located between two valleys (see Figure 4). No water was present in
the bottom of the northern valley on the property and the valley area is underlain by well drained
sand. The valley on the south is on and/or just south of the property line. There is indication of
periodic water flow in this valley, but no water was present at the time of our site visit on
February 1, 2022. These valleys appear to be primarily remnant erosional features that formed at
the end of the last glacial period when erosion rates were very high on the bare landscape right
after ice retreated from the area.
:�-.i
STRATUM GROUP
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Geologic Hazard Assessment
Figure 7. Gentle slopes on the lower (western) upland of the subject property.
The eastern portion of the property consists of a plunging ridge between two valleys (see Figure
4). The valley side slopes range between 15 and 35 degrees (Figure 8) up to the ridge line and
ridge line plunges around 15 degrees to the west-southwest. The south sides of the ridgelines are
steeper than the north sides. The Twana Way roadway and a driveway that descend from the
road toward the shoreline are cut into the flanks of the slopes of the ridges, which on the steeper
south sides of the ridges results in 2- to 4-foot high cut slopes above the road that reach 35 to 50
degrees in slope and 2- to 4-foot tall, 30- to 40-degree fill slopes below.
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Figure 8. Moderate slopes descending from the south ridgeline on the eastern portion of the property upland.
The upland area is forested with a mix of trees including Douglas fir, western red cedar, western
hemlock and big leaf maple. The understory consists predominantly of sword fern and includes
bracken fern, salal, evergreen huckleberry and other brush.
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GEOLOGIC HAZARD ASSESSMENT
The upland slope area between Twana Road and the shoreline bluff slope is gently sloping and is
outside of any landslide or erosion hazard area. Soils observed in test pits on this lower upland
were well drained and capable of accepting additional water input contributed by a septic system
and stormwater runoff from the home. The soils are well drained and generally coarse grained
and will not be subject to seismic induced liquefaction. The portion of the property outside of
any landslide or erosion hazards areas is indicated on Figure 9. The slopes and shoreline bluffs
and shoreline processes are described below to support our conclusions regarding the geology
hazards at the site.
Figure 9. Lidar bare earth image showing area outside of any landslide hazard area and buffer.
Slopes on Eastern Portion of Site
The slopes above Twana Road consist of two valleys with a ridge between. The ridge slopes and
valley sides are moderate slopes and no indication of potential landslides is present. Some minor
ravel of soil is present on the cut slopes associated with Twana Road.
The steep headwall areas of these valleys appear to have had some shallow sliding in the past
that sent slides part way down the valleys, but we interpret these landforms to be relict. The
upper headwall areas of the north valley appear to be steep enough that shallow slides could take
place, but the gradient of the valley, width of the valley and lack of water flow is such that we do
not anticipate that shallow slides from the steep headwall of the valley would reach the subject
property.
STRANM GROVP
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Shoreline Bluff Slope Stability_
The shoreline bluff at the site is underlain by dense alluvial sediments consisting primarily of
dense sand and gravel consistent with Whidbey Formation with the lower portion of the bluff
underlain by very hard silty glacial till consistent with Double Bluff Drift (see Figure 5). These
bluff face sediments are capable of maintaining steep slope angles for long periods of time. The
glacial drift is very hard and resistant to erosion. The steeper areas will be subject to ravel and
shallow surface failures as the upper soil weathers or if the slope is undercut by erosion.
Currently there is only minimal erosion at the base of the shoreline bluff at the very southwest
corner of the site (Figure 10).
Figure 10. View of shoreline bluff from the south. Note minor erosion at the base of the bluff exposing the very hard
glacial till located at base of the bluff. To the north, left side of the picture, the shoreline changes to an accretion
shore form with vegetation growing on the accretion area fronting the glacial till bluff slope.
The Jefferson County shoreline stability map which is the same as the Washington Coastal Atlas
indicates that there is an `unstable recent slide' at the property (Figure 11). We observed no
evidence of recent sliding other than minor ravel on the shoreline bluff slope. There is steeper
section of bluff on the northern portion of the bluff slope that lacks trees and has lacked trees
since at least 1977 (see aerial image below) and possibly since the 1940s (see aerials below — the
1940s and 1951 images are lower resolution that the oblique aerials from Ecology). This small
treeless slope may be why the map (which is from the 1970s) indicates a recent slide; however,
there is no evidence of recent sliding at this location other than the aforementioned ravel and the
extent of the area shown on the map is far larger than the very limited treeless area on the slope
and includes upland areas that clearly have shown no slope movement. This treeless area is
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Geologic Hazard Assessment
above the accretion shore line area may have had erosion at the base of the bluff many decades
ago when the accretion area did extend to the front the bluff at this location (accretion shores can
shift) and the thin topsoil on the lower part of the bluff over very hard glacial till has not been
able to support trees. We noted that trees and brush have become established on the accretion
shore area fronting this small treeless bluff area, but also note that the accretion shore could be
overtopped by very high tides combined with storm surge.
The Jefferson County shoreline stability map indicates the bluff to the south of the property is
`unstable old slide'; however, the bluffs to the south have multiple recent shallow failures and
very active erosion at the base of the bluff is resulting in ongoing sliding (Figure 12). This bluff
area is mapped as feeder bluff and feeder bluff exceptional by the Coastal Atlas consistent with
our observations.
.] S66 Hy&n
. CI Soil. MRh�.v-
.o Wmlm�d.
.� M.bl Mmmlm USFWS
Sp—0.1 USFWS
FEMA FIRM NW.
. Q FEMA Food lows
-p Geohemid a...
. ] L..ddd. H—d
�Q Shun. Skp.S�Oiy
Umuble-recerrt.IMe
U—bl..I,
U—bledd.ld.
Modred
SxariW.
aYe w ! - � .ro
Figure 11. Jefferson County Shoreline Stability Map
STRATUM GFMP
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1940s (USACOE)
1951 (USGS)
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$s�t►T M GRGUP
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Geologic Hazard Assessment
1977(Ecology)
1990(Ecology)
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2016(Ecology)
Beach Processes and Bluff Retreat
The beach at the property is located towards the northern end of an approximately 10 mile long
drift sector with sediment transported from south to north along the shore. Most of this drift
sector is lined with fairly high feeder bluffs (Figure 12) and there is very little shoreline armoring
that would reduce the sediment supply. Numerous very large landslides are located along the
drift sector including a slide 0.4 miles to the south that covered the entire beach area 1 Os of feet
deep with sediment over a distance of 550 feet in 1998, and there are multiple large areas of high
bluffs of exposed glacial sediment that are eroding and raveling onto the beach feeding the
beach.
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Geologic Hazard Assessment
Figure 12. View of eroding bluffs south of property and large 1998 slide area 0.4 miles to the south.
There is a slight change in shore orientation and openness to larger fetch along the shore area just
to the south of the property. This is likely due to the presence of the very hard glacial till that is
resistant to erosion at the base of the bluff at the subject property. The combination of the hard
glacial till and the slight change in shore orientation is such that shoreline erosion at the subject
property is very low relative to the shore areas to the south which do not have glacial till at the
base of the slope and have a slightly more south oriented aspect.
The shore form at the property transitions from a feeder bluff to the south to a transport zone
(bluff backed beach on Jefferson County map) to an accretion zone on the north part of the shore
at the site. There was no indication of recent erosion having taken place during the very high tide
storm surge of January 11, 2022 along the base of the slope on the property. No erosion of the
accretion area below the north portion of the site was observed and water did not reach the base
of the slope on the northern portion of the site where the trail is located during the January 11,
2022 event. There has been no appreciable change in the location of the top edge of the shoreline
bluff over the historic record based on our review or aerial photographs dating back to the 1940s.
The specific location of the change over from transport zone to accretion may have shifted
slightly in the past such that there have been periods where the bluff area now fronted by the
accretion shore form was subject to periodic erosion as the southern edge of the accretion shore
area may have shifted.
Based on the beach conditions, shoreline bluff materials of very hard and dense glacial till, the
very low erosion rate observed over the past 50 years in the oblique aerial imagery, and no
change in the location of the top edge of the bluff over the historic aerial photographs record, we
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Geologic Hazard Assessment
estimate that the long term shoreline bluff retreat at the site has been less than 1 inch per year.
While no top edge of bluff retreat is evident in the historic record, retreat of the top edge of the
bluff should be expected eventually as an episodic event with many years (decades) where no
retreat will take place at the top edge of the bluff. Over time the upper bluff will become
undermined as erosion and ravel take place on the slopes below and shallow small scale slides
should be expected to reach the top edge of the bluff.
Consideration of Sea Level Rise
While past shoreline bluff retreat has been very slow and we estimate that the long-term rate has
likely been less than 1 inch per year, relative sea level rise projections for the year 2100 are
estimated to be between 1.0 and 2.8 feet for the likely range of relative sea level rise under low
to high green house gas levels (Miller et al., 2018). The increase in sea level will result in a
greater frequency of high water reaching the base of the slope and hence an increase in erosion
rate. However, the increase in erosion will take place along the entire shoreline drift sector and
will be even more pronounced at the current feeder bluff areas to the south. The increased
erosion to the south will add sediment to the beach fronting the subject property and thus will
partially off set the sea level rise increase of erosion at the subject property as the entire shore
reach and beach adjust to the change in sea level.
Due to the change of seal level, we assume that there will be some increase in erosion rate and a
corresponding change in bluff retreat. We estimate that the long term bluff rate accounting for
sea level rise over the next 100 years will be 2 inches per year. This corresponds to top of bluff
retreat of 8.3 feet over the next 100 years. An additional 20 feet should be added as an addition
safety buffer for larger scale ravel or higher erosion rates than what we are estimating or other
potential change in conditions along this shore reach.
Seismic event considerations
Test pits on the site found that the upland area where the home would be located is underlain by
coarse well drained sediment. This sediment will not be susceptible to soil liquefaction from
seismic events.
Given the steepness of the shoreline bluff, small scale slides should be expected on the bluff
slope in the event of a large seismic event. We observed no evidence of past seismic induced
slope movement such as lateral spread on the uplands of the property on the ground or within
lidar bare earth imagery
Tsunami Hazard
The shoreline at the site could be impacted by earthquake -induced tsunamis. The tsunami
inundation map for a Cascadia extended L 1 magnitude 9.0 earthquake indicates approximately 4
feet of inundation on the higher parts of Long Spit which begins at the subject property (Figure
13). The modeled tsunami event is considered to exceed 95% of the potential tsunami events
from the Cascadia Fault (Dolcimasculo and others, 2021). Hence, a Cascadia earthquake will
tGROUP
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Geologic Hazard Assessment
have minimal impact on the subject property with the proposed building site well above any
potential inundation and potential erosion at the site being minimal.
The Seattle Fault tsunami model indicates an inundation at Lang Spit of less than 4 feet (Figure
14).
Localized earthquakes such as an earthquake generated on the Dabob Bay Fault or other fault
zones in the area could also generate tsunamis but have not been modeled. These tsunamis may
be higher, but are very unlikely to be high enough to reach the upper bluff slopes. Local
landslides may also generate waves. The large landslide that took place about 0.4 miles south of
the property was reported to have generated a wave of 7 feet per an observation of a property
owner on the Bolton Peninsula across the bay from the landslide.
Modeled
inundation
depth (feet)
20
16
_ 12
M a
Figure 13. Tsunami hazard map from Washington Geologic Survey (2021) showing modeled inundation depth for
an extended L1 magnitude 9 earthquake on the Cascadia Fault at Long Spit, the accretion shore form that begins at
the south end of the property.
x..h
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Geologic Hazard Assessment
0
5
2
Figure 14. Tsunami hazard map from Washington Geologic Survey (2022) showing modeled inundation depth for a
7.5 earthquake on the Seattle Fault at Long Spit, the accretion shore form that begins at the south end of the
property.
CONCLUSIONS AND RECOMMENDATIONS
Based on our geologic hazard assessment, it is our opinion that construction of a single-family
house and associated septic system on the lower upland on the subject property will not be at risk
from landslides or erosion within the expected life of the structure as long as the building and
septic systems are located at least 30 feet back from the top of the steep shoreline bluff slope.
Furthermore development within the area indicated on Figure 9 will not increase the risk of
landslides or erosion on or off the site as long as the recommendations of this report are
followed.
Stormwater management: Stormwater collected from structures built on the property should be
dispersed consistent with the Stormwater Management Manual for Western Washington. Soils
on the property upland are capable of readily accepting stormwater infiltration and we did not
identify any areas of seepage or springs on the bluff slope. Stormwater should not be discharged
onto or within approximately 30 feet of the shoreline bluff slope.
Yard waste and debris: Ground cover vegetation within 20 feet of the top edge of the slope and
on the bluff slope should not be disturbed. Trees within the buffer may be thinned or limbed for
view purposes. However, if the trees are thinned, trees should be left on at least 30-foot centers.
In addition, no debris or yard waste should be placed on or near the steep coastal bluff or other
steep slopes on the property. Yard waste can eventually builds up and can form a wet unstable
mass that will slide down the bluff damaging the slope and increasing the likelihood of a future
slope failure.
rr�j•,
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Geologic Hazard Assessment
In addition to our construction recommendations, new construction on the subject property may
also be subject to buffer requirements established in the Jefferson County Shoreline Master
Program. Final construction setbacks should reflect whichever setback is largest.
Stratum Group appreciates the opportunity to be of service to you. Should you have any
questions regarding this assessment please contact our office at (360) 714-9409.
Sincerely yours,
Stratum Group
Dan McShane, L.E.G., M.Sc.
Licensed Engineering Geologist
STiN1T17M GROUP
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ATTACHMENT F
Rathvon Single Family Home
Construction Project
Cumulative Impacts Assessment
January 241h, 2025
Prepared for:
Richard & Renee Rathvon
20 Liberty Knoll
Colts Neck, NJ 07722-1361
Regarding:
660 Twana Way
Quilcene, WA 98376
Jefferson County Parcel # 701164005
" SE ��
SSM7�" �) �
MARINE SURVEYS & ASSESSMENTS
2601 Washington Street
Port Townsend WA 98368
360-385-4073
info@msaenvironmental.com
Table of Contents
2 Project Overview
2.1 Introduction.................................................................................
2.2 Resources reviewed prior to MSA conducting fieldwork ...........
2.3 Habitat conditions observed on site ............................................
3 Jefferson County Cumulative Impacts Regulatory Code
4 Cumulative Effects Assessment
5 Conservation Measures to Avoid & Minimize Impacts
6 Conclusion
7 References
List of Figures
1
.1
.1
.2
5
7
12
15
16
Figure 1. Rathvon single family home site plans by McClellan Tellone, Architecture Firm ......... 3
Figure 2. Properties in the vicinity of Rathvon proposed single-family home ............................... 8
Figure 3. Additional properties north of Figure 2 (north of Rathvon proposed single-family
home).............................................................................................................................................. 8
Figure 4. Additional properties south of Figure 2 (south of Rathvon proposed single-family
home).............................................................................................................................................. 9
Figure 5. Dabob Bay Natural Resource Conservation Area ......................................................... 10
Attachments
Attachment 1. Photo Documentation
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report i I vl S A
1 Project Overview
1.1 Introduction
Marine Surveys & Assessments (MSA) was authorized by Richard and Renee Rathvon to
complete a Cumulative Impacts Assessment to meet Jefferson County Code (JCC) criteria for the
permitting of a single-family home construction project located on their 5.47-acre property
(parcel # 701164005). In an email dated November 6th, 2024, the Jefferson County Department
of Community Development requested additional information after reviewing the Rathvons'
shoreline permit application (SDP2023-00020). One of the requests in that email stated, "JCC
18.25.270(3) and JCC 18.25.590(3) require a cumulative impact assessment. Submit an
addendum to the Peninsula Environmental report that addresses cumulative impacts." Rich
Rathvon reached out to Peninsula Environmental, who had prepared a stream assessment report
for the property (Bornsworth et. al. 2022), but they were not available to complete this request
due to staffing issues. Thus, MSA was retained to prepare this addendum.
To be able to provide an accurate assessment of the project's potential cumulative impacts, MSA
biologist Meg Amos visited the site on December 301h, 2024, and completed a habitat survey.
Weather conditions during the visit were overcast, windy, and dry with a temperature of 42'
Fahrenheit. The habitat survey covered all portions of the parcel located within shoreline
jurisdiction, including walking a pathway down to the beach.
This report documents the habitat conditions observed on site and assesses the cumulative
impacts, only. This report is not intended to be a full impacts assessment. It is MSA's
understanding that a full impacts assessment (such as a Habitat Management Plan as defined by
JCC 18.22.650) is only required when a project encroaches into a critical habitat area or its
associated buffer. A separate stream assessment report has been prepared by Peninsula
Environmental (Bornsworth et. al. 2022), and a geotechnical report and update has been prepared
by Stratum Group (McShane 2024).
1.2 Resources reviewed prior to MSA conducting fieldwork
• 1974 National Wetland Inventory (NWI) maps, United States Fish and Wildlife Service,
■ Web Soil Survey: National Cooperative Soil Survey. United States Department of
Agriculture (USDA), National Resources Conservation Service (MRCS),
• Jefferson County Critical Areas Code Chapter 18.22,
• Jefferson County Shoreline Master Program Chapter 18.25,
• Jefferson County Open Data Portal — critical areas, shoreline permitting, contours, and
elevation hill shades layers,
• Washington Department of Fish and Wildlife (WDFW) Priority Habitats and Species
(PHS) online mapper,
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report 1 I M S A
• Washington Department of Natural Resources (WA DNR) Forest Practices Application
Mapping Tool (FPAMT) for viewing typed streams.
1.3 Habitat conditions observed on site
The majority of the Rathvon parcel is covered in mature mixed conifer forest, primarily
consisting of Western redcedar (Thuja plicata) and big leaf maple (Acer macrophyllum). To the
north and south are similar properties that are already developed with single-family homes. The
shoreline of Dabob Bay is located to the west, and undeveloped forestland is to the east. There is
a non -fish seasonal (Ns) stream located primarily offshe to the south; however, a short segment
of the stream (approximately 80-linear feet) is located in the southeast corner of the property.
The stream runs from east to west and flows into Dabob Bay. An existing driveway enters the
property from the east, then dips back outside of the property line to the south, then back onto the
Rathvon parcel running north/northeast, bisecting the parcel and continuing north onto the
neighbor's property (Figure 1). This driveway is a legal easement for ingress and egress that
serves the two properties at the end of the road and is not a public access point. There is a
permitted well located to the northeast of the proposed building footprint, on the east/northeast
side of the roadway. During the habitat survey, water was observed to be flowing out of the
ground in this area and running across the road, with the area around the well fully saturated.
The property has been fully surveyed by a licensed Professional Land Surveyor, and a site plan
has been created by McClellan Tellone (Figure 1). The proposed building footprint and critical
areas buffers (shoreline and stream buffers) are clearly flagged out on -site, including building
setbacks.
An existing dirt pathway (approximately 18-feet wide) leads to the beach, where the substrate
appears suitable for forage fish spawning, with small to medium gravel mixed with sand. From
the beach there are visible structures to the north and south; the neighboring property to the north
has a beach house and other structures located just landward of the OHWM, and the neighboring
property to the south has stairs to the beach. The riparian zone on the Rathvon parcel was
observed to be natural and intact with driftwood and gravel up to the beach -upland interface. No
wetlands or wetland vegetation were observed while on site.
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report 21 M S A
Figure 1. Rathvon single family home site plans by McClellan Tellone, Architecture Firm
O
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report 3 1 M S A
While on site, the MSA biologist observed the following vegetation species:
Herbaceous plants
• Dune grass (Leymus mollis)
• Foxglove (Digitalis purpurea) — non-native
• Miner's lettuce (Claytonia perfoliate)
• Piggyback plant (Tolmiea menziesii)
• Slender -footed sedge (Carex leptopoda)
• Thistle (Cirsium sp.)
Shrubs, ferns, and woody vines
• Evergreen huckleberry (Vaccinium ovatum)
• Nootka rose (Rosa nutkana)
• Salal (Gualtheria shallop)
• Snowberry (Symphoricarpos albus)
• Sword fern (Polystichum munitum)
• Tall Oregon grape (Mahonia aquifolium)
• Trailing blackberry (Rubus ursinus)
Trees
• Beaked hazelnut (Corylus cornuta)
• Big leaf maple (Acer macrophyllum)
■ Douglas fir (Pseudotsuga menziesii)
• Red alder (Alnus rubra)
• Western redcedar (Thuja plicata)
Abundant invasive English holly (Ilex aquifolium) was also observed to be present on the
property. Some snags with potential nesting cavities were noted on site, but none were observed
to be suitable for Northern Spotted Owls, and no trees were observed to have suitable sized limbs
for nesting Marbled Murrelets.
Notes were taken on all trees within or immediately adjacent to the proposed building footprint
to document trees that will require removal for construction. Diameter at Breast Height (DBH)
was also recorded for each tree. All of these trees consisted of Western redcedar and big leaf
maples, the majority of which had some form of rot or deformities. Additionally, all of the trees
noted are located outside of the 150-foot shoreline critical area buffer and 10-foot building
setback (160-foot total setback), and well outside of the 50-foot stream setback to the south.
These trees are documented below, however the list may not be comprehensive because there
were additional trees located outside of the building footprint that may also need to be removed
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report 41 M S A
due to proximity. All of these additional nearby trees consisted of the same two species, and all
are located outside of the critical area buffers and setbacks.
Trees that will require removal for construction:
1. Big leaf maple — 34-inch DBH, rotting/diseased,
2. Big leaf maple — 14-inch DBH,
3. Western redcedar — 42-inch DBH, very close to building corner. Evidence of use by red
breasted sapsucker,
4. Western redcedar — 34-inch DBH, rotten/diseased, forked growth pattern,
5. Western redcedar — 13.5-inch DBH,
6. Western redcedar — 29-inch DBH, outside of house footprint near east side,
7. Western redcedar — 23-inch DBH, outside of house footprint near east side,
8. Western redcedar — 34-inch DBH, outside of house footprint near west side, & 10-feet
east of surveyed 160-foot buffer and setback boundary,
9. Western redcedar — 21-inch DBH, outside of house footprint near west side, & 10-feet
east of surveyed 160-foot buffer and setback boundary.
Additionally, the MSA biologist noted any wildlife observed while on site, which included the
following species:
• Bald eagle (Haliaeetus leucocephalus) — visual observation,
• Blacktail deer (Odocoileus hemionus columbianus) — visual observation,
• Common raven (Corvus corax) — visual observation,
■ Golden -crowned kinglet (Regulus satrapa) — auditory observation,
■ Gull (Lanus sp.) — visual observation.
• Hairy or downy woodpecker (Leuconotopicus villosus or Picoides pubescens) —
excavations on trees,
• Pacific Wren (Troglodytes pacificus) —auditory observation,
• Pileated woodpecker (Dryocopus pileatus) — excavations on trees,
• Red breasted sapsucker (Sphyrapicus Tuber) — excavations/feeding sign on trees.
2 Jefferson County Cumulative Impacts Regulatory Code
The Jefferson County Shoreline Master Program (SMP) states the following code requirements
(listed below) regarding the assessment of cumulative impacts for projects located within
shoreline jurisdiction. Shoreline jurisdiction extends from the Ordinary High Water Mark
(OHWM) landward for 200-feet, and is regulated by the State Shoreline Management Act of
1971. This 200-foot jurisdictional area differs from the County protective shoreline critical area
buffer, which is 150-feet (JCC 18.25.270(4)(e)(i)). Although the proposed single-family home
and septic development project is located outside of the 150-foot shoreline critical area buffer
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report 5 1 M S A
and 10-foot setback, it is located partially within the 200-foot shoreline jurisdiction, thus these
additional requirements apply.
JCC 18.25.270(3) provides:
(3) Regulations — Cumulative Impacts.
(a) The county shall consider the cumulative impacts of individual uses and
developments, including preferred uses and uses that are exempt from permit
requirements, when determining whether a proposed use or development could
cause a net loss of ecological functions.
(b) The county shall have the authority to require the applicant/proponent to
prepare special studies, assessments and analyses as necessary to identify and
address cumulative impacts including, but not limited to, impacts on fish and
wildlife habitat, public access/use, aesthetics, and other shoreline attributes.
(c) Proponents of shoreline use and development shall take the following factors
into account when assessing cumulative impacts:
(i) Current ecological functions and human factors influencing shoreline
natural processes; and
(ii) Reasonably foreseeable future use and development of the shoreline;
and
(iii) Beneficial effects of any established regulatory programs under other
local, state, and federal laws; and
(iv) Mitigation measures implemented in conjunction with the proposed
project to avoid, reduce and/or compensate for adverse impacts.
(d) The county shall prohibit any use or development that will result in
unmitigated cumulative impacts.
JCC 18.25.590(3) provides:
(3) In the granting of all conditional use permits, consideration shall be given to the
cumulative environmental impact of additional requests for like actions in the area. For
example, if conditional use permits were granted for other developments in the area
where similar circumstances exist, the sum of the conditional uses and their impacts
should also remain consistent with the policies of RCW 90.58.020 and should not
produce a significant adverse effect to the shoreline ecological functions and processes or
other users.
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report 6 1 M S A
3 Cumulative Effects Assessment
The Rathvons are proposing to construct a single-family home and septic on their 5.47-acre
property. A permitted well has already been installed. No beach structures, such as stairs to the
beach, are planned, since none are required for beach access (there is an existing dirt pathway to
the beach). Additionally, no expansion or widening of the existing roadway is planned. Only
typical maintenance, such as re -gravelling within the existing footprint, is planned to occur.
Cumulative effects, which take into account this project as well as future development in the
area, are reasonably certain to occur around the larger geographical area. The project area
includes many other similarly developed rural residential shoreline properties to the north and
south. Cumulative habitat alterations from increased development could impact Endangered
Species Act (ESA) listed species and/or their critical habitat areas, as well as other sensitive fish
and wildlife species and habitats, human recreational activities and public access, and aesthetics.
These potential adverse cumulative effects could be caused by physical obstructions from
development, changes in stormwater flow on the landscape, changes in turbidity and pollution
levels, and other such factors.
Although the Rathvon property was one of the first properties purchased in the vicinity in 1971,
it appears to be one of the last 5+ acre parcels in this area (west of Toandos Road) on which a
single-family dwelling will be constructed. Beginning in the late 1970's, single-family dwellings
were constructed on most of the waterfront and non -waterfront lots in the immediate vicinity not
currently owned by the Department of Natural Resources (DNR). See Figures 2 through 4.
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report 71 M S A
Figure 2. Properties in the vicinity of Rathvon proposed single-family home*
*Dwelling notations are included for properties west of Toandos Road. Figures 2-3 were created by Rich
Rathvon using imagery from the Jefferson County Open Data Portal.
Figure 3. Additional properties north of Figure 2 (north of Rathvon proposed single-family home)
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report 8 1 M S A
Figure 4. Additional properties south of Figure 2 (south of Rathvon proposed single-family home)
All properties located in the immediate vicinity surrounding the Rathvon parcel already contain a
single-family dwelling. The only possible exception is the Bennett property (parcel #
701153025), located to the southeast of the Rathvon parcel (Figure 2), which currently has a yurt
(according to the Rathvons). Additionally, the terrain near the cliff on the Bennett parcel would
likely require that any future proposed structures be built on the north side of Twana Way, and
the property may not be developed at all if it is purchased by the Washington Department of
Natural Resources (WDNR) or Northwest Watershed Institute (NWI), who have been pursuing
the acquisition of properties in the area for conservation.
Many of the properties to the north, south, and east of the Rathvon parcel are already owned and
managed by WDNR or NWI, with only one entirely undeveloped private property located west
of Toandos Road appearing to have the potential of being developed in the future (Parcel #
701094002, Figure 3). WDNR and NWI have acquired, and continue to acquire, property in the
area for conservation. This protection of the land will help maintain the ecological conditions of
the immediate area and will ensure less cumulative impacts that could be caused by development
in the area. Dabob Bay is part of the growing Dabob Bay Natural Resource Conservation Area,
which is overseen by the WDNR to ensure the protection of the regional ecology and habitat
(WDNR 2024, Figure 5).
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report 91 M S A
Figure 5. Dabob Bay Natural Resource Conservation Area*
Dabob Bay Natural Resource Conservation Area
*Figure annotations created by Rich Rathvon
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Additionally, because the Rathvon parcel and surrounding properties are all zoned as RR-5 -
Rural Residential, no more than one single-family dwelling can be constructed on each parcel,
and only one Accessory Dwelling Unit (ADU) of 1,250 square feet or less is allowed (including
garages and basements). This zoning, along with county critical areas code requirements, helps
to ensure that the area will not have unmitigated development or significant cumulative impacts
from future development.
The Revised Code of Washington (RCW) Chapter 90.58.020 discusses preferred uses in
shoreline jurisdiction and calls for a balance between private property owner rights, sensitive
shoreline ecology, and public interest. This code also supports local jurisdictions in developing
and following Shoreline Master Programs, such as the Jefferson County Shoreline Master
Program (JCSMP). RCW Chapter 90.58.020 states that,
"the shorelines of the state are among the most valuable and fragile of its natural
resources and that there is great concern throughout the state relating to their utilization,
protection, restoration, and preservation .... much of the shorelines of the state and the
uplands adjacent thereto are in private ownership; that unrestricted construction on the
privately owned or publicly owned shorelines of the state is not in the best public interest;
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report I0 J M S A
and therefore, coordinated planning is necessary in order to protect the public
interest associated with the shorelines of the state while, at the same time,
recognizing and protecting private property rights consistent with the public
interest. There is, therefore, a clear and urgent demand for a planned, rational, and
concerted effort, jointly performed by federal, state, and local governments, to prevent
the inherent harm in an uncoordinated and piecemeal development of the state's
shorelines."
The Rathvons plans for their single-family home construction project have diligently taken into
consideration the regulatory code outlined in the RCW and JCSMP, including JCSMP Chapter
18.25.500, which similarly states that:
"(a) Residential use and development shall be planned, designed, located, and operated to
avoid adverse impacts on shoreline processes, aquatic habitat, biological functions, water
quality, aesthetics, navigation, and neighboring uses."
The conditional use permit criteria written in the Jefferson County Code (JCC 18.25.590) allows
for the construction of a single-family home in a manner that mitigates adverse impacts to the
shoreline environment. These provisions are designed to "allow greater flexibility in
administering the use regulations of this program in a manner consistent with the policies of
RCW 90.58.020." The Rathvons are planning the construction of their single-family home in
accordance with the conditional use permit criteria while also abiding by the Jefferson County
Shoreline Master Program regulations (Chapter 18.25), the Jefferson County Critical Areas Code
(Chapter 18.22), and the County development standards (Chapter 18.30).
In accordance with the above regulations, the Rathvons have completed the following planning
activities:
I . The proposed development is planned to be entirely outside of all critical areas buffers
and building setbacks, and these buffers/setbacks have been clearly flagged out on site.
2. A septic design and permit application has been submitted, received, and approved by the
county. The septic system is designed in a way that will avoid groundwater and shoreline
impacts to the best practicable extent possible, and the proposed location is outside of all
critical areas buffers and building setbacks.
3. A well has been sited and drilled in accordance with Jefferson County regulations. The
well is located outside of all critical areas buffers, building setbacks, and outside of
shoreline jurisdiction.
4. A survey was completed by a licensed Professional Land Surveyor on the property, and a
site plan has been prepared by McClellan Tellone (architecture firm) which shows the
proposed building location and critical areas buffers/setbacks overlaid on the topography.
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report I I I M S A
5. An additional site plan that outlines all proposed ground disturbing activities was
provided by the Rathvons to Jefferson County to satisfy code requirements.
6. A stormwater management plan was prepared to minimize potential impacts to the
shoreline and stream habitats and to abide by county code requirements.
7. The home has been designed in compliance with the State Energy Code and county
requirements, which mandate that all new single-family homes be built by more energy
efficient standards.
8. A geotechnical assessment was completed by Stratum Group and updated after public
comments/questions arose.
9. A stream assessment was completed by Peninsula Environmental.
10. A habitat survey was completed by MSA, along with this cumulative impacts analysis.
Collectively, adherence to these regulations and policies ensures that the development of this
proposed single-family home will be in a in a manner that:
a. manages and mitigates any adverse short-term impacts;
b. minimizes any adverse long-term impacts (including potential cumulative impacts to
the ecology, public use/access, and aesthetics); and
C. ensures the protection of shoreline ecological functions.
4 Conservation Measures to Avoid & Minimize Impacts
Additional conservation measures presented here include avoidance and minimization efforts
that have been considered to ensure that all proposed development is located, designed,
constructed, and maintained in a manner that protects ecological functions and ecosystem -wide
processes. This section also describes the steps that have been, and will be taken during planning
and construction to find the least environmentally damaging practicable alternative to achieve the
project goal. It is the opinion of MSA biologists that no additional mitigation, beyond the BMPs
described below, should be required for this project, since the proposed construction is located
entirely outside of all critical habitat area buffers and building setbacks.
The following mitigation sequencing steps, as described in WAC 173-26-201(2)(e) and JCC
18.22.660(2), were considered during project development and site selection:
a No action: To avoid the adverse impact altogether by not taking a certain action or parts
of an action.
o "No Action" would not achieve the project goal.
a Minimizing impacts by limiting the degree or magnitude of the action and its
implementation by using appropriate technology or by taking affirmative steps to avoid
or reduce impacts.
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report 121 M S A
o The proposed single-family home construction project includes the minimum
footprint necessary to achieve the goal. Best Management Practices (BMPs)
discussed below will be implemented during construction to minimize impacts.
Additionally, the house will be constructed in accordance with the recently
revised Washington State energy conservation standards, and will be placed
outside of all critical areas buffers and building setbacks. The Rathvons are not
seeking a buffer reduction or averaging even though they are lawfully allowed to
do so pursuant to JCC 18.25.270(5)(b), and their structure will be placed further
from the shoreline than neighboring homes' existing placement.
s Rectifying the impact by repairing, rehabilitating, or restoring the affected environment.
o BMP's will be used during construction, damage to native vegetation will be
avoided wherever possible, and any damaged vegetation will be chipped and
reused on site. The Rathvons have also stated that they plan to plant additional
native plants on their property after the construction is complete.
• Reducing or eliminating the impact over time by preservation and maintenance
operations.
o Opportunities to reduce or eliminate the permanent direct and indirect negative
impacts from the project are described below in the list of BMPs.
• Compensating for the adverse impact by replacing, enhancing, or providing substitute
resources or environments.
o Any disturbed ground outside of the construction footprint will be covered in
clean woodchips after construction is complete.
• Monitoring the impact and the compensation project and taking appropriate corrective
measures.
o No monitoring is necessary for this project, since the proposed construction is
located outside of all critical habitat areas and their associated buffers and
building setbacks.
To minimize potential impacts to ESA -listed and priority species and habitats that may be
associated with this project, as well as potential impacts to the public easement, the following
BMPs are recommended by MSA for implementation at the site:
• Before any construction work begins, site construction limits for clearing, tree protection,
and runoff will be clearly laid out on site,
• Prior to any construction activity, a silt fence and straw wattles will be installed between
the construction area and the OHWM of the shoreline and stream,
• Any disturbed earth resulting from construction activity will be covered with clean
woodchips to mitigate sediment runoff,
• All staged building materials will be confined to the existing compacted gravel
roadways/paths,
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report 13 1 M S A
• Any damage to the existing roadway should be restored to its original condition or better.
General Best Management Practices for Small Construction Sites
Hand -tools should be used whenever practicable, consistent with standard building
practices,
• Marking the critical root zone (CRZ) of trees with paint, flagging, or other to avoid
running equipment and stockpiling materials in CRZ, therefore limiting soil disturbance
and compaction. Additionally, any necessary heavy equipment and/or truck access should
entail a layer of clean woodchips, or sufficiently wide and thick steel plates in the vehicle
wheel path to avoid rutting and damaging the vegetation,
• Construction should not be conducted during heavy precipitation events, regardless of the
protection of vegetation. If vegetation is damaged, or rutting occurs, it is recommended
that those areas be re -planted with native vegetation. If planting is necessary, a layer of
clean woodchips should also be installed around plants at a minimum depth of 3 inches,
• Limit the extent of clearing operations and phase construction operations,
• The duff layer, native topsoil, and natural vegetation should be retained in an undisturbed
state to the maximum extent practicable.
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report 14 1 M S A
5 Conclusion
The full scope of cumulative impacts cannot be quantified in this assessment, but with
appropriate regulations in place, and the actions described in the above sections, it is unlikely
that ESA -listed species, critical habitat areas, or human activities will be significantly affected by
the construction of this single-family residence. Significant adverse cumulative impacts are
especially unlikely in this area due to the fact that most of the surrounding properties are already
developed or protected for conservation, and zoned for one single-family home per parcel.
Final jurisdictional authority and permitting on this project will be the responsibility of the
appropriate local, state, and/or federal government agencies involved. All information contained
in this report should be reviewed by the appropriate regulatory agencies prior to approval or
issuance of permits.
Sincerely,
671L_ o
Jill Co per
Senior Ecologist
Meg Amos
Senior Ecologist
t•srasshsrr
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report 15 1 M S A
6 References
Bornsworth J., Donadio L, and Sutter K. 2022. Stream Assessment Report for 660 Twana WY, Quilcene,
WA 98376. Dated December 19', 2022. Peninsula Environmental.
McShane, D. 2024. Geologic Hazard Assessment Report and Update. Original report dated February 15,
2022; Update dated November 14, 2024. Stratum Group.
Washington Department of Natural Resources. 2024. Article titled "Dabob Bay Natural Resources
Conservation Area to Expand 3,943 Acres," dated October 2, 2024. Available at:
https://www. dnr.wa.gov/news/dabob-bay-natural-resources-conservation-area-expand-3943-acres
Jefferson County Municipal Code. Chapter 18.22 Critical Areas.
Jefferson County Shoreline Master Program. Chapter 18.25 Jefferson County Municipal Code.
U.S. Department of Agriculture (USDA). 2013. Soil Conservation Service. Soil Survey of Jefferson
County Area, Washington. December, 2013. Accessed December 2024.
U. S. Fish and Wildlife Service (USFWS). 2024. National Wetlands Inventory (NWI) website. U.S.
Department of the Interior, Fish and Wildlife Service, Washington, D.C. Accessed December
2024.
Washington Department of Fish and Wildlife (WDFW). 2024. Priority Habitats and Species (PHS) report.
Accessed December 2024. Available at: htlp:llwdfw.wa..vov/jnappinK�/phs/
Washington Department of Natural Resources (WDNR). 2024. Forest Practices Application Mapping
Tool (FPAMT) for viewing typed streams. Accessed December 2024.
Rathvon Single Family Home Construction Project — Cumulative Impacts Assessment Report 16 1 M S A
Attachment 1.
Photo Documentation
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