Coastal Processes Assessment and Beach/Bank Recommendation for Shore North of Lummi Island Ferry Terminal, Lummi Is., WA

Bank Erosion

 

For Full Report File with pictures: Johannessen Geological Report 2008 https://liwec.wordpress.com/?attachment_id=605

Coastal Processes Assessment and Beach/Bank Recommendation for Shore North of Lummi Island Ferry Terminal, Lummi Is., WA

COASTAL GEOLOGIC SERVICES, INC.

701 Wilson Ave., Bellingham, WA 98225-7348 (360) 647-1845 jim@coastalgeo.com http://www.coastalgeo.com

Prepared for: Lummi Island Community Land Trust, Ms. Wanda Cucinnota
Prepared By: Jim Johannessen,
Licensed Engineering Geologist and MS,
Coastal Geologic Services Inc.
September 5, 2008
Introduction and Purpose
The objective of this study by Coastal Geologic Services Inc. (CGS) was to provide assessment and
recommendations relative to bank stability, coastal processes, potential soft shore protection for the bank
adjacent to the road, and potential beach habitat enhancement for the project area. The project area is
defined as the bank property that extends 600 ft north of the Lummi Island Ferry Terminal on NE Lummi
Island, as well as the north shore of the riprap fill area that contains the parking lot and loading zone for
the ferry. The work by Coastal Geologic Services Inc. (CGS) was in conjunction with work by the Lummi
Island Land Trust (LILT) and Fairbanks Environmental, and other project partners. The overall goals of
the CGS work were to enhance and/or protect habitat on the bank and upper beach to the degree
possible and to try to provide a soft shore protection design for bank reaches in the project area where
the need for erosion control to protect the road shoulder and preclude the need for rock or other hard
armoring of the shore in the short or medium term. It is our understanding that this work was grantsupported.
Beach and Coastal Processes
The Lummi Island Ferry Terminal was constructed over the intertidal and subtidal and therefore has had
an impact on coastal processes. The coastal processes of the northern portion of eastern Lummi Island
can be explained in terms of the occurrence of bedrock outcrops at the shore and the coastal sediment
transport system. The northern approximately one-third of the east shore of Lummi Island contains
beaches with loose sediment and the occurrence of the bedrock outcrops has controlled the distribution
and orientation of beach segments. In other words, broad beach areas generally occur between the
intertidal sandstone outcrops.
A systems view of the coast of this portion of Lummi Island needs to consider coastal sediment transport
(littoral drift) as the most fundamental process. The term “net shore-drift” has been used in the Puget
Sound region to describe the long term, net littoral transport direction (Jacobsen and Schwartz 1981). Net
shore-drift is typically driven by predominant (strongest) and prevailing (most frequently occurring)
southerly winds. This causes northward drift in areas with any significant open water distance (fetch) from
the south, which includes this portion of the island.
Coastal Processes Assessment & Recommendations for Lummi Island Ferry Terminal
Sep. 5, 2008, p 2 COASTAL GEOLOGIC SERVICES, INC.
Johannessen and MacLennan (2007) compiled and mapped the historic net shore-drift throughout the
Puget Sound region for the US Army Corps of Engineers and the Puget Sound Nearshore Partnership.
This mapping had a net shore-drift cell originating in Sunrise Cove and extending northward to the tip of
Lane Spit. Littoral sediment is transported northward in a series of partially connected beach segments
historically, with beach sediment bypassing several intertidal sandstone outcrops.
The Lummi Island Ferry Terminal was constructed in approximately 1980. With the construction of the
Ferry Terminal, the net shore-drift system was altered. The fill and rock armoring extended approximately
200 ft waterward of the natural bank. The rock armoring at the terminal extended down into the subtidal
and the terminal itself acted as a large groin. A groin is a cross-shore structure that traps sediment on the
up-drift side, helping to retain a wider beach width, while simultaneously causing sediment starvation and
increased wave refraction on the down-drift side.
The net shore-drift of Whatcom County was mapped by Jacobsen (1980). That study documented the
current net shore-drift cells as of 1980. At that time, the original longer drift cell did not function the same
due to the Ferry Terminal bisecting the drift cell into two different cells. Jacobsen mapped two separate
drift cells in 1980. One drift cell ended at the beach immediately south of the Ferry Terminal and the
northern cell started just north of the Ferry Terminal and ran to the tip of Lane Spit.
At the time of the 2008 field assessment the beach south of the Ferry Terminal had accreted waterward
to the extent that net shore-drift continued around the waterward end of the rock armoring (Photo page).
This was visible in the form of a continuous band of sand in the shallow subtidal which extended
northward from the tip of the Ferry Terminal fill in the form of a large sandbar overlaying a more gravelrich
platform. This accreted beach area south of the Ferry Terminal allowed net shore-drift to continue
around the fill to bring the current interpretation of net shore-drift is back to the historic configuration with
a longer drift cell. However, in the interim decades, the beach immediately north of the Ferry Terminal had
been “starved” of sediment (had a reduction in sediment supply) due to the construction of the Ferry
Terminal. In the present configuration, the terminal fill area causes net shore-drift sediment to form a bar
(intertidal) that trends to the north, with sediment staying (Figure 1).
Site Conditions
The beach at the site is composed of three distinct parts: The intertidal beach adjacent to the north side of
the parking lot area, the wide accreted beach immediately north of the parking lot along the bank that
extends approximately 260 ft the large fir trees on the lower bank, and the narrow likely erosional beach
in the north end of the study area. The three areas are described briefly below.
Intertidal Beach by Parking Lot
The beach adjacent to the north side of the ferry parking lot was completely below the Mean Higher High
Water (MHHW) line. This beach abuts the rock riprap side slope of the fill area. The eastern portion of this
beach extended from the loading ramp around to the vicinity of the sandstone outcrop on the intertidal
beach. This eastern area appeared to be at elevations approximately mid-tide level at the toe of the rock.
West of the sandstone outcrop on the intertidal beach a broader sand and gravel beach exists at the toe
of the riprap throughout both of these reaches small riprap has settled to the upper beach in a band
Coastal Processes Assessment & Recommendations for Lummi Island Ferry Terminal
Sep. 5, 2008, p 3 COASTAL GEOLOGIC SERVICES, INC.
generally 5-15 ft wide. The sandstone outcrop on the intertidal helps maintain the elevation of the western
beach along the riprap. Beach substrate on the eastern beach is primarily sand along with gravel and
possibly fine sand.
The high-tide beach (the sloping upper portion of the broader beach system) was up to 35 ft wide in this
western reach. Waterward of this, a broad sand flat extended a long distance with slope towards the
northeast. Native eelgrass (Zostera marina) and non-native eelgrass (Zostera japonica) were preset in
this area as covered by Fairbanks Environmental.
Southern Beach
This beach extended approximately 180 ft, as measured from the western edge of the riprap at the
parking lot to approximately 25 ft east of three big dying Douglas firs. The beach along the marine bank
that extends north from the parking lot had a much broader high-tide beach than the other two beach
areas. This area had a broad sandy backshore, which extended to a maximum distance of 40 ft in the
“corner” just north of the parking lot. This landward portion of the backshore area contained abundant
dunegrass (Elymus mollis), willow (Salix spp), bigleaf maple (Acer macrophyllum) or vine maple (Acer
circinatum) or (Acer spp). Drift logs were moderately dense in the backshore, some of which appeared to
be quite old. Several creosote treated logs and timbers were also present in this area.
The high-tide beach face was composed of sand with moderate amounts of gravel (pebble and granule).
The width of the intertidal high-tide beach face was generally 20-25 ft. A moderate density of small woody
debris was present on the lower high-tide beach during the May 5, 2008 site visit. Waterward of the hightide
beach was the same sand flat discussed above also extending to the sandstone outcrops.
Northern Beach
The beach in the northern portion of the study area was much narrower than the southern beach and also
composed of different sediment. This section extends approximately 360 ft from the end of southern
beach to the beach access stairway. The backshore was generally limited to 5-15 ft wide. Intermittent
accumulations of drift logs were witnessed in the field during the January and May field visits. This
included old root wads and a variety of large and small woody debris sizes (See Photo page).
The backshore sediment consisted of a mixture of sand and gravel (primarily pebble). The high-tide
beach face was composed primarily of small pebble (generally smaller than 3/4 inch diameter) with sand
and granule. However, larger pebble was present along with isolated boulders.
The beach and backshore become very narrow where the beach approaches the two small overwater
buildings. Here the percentage of sand decreases. A short distance south of the two small overwater
buildings, a 3 ft wide concrete culvert discharges stream flow onto the high-tide beach. Flow was
observed crossing the high-tide beach and low-tide terrace during both field visits.
The low-tide terrace in this northern beach reach contained far more gravel than the southern beach.
Gravel sizes ranged up to pebble and cobble among abundant sand and several isolated boulders.
Coastal Processes Assessment & Recommendations for Lummi Island Ferry Terminal
Sep. 5, 2008, p 4 COASTAL GEOLOGIC SERVICES, INC.
Several reaches of moderate sized rock revetment (rip rap) were present in the northern portion of the
northern beach. Rock appeared to extend waterward on the beach to slightly below MHHW. The rock
revetment fronting the two small overwater buildings was approximately 4-5 ft high and the buildings were
supported on primarily creosote treated piles above the rock work. This rock revetment was constructed
of generally 3-5 ft angular rock which appears to have been from the Lummi Island rock quarry. North of
these buildings, what appears to be a separate reach rock revetment extended up to the sandstone
seacliff at the north end of the study area. The overlook was constructed above this, along with the beach
access stairway.
Geology and Marine Bank
A steep marine bank was present landward of the southern and northern beach areas. The height of the
bank ranged from 12 to 16 ft above the beach, as measured by Barry G. Herman, PLS. The bank
appears to have been formed by erosion at the toe, through direct wave attack. The bank slope was
measured in the field at 30 to 40 degrees, which agrees with the topographic survey.
The geology of the marine bank was investigated through a series of hand excavations. The first
excavation site was midway along the southern beach. A small amount of groundwater seepage was
apparent at the base of the bank. At 4 ft up the bank the deposits were composed of silty clay with
occasional pebble dropstones. Farther up the bank at 8 ft deposits were composed of a silty matrix with
minor amounts of fine sand and pebble to gravel dropstones.
The second excavation site was approximately 100 ft north of the break between southern beach and
northern beach characterized in this report. A considerable amount of groundwater seepage was
apparent in this area ranging from the base of the bank to approximately 3 ft up the bank. Seepage was
identified at about 3 ft up the bank by a clumping of horsetails. Exposed deposits from toe erosion and
hand excavations yielded more extensive blocky clay with possible laminations towards the base of the
bank and absence of dropstones. This unit transitioned to a silty matrix with occasional pebble and
gravel dropstones at approximately 5 ft up the bank. Higher up the bank, at approximately 10 ft fine sand
was evident in the silty matrix along with more frequent pebble and gravel dropstones.
The geology of the marine bank at both excavation sites was interpreted to be Vashon Glaciomarine Drift
(GMD) and is consistent with previous geologic maps and reports produced by Aspect Consulting (2006)
and Lapen (2000) of Washington Department of Natural Resources. This unit is described by Aspect
Consulting (2006) as deposited by floating glacial ice and displaying two characteristics: pebble to
boulder dropstones in a silt matrix and fine grained silts and clays without dropstones, both of which were
observed in the field on May 2008. Seepage was observed at the north end of the study area
approximately 4-6 ft above bank toe. Less seepage was observed at the bank along the southern beach.
The Ferry parking lot was assumed to have been constructed on fill and was also defended by a large
quantity of rock riprap. This area was not investigated in detail, as the fill could not be observed due to the
quantity of rock covering it.
Coastal Processes Assessment & Recommendations for Lummi Island Ferry Terminal
Sep. 5, 2008, p 5 COASTAL GEOLOGIC SERVICES, INC.
Shore Change
A shore change analysis was performed using the best quality vertical air photos that corresponded with
approximately the time of the Ferry Terminal construction (circa 1980) and the most recent photo. A
vertical photo from the WA Dept. of Ecology from 1977 and a Pictometry image from 2004 were used in
ArcGIS for this. The features that showed up best on both air photos were the waterward edge of the drift
log zone and the toe of the high tide beach, features that have been used in similar coastal studies
(Fletcher et al 1997, Dolan Hayden 1983).
The shore change data (Figure 3) shows that the north beach and the northern portion of the southern
beach and backshore had eroded between 1977 and 2004. The amount of horizontal erosion generally
varied between 5 and 15 ft in this time, for rates of 2.2 to 6.7 in/year. The most rapid erosion was
observed between 25 and 150 ft southern of the stream crossing the north beach. A hinge point, or a
transition area from erosion to accretion, was present approximately 180 ft north of the riprap of the
parking/loading area. South of this point, accretion occurred. The amount of accretion increased to the
south. Accretion varied between 2 and 20 ft horizontally in the 27 year period, equivalent to 0.1 to 8 in/yr.
The erosion in the north was most likely due to some reduction in the net shore-drift rate due to the
construction of the Ferry Terminal, combined with gradual natural erosion, as the terminal interrupted
northward transport gravel and sand for most of the period since construction (see Beach and Coastal
Processes above). The accretion was due to both the wave shadow caused by the Ferry Terminal during
times of southerly and southeasterly winds and also the increased temporary southward drift of sediment
during northeasterly winds. This is the area with the wide sandy backshore.
Coastal Processes Assessment & Recommendations for Lummi Island Ferry Terminal
Sep. 5, 2008, p 6 COASTAL GEOLOGIC SERVICES, INC.
Conclusions and Recommendations
Bank Erosion Mitigation
The bank in the central and northern portions of the study area, immediately below Nugent Road, has
experienced a moderate amount of coastal erosion in recent decades. The reduction in net shore-drift
sediment supply due to the construction of the Ferry Terminal, in combination with the moderately large,
indirect wave fetch, have resulted in intermittent wave attack reaching the bank toe. Evidence of drift log
mobility during storms certainly contributed to the erosion. Overall, it appears wave attack at the toe of the
bank is the driver of coastal erosion. The coastal erosion appears moderate and the road in not in
immediate danger such that a “hard” bulkhead such as a rock or concrete wall is not necessary a present,
or moving the road landward. However, a compact soft-shore protection design appears appropriate to
slow the intermittent erosion of the bank. This is stated, as it appears that only several storms per year
cause significant wave attack at the bank toe. In addition, coastal erosion in the Puget Sound region
appears to have been exacerbated in recent years by global climate change—increased storminess and
accelerated sea level rise (Mote et al. 2008, Johannessen and MacLennan 2007, Snover et al. 2005).
Soft shore protection entails the use of natural materials such as gravel and large wood debris (LWD) to
enhance the stability of beaches (Johannessen 2002, Johannessen 2000).
Two shoreline reaches were identified that warranted bank toe erosion protection within the study area.
These areas were characterized by very minimal road shoulder setback, generally 3-7 ft from the top of
bank. Measurements were made in the field and road shoulder width is also graphically shown in Sheet 1.
The two reaches identified are in a 66 ft long section of the southern beach and bank and the second
section is a 110 ft long reach in the northern beach reach. The southern reach extends through an
undefended bank toe in the area where toe erosion has been widespread, as documented in the Site
Conditions section. This area has a 12 ft high bank with an approximate slope of 30 degrees. The
northern reach extends southward from the older rock shore protection and ends at the single 5 ft boulder
along the bank toe. This area contains a bank of 16 ft high with an approximate slope of 40 degrees. This
reach has experienced extensive bank toe erosion and a number of small slides in the recent past.
The intent of the erosion control is to minimize (but not halt) future erosion and try to preclude the need
for a “hard-armored” structure, such as a rockery (steep-faced rock bulkhead), in the future. The use of an
anchored log, soft shore protection approach is recommended for these two reaches, since bank erosion
is not at a rapid rate and the use of a soft-shore protection design appears feasible in this location with
lesser impacts than a structure such as a rockery would cause. The relative wave energy at the bank in
the study area appears moderate and the anchoring qualities of the geologic deposits appear relatively
good such that soft shore protection is appropriate for a site where an absolute halting of erosion through
installation of a bulkhead is not required.
Primary elements of the design are installing large logs from an imported source and from on-site, along
with a lesser number of stumps (LWD). In addition, the area immediately adjacent to the bank toe would
be augmented with gravel in a narrow (18 ft wide), raised storm berm. This would be installed both higher
and coarser than what is at the site (Sheet 2).
Coastal Processes Assessment & Recommendations for Lummi Island Ferry Terminal
Sep. 5, 2008, p 7 COASTAL GEOLOGIC SERVICES, INC.
Approximately 0.5 to 0.75 ft (vertically) of the uppermost beach sand and gravel would first be excavated
and moved slightly waterward (Sheets 1 and 2). Gravel would be imported, and the toe of the gravel berm
would be keyed into the backshore in the excavation area. The reasoning behind this is to allow for
improved drainage through the upper beach berm and increase the stability due to the presence of
relatively heavier gravel during high water storms. The imported gravel should consist of washed, round
rock (13/4 - 2” inch “drain rock”). This material would be placed into the excavated area and extend
landward up to the bank scarp (Sheet 2). This footprint would be entirely landward of the mean higher
high water line (MHHW; elevation +9.15 ft MLLW) by approximately 15-20 ft. The imported gravel would
generally be 1.5-3 ft thick vertically, with the thickest portion near the bank toe. The gravel protective
berm would be limited to approximately 6 ft wide crossshore, from the bank toe waterward (Sheet 2).
The design here would rely on the largest available logs from on site and imported logs, and
approximately 2 of the largest available root masses (stumps), with 10-15 ft of stem attached. Douglas fir
and cedar are the species that last the longest and these are the only species acceptable for this project.
After the number of large logs on-site is determined close to the time of construction, the rest of the wood
could be obtained by on-island sources or brought by a barge in the form of used “boom sticks” (logs that
have been used for the perimeter of log rafts) are often the best size and quality that can sometimes be
acquired much cheaper than whole logs on land.
Long logs would be placed in the imported gravel with the base even with the surface of the pre-existing
beach grade, as it is important to not place logs too high as they can be undermined during a storm. Also,
it is important to place the logs near the bank toe to minimize wave scour during tides that are lower than
storm high tides where protection of the bank is most important. Shorter logs and root masses would be
placed above and even with the longer logs in a near cross-shore orientation (Sheet 1). The crossing logs
will not only aid in the stability of the longer logs and gravel but also help accrete (catch) additional natural
drift logs and other LWD.
The materials required for import are as follows:
1. 375 tons (280 cubic yards): 1 3/4 - 2” washed, rounded gravel (sound rock-needs to be
approved by geologist)
2. 2 – 60 ft long logs (cedar or Douglas fir), minimum diameter 22“
3. 2 – 50 ft long logs (cedar or Douglas fir), minimum diameter 22“
4. 2 – 45 ft long logs (cedar or Douglas fir), minimum diameter 22“
5. 4 pieces 15-18 ft long, 22”+ dia. sound logs (Douglas fir or cedar)
6. 2 pieces 15-18 ft long, 24”+ dia. sound root masses (Douglas fir or cedar)
7. 9 ecology blocks (2x2x6 ft) with 3 inch hole in center of form, or drilled,
or alternatively 18 Manta Ray (MR-4) anchors
5. 300 ft 3/8 inch marine-grade, galvanized lashing chain
6. 32 6” galvanized staples and 12 3/8” galvanized shackles
Coastal Processes Assessment & Recommendations for Lummi Island Ferry Terminal
Sep. 5, 2008, p 8 COASTAL GEOLOGIC SERVICES, INC.
All logs would be anchored in place with either ecology block “deadman” anchors or alternatively, with
Manta Ray anchors. The holding power would be substantial better and the cost would also be much
lower with the deadman anchors.
The 36 inch culvert that conveys stream flow under Nugent Road to the beach should not be buried in
construction of the soft shore protection design. Gravel will be kept low in this area and the logs should
not cross the stream, in order to keep the channel flowing across the upper-most beach.
The excavated native beach sediment from below the new protective berm would be placed atop the
landward-most portion of the enhanced storm berm, with a lesser amount placed immediately waterward
of the imported gravel. Native dunegrass (Elymus mollis) would then be planted in sediment placed atop
the storm berm shortly after construction in a roughly 2 ft grid along with other vegetation as
recommended by Wanda Cucinotta. Dunegrass is the green-blue, tall, backshore grass species that
grows naturally in backshore areas, including at and near the site. Dunegrass would augment the stability
of the constructed storm berm through its root strength. The dunegrass could be harvested by simply
getting the rhizomes (roots) that spread laterally from the shoots in backshore areas, or purchased from a
local nursery that specialized in native species (such as Fourth Corner Nursery in Whatcom County).
Dunegrass often comes bare-root, at a low cost. The roots should be buried under 1-2 inches of sandy
sediment and watered occasionally in the first few dry months.
The recommended soft shore protection will likely require using a barge for materials and equipment
delivery, as no access down the banks appears to be available. Also, a source of rounded gravel is does
not seem to exist on the island, such that eh ferry or other water transport would be required.
Approximate costs for the recommended soft shore protection are on the order of $30,000 - $50,000. If
local LWD can be acquired, this will keep the costs down. Also if ecology blocks can be used for anchors,
this will also keep costs down. If LWD and Manta Ray anchors are used and off-island contractors are
used, the total costs may exceed the upper end of the estimate.
Large-Scale Beach Nourishment Feasibility
Beach nourishment was not recommended for the study area. The beach north of the Ferry Terminal
appears fairly “healthy” with a reasonable amount of potential forage fish spawning substrate present (as
further discussed in the accompanying report by Fairbanks Environmental). The southern beach is quite
wide with a considerable area of backshore. The entire northern beach was narrower than the southern
beach, and this is likely partially due to net shore-drift reduction due to the construction of the Ferry
Terminal, as discussed above. However, due to the northward net shore-drift, this beach appears near as
wide as it could be. The rock outcrops at the north end of the northern beach appear to act as small
groins in holding the beach in a relatively stable configuration. Potential littoral drift appears greater in this
northern beach due to the greater exposure to southerly southeasterly wind waves. Considering these
factors together, the conclusion was reached that beach nourishment sediment that would be placed in
this area would likely be transported northward in the short to medium term and would therefore have a
limited residence time and short term benefit only for potentially increasing forage fish spawning areas.
Coastal Processes Assessment & Recommendations for Lummi Island Ferry Terminal
Sep. 5, 2008, p 9 COASTAL GEOLOGIC SERVICES, INC.
The consideration of beach nourishment should be revisited in the future if erosion continues in the
northern reach, as net shore-drift sediment that now is transported around the Ferry Terminal may not be
enough to offset the trend of erosion that has occurred in the past few decades.
Drainage Control
The southern portion of the southern beach reach contains old rock shore protection. Some of this rock
extends a good distance up the bank face to include the area on the bank face where the southern 12
inch corrugated metal pipe. Therefore water exiting this pipe generally falls on the rock and does not
cause additional bank erosion and no action is required for this culvert.
The next drainage pipe to the north is an 18 inch corrugated (aluminum) metal pipe which drains portions
of the new parking lot and overflows from the infiltration ponds. This culvert outflow is perched well above
the level of the beach and contributes to bank erosion. This culvert should be lengthened by bolting an
angle joint (30 degree bend) and culvert pipe extension to bring the outvert to within one foot of beach
level. Several ft of the existing culvert will need to be cut off first to both shorten the pipe and bring it
closed to the present bank face and to allow for a clean attachment area.
A 36 inch cement culvert was located at the bank toe on the north end of the study area. This culvert
conveys stream flow to the beach and is discussed in detail by the accompanying report by Fairbanks
Environmental, such that no additional recommendations are provided here.
Other Recommendations
Planting portions of the rock face on the north side of the Ferry Terminal is recommended to provide
some habitat diversity and shade. Shade would be most beneficial above the upper intertidal beach
(generally +6.5 to +9.5 ft MLLW) to improve potential forage fish spawning habitat. Planting should be upslope
from the area frequently inundated by salt spray, generally above elevation +12 ft MLLW, where
other “weedy” vegetation is present at low density. Specific methods are not included here, however
some advice on methods was discussed with a Washington Dept. of Transportation landscape architect,
and this contact was passed on to Wanda Cucinotta.
Another area that would benefit from vegetation enhancement is the bank crest and upper bank face in
the vicinity of the stream crossing and north of the stream. This would first require removal of Himalayan
blackberry and other exotic species, and then introduction and maintenance of appropriate fibrous-rooted
native vegetation, as determined by Wanda Cucinotta. This would aid in improving slope stability over
time.
Creosoted logs and timbers that are present in the backshore of the study area should all be removed
and disposed of at an approved upland facility, as has been done in the past on the island. Washington
DNR may be able to assist with this.
Other recommendations included in the accompanying report by Fairbanks Environmental should also be
carried out, such as water quality work for the parking/loading area, as well as other recommendations.
Coastal Processes Assessment & Recommendations for Lummi Island Ferry Terminal
Sep. 5, 2008, p 10 COASTAL GEOLOGIC SERVICES, INC.
Limitations of This Report
This report was prepared for the specific conditions present at the subject property to meet the needs of
specific individuals. No one other than the client should apply this report for any purposes other than that
originally contemplated without first conferring with the geologist who prepared this report. The findings
and recommendations presented in this report were reached based on a several brief field visits. The
report does not reflect detailed examination of sub-surface conditions present at the site, documentation
of which are not known to exist. It is based on examination of surface features, bank exposures, soils
characteristics, beach features, and geologic processes. In addition, conditions may change at the site
due to human influences, floods, earthquakes, groundwater regime changes, or other factors. This report
may not be all that is required by a construction contractor to carry out recommended actions. Great care
must be exercised when working on unstable slopes or close to foundations.
For any questions regarding this memo please feel free to contact Jim Johannessen with Coastal
Geologic Services at (360) 647-1845. Thank you for choosing to work with CGS.
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Sep. 5, 2008, p 11 COASTAL GEOLOGIC SERVICES, INC.
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Washington State. A report by the University of Washington Climate Impacts Group and the Department of
Ecology.
Snover, A.K., P.W. Mote, L. Whitely Binder, A.F. Hamlet, and N.J. Mantua. 2005. Uncertain future: climate change
and its effects on Puget Sound. A report for the Puget Sound Action Team by the Climate Impacts Group
(Center for Science in the Earth System, Joint Institute for the Study of the Atmosphere and Oceans,
University of Washington, Seattle.
Coastal Geologic Services Inc.
Jim Johannessen,
Licensed Engineering Geologist and MS
ATTACHMENTS:
Figure 1. Oblique aerial photo of the site, from 2006 by WA Dept. of Ecology.
Figure 2. Oblique aerial photo of the site and northern bedrock shore from 2006 WA Dept. of Ecology.
Figure 3. Shore change map 1977-2004.
Photo Page. Lummi Island Ferry Terminal on May 5, 2008
Sheet 1. Topographic site plan map
Sheet 2. Proposed cross sections
Coastal Processes Assessment & Recommendations for Lummi Island Ferry Terminal
Sep. 5, 2008, p 12 COASTAL GEOLOGIC SERVICES, INC.
Figure 1. Oblique aerial photo of the site from 2006 WA Dept. of Ecology.
Figure 2. Oblique aerial photo of the site and northern bedrock shore from 2006 WA Dept. of Ecology.
South Beach
North Beach
Figure 3. Change in log-line and toe of high tide beach between 1977 and 2004.
Legend
log-line 1977
log-line 2004
toe high tide beach 1977
toe high tide beach 2004
1:900
Feet
010 30 60 90 120 150
1" = 75'
Coastal Processes Assessment & Recommendations for Lummi Island Ferry Terminal
Sep. 5, 2008, p 13 COASTAL GEOLOGIC SERVICES, INC.
Photo Page. Lummi Island Ferry Terminal (top), south beach (middle) and north beach (bottom) on May 5, 2008.
Prepared for: Lummi Island Community Land Trust, Wanda Cucinnota

COASTAL GEOLOGIC SERVICES, INC.

701 Wilson Ave., Bellingham, WA 98225-7348 (360) 647-1845 jim@coastalgeo.com http://www.coastalgeo.com

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