ambleside – dundarave long term shoreline planning framework

Transcription

THE WATERFRONT COMMUNITY
AMBLESIDE – DUNDARAVE
LONG TERM SHORELINE PLANNING FRAMEWORK
March 1, 2005
ENGINEERING ADVISORY COMMITTEE
EXECUTIVE SUMMARY
On July 5th, 2004 Council passed the following motion:
“Council authorizes the formation of an EAC subcommittee to prepare a report to
the EAC with recommendations on action that can be taken by the Municipality
to reduce erosion, preserve habitat and best manage maintenance costs for the
Ambleside and Dundarave waterfront areas.”
The subcommittee has reviewed over twenty reports (dating back to 1963) and has discussed
shoreline issues with District staff and interested specialists and agencies. Based on this review
process the EAC has prepared the report that follows.
We Found:
•
That no District department (Parks, Planning, Engineering) is accountable for preserving the
long term integrity of the West Vancouver Shoreline.
•
That recommendations from past reports to enhance the knowledge base related to coastal
processes and aquatic habitat, to mitigate erosion and to enhance public access to the
foreshore... have generally not been implemented.
•
That shoreline structures (piers, groynes, seawalls, culverts) which intrude into the shore
zone from Dundarave Pier to Ambleside were originally located without consideration to
their impact on shoreline sediment transport and habitat values.
•
That the foreshore relies on a supply of sediment discharged from creeks along the West
Vancouver foreshore. These sediments naturally move from west to east. The piers and
groynes between Dundarave and Ambleside alter and diminish the westerly transport of
these sediments such that it is has been considered necessary to import sand from outside
sources to maintain Ambleside beach.
•
That: the seawalls on District and private property (many of which encroach on the intertidal zone); The 2 km rip-rap section between 24th and 21st Streets; and the concrete lockblock seawall east of Dundarave Pier… have eliminated original low gradient shoreline.
These man-made works have steepened the upper shoreline resulting in accelerated erosion
and impacts during storm events.
•
That there is minimal opportunity for the public to safely access the waters edge between
Dundarave Pier and 21st Street because of the lock-block and the uninterrupted rip-rap. In
this section, natural habitat for fish, birds and aquatic plants has been lost or diminished
due to erosion.
Ambleside – Dundarave Long Term Shoreline Planning Framework
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We believe:
•
That improved awareness of West Vancouver’s shoreline processes and environments is
essential to enable a long term reduction of erosion and maintenance costs while
enhancing environmental values.
•
That the District’s 1991 Waterfront Directions Study remains a sound investment that
should be re-visited to review progress made and opportunities outstanding.
•
That the District requires a “Long Term Shoreline Directions Plan” that will serve as a
guidance document for all future activities along the Dundarave-Ambleside foreshore.
•
That in order to responsibly prepare a “Long Term Shoreline Directions Plan” the District
needs to commission studies that provide the knowledge base and analysis required to
develop measures that will enhance both environmental and public use opportunities
and provide long-term maintenance cost savings.
•
That pilot projects should be constructed in the next few years to demonstrate to both
the District and the regulatory agencies that subtle changes to the existing rip-rap works
can reduce wave damage and provide enhanced fisheries habitat and public access. For
example; create pocket beach by relocating existing rip-rap to offshore shallow reef and
by placing boulders (from District building excavations) to form the beach, habitat and
public access.
The EAC has formulated a list of more than 30 items warranting attention and action (see
Appendix 1). The list requires review by staff and Council for prioritization and resource
allocation. Some of the action items can be readily implemented at nominal cost while others
require dedication of funding or resources.
We Recommend:
1)
Priority Recommendation:
•
That the District formulate a specific Three Year Initiative “Focus on the Shoreline” with
the goal of addressing knowledge gaps and advancing shoreline pilot projects.
•
That the District create a specific project budget for this initiative with a 50% allocation
for advancing the knowledge base and the remaining 50% to fund tangible work to
reduce maintenance costs and to construct pilot projects.
•
That, in order to foster integration across departments, the District create a crossdepartmental team with funding and deliverables split evenly between Parks,
Engineering and Planning.
•
That the District review progress after three years to assess ongoing action and
priorities.
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2)
Core Recommendations
•
That staff re-visit previous studies and particularly the 10 to 15 year implementation
goals of the 1991 “Waterfront Directions Study” to review progress made and update
approaches to enhance implementation, planning and knowledge base for the next 20
years.
•
That the West Vancouver Geographic Information System and modelling tools address
the negligible data currently shown for the District’s shore zone and work with other
levels of government agencies and interested partners to advance the information base
at least cost.
•
That the District prioritize obtaining baseline information recommended herein or
identified in previous West Vancouver District Reports over the next five years.
•
That the District develop a cross departmental team with responsibility to develop a
“Long Term Shoreline Directions Plan” that will not only address the issues of erosion
control, habitat preservation and mitigation of maintenance costs but that will also serve
as a guidance document for future activities that can impact the foreshore.
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TABLE OF CONTENTS
EXECUTIVE SUMMARY............................................................................................................... I
1.0
INTRODUCTION .............................................................................................................. 1
2.0
A SHORELINE WALK – DUNDARAVE PIER TO AMBLESIDE BEACH ................... 2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
4.0
DUNDARAVE BEACH AND PIER/GROYNE...................................................................................... 2
CONCRETE LOCK-BLOCK SEAWALL 26TH ST. TO 25TH ST. ........................................................... 3
RIP-RAP ARMOURED SEA-WALK - 25TH TO 21ST ST. ................................................................... 3
NAVVY JACK POINT ...................................................................................................................... 5
MCDONALD CREEK AND LAWSON CREEK ................................................................................... 6
LAWSON BEACH AND LAWSON PIER ............................................................................................ 6
LAWSON PARK TO 14TH ST. PIER ................................................................................................... 7
14TH ST. PIER AND BOAT RAMP ..................................................................................................... 8
AMBLESIDE BEACH ....................................................................................................................... 9
REFERENCE DOCUMENTS........................................................................................... 11
SELECT HIGHLIGHTS FROM REVIEWED REPORTS ....................................................................... 11
DATA LIMITATIONS ..................................................................................................................... 11
MAINTENANCE COSTS AND BUDGET ALLOCATIONS....................................... 13
5.0
FUTURE SHORELINE WALKS - LONG TERM SHORELINE PLANNING
CONSIDERATIONS ................................................................................................................... 14
5.1
5.2
5.3
5.4
5.5
5.6
WATERFRONT BEACH PRESERVATION – IMPROVING THE KNOWLEDGE BASE .......................... 14
REDUCING LONG TERM SHORELINE MAINTENANCE COSTS ...................................................... 14
PRESERVING AND ENHANCING NATURAL BEACH FORMS AND HABITATS................................ 14
DEVELOPING AN OPERATIONAL SHORELINE MAINTENANCE PLAN ........................................... 17
ANTICIPATING AND MITIGATING THE IMPACTS OF SEA LEVEL RISE ......................................... 18
PUBLIC AWARENESS/CONSULTATION ........................................................................................ 18
6.0
EROSION MITIGATION, MAINTENANCE MANAGEMENT AND HABITAT
ENHANCEMENT ISSUES AND ACTION MEASURES......................................................... 19
6.1
6.2
6.3
6.4
6.5
6.6
6.7
7.0
7.1
7.2
7.3
7.4
7.5
8.0
8.1
8.2
DUNDARAVE (25TH STREET PIER TO 24TH STREET) ...................................................................... 19
24TH ST. TO NAVVY JACK POINT ................................................................................................. 20
MCDONALD CREEK SEAWALL AND CREEK OUTLET .................................................................. 21
JOHN LAWSON PARK VICINITY ................................................................................................... 21
15TH STREET TO 14TH STREET ....................................................................................................... 22
14TH STREET PIER AND BOAT LAUNCH ....................................................................................... 22
AMBLESIDE BEACH ..................................................................................................................... 23
SHORELINE JURISDICTION ISSUES........................................................................... 24
MUNICIPAL – ENGINEERING/PARKS,/PLANNING/ PUBLIC WORKS ............................................. 24
GREATER VANCOUVER REGIONAL DISTRICT ............................................................................. 24
PROVINCIAL – MWLAP.............................................................................................................. 24
FEDERAL – F&O, ENVIRONMENT CANADA, COAST GUARD, BIEAP ETC. ................................ 24
PRIVATE LANDS .......................................................................................................................... 25
RECOMMENDATIONS................................................................................................... 27
PRIORITY RECOMMENDATION: ................................................................................................... 27
CORE RECOMMENDATIONS ......................................................................................................... 27
APPENDIX 1 – SHORELINE PLAN ACTION LIST ................................................................. 1
APPENDIX 2 – MAINTENANCE COSTS.................................................................................. 1
APPENDIX 3 – SELECTED EXCERPTS FROM PAST REPORTS .......................................... 1
APPENDIX 4 – REFERENCE DOCUMENTS ............................................................................ 2
APPENDIX 5 – PICTORIAL SHOREWALK
APPENDIX 6 - Accompanying CD containing
Report and Pictorials
Aerial Photos
Reference Documents in PDF format
Supplementary Slideshows and Movies
Engineering Advisory Committee
1.0
INTRODUCTION
From Dundarave Pier to the Ambleside Beaches the West Vancouver public shoreline is a defining
component of the community. Indeed, the District’s logo itself depicts the connectedness of the
”Waterfront Community”.
In response to a referral regarding Shoreline issues, the Engineering Advisory Committee alerted council
to an apparent lack of knowledge and policy base for overall shoreline issues.
Subsequently, Council, at its July 5th, 2004 meeting passed the following motion:
“Council authorizes the formation of an EAC subcommittee to prepare a report to the EAC with
recommendations on action that can be taken by the Municipality to reduce erosion, preserve habitat and best
manage maintenance costs for the Ambleside and Dundarave waterfront areas.”
The following document tables issues and provides recommendations to support Council’s direction.
A significant list of past documents, primarily funded by the District, was recovered and reviewed (see
Appendix 1) including the 1990/91 report “West Vancouver Waterfront Directions Study: Ambleside
to Dundarave”. This comprehensive report laid out a 15 year plan and implementation strategy
validated with significant public consultation. Some suggestions have been actioned, others remain
dormant. It seems timely to revisit the “Waterfront Community’s” current directions and goals going
forward from 2005.
The following glossary describes some technical terms used in this report:
•
Littoral – pertaining to the shore and inter-tidal zone i.e. littoral transport of beach sands and
cobbles.
•
Groyne – a structure which blocks or accumulates movement of beach sediments along a shore.
Typically in West Vancouver constructed as rock structures or filled piers.
•
Drift sill – low impact groyne which lies flush with the natural storm beach profile. May also be
a natural formation such as a bedrock drift-sill.
•
Inter-tidal – the extent of the beach profile between the low tide line and high tide line.
•
Sub-tidal -- the extent of the beach below the low tide line.
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2.0
A SHORELINE WALK – DUNDARAVE PIER TO AMBLESIDE BEACH
The coastal sub-units and associated issues are tabled for reference. This Shoreline Walk begins at
Dundarave Pier and terminates at the east end of Ambleside Beach.
2.1
Dundarave Beach and Pier/Groyne
Dundarave Pier was designed 100 years ago as a
convenient offloading wharf. The location offered
the shortest practical distance from land to a
depth suitable for mooring a deep draft vessel.
After many alterations, the facility now acts as a
promenade, a beach retaining groyne and a
breakwater with transient access float.
Past reports(19,20) (numbers refer to reports listed
in Appendix 4) have noted typical groyne-induced
erosion on the down-drift (easterly) side.
Interruption of littoral sand and gravel supply can
have subtle long-term repercussions for downstream shoreline and habitats. Detailed awareness of long
term processes could benefit decisions affecting the quality of the existing recreational beach,
preservation of downstream habitats, and reduced operational and storm damage expenditures for the
shoreline as far as Navvy Jack Point by avoiding the long term trend to narrowing of inter-tidal width
(which helps limit wave overtopping and impact).
Up-drift of the pier/groyne the limited supply of sands and cobbles accumulate as a beach. In summer,
the fair weather beach steepens. In winter, storm waves cut down the beach so that the sand
component, in particular, flows past the tip of the pier/groyne into deeper water. Occasional by-passing
of small volumes of upper beach cobble materials across the pier barrier prior to erosion, could be
considered to restore the continuity of a pre-pier sediment transport regime. This could incidentally
improve childrens swimming safety by reducing the surprising cobble “drop-off” at low tide water’s
edge.
The beach and pier accumulate winter log debris and the accumulated logs float free forming floating
mass againset the pier on the highest tides. The merits of having these logs boomed by log salvors on
mid winter high tides might be worth reviewing. Driven by storm waves the larger logs can cause
downstream damage such as broken parapet curbs, scouring of beach and rip rap and destruction of
piled structures such as Ambleside pier.
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2.2
Concrete Lock-Block Seawall 26th St. to 25th St.
The vertical concrete face of this section of
the sea-walk reflects and amplifies wave
energy. Storm wave impact and overtopping
causes damage and debris impacts. ($$ repair
to replace fill in 2001) The upper cobble/sand
beach along this section (which persists due to
seasonal sediment input from the Marr Creek
outfall) is highly mobile and frequently scoured
down to bedrock. While the wall has been
recently repaired, it is suggested that
alternative “softer” approaches be developed.
For example, habitat boulder gardens, (from
District excavations for instance) could help
diffuse wave impacts, and encourage habitat diversity and stability. Placement of nearshore rock habitat
reefs could be considered to recover sand smothered kelp substrates and rebuild a healthy and storm
resistant shore. A perched upper cobble foreshore would reduce wave impacts and increase habitat
values by reducing the mobility and erosion of intertidal subtrates. It is notable that sea-level rise would
signifigantly increase both future habitat impacts and damage costs in this area.
2.3
Rip-Rap Armoured Sea-walk - 25th to 21st St.
The primary character of the next
2 km is angular rock rip-rap which
protects the sea-walk and the
underlying GVRD sewer pipe
from 2 – 3 m storm waves. The
residual inter-tidal area is a
mixture of exposed sandstone
and sand/cobble/boulder beach.
The rock is unfortunately a
somewhat hazardous linear
barrier to water access.
The rock berm replaces the original upper backshore and
eliminates sand and cobble supply from this escarpment area.
With sediment starved processes and a diminished sediment
supply it is likely that storm actions on the sand/cobble beach
fronting the rip-rap are slowly sorting, separating and
transporting the sands which underlay the cobble beach face.
Over the long term selective erosion of the sands would see
the inter-tidal zone narrow and lower in elevation. The
sand, cobble and boulder inter-tidal beach is not only a rich
invertebrate habitat; it also acts as the underpinning
foundation for upper shore profiles. A wide beach causes
waves to break offshore and not directly onto the sea-walk
and riprap. Long term erosion of the underlying sand,
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combined with predicted sea-level rise would dramatically aggravate the frequency, duration and
intensity of storm wave impacts and overtopping.
Past reports to the District (1,11,22) have repeatedly suggested alternatives to hardened shorelines.
Benefits could include: mitigation of storm damage and beach loss, improved habitat, as well as improved
water access and aesthetics. It was suggested that existing armour rock could be re-worked, embedded
drift log features be further refined and stable riparian vegetation be encouraged in an ongoing pilot
project to refine and improve upon such approaches. While pro forma habitat compensation was
implemented, these long standing recommendations did not become a visible feature of the $3.8 million
GVRD/West Vancouver sewer and promenade repair project perhaps because of the level of detail
required and the time and funding constraints. The idea of returning to the detail issues to develop
pilots and detail “shelf” plans has continuing value in preparation for any future works or repair projects.
For example, a pilot project might involve subtle re-working of shoreline boulders and drift logs to mimic natural
formations of one or two cobble beach fillets. When oversize drift-logs strand on high tides there could be an
opportunistic policy of quickly anchoring and embedding with gravel, selected drift logs into the permanent
beachscape and as buffers to protect and deflect future floating debris impacts.
Modified Photo
Predictions of climate change infer that “200 year” storms such as the 2001 event will increase in
frequency. In addition, increased water levels and duration of high water level exposure periods will
increase the risk probability that storm waves will coincide with high tide conditions. Increasing wave
damage to shorelines is widely anticipated worldwide in the coming years. The sea-walk itself is
currently less than 1m above known extreme water levels (1982). The section in the vicinity of 23rd St
is particularly prone to wave overtopping at typical high tides of 14 to 16 ft. Over the next 50 to 100
years the response to any sea level rise will be either
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1) increasing expenditures on armouring and hardening of the shoreline
and , increased insurance premiums based revised risk assessments.
OR
2) Fostering evolution of a wide healthy fronting intertidal foreshore to disperse wave energy in a
natural manner and maintain full habitat productivity.
Small pilot projects would provide a working model for the latter response.
2.4
Navvy Jack Point
Past studies and reports have noted the critical role of
Navvy Jack Point in defining and limiting long-shore
sediment transport and both updrift and downdrift
shoreline character. District funded reports(20,19,22,11)
dating back to the ‘70s have also repeatedly
recommended obtaining better definition of the tidal
currents and littoral dynamics.
Specific suggestions have included:
•
determining the rates of loss of material to
deep water at the point.
•
encouraging cobble beach retention and
possibly creating a pocket beach providing
storm protection, improved habitat and water-access.
•
Considering a public access feature in a location that offers the latest evening sun exposure
along this stretch of shoreline. (19,22)
•
near-shore inter-tidal reef or rock formations to enhance natural headland functions and
habitats.)
A dive survey and interpretation would be invaluable in understanding the existing natural regimes and their
contributions to reducing erosion and habitat diversity with a view to both preserving and enhancing those values.
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2.5
McDonald Creek and Lawson Creek
These small creek outlets located down-drift of
the Navvy Jack “loss point” renew and feed the
shoreline sediment supply from Lawson Park to
Ambleside Beach. Despite their culverted form,
the creeks provide fish and bird habitat. District
reports dating back to 1977 (19,22,11) have identified
the desirability of restoring the creeks to a more
natural form.
A line of armour rock buried in the beach
ensures that accumulated cobble and sand is
“blown” into deep water during heavy rainfall
events rather than dispersing into broad
meanders across the foreshore as a natural creek
outlet would do.
Once injected onto the foreshore,
McDonald sediment supply is quickly
transported along due to the
adjacent concrete seawall. The
reflective seawall accelerates
erosional transport of beach
sediments. In the past, random
armour rock has been dumped along
the wall face to reduce this effect.
Alternatives could be piloted to
foster a less erosional shoreline with
more natural looking intertidal boulder groupings and attention to shoreline features to disperse wave
energy, reduce overtopping and enhance shoreline values.
2.6
Lawson Beach and Lawson Pier
The combination of the creek-supplied sand
and cobble and the groyne effect of the
Lawson pier has created a beach and tidepool/estuary which could be enhanced in the
longer term.
Similar to other West Vancouver piers,
Lawson Pier was designed 100 years ago to
provide the shortest (cheapest) distance
from land to a deep water wharf face. The
current solid pile-wall structure, while
deteriorated, is tolerant of drift log impacts.
During major storms, as with Dundarave
Beach, the accumulated fair weather beach
profile may be quickly flattened (eroded) and
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it is probable that beach material that would otherwise have “leaked” past the structure may be eroded
and lost over the deep water drop-off. During average conditions, gaps and breaches in the
deteriorated pilings allow some upper beach sand “leakage” which fortuitously helps preserve the
tenuous sediment supply to preserve down-drift shores. This leakage is a fortuitous but unintended
emulation of a “detached” groyne. The desirable aspects could readily be enhanced in future repairs or
redesigns to preserve the updrift as well as the downdrift shore profiles.
A 1975 hydrographic survey funded by the District shows a bulge in the deep-water contours just of the
pier tip. A visual dive survey could assess whether this is coincidence or whether it represents accumulations of
deflected beach sediments by the pier.
2.7
Lawson Park to 14th St. Pier
The cobble-armoured sandy beach east of the pier
benefits from a zone of reduced wave energy both
due to orientation and the wave protection behind
Lawson Pier. Access to the water’s edge and
longshore beach walking is possible in some areas
however the upper beach has narrowed.
Healthy dune grass and drift log environments are
typical between Lawson Park and the park at 15th
St. To the east, private and municipal concrete
seawalls have contributed to “textbook”
degradation of upper beach elevation and width
that has been remarked upon since 1977 (11).
Three concrete cased storm-drain pipes
immediately east of the seawalls also influence
beach dynamics, acting as overtopping drift sills which anchor the upper beach profile to the west. The
outflows encourage a mussel colony. A large embedded tree stump also helps to anchor the beach
profile.
The pipes are in poor condition. In the long run these outalls could be restored to a more natural
formation. In the short term it is suggested that the broken pipe could be removed to improve natural beach
transport, to introduce fresh water discharges higher on the foreshore and simply to improve aesthetics in front of
a public waterfront park.
A 1992 study (22) suggested creation of a “perched” beach as
a mitigating response to the seawall impacts between 15th St
and 14th St. Degradation has continued since that time. The
two acquired municipal lots have seawalls, which aggravate
the barrier of what is now more than a 7ft vertical face at the
municipal allotment garden seawall. The municipal walls have
been repaired in the past. Should these walls require future
expenditure, removal/demolition should be an option for
serious consideration. It has been noted that when these
expensive lots are acquired the funding for rehabilitation is as
little as $5,000. If/when further waterfront lots are acquired,
removal of seawalls could be most economically done in
concert with demolition of the buildings. Fostering recovery
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to a natural shore profile would include enhancement of aquatic habitat from sub-tidal kelp and
rockweed substrates to upper beach dune grasses and inter-tidal cobble/sand. Left unchanged, the
seawalls will continue to aggravate undermining and overtopping.
Given the long recognized but ongoing impacts of the seawalls, past recommendations to remove man
made barriers along the natural shoreline(1,11,22) and the 30 year old plan to assemble contiguous
waterfront in this area it is suggested that a detailed pre-design of a future restored shoreline be
developed to assist in long term planning and opportunities. In the long term such a plan could include a
natural path near the high tide level to allow access along the waterfront under most tide conditions and
providing for recovery of aquatic habitat and dune grasses.
2.8
14th St. Pier and Boat Ramp
The launching ramp chonically infills with
sand and cobbles. It is common to see boats
return to a summer afternoon low tide and
have to struggle over the sand bar with
vehicle and trailer.
The cobble/sand bar streams from the tip of
the “overfull” 14th St. beach. The cobble bar
in turn, fosters infill of a wider sand bar
under the float and over the ramp. The
sands are, however, too fine to form a stable
beach below the armour rock resulting in
less than optimal shore conditions in this
high visibility location. Vinson Creek Outfall is embedded in the rockfill groyne. The outflow provides
nutrients to the local mussel population but is most likely very low in coarse sediment content.
It is suggested that a planned one day per year maintenance regime be considered to better adapt to the
undesired sediment transport impacts at the 14th St. Pier. e.g. Prior to their erosion during the winter
storm period, clean, coarse sands and cobbles might be moved from the up-drift to the down-drift side
of the pier to improve the beach quality and stability from the pier to the sailing centre. It is also noted
that there is a chronic low tide percolation drainage flow which appears to erode the fine sand beach at
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the rip-rap toe. The source of this flow could be natural or it could be leakage from the fountain or from
the pipe connections for the Vinson Creek outfall.
Many communities along the coast install deep water “summer floats” for transient vessels. Connection
of a seasonal float to the outer pier is an option, which could provide for transient boat access during
summer low tides independent of infill issues. Depending on orientation it could also act as a floating
breakwater for the activities of the sailing centre.
2.9
Ambleside Beach
Ambleside Beach was constructed in 1965 with 110,000 cu yds of sand and cobble pumped from the
sand banks west of Navvy Jack Point. Additional work was done in 1987 when significant losses of sand
to deep water threatened erosion along the sea-walk. At that time, the current rock groynes were built
to better contain and reduce losses of beach materials. The recreational beach has performed
relatively well. There are apparent differences in the sediment regimes between the upper beach sands
and the lower beach which affect the overall stability and from time to time it considered necessary to
“top up” the upper beach to compensate for beach losses around the tip of groyne(1) (with the statue).
The goal for the beach should be to ensure the retention of all naturally available sediment input so as to avoid
the need for future expenditures on truck imported sands (from as far away as Richmond). It is not known
whether this goal is being achieved hence a survey is suggested to guide long term planning for beach
maintenance.
It is noted that the original groynes, as-built did not include a lowered crest elevation and a lengthened
drift sill to -5m depth which was suggested in one 1977 report. Depending on a detailed review there
could be some long term benefits in re-working the sea end of the groynes to terminate at about -5m
depth rather than the current 0 m depth. If desired the rock for this work could be sourced by
lowering or sloping the crest elevation of the existing structure which is redundant with respect to
beach performance. A softer sub-tidal drift sill could also be accomplished without any heavy armour
rock by placement of a mound of large river rock. Examples of low, sloped drift-still groynes may be
seen along the Stanley Park, False Creek and Spanish Banks waterfronts. They offer a flatter beach
profile, reduced storm sediment losses and improved stability of the critical lower beach which is the
“unseen” foundation that supports the stability of the upper shore.
9
If beach replenishment is deemed necessary, it is suggested that native coarse sand meeting the intent of
the original design be used and placed in the backshore area. Preferably, hydraulically clean sands
dredged from just offshore would be used for both cost and environmental reasons. It was highlighted
in the original beach design contract that fine sands would be quickly transported offshore by wave and
current. This loss is not only costly but can cause negative impacts on offshore benthic habitats. On the
other hand, in addition to reducing expensive sediment loss, the more stable the sub-tidal beach, the
more likely the near-shore zone will be to develop expanded eelgrass meadows as are found at the less
mobile westerly end of the beach.
Regarding the current groyne geometry; a preventive maintenance practice of transporting coarse beach
sediments from the upper beach at the eastern terminus to the upper beach at the western was
recommended in the original beach design documents. Such minor annual re-distribution could reduce
terminal erosion losses to the system during major storm events and could be managed in such a way as
to avoid harmful alteration to fish habitat. The recreational quality and safety of the beaches adjacent to
both the Launch Ramp and Sailing Club ramp could benefit from minor seasonal re-distribution.
As mentioned, it has also been suggested in the past that the groynes would benefit from being lower in
crest height and longer in length than they now stand. Such a profile could lead to both reduced losses
of sands and improved aesthetics. It would also allow for passage of floating log debris, however, that
would only pass the debris onwards to the Port’s jurisdiction.
The cobble embayment between groynes 1 and 2 currently has a geometry which quickly bypasses any
materials which leak past groyne 1, particularly the sand component. With some tweaking this second
beach could be also be utilized to better retain sands and fine cobbles, not only avoiding terminal losses
but also providing a natural reservoir of beach sediments. With minor re-working of the groyne profile
it could potentially serve as an economical source of supply for beach materials needed to replenish
erosion. It is noted that the height of the rockwork shoreward of this groyne is probably unnecessarily
high and additionally is a somewhat artificial physical and visual barrier. Upon review, this apparently
redundant rock could potentially be utilized in any sub-tidal tip extension.
Physical beach maintenance has both impacts and benefits for fish habitats. A full understanding of the
biophysical regime through surveys and review would be a sound investment to establish sensitivities
and potentials. Lack of research and detail to the full environmental balance has led regulators to be
generally “against” recreational beach development and maintenance. Without a comprehensive
understanding of the full beach system balance and values, opportunities for combining enhanced habitat
values with less erosion and higher recreational values may be missed.
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3.0
REFERENCE DOCUMENTS
Reports and documents reviewed as part of this study are listed in Appendix 1.
3.1
Select Highlights from Reviewed Reports
The District has commissioned many studies over the last 30 years relative to the shoreline and
waterfront. As of 2005 many past recommendations appear as valid as when they were first tabled.
An extensive list of excerpts are included in Appendix 1. The following statements are extracted from
the 1986 “Report to the District of West Vancouver on Foreshore Enhancement Measures - Point
Atkinson to Ambleside Beach” as an example of the status of the report recommendations.
a)
“The history of foreshore development and characterization of present day coastal processes along
the West Vancouver shoreline has not been effectively addressed in past reports…however, a
description of current patterns, shear zones and the effect of currents on the foreshore has not
been undertaken… There has been little description of the geomorphology of the shoreline
concerning sediment sizes and sources and transport zones”…status – not done.
b)
“Without a geomorphic history of shoreline development and a description of present processes an
adequate analysis of erosion and accretion cannot be made”…status – not done.
c)
“Successful maintenance of a sandy beach at Ambleside will require a scheme designed in balance
with the natural processes”…status –generally successful – warrants review of the
balance to quantify values and further optimize long term function..
d)
“Shoreline development between 13th and 19th Streets has been addressed mainly in planning
reports and the schemes presented have not been studied for technical feasibility. The degradation
of the beach likely to occur with construction of a seawall has been mentioned although effects on
Ambleside Beach of any development to the west have not been discussed”…status – not done.
e)
“The studies undertaken to date and reviewed here do not provide a complete description of the
foreshore sections in need of preservation. Suitable safeguards for protecting the West Vancouver
foreshore have not been discussed”…… pg 2-10 status – not done.
f)
“A detailed oceanographic and geomorphic data base would be a desirable asset in the planning
and development of preservation and restoration works along the West Vancouver foreshore. A
suitable data base would identify sediment sources and transport patterns, shoreline development,
wave climate and tidal current patterns.” status – not done
3.2
Data Limitations
The following data limitations continue to impede sound waterfront planning. Some have been
mentioned in the past. With the technology currently available the ability to acquire and integrate the
missing data has drastically improved over the past 20 years. Suggested topics for action follow and a
more extensive list is included in Appendix 4 – Action Items.
a) Extend the data gathering mandate of the District’s GIS program to include the near-shore
areas within municipal jurisdiction. Focus on including shoreline data relevant to shoreline
processes.
11
b) Establish topographic surveys of critical waterfront to enable long term monitoring of the
effects of erosion, accretion and sea level rise.
c) Outline and prepare an implementation plan to improve understanding of the subtle longer
term dynamics and relationships of shoreline processes. Invite and encourage scientific
partnerships with universities and higher levels of government with related responsibilities.
d) Re-visit past comprehensive District reports to avoid repetition and maximize returns on
past investments of staff time, consultant funding and citizen effort.
e) Prepare and anticipate future storm damage issues. Be prepared in advance with plans for
improvements rather than a reactive “band-aid” approach.
f)
Plan for sea level rise issues and tsunami vulnerability awareness.
12
4.0
MAINTENANCE COSTS AND BUDGET ALLOCATIONS
Past costs related to shoreline issues are included in Appendix 2. These items represent only those
costs that were readily identifiable as discrete expenditures. Staff commented that shoreline
expenditures were not readily separated as a cost “line object” over time.
It is noted that year to year capital, operational and planning expenditures are generally considered to
be within the budget allocated to Parks and Recreation but that from time to time capital and
operational projects are driven by other departments.
Staff have commented that there is a lack of any clear “ownership” of shoreline issues by a single
Department of the District. The District has the rare advantage of more or less contiguous control of a
high value coastal unit between Dundarave and Ambleside. It is suggested that the “jurisdiction” and
“accountability issue be specifically addressed to ensure truly integrated coastal management.
One option might be to create a “Focus on the Shoreline” initiative that would integrate the District’s
approach to the shoreline across departments and dedicate a specific budget allotment to getting ahead
of generic annual operations and maintenance.
13
5.0
FUTURE SHORELINE WALKS - LONG TERM SHORELINE PLANNING
CONSIDERATIONS
5.1
Waterfront Beach Preservation – Improving the Knowledge Base
From Dundarave to Ambleside the shoreline is a contiguous and fragile system. In the past 100 years
structures have been incrementally placed as single stand-along projects with limited understanding of
the long term effects on the overall shoreline regimes. In 2005 we continue to have knowledge gaps
which were “flagged” in the 70’s, 80’s and 90’s but which remain outstanding. Today, we have the
technology and techniques to address many of these shortcomings in order to preserve and enhance the
values of West Vancouver’s primary asset over the long term.
A table of issues is presented in Appendix 1. At the top of the list are:
•
Implementing biophysical and geophysical surveys of shoreline elevations and composition from
sub-tidal to above high water (marine riparian).
•
Defining beach transport pathways and loss points.
•
Defining aquatic and riparian habitats and their interaction with the physical shore.
5.2
Reducing Long Term Shoreline Maintenance Costs
Storm damage is an “unexpected” or episodic event. However, it is a given that we can expect these
“unexpected” events. With forethought and planning we might:
•
Invest small sums in prevention to avoid “disaster” damage costs.
•
Re-think and pre-plan, using minor repair projects to pilot alternative natural approaches to
reduce maintenance costs and to enhance the foreshore for public use and habitat values.
•
Avoid escalating armouring investments with resultant loss of natural shoreline qualities.
•
Invest in a foundation of sound knowledge in order to address regulatory requirements.
•
Reduce the costs of Insurance based on reduced risk of storm damage.
5.3
Preserving And Enhancing Natural Beach Forms And Habitats
The original shoreline consisted of diverse forms with cobble-sand drift-log beaches and longshore sand
and cobble transport to the terminus at the Capilano River. Included in this continuum were sections of
exposed bedrock and boulders, creek estuaries that discharged to the upper foreshore, wave cut
escarpments that balanced sediment supply and good access from tide-line to the waters edge for fish,
birds and humans. As the urban environment developed, property lines and structures superimposed
artificial boundaries on the foreshore. Working with natural processes is the most affordable option in
the long run… improved understanding of West Vancouver’s waterfront would be a sound investment.
In future repairs and shoreline planning it is possible to steer longer term approaches to work with
nature to dissipate storm wave energy and its impacts. It is suggested that such approaches be explored
and perhaps in conjunction with planned repairs or maintenance work that the District put in place
some small scale pilot projects to demonstrate and prove the multiple advantages of this approach.
Some suggested pilot projects might include:
14
a) Placing boulder habitats to diminish wave impacts and run-up and encourage expanded growth of
substrate limited kelp forests. Potential pilot project locations include zones fronting the lock block
seawall at Dundarave, the over-steepened rip rap zone at 24th and the area of degraded beach fronting
the 1400 block seawalls in Ambleside.
b) Re-structure existing rock armour to demonstrate a naturally complete shore profile at one or two points
along the 2 km of sea-walk area. A small fillet or pocket cobble beach could be evolved through
placement or re-arrangement to form subtle sloped boulder drift sills or tombolas. The pilot concept
would be to retain a dune-grass/drift log /cobble upper beach, a narrow inter-tidal fillet of cobble beach,
encouraged with intertidal and sub-tidal random boulder groupings. This approach was recommended in
past reports. (22)
c) Further develop embedded large drift log features along the foreshore.
Drift logs are a natural feature of west coast beaches. On the negative side they are an expensive
nuisance and can cause significant impact damage to structures such the pilings at Ambleside Pier
during storms. However, when embedded into beaches they can foster habitat values for bird and fish,
support biologic communities and interact to enhance beach stability. As a shoreline feature they can be
aesthetic and provide an storm resistant alternative to “park bench” seating. With improved
implementation, suitably placed and secured drift logs could contribute to protecting the sea-walk from
overtopping impacts during high tide events. That is, using natural features to provide a debris and
overtopping buffer as an alternative or supplement to curbs and parapet walls.
Placement of cable-tethered logs has been implemented however the details fo the implementation are
not yet achieving full potential and could be further improved for cost, function and aesthetics.
15
Going forward, opportunistic securing of selected stranded drift logs could be implemented at very low
cost
16
5.4
Developing an Operational Shoreline Maintenance Plan
Most of the man-made structures that intrude into the shore zone from Dundarave Pier to Ambleside
were originally located without full knowledge of long-shore sediment transport. When coastal
processes are altered by man made structures it is often desirable to restore continuity of the original
coastal regimes through seasonal operational maintenance.
Groynes began as loading piers, seawalls were constructed one at a time, outfall pipes and culverts were
placed and armoured without regard to impacts other than discharge, railway rights of way were
physically converted to sewer corridors and walkways.
Neither the individual nor the cumulative effects on the shoreline system were considered. It would be
useful to examine the current system dynamics and consider whether low cost maintenance actions
could limit upper shore erosion and mitigate past and ongoing impacts.
Suggested elements of an operational maintenance plan might include:
a) Enhanced upper shore retention of creek sediment input through naturalized day-lighting of creek
outlets.
b) Occasional bypassing (i.e. sidecast over the obstructiont) small quantities of beach material from the updrift to the down-drift side of the solid groynes called Dundarave Pier and Ambleside Pier. Without
bypassing, the groyne steepened beaches become “overfull” between storm events. When the summer
beach is flattened during a storm there are losses of sand and cobble into deep water. Small scale bypassing of barrier structures to maintain the upper beach down-drift of the barrier could mitigate
downstream shoreline impacts and reduce costs for sand imports. The desirable recreational quality of
the beaches could also be improved.
c)
Reduce losses of Ambleside beach material at the easterly end. Once the beach profile accumulates to
full capacity against the west groyne 1, a major storm event will cause migration around the tip and
subsequent losses to deep water or the Capilano tidal flats. These coarse sands could be utilized to
restore lowered upper beach profiles in the vicinity of the sailing club and launching ramp at little cost
and as was planned in the original design.
17
5.5
Anticipating and Mitigating the Impacts Of Sea Level Rise
There has been 10 cm of rise in the last 100 years
and through the next 100 years is expected to
dramatically accelerate to between 10 to 100cm of
rise. This will submerge parts of the seawalk
during high tides. The greatest damage potential
occurs when a storm wave event occurs during
high water. Higher water levels will mean that
these conditions will coexist for a much higher
percentage of time during storm season. Planning
for this long term trend could help develop
sensitive and low cost approaches that would
mitigate wave impacts that would otherwise result in high cost damage to the seawalk.
Maintenance of a wide healthy shoreline profile could mitigate the impacts of sea level rise. In addition,
the long standing plan to acquire all waterfront properties will allow the District to plan to avoid
intruding shoreline infrastructure while maintaining high value public use.
5.6
Public Awareness/Consultation
Past reports (17,22) have suggested bringing educational and interpretive signs to the waterfront. In fact
the 1991 contract for the Sea-walk included a provisional item for signage of creeks which was
apparently not fulfilled.
An informed public would be better able to value and guide the future of the West Vancouver shore.
Examples for interpretive signage include:
•
What sea birds are those and why are they hovering around the outfall or creek outlet?
•
What is happening to this shoreline?
•
Does this creek really feed sediment and nutrients to this beach?
•
What creek is this?
•
Where/What is Navvy Jack Point and what is out there below the water?
•
Why is there kelp at this spot only?
•
Where do the fry rear, the sandlance and surf smelt spawn, herons roost?…etc.
Effective public consultation is essential to the success of any public project. Stakeholders, potential
partners and regulatory agencies should be involved at the early planning stage to ensure they
understand the project goals and to seek their input for project implementation. Interested groups
should include:
•
Hollyburn Sailing Club
•
Streamkeepers and other volunteer and stewardship groups.
•
Other unorganized groups (i.e. kayakers, divers, etc.)
•
Interested regulatory authorities
•
Other jurisdictional partners, i.e. Regional District, Province, Federal.
18
6.0
EROSION MITIGATION, MAINTENANCE MANAGEMENT AND HABITAT
ENHANCEMENT ISSUES AND ACTION MEASURES
For each coastal unit, the following table describes specific erosion issues and possible mitigation
measures, maintenance requirements, cost reduction measures and habitat and recreational features and
enhancement suggestions.
6.1
Dundarave (25th Street Pier to 24th Street)
Issues/Unknowns
Actions
Are bypassing sands being lost to deep water and/or
smothering sub-tidal kelp substrate?
Diver/Engineer survey.
Does overfilled beach profile selectively retain cobbles
while sorting and losing sands past the tip? Should
cobble fractions of overfilled beach material be
seasonally bypassed over the groyne to pocket beach
above tide line. Should groyne design be modified, if reconstructed or repaired, to allow sand/cobble bypass?
Analysis/monitoring required.
1988 DFO habitat compensation report was
Verify results and current situation
1) concerned about sand covering kelp substrate and
2) proposed cobble/boulder inter-tidal habitat as
compensation for lock block seawall.
Wave impacts on seawall, overtopping in storms and
loss/instability of intertidal habitat.
Enhance kelp substrates (sub-tidal boulders).
Enhance mussel substrates (intertidal boulders)
Reduce magnitude of wave reflection effects (intertidal
boulders and kelp)
Engage report to analyze potential for boulder
placement to accomplish reduction of damage, improve
safety, enhance habitats, and recover lost bypassed
sediments from pier.
Source “free” rock from Sea to Sky? or round field
rock from nearby excavations?)
Floating debris and Storm Damage.
Large volumes of debris logs accumulate at Dundarave
Pier during winter months. Log debris removal is a
continuing expense all along the shoreline ($36,000 in
2004 plus $10,000 to Fraser Debris trap). Monitor
November/December log accumulation and explore the
pros and cons of encouraging log salvors to target the
Dundarave floating log accumulation on high tide
events. Review current and proposed new structures
for log impact resistance. Select suitable debris logs for
shoreline habitat and protection features.
19
6.2
24th St. to Navvy Jack Point
Issues
Actions
Permanent loss of functional upper beach due to rip-rap
fill.
Loss of upper beach riparian vegetation and habitat.
Increased wave energy and overtopping due to
hardening.
Chronic high water debris damage and removal costs.
Elimination of cobble/sand supply due to rip-rap shore.
Elimination of upper beach long-shore transport zone
due to rip-rap.
Diminished seabird inter-tidal habitat due to
submergence depths fronting rip-rap rock shoreline.
Lack of human access to water due to uninterrupted
and unstable shot-rock shoreline.
Kelp habitat limited by sub-tidal sand and lack of
suitable sub-tidal boulders.
Long term increasing wave impacts due to steepening
intertidal beach topography.
Long term increasing wave heights due to sea level rise.
Intensity and height of storm waves at 23rd St area.
Consider piloting several fillet pocket beaches along this
2 km section by subtle changes to existing rock
placements and placement of natural (not shot-rock)
rounded field boulders from local building excavations
(establish local stockpile location?). Provide diversity,
access and habitats while observing performance as
alternative to ongoing armouring of the shoreline in
response to sea level rise and storm damage. Further
refine implementation of tethered/embedded drift logs
to provide both habitat and protection from
overtopping debris.
Loss of sands and cobble sediments to deep water at
Navvy Jack Point.
Follow through with recommended survey (19) to
determine the degree to which littoral sediments are
lost to deep water at Navvy Jack point. Prepare
concepts of how losses might be reduced in concert
with diversity/access features…i.e. boulders to
encourage mini-tombolo formation possibly linked to
future look-out suggested in various reports (19,22)
The combination of geometries aggravates storm wave
impacts in this area. Creation of an shallow rock reef
(currently sand bottom) along this section could
potentially diminish the intensity of wave impacts,
preserve the inter-tidal shore and provide storm
resistant kelp substrates. Should the concept be
developed, it would be interesting to research whether
barged rock could be obtained for free in return for
provision of a “beneficial use” disposal site.
20
6.3
McDonald Creek Seawall and Creek Outlet
Issues
Actions
Seawall accelerates shoreline sediment transport.
Seawalk erosion aggravates overtopping and damage.
Introducing and re-arranging inter and sub-tidal boulder
clusters and fillets to cause waves to spill and refract to
diminish seawall impacts.
Move drift sill to foster wider cobble beach updrift of
outfall to create a wave- breaking shoal and mitigate
wave reflection.
Ongoing damage to granite curbstones due to
combined wave/debris impact and freeze/thaw
fracturing of cemented connection.
Consider returning to no curbs along vulnerable
sections or develop alternative detail. Reduce wave
impacts by gradually enhancing width of fronting
shoreline over time.
An artificial line of armour rocks embedded in the
beach act both acts as a drift-sill and channels high
velocity creek discharge. It was likely placed to protect
the adjacent seawall from undermining. The situation
was noted by Bauer in 77 as being on the “wrong” side
of the creek outlet. The down-drift rock placement
encourages infill/blockage of cobbles into the culvert
and also diminishes habitat values by forcing as “straight
line” flushing to the low water line.(contrast to situation
at Lawson Creek)
Consider relocating shoreward boulders and placing
lower on the shoreline to reduce the impacts on
longshore sediment regime and enhance habitat values
around creek mouth. Diminish wave impacts and
erosion along seawall by encouraging a natural up-drift
cobble accretion.
6.4
John Lawson Park Vicinity
Issues
Actions
Unknown degree of pier/groyne induced sediment
losses to downdrift shoreline.
Diver supported observation and report. Factor findings
into future repairs, maintenance and re-designs.
Future of Lawson Creek estuary
Define long term potentials for enhancement. Provide
pre-design concept. Consider tethering existing largest
drift logs and stumps with hand driven “sting-ray”
anchors to retain benefits and avoid storm damage to
structures if they should be mobilized by a high tide
storm. Review long term retention of concrete seawall
versus restored beach.
21
6.5
15th Street to 14th Street
Issues
Actions
Restoring healthy full beach profiles to west of park
from 15th to 14th St?
Review long term rationale for retention of easterly
seawall at 15th Street Park. Secure embedded stump
with stingray soil anchor (note potential for major
damage to Ambleside pier if a floating stump of this size
was wave driven).
Storm drain outfalls; their appearance, habitat values
and functions both intended and unintended.
Clean up the appearance of these outfalls, however,
note their present effect as beach stabilizing drift sills.
Consider whether discharging higher on the beach
profile could enhance biological values. Consider fresh
water discharges for long term integration into park
estuary/creek features particularly should they need
future replacement or repair. Review significance of
chronic red staining of surrounding beach. Short term,
demolish upper pipe sections to widen outflow for
habitat benefits and to improve beach park aesthetics.
Deposit broken remnants sub-tidally to create habitat
on sand bottom. Long term, in conjunction with
seawall issue consider returning outflows to naturalized
regime (i.e. “daylighting”).
The beach in this 1400 block is narrowing and lowering.
The concrete seawalls along this shoreline, many of
which apparently were constructed or extended
seaward of the high water property line, continue to
aggravate the erosional losses.
Investigation options in this area could focus on
reversing the ongoing loss of beach width and height.
To deal with the issues of individual seawall removal
while private properties remained, a proposal for a
perched beach was tabled in 1991 (22) It is suggested
that this stretch of shoreline be subject to a dedicated
rehabilitation study to guide future actions. It could be
possible in the long term for instance to restore a walkable upper beach between the 14th Ave pier to the park
at 15th Street and beyond. Other alternatives could
include rock drift sill placement beneath the timber pier
to encourage a wider up-drift beach. Similar work
could also provide for additional artificial reef habitat
around the public fishing pier.
The District has acquired and subsequently repaired
seawalls that came with acquired lots rather than
including seawall remediation or demolition with house
demolition. The seawalls contribute to the erosion,
habitat and access problems and the municipal park lots
continue to be a contrary example of shoreline best
practice.
6.6
14th Street Pier and Boat Launch
Issues
Actions
The ramp shoreline area is in poor condition,
functionally environmentally and aesthetically. A small
degree of low impact preventive maintenance could
dramatically improve this area.
Engineer/Biologist assessment and report. Labour
project to relocate intertidal debris rock, investigate
source of seepage outflow etc. Consider side-casting
cobble bar to restore upper beach at rip-rap.
22
6.7
Ambleside Beach
Issues
Actions
The beach as designed is functioning relatively well. As
anticipated in the design, incremental loss of cobble and
sand around the east end of Groyne 1 is apparent. The
original design specifications anticipated annual redistribution of beach sand from the east to the west
end to mitigate these losses.
Recovering and re-distributing beach material that
would otherwise be lost or swept into the lagoon areas
requires full consideration of fish habitat protection.
Beach performance and future Cost avoidance.
A review and projection of expenditures and losses of
sand over the last ten year period is suggested. Minor
adjustments to the existing groynes might offer long
term savings. Should clean, coarse, hydraulic sand be
required in future, seek to obtain without cost from
port dredging operations. and /or plan for
replenishment from nearby offshore deposits.
An engineer/biologist analysis and report would be
required to establish non harmful methods and validate
for regulatory approval.
23
7.0
SHORELINE JURISDICTION ISSUES
7.1
Municipal – Engineering/Parks,/Planning/ Public Works
The primary issue within the District appears to be the lack of an identifiable accountability center for
the overall integrity of the West Vancouver public shoreline. While there may be some assumption that
by default, the waterfront is the purview of Parks and Environment, this has traditionally been limited to
the maintenance of established individual park frontage, not the shoreline “system” as a whole. The
critical intertidal and subtidal zones which are the foundation of the traditional property based
“Waterfront” seem to fall “between the cracks” In discussions, the committee and staff concur that
each division has its own perspectives, expertise and files. The structure is based on municipal
departmental roles that “standard practice” but in the case of a “Waterfront Community”, do not
encourage day to day integration along the Shoreline theme.
Suggestion - Confront and prioritize shoreline management creating cross roles and responsibilities to
advance coastal planning and operations? Consider creating a term assignment of a “Shoreline Project
Team” with budget, a vision and performance targets.
7.2
Greater Vancouver Regional District
A traditional partner in infrastructure works such as the sewers under the sea-walk and health of the
environment…..seek collaborative support for waterfront demonstration projects and contributions to
integrated shoreline planning.
7.3
Provincial – MWLAP
BC has assigned the District control of a water lot out to 1000 ft from the shore. This tenure is
important for the District to maintain and utilize.
More complex perhaps are the issues of riparian rights and regularization of foreshore intrusions both
legal and illegal. The District should ensure that the Province supports its efforts to implement sound
shoreline management through its riparian policies and regulations.
7.4
Federal – F&O, Environment Canada, Coast Guard, BIEAP etc.
a) DFO Habitat –A biologist habitat officer’s first responsibility is to ensure that there is “no
net loss” of productive fish habitat. DFO habitat officers follow the risk averse
“precautionary principle” policy which requires that in the case of insufficient information or
science the regulatory approach must be very conservative. DFO resources are lacking to
perform site or project specific data gathering and investigations. Often there have been
poorly executed past projects which influence judgements. A proponent who invests in
front-end science to validate and adjust their proposals will usually find that DFO Habitat
will be better able to support, rather than regulate against. In taking a well researched high
level view of a coastal unit it is more likely that NET GAIN rather than LOSS can be
achieved.
Monitoring of impacts and benefits is always a concern as is compensation for impacts
caused. To err on the side of the precautionary principle, in general DFO habitat officers
may require twice as much compensation for an anticipated impact if the compensation
24
will take some time to be proven or to mature. Monitoring will also be required and
agreements signed to remedy any failure of compensation projects.
It is therefore in the interests of all parties that habitat enhancement be implemented
and proven in advance of any works that might require “compensation”. In other words,
an integrated plan for long term shoreline protection, enhancement and maintenance would
be well served by starting out with the enhancement project to establish a proven reserve
of habitat “credits” that could then reduce overall costs for unavoidable “impacts” and
provide coverage for areas where there is some disagreement that cannot be economically
resolved.
A well considered long term plan which offers a NET GAIN of productive habitat is the
best of all possible outcomes. This should be a straightforward objective of the Long Term
Shoreline Plan. If laid out clearly such a plan will enable any short term effects in the
creation of individual pilot projects to be considered in the context of the net gain.
b) DFO Oceans – This branch promotes integrated coastal zone management. Development
of a long term Shoreline Plan for West Vancouver would provide a demonstrative example
of urban coastal zone management which could only be supported and encouraged by this
sector.
c) DFO Science – This branch is a resource for research and an avenue to connect to other
related researchers. DFO Science is charged to direct “applied” science resources to
resolve oceans related issues. These researchers could be invited to participate and support
future District needs relating to the DFO Oceans mandate.
d) Department of Transport – Navigable Waters Protection Branch
NWPA has the mandate to ensure navigational safety. Changes to structures and shorelines
or shoreline tenures which might impact navigation will require review and permitting by
NWPA. They will also refer the application to other interested provincial and federal
agencies as required.
e) Environment Canada – Canadian Wildlife Service
The primary point of interest for CWS related to the District Shoreline will be bird habitat.
CWS sponsors academic monitoring of seabirds in Stanley Park by BCIT students for
example. For $300 per student CWS could engage similar monitoring programs along the
District Waterfront to determine the populations dynamics and habitat impacts of over
wintering seabirds.
f)
7.5
Burrard Inlet Environmental Action Program – coordinating and referral agency for works
affecting Burrard Inlet.
Private Lands
The District has been incrementally pursuing a 40 year old policy to acquire waterfront private
properties to provide a continuous public waterfront. The objective has not yet been fully achieved and
25
the District waterfront holdings include isolated lots which may at some point be assembled into
contiguous waterfront.
Property boundaries and structures and natural shoreline boundaries are often not compatable in the
long run. There are ongoing issues with some of these lots such as riparian intrusions and seawall
induced erosion that would benefit from fulfilling the desired public ownership plan so that natural
boundaries may be recovered and remedial shoreline recover works initiated.
26
8.0
RECOMMENDATIONS
8.1
Priority Recommendation:
That the District formulate a specific Three Year Initiative “Focus on the Shoreline” with the goal of
addressing knowledge gaps and advancing shoreline pilot projects.
Consider special project funding of $200K?? per year (50% to advance knowledge base 50% to
implement enhanced maintenance and pilot projects)
Fund the integrated initiative as a specific item outside of operational departmental program budgets.
However, savings and efficiencies through aligning and complementing departmental programs would be
anticipated.
Create a cross-departmental collaborative team with funding and deliverables split between Parks,
Engineering and Planning.
Review progress after three years to assess ongoing action and priorities.
8.2
Core Recommendations
That staff re-visit previous studies and particularly the 10 to 15 year implementation goals of the 1991
“Waterfront Directions Study” to review progress made and update approaches to enhance
implementation, planning and knowledge base for the next 15 years.
That the District develop a cross departmental team with responsibility to develop a Shoreline
“Directions” Plan that will not only address the issues of erosion control, habitat preservation and
mitigation of maintenance costs but that will also serve as a guidance document for future activities that
can impact the foreshore.
That the current West Vancouver Geographic Information System illustrates the deficiencies of
knowledge and data for the District’s shore zone and that steps be taken to include data and topography
at least to the boundary extent of the District waterlot with particular emphasis on the nearshore zone.
That the District prioritize obtaining baseline information that has been recommended herein or
identified in previous West Vancouver District Reports over the next five years.
Specific examples:
•
Detailed diver supported hydrographic survey, inventory and video record of sub-tidal
geomorphology and habitat noting any limitations and opportunities to enhance existing natural
features. Identification of ongoing impacts and opportunities plan to preserve and enhance the
West Vancouver shore.
•
Particular attention to pathways and losses of beach materials due to constructed works such as
municipal piers, groynes, culverts, seawalls and outfalls, with a view to shore improvement and
best management.
•
Survey and review of Ambleside Beach dynamics and profile to determine effectiveness of 1982
groyne headland to support park planning and cost management.
27
•
Document known foreshore and sub-tidal habitat linkages of biota including but not limited to…
aquatic birds, kelp and eelgrass forests, amphipods, salmonids, sand lance and smelt, aquatic
mammals. Involve UBC and CWS.
•
Review “human contact and interaction with the water” as recommended in 1991 with emphasis
on “addressing barriers through encouraging natural beach processes and forms.”
•
Review existing shore infrastructure and develop a long term plan for repair, replacement,
modification or removal.
28
APPENDIX 1
SHORELINE PLAN ACTION LIST
#
Task/Goal
How
Why?
1
Produce terms of reference for
an integrated Long Term
Shoreline Planning Document
for West Vancouver
Commence discussions and
prepare plan of actions.
To provide a direction and focus for the
West Vancouver and its Public
Waterfront.
EAC, Council, Staff,
Volunteers.
In kind
now
1
2
Improve knowledge of nearshore sediment pathways and
related biological communities
Aerial and video data
complemented with diver
towed sled survey with
interpretation.
To define shoreline processes and loss
points to guide planning and design.
Biologist/Engineer/Dive
r Consultant for survey
and report.
$15K
soon
1
3
Obtain shoreline specific aerial
photography.
Add specific requirements
to generic photography of
the district.
To obtain best detail by scheduling for
clear water, low tides. (i.e. May 24)
Modify generic
contracts.
And/or spot
photography by others
Nominal
May
2005
1
4
Review/refresh 40 year
committment to assemble a
continuous public seafront
from Dundarave to Ambleside
Beach.
Council, municipal staff
Private and municipal seawalls and
intrusions continue to impact the
natural shoreline. A vision of the final
form of the shoreline could facilitate
recovery to a natural beachscape over
time
Council and staff time.
And/or consultant
?10K
depending
on scope
2005/06
1
5
Obtain detailed
characterization of biological
communities, fish, bird, plant…
Prepare terms of reference
for studies….. identify,
engage volunteers, partner,
agencies, universities, staff
to carry forward.
To benchmark current populations,
mitigate or reverse human impacts and
understand limiting factors.
Staff Volunteers, DFO,
CWS to determine
terms of reference,
Partner funding or
academic involvement?
Incremental
and
partnered
2005
onward
1
Resources
Cost $
Time
Priority
APPENDIX 1 – SHORELINE PLAN ACTION LIST
A1-1
#
Task/Goal
How
Why?
Resources
6
Obtain historic survey data and
air photos for near-shore.
Consolidate from all known
sources
To quantify and benchmark incremental
long term change.
worksheets from CHS,
GVRD, BIEAP, DFO
minor
2005
1
7
Review Beach Replenishment ,
historic, ongoing and
supplemental
Example: what is present
day volume of Ambleside
Beach versus 1985
To reduce maintenance costs and
improve quality and stability of existing
beaches.
Review long term
trend and annual
maintenance plan.
Consultant? review.
$5K
2005
1
8
Itemize historic and projected
expenditures for coastal
operations such as beach
replenishment, storm damage
etc.
Review historic costs and
future projections. Review
designs to mitigate or
respond with forethought.
To highlight net costs and potential cost
savings.
Municipal records.
Part of
municipal
capital plans.
2005>
1
8b
Review District Budgetary
framework and how structure
could be limiting an integrated
approach to the Waterfront.
Review any stove-piping
issues or restrictions on
developing multi-year
integrated approaches
versus project by project.
To address the fact that the Shoreline is
a system that does not recognize
artificial boundaries whether physical or
bureaucratic.
Staff/ Council
Committee
Effort and
time
2005
1
9
Review and table all reports
for planning of existing
shoreline public spaces and
structures.
Consultant, volunteers, staff
To table the current foundations for
long term planning. To review the
“plans for planning” To ensure linkage
to District databases such as the GIS.
Consultant $5K?
Paper
gathering
from
District
records
2005
1
10
Identify desirable short term
minor waterfront maintenance
items. i.e. minor works, rock
placement, planting, beach
preservation.
Observe and note for
consideration/implementati
on.
To identify and plan for action
Volunteers, staff,
consultants.
$5K typical
per item.
2005>
1
Cost $
Time
Priority
A1-2
#
Task/Goal
How
11
Enhance public appreciation
and understanding of the
shoreline processes and values.
Research content and
provide displays along seawalk such as creek outlets,
tidal features, “what bird is
that” posters etc.
To inform, educate and provide
enjoyment to sea-walkers. Note:
Creek signage item in Sea-Walk
contract was not actioned.
Volunteer or staff time
to research and
recommend
interpretive signage.
Funding to implement
interpretive signage.
$5K
2006>
2
12
Review desirability of removing
“legacy” seawalls on public
beachfront
Consultant, staff
To reverse artificial impacts and losses
of beach front and return to a natural
state.
Restore shoreline,
demolish seawalls at
time of house
demolition /deposit
cobble back shore
material.
minor
2005 for
action in
future.
2
13
Review infrastructure such as
piers, outfalls, stream discharge
box culverts, jetties and ramps
and identify issues, costs,
future potentials.
Engineer/Biologist team in
consultation.
Consolidate historic
reports and fit into larger
context.
To have a plan in hand. To direct
maintenance funding towards long term
improvement rather than simple
replacement.
Muni staff, volunteers,
private consultants.
$10K
2006>
2
14
Establish survey references to
enable determination of long
term changes shorelines from
HWL to LWL and nearshore
area.
Survey beach profiles on
recurring basis to a high
level of accuracy…request
Provincial LIDAR surveys.
To enable awareness of incremental
shoreline losses …Link to District GIS
which currently has no data past the
shoreline.
Municipal survey crews
and/or interested
partners BC, DFO,
GVRD
Staff time
2006>
3
Prepare complete report on
sediment budget and patterns
Academic Study
2006-08
3
15
Why?
Resources
Detailed “profiler”
nearshore
hydrographic PWGSC
To establish shoreline regimes to high
level of detail
University research
grant for grad student?
Cost $
Time
Priority
Partner
funds?
$20K
$15K
A1-3
#
Task/Goal
How
Why?
Resources
Cost $
Time
Priority
from creek watersheds to final
accretion terminus.
16
Prepare complete report on
bird values and utilization of
shoreline
Academic or CWS /
Volunteers
To establish relationships of shoreline
attributes to visits by migratory and
overwintering aquatic birds.
Copy current
CWS/BCIT program
$300 per student?
$2K
2006>
3
17
Table long term capital plans
for shoreline infrastructure
projects.
Review known projects
such as repairs or rebuilds
of storm outfalls, jetties,
wharves, ramps, floats,
seawalk etc
To enable early warning and fitting in to
an integrated shoreline plan for better
outcome and lower cost.
Consultant $5K, Staff,
EAC
$5K
2006>
3
18
Establish shoreline “risk zone”
for wave/debris damage or
inundation.
Consolidate and validate
design storm wave, long
term maximum sea level,
tsunami zone.
To improve design guidelines and enable
long term validation/tuning and
awareness of sea level rise effects.
Consultant and/or
students with data
from muni staff.
$10K
2007>
3
19
Determine values of enhanced
natural shoreline to live-ability
of Ambleside and Dundarave
Planning Staff discussion and
review. Real estate
appraisers.
To “crystal ball” the dynamics and
multipliers stemming from a well
planned, accessible, public waterfront
adjacent to high density residential
areas.
PAC, Muni Staff,
consultants?
$20K
2007>
3
20
Determine linkages of public
waterfront to viable village
economy such as restaurants,
sidewalk cafes etc.
Planning Staff, business
community
To consider the synergies between
public enjoyment of the seafront and
desired services
PAC, Muni, Chamber
of Commerce
$20K
Now?
1
21
Review boat access points to
Review transient floats and
To provide for safe, reliable, low impact
PAC Recreational
$5K
2006
3
A1-4
#
Task/Goal
How
Why?
Resources
Cost $
Time
Priority
waterfront for drop offs and
pickups and no barrier access
for kayakers.
piers, boat ramp, yacht club
usage and deficits
access by boat to West Vancouver
shoreline.
users, Yacht Club.
22
Obtain video digital image
records of storm events past
and future.
Task volunteers and staff
To improve theoretical design
parameters such as storm waves.
Volunteers, staff,
residents of waterfront
high-rises.
In kind
Now>
3
23
Estimate Long Term Beach
Profile Change
Review historic surveys,
pictures of storm sewer
pipe outlets and other
sources
To identify long term change
Muni staff to recover
files,
consultants/volunteers
to review.
$5K
2006>
3
24
Project future beach
nourishment needs at
Ambleside
Review original design and
estimate rates andpathways
of change/loss.
To quantify losses and inputs and plan
to minimize long term cost and
maximize habitat values..
Muni staff to table files,
volunteers or
consultant to review.
$2K
2005
2
25
Enhance wave models done for
Seawalk to examine near-shore
interactions such as submerged
tombolo protective effects of
sub-tidal boulders and kelp.
Determine what potentials
and conceptual options.
To minimize long term cost of storm
damage and restore enhance nearshore
habitats to compensate for littoral
impacts.
Original Consultant to
amend past model. $5K
$20K
2007
4
26
Review Significance of Sea
Level Rise
Review impacts to date and
for 100 years
To plan ahead for shoreline impacts and
planning
Consultant
$5K
2006
2
27
Examine
enhancement/maintenance
details for 14th Ave Groyne
To examine cost effective
options for improvement
Consider configuring armour rock to
drift sill, enhancing habitat under wharf,
addressing ramp/float infill etc
Staff, coastal engineer,
biological consultant
$3K
2005
2
A1-5
#
Task/Goal
How
Why?
Resources
Cost $
Time
Priority
Beach and Ramp
28
Define anticipated Tsunami
Inundation Zones along
Shoreline
Define, mode of anticipated
waves and inundation limits
To be aware of inundation zones and
take mitigating planning decisions for
the long term
Collaborative study
with Fed Science
Resources, Province
PEP.
$1K?
2005/6
1
29
Repair/remove 15th Street
Outfall Pipes
Demolish upper pipes and
remove broken concrete
pipes
To begin to bring fresh water flows
higher up the shore profile to enhance
inter-tidal habitat values and to improve
aesthetics of beach park sea-views.
District forces
$1K
2005
2
30
Address impacts of the beachembedded armour rock at
McDonald Creek.
Re-arrange existing rocks
to reduce impacts…replace to enhance stream
braiding and retain beach
sediments in upper beach
transport zone.
To restore enhanced habitat and beach
sediment process and reduce artificial
channelization of flow, nutrients and
sediment to deep water with resulting
losses to upper beach longshore
processes. Noted in 77 Bauer report.
District forces
$1K
2005
2
31
Stockpile “Field” Boulders for
Shoreline Works and habitat
creation
Provide designated deposit
area for select boulders
from district excavations.
Provide to contractors at
cost.
To provide rounded, dark, weathered
alternative to typical angular “shot
rock” for natural shoreline features.
Emulate approach of City of Vancouver.
Convenient deposit
could reduce
excavation disposal
costs and provide free
shore works material –
District to administer.
$0
2005
3
32
Investigate potential for free
rock supply from Sea to Sky
Highway work
Staff liaise with Province
and Contractors and EC
Ocean Disposal Branch
Potential Beneficial use of rock that
might otherwise be Ocean Dumped
Staff/consultant
$0
2005-10
2
A1-6
APPENDIX 2
MAINTENANCE COSTS
APPENDIX 2 – MAINTENANCE COSTS
Year
Description
Department
Type of Funding
Cost
2005
Dundarave Ramp
Marine Inspections
and repairs
Maintenance as per
2004
Selected action item
from ShorePlan
??
??
Horseshoe Wharf
Upgrade
Seawalk Drainage
and RipRap Repair
Piers Wharves
Floats Maintenance
Beach Cleanup
Seawalk regular
maintenance
Seawalk horticulture
??
??
Parks
Parks
Capital
Capital
$25,000
$75,000
Parks
Maint
$120,000
2004
Parks, Engineering,
Planning
Engineering
Planning
Parks
$50,000???
capital
??
??
$165,000
Parks
capital
$80,000
Parks
maint
$36,000
Parks
Parks
maint
maint
$46,000
$13,000
Parks
Engineering
Planning
maint
$25,000
??
??
NOTES:
The above summary of Shoreline related costs represent the Districts Budget for ALL of the West
Vancouver Shoreline, not just the Ambleside to Dundarave Section.
Do we need to insert in the current situation with regards to budgeting for waterfront and whether or
not it is within a department or across departments etc.
What is currently projected in the 5 and 10 year plans? I.e. maintenance/operations; annual surveys;
annual air photography
Special projects: for example
•
Repairs to seawalk curbings
•
Pilot beach project at 23rd st
•
Biophysical survey
Need to add “outside” potentials for funding and partnerships.
The difficulty in assembling Shoreline costing data past, present and future, is indicative of the lack of
profile for the Waterfront as an identifiable item…. Staff help is needed to take this costing section
forward.
A2-1
This summary sheet is for the December 2001 storm event only. Many of these costs were eventually covered by insurance, however the long term impacts
of this event or future repeats of this event on Insurance risk premiums that will be charged is unknown. It is notable that the storm damage could have been
much worse had it coincided with the highest tides.
APPENDIX 3
SELECTED EXCERPTS FROM PAST REPORTS
APPENDIX 3 – SELECTED EXCERPTS FROM PAST REPORTS
The following comprise paraphrased excerpts from reports listed in the bibliography. Some of the
reports are available on the accompanying CD.
1)
West Vancouver – Waterfront Directions Study 1992
Dundarave to Ambleside -- By Guzzi Perry and Associates, Cornerstone Planning Group Limited ;
Hotson Bakker, Architects; Hay and Company, Coastal Engineers.
Selected excerpts:
“For the Waterfront Directions Study to have a lasting impact, a
means to implement the study concepts must be formulated. An
implementation strategy, outlined at the end of the report,
identifies four pilot projects to occur concurrently over the entire
site, followed by a number of subsequent projects.”
“The full implementation of the study concepts is an ambitious task
that demands a long term commitment from the municipality and
sustained interest from the community. In light of the stunning
natural beauty of the site and its exceptional value as a public
amenity, the West Vancouver waterfront has tremendous
potential to become a shining example for parks in the region and
the country.”
“Three important subject categories were explored through the community consultation process. They are:
1.
2.
3.
Visions for the Future of the Waterfront
Waterfront Issues
Waterfront opportunities
Variety and Diversity along the Edge:
“Create a rich diversity of design along the
waters edge in order to provide visual interest
and a range of activity areas for the user. This
can be achieved by creating a series of precincts
within the park, each having a subtly distinct
character of their own, yet contributing to the
cohesion of the waterfront parks.”
Heightening the Water Experience:
“The point at which water meets land is often
ignored in the design of parks and walkway
systems. It is important that people be able to
see and reach beach level with its changing
conditions.”
A4-1
“Increase the sense of water on the site by heightening public interaction with the water’s edge. This can be
achieved with changes to the rip-rap edge to allow physical contact with the water and the beach….” Pg 27
Regeneration of a Natural Landscape:
“Although edge conditions to most urban areas are man-made, it is important to re-establish a sense of natural
landscape, both for environmental and historic reasons. This might mean the reintroduction of native trees,
opening up a channeled stream to its former natural character, or altering the shoreline in such a way that it
can transform into a more natural state.”
“Ensure that areas of the site are developed in a way that a naturalistic landscape can be present as a contrast to
the man made, more urbanized elements.” Pg 28
The Concept Plan – pg 44
The intention of the study is to identify directions for the development of the Waterfront …..
The plan is intended to be a flexible guide for the future growth of the waterfront…..
Concept Plan, selected items:
19th Ave to Dundarave
…Improve access to water in some areas….
…Consider visual quality of the escarpment in design of spaces along seawall. (photo)
Navvy Jack Point…. This is the most
favourable location on the entire site for the
(re) creation of a natural beach. This can be
accomplished by constructing a headland,
possibly submerged, with or without pier, to
create a natural beach. Provide weather
protection, provide water/beach access,
develop marine interpretive display. (photo)
A4-2
Argyle Village 14th to 16th…..”the existing
seven foot retaining wall to the beach would
be reduced through the creation of a
“perched” beach
….Create public access points to the beach
pg 50a (photo)
John Lawson Park….. existing pier in poor condition. Rebuild pier
McDonald Creek
- Enhance appearance of McDonald Creek….
Implementation Strategy…. It is important that a time frame be developed (10 to 15 years) to provide a
focus and sense of purpose for the implementation of the study concepts….. …. Tapping into available
funding sources to augment the municipality’s capital budget …would certainly hasten the implementation
process….. (list of sources)
A4-3
2)
Habitat Compensation Report to DFO – Dundarave Lock-Block Seawall – G Smith RP Bio
to B. Clark DFO 1989
“….placing cobble/boulder material would encourage
the development of additional kelp beds which would
provide beneficial refuge and feeding areas for young
salmonids. ….. considering the high value of kelp beds
for young salmonids, the proposed work would be
expected to provide significant benefit to the
productive capacity of the Dundarave foreshore….”
3)
Dayton and Knight – Report to District on Foreshore Enhancement Measures - Point
Atkinson to Ambleside Beach, 1986
2.2 Evaluation
a) ….. The history of foreshore development and characterization of present day coastal processes along the West
Vancouver shoreline has not been effectively addressed in past reports…….however, a description of current
patterns, shear zones and the effect of currents on the foreshore has not been undertaken… There has been little
description of the geomorphology of the shoreline concerning sediment sizes and sources and transport
zones….
b)…. Without a geomorphic history of shoreline development and a description of present processes an adequate
analysis of erosion and accretion cannot be made…..
c)…Successful maintenance of a sandy beach at Ambleside will require a scheme designed in balance with the
natural processes…
d)…Shoreline development between 13th and 19th Streets has been addressed mainly in planning reports and the
schemes presented have not been studied for technical feasibility. The degradation of the beach likely to occur
with construction of a seawall has been mentioned although effects on Ambleside Beach of any development to the
west have not been discussed….
A4-4
f)….The studies undertaken to date and reviewed here do not provide a complete description of the foreshore
sections in need of preservation. Suitable safeguards for protecting the West Vancouver foreshore have not been
discussed…… pg 2-10
“A detailed oceanographic and geomorphic data base would be a desirable asset in the planning and development
of preservation and restoration works along the West Vancouver foreshore. A suitable data base would identify
sediment sources and transport patterns, shoreline development, wave climate and tidal current patterns.”
4)
District of West Vancouver Contract 32.52.1 Ambleside Beach Erosion Control 1985
2.04 “Type 3 sand fill shall be imported reasonably coarse material to avoid being washed offshore and shall
conform to the following gradation limits…….
3.05 The (ramp) basin shall be dredged to the line and grade as shown on the drawings. Dredged material may be
used as fill material elsewhere on the project….
5)
Ambleside by the Sea – Waterfront Program Review Part II – Basis for a Plan – 1985, Planning
and Development Dept – District of West Vancouver
1 The Plan..
b) Continued acquisition of all lands with the possible exception of the 1700 Block
c) Creation of major park and recreation areas stressing active interaction with the water.
1988 - West Vancouver Shoreline Study for District of West Vancouver – Dayton and Knight, Hay and Co.
“The results and conclusions of the study will provide the basic data necessary for the development of foreshore
enhancement concepts, erosion protection measures and design.” Pg 1
“Creeks and streams are the main natural source of sand size sediments along the West Vancouver foreshore”
“The armoured shoreline at the surface has the appearance of cobble but is underlain by a mixture
of sizes, mostly sand….removal of surface cobble will expose the sand to wave action possibly
resulting in a lowering of the foreshore…..lowering of the foreshore in turn may lead to wave run-up
further into backshore areas resulting in erosion of berms or escarpments or increased stress on
seawalls if present.” Pg 4
“The presence of the (Dundarave) pier has interrupted the eastward sediment transport …. The pier appears to
be full on the updrift side and it is believed that sediments bypassing the pier are being deposited in deep water.”
Pg 10
“The potential for littoral drift between 14th and 19th Streets is strong leading to the development of a wide, coarse
cobble beach…
“The southeastern end of (Ambleside) beach has continually experienced sediment loss due to beach alignment
and has prevented the north end from stabilizing. Several past attempts have been made to stabilize the southeast
A4-5
end with short groynes. Recent construction of a stabilizing headland on the southeastern end of the beach will
act as a hard point allowing a stable planform to develop. Pg 11 ??
“The natural supply of sediments (along Dundarave unit) derived from wave cutting of the backshore banks has
been virtually eliminated with the advent of urbanization and the development of seawalls and other protective
measures.” Pg 14
Little sediment appears to be bypassing the 25th St Pier to the upper foreshore down-coast as evidenced by the
comparative lack of fine sediments east of the pier.
Upper foreshore sediments are leaking past both the pier at Lawson Park and the rock groyne at 14th St forming
small bars in the lee of the structure. The seawall between 14th and 15th Street is showing signs of undermining as
a result of a lowering of the beach.” Pg 15
Supply of finer sediments by Vincent, Lawson and McDonald Creeks contributing to the foreshore may continue
the development of the lower foreshore sand bars off the piers at 14th and 17th Streets. Pg 15
“Little evidence of foreshore enhancement was observed along the entire shoreline except for past and present
development at Ambleside Beach, however protection against shoreline erosion has been applied at numerous
locations in the form of seawalls and riprap revetments. The use of appropriate foreshore enhancement to
not only improve beaches for recreational use but also two provide protection against shoreline
erosion has not been attempted…
Several solutions to enhancement/erosion protection could be applied to the West Vancouver shoreline. The
application of sloping groynes and headlands anchoring sand beaches and the introduction of sediments to
coves are appropriate at some locations.
…At this location (Navvy Jack Point) the rip-rapped bank supporting the sea-walk could be removed and
used in headland construction. The associated beach would provide a desirable amenity for the
adjacent apartment dwellers, as well as protect the sea-walk from erosion.
6)
Wolf Bauer – Preliminary Shore – Resource Overview 1977
The natural function of this latter shore system has been reduced considerably however, by extensive bulkheading, groining, and riprap revetments, - all tending to starve down-drift accretion beaches in the Ambleside
drift-terminal area.
Most of the intruded and eroding Class II and II beaches west of Ambleside contain insufficient gravel to maintain a
storm protective berm along the upper foreshore drift-belt. Some of these shores can be upgraded to Class I and
II beaches with the addition of groin-cobbles, berm-gravel and dune grass planting to produce dry driftwood
beaches with protective backshores in front of present eroding bulkheads…. Pg-5 1977
Ambleside Beach Enhancement…. The park shore represents the accretion terminal of a drift-sector system in
which about two miles of glacial till shorelands supplied a former spit with berm maintenance materials. These
receding feeder shores, however, are not only short of gravel for stable berm building, but most of
their beach-feeding action has been reduced by drift interrupting groins and by bulkhead
revetments.
“Beach-process systems still operate along the eastern portion near the First Narrows to a point about two miles
west of Ambleside Park. The natural function of this latter shore system has been reduced considerably, however,
A4-6
by extensive bulkheading, groining and riprap revetments, - all tending to starve down-drift accretion beaches in
the Ambleside drift-terminal area.”
“…Several creeks have their outlets placed on the west or up-drift side of adjoining groins and docks. In that
position they are subject to accretion blockage during heavy storm-drift action. In the natural environment, such
stream channels are made to curve down-drift by up-drift berm and spit formation…if these outfalls were to be
ducted under and across the adjacent structures (as done with Marr Creek outlet) so as to discharge down-drift
(east) there-from, any plugging and channel clearing would be eliminated, and the western up-drift beaches can be
enlarged to terminal pocket beaches with broad Class I backshores that would remain relatively stable under
storms.”
7)
Swan Wooster Report on Storm Damage 1975 – Conclusions
“Properly designed groynes act not only to retard erosion but also to maintain as-uniform-as-possible degree of
erosion along a beach front. They do this by …. In this regard the height of the seaward end of groynes,
particularly those on sandy foreshores should be kept low. (photo)
“The excessive height of the existing Ambleside beach
groynes inhibits the passage of material over them…….
Lowering the groynes to a height of 2ft to 3ft above the
intended beach surface would improve the situation” pg 8
“….There must also be a planned beach maintenance
program. This must involve maintenance of the groynes,
and reclamation of accreted material from the east end of
the beach followed by its redistribution at the west end….
Pg-7”
…re-built groins are too high and should be lowered to
2-3ft above beach….
8)
Swan Wooster Marine Erosion at Ambleside Park – 1963
Littoral drift (the longshore movement of beach material in the surf zone due to wave action) is from west to east
in the project area……. Such material, in rounding Navvy Jack Point, tends to be forced out into deeper water and
is consequently lost to (supplying) the upper beach in the Ambleside Park Area…. Pg3
…..The introduction of a rigid revetment such as the existing seawall…, is likely to have a detrimental effect on the
lower beach, and there is some evidence of lowering of the beach immediately below the toe…. While many such
sea walls have been built in the past on beaches of friable material, modern practice does not recommend the use
of rigid structures in such circumstances…… ….. In essence, the most efficient form of shore protection
is the maintenance of a natural gently sloping protective beach throughout the entire wave
zone……pg-7 Swan Wooster 1963
….Ambleside Beach…. Would require no maintenance whatsoever for a period of some 7-10 years. At the end of
this period a limited amount of dredging might be required to replenish any eroding areas with material taken from
deposition areas……..
….Reclamation and redistribution of beach material should be carried out at least once per year….
Pg 8
A4-7
APPENDIX 4
REFERENCE DOCUMENTS
A4-1
APPENDIX 4 – REFERENCE DOCUMENTS
1.0
REPORTS REVIEWED
1.
December 1963 – “Marine Erosion at Ambleside Park” – Swan Wooster Engineering
2.
July 1965 – “Contract No. 1 – Ambleside Beach Erosion Protection” – Swan Wooster Engineering and
various letters.
3.
December 30, 1965 and February 25, 1966 Letters – Swan Wooster Engineering – Centennial Seawalk
4.
March 1967 – Contract for Ambleside Slough Control Structure and Bank Protection, Swan Wooster
Engineering and various letters.
5.
December 1968 – Ambleside Park, Proposed Reclamation Scheme III – Swan Wooster.
6.
September 1969 – Foreshore Reclamation Study – Swan Wooster Engineering.
7.
June 12, 1975 – “Ambleside Beach – Report on Storm Damage” Swan Wooster Engineering
8.
April 1975 – John Lawson Pier Preliminary Report – Swan Wooster Engineering.
9.
May 1975 – “Centennial Seawalk Report on Damage”– Swan Wooster Engineering.
10.
May 1977 – “Shore Resource Overview, Beach System Status, Beach Park Potentials” – Wolf Bauer.
11.
March 1980 – Ambleside Erosion – Protective East – Beach (minimum) – Wolf Bauer.
12.
March 1981 – “Design Implementation Plan for Ambleside”, Nielsen Architect.
13.
November 1981 – “Marine Task Force Report”, Morfitt et. al.
14.
March 1982 – Ambleside North – South Connectors – Dino Rapanos.
15.
July 1982 – “Ambleside Beach Stabilization Project” – Wolf Bauer.
16.
March 1983 – “Ambleside-by-the-Sea Discussion Paper” – West Vancouver Planning Department.
17.
1985 – “Ambleside-by-the Sea – Waterfront Program Review, Part II – Basis for a Plan”, West Vancouver
Planning and Development Department.
18.
*jDecember 3, 1986 – “District of West Vancouver, Foreshore Enhancement Measures – Point Atkinson
to Ambleside Beach” Dayton & Knight Ltd..
19.
*Hayco 1988 – “District of West Vancouver, West Vancouver Shoreline Study – Point Atkinson to
Ambleside”, Hay and Co., September 1988.
20.
December 15, 1988 – “Habitat Compensation (for Seawall), Physical Environment, Dundarave,” Hay and
Company.
A4-2
21.
*Smith 1989 – Fisheries and Oceans, letter report re habitat inspect and compensation 24th – 25th Street,
Geoff Smith, January 3, 1989.
22.
January 1992 – Waterfront Directions Study, Gozzi Perry/Cornerstone Planning.
23.
March 2002 – Argyle Waterfront Acquisition – Summary History, District of West Vancouver.
24.
*January 2002 – “District of West Vancouver, English Bay Foreshore 19th to 24th Street, Hay & Co.
25.
May 5, 2002 - “Coast River Environmental Services May 5, 2002 Interim Monitoring Report for Hollyburn
Relief Sewer (Phase II) Construction Project.
26.
Argyle Waterfront Acquisition – Summary History Updated March 2002.
27.
February 15, 1999 - Biophysical Assessment and Preliminary Environmental Impact Review for Proposed
Seawall Construction at Historic John Lawson Residence. “Hatfield Consultants Ltd”
28.
September 1996 Letter re: Dundarave Seawalk – Subgrade Stabilization - Hay and Company
29.
September 1997 “Report on Waterfront Site Assessments” Hay and Company
2.0
CONTRACT DOCUMENTS
1.
*1987 Dayton & Knight Ltd., Drawing No. 32.52.1, Sheets 1 to 5, Ambleside Beach Erosion Control.
2.
*1988 Dayton & Knight Ltd., Drawing No. 32.52.2, Sheets 1 to 8, Seawalk, 24th Street to 25th Street.
3.
*1988 Dayton & Knight Ltd., Drawing No. 32.52.2A, Sheet 1 to 2, Existing Topography, Seawalk, 24th to
25th Street.
4.
*1988 Dayton & Knight Ltd., Drawing No. 32.52.2B, Sheet 1, Habitat Compensation, Seawalk, 24th to 25th
Street.
3.0
BIBLIOGRAPHY
Proceedings of the DFO/PSAT Sponsored Marine Riparian Experts Workshop, Tsawwassen, B.C., February 17-18,
2004
Marine and Estuarine Riparian Habitats and their role in Coastal Ecosystems, Pacific Region. Levings, C., Jamieson,
G.
On the Living Edge, Your Handbook for Waterfront Living – 2002 British Columbia Edition - Sarah Kipp and Clive
Callaway
4.0
CONTACTS and ACKNOWLEDGEMENTS:
District Staff and in particular Mike Miller provided access to reports and encouragement..
The West Vancouver Museum and Archives and staff were invaluable in researching historic photographs, news
clippings and aerial photographs.
Other people who contributed advice, information or direction in no particular order (apologies for anyone
missed)
A4-3
Mike Miller, Parks and Environment West Vancouver
Jonathon Sector – Sector Environmental Consulting
Wolf Bauer – Coastal Processes Engineer (retired)
Dr. Colin Levings – Research Scientist DFO (Habitat)
Bob Trydal – City of Vancouver – Past Engineer for Vancouver Parks
Hugh Hamilton – W Van Streamkeepers Director
Rob- Bell Irving Community Advisor DFO
Dr. Phil Hill National Research Canada Geological Survey Canada
John Harper – Coastal and Oceans Consulting
Brian Emmet – Archipelago Marine Resources
Dr. Bill Crawford – Scientist - Institute of Ocean Sciences DFO
Dr Donald Dunbar, Ocean Applied Research
Ralph Everts _ Hay and Co
Oz Isfeld – Hay and Co
Mike Tarbotton – Triton Consulting
Sean Boyd – Environment Canada (Aquatic Birds)
Carol Ogbourne BC MLWA Coastal Air Video
Scott Christie – Foreshore Technologies Inc.
Chistine Grabing – West Vancouver (photos)
Corrino Salomi DFO Habitat
Note:
This report is a product of volunteer effort on behalf of the District of West Vancouver by members of the
Shoreline Sub-committee of the Engineering Advisory Committee 2004-05.
Shoreline Sub-committee members: Adrian Rowland P.Eng (Chair), Brian Walker P.Eng., Tiit Piikksalu P.Eng.,
Jacques Robert P.Eng., Steve Hayto P.Eng
APPENDIX 5
A4-4
PICTORIAL SHOREWALK
A4-5

ambleside – dundarave long term shoreline planning framework

Transcription

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