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Waitākere
Ranges Local Board
25 September
2014
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Waitākere Ranges Heritage Area Business Stocktake
File No.: CP2014/16213
Purpose
1. This
report provides information for the Waitākere Ranges Local Board on the outcomes of the Waitākere
Ranges Heritage Area Business Stocktake.
Executive summary
2. The
Waitākere Ranges Local
Board commissioned a stocktake of businesses within the Waitākere Ranges Heritage Area (WRHA)
in April 2014. The stocktake was conducted in May-July 2014. This report
provides information about the outcomes of the stocktake and offers some
options for future projects to support local businesses.
3. The
economic well-being of the WRHA is one of the objectives of the Waitākere Ranges Heritage Area Act 2008
(the Act). Economic activities within the WRHA have been acknowledged in the
Local Board Plan 2011 and the draft Local Board Plan 2014.
4. The
findings from the stocktake give a more detailed understanding of existing
businesses in the WRHA. A database of businesses is now able to be created
which allows the Local Board to effectively target any future efforts to
support sustainable rural economic well-being in the WRHA. Options for future
projects to support businesses in the WRHA are provided.
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Recommendation/s
That the Waitākere
Ranges Local Board:
a) Note
the outcomes from the Waitākere Ranges Heritage Area business stocktake.
b) Note options for future projects to support local businesses in
the Waitākere Ranges
Heritage Area.
c) Approve the publication and distribution of a newsletter targeted
at businesses in the Waitākere Ranges Heritage Area.
d) That costs
associated with a targeted business newsletter be covered through the $3,000
currently allocated for 2014/15 under the topic ‘small business facilitation’
within the endorsed WRHA Implementation Programme.
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Comments
Background
5. An
‘economic development overview’ of the whole of the Waitākere
Ranges Local Board area was prepared in February 2014
by the Economic Development Unit. While the overview provided general
information about the Local Board area’s economy, specific economic information
about the WRHA was not provided as gathering this information was outside the
scope of the Overview.
6. Staff
from the Economic Development and the North West Planning Units identified that
prior to proceeding with any initiatives to support economic activities in the
WRHA, more information about the existing businesses was needed. In April 2014
the Local Board approved the development of a stocktake of businesses within the
WRHA. The stocktake was conducted in May-July 2014. The main objectives of the
stocktake were to:
· understand in greater
detail the nature of economic activity in the WRHA
· develop a database to
enable any efforts to support businesses in the WRHA to be targeted
effectively.
Strategic
and statutory context
7. The
Act recognises the national, regional and local significance of the WRHA and
requires the protection and enhancement of the heritage features for present
and future generations. The Council is required to have regard to the purpose
of the Act and its objectives
when making decisions. The Local Board has a key role in acting as a steward
for the WRHA and by implementing the Act.
8. Providing
for economic well-being in the WRHA is recognised as one of the objectives in
the Act. Section 8(i) of the Act states:
‘The objectives of
establishing and maintaining the heritage area are –
… to recognise that
people live and work in the area in distinct communities, and to enable those
people to provide for their social, economic, environmental, and cultural
well-being’
9. Any
initiative to promote economic well-being of people who live and/or work in the
WRHA will need to consider the broader objectives the Act that seek to protect,
restore and enhance the WRHA and its heritage features.
10. The
WRHA is recognised as an Outstanding Natural Landscape in Chapter 7 of the
Auckland Plan. The Proposed Auckland Unitary Plan (PAUP) acknowledges the
national, regional and local significance of the WRHA. It provides objectives,
policies and rules to guide use and development in the WRHA.
11. The
Local Area Plans prepared under the Act incorporate objectives and actions to
support economic well-being in the respective local areas within the WRHA.
12. People
working in the WRHA were acknowledged in the Local Board Plan 2011 under the
priority ‘stewardship of the Waitākere Ranges Heritage Area’. Under this priority the Local Board intended
that the WRHA ‘is protected and enhanced and appropriate tourism of the
world-class beaches and ranges is managed. People enjoy living, working and
visiting the area while respecting the natural and built heritage of the area’.
13. The
draft Local Board Plan 2014 acknowledges that there is currently a lack of
detailed information about economic activities in the WRHA. The draft Plan
notes that a stocktake of existing business activities is required to enable
the Local Board to support sustainable rural economic activities in the WRHA.
Findings from the stocktake
14. The
full stocktake report is given in Attachment A to this report. The database in
Attachment A is abridged for the purpose of this report. Some of the main
findings from the stocktake report are given below.
· 939 businesses have
been identified within the WRHA.
· Of these
businesses, 655 (about 70 percent) are concentrated in the eastern foothills
(Titirangi, Henderson Valley / Swanson, Oratia and Waiatarua). The rural and
coastal areas have the least number of businesses.
· The businesses are
classified according to the Australian and New Zealand Standard Industrial
Classification (ANZSIC).
· The locations of
businesses are identified with GIS coordinates that provides a spatial
appreciation of the location of businesses.
· Consulting /
business services, building services and creative industry are the top three
sectors represented by businesses in the WRHA.
· The composition of
sectors is different in the rural/coastal areas and semi-urban areas. For
example, in Piha and Karekare, accommodation is the most prevalent sector,
while in Titirangi the predominant sector is consultancy / business services.
· The majority of
businesses in the WRHA are small and home-based, servicing customers both
within and in close proximity to the WRHA.
· Motivating factors
for businesses to locate in the WRHA include
o a unique and attractive lifestyle not available elsewhere in the
Auckland region
o an ideal place to ‘escape’ from the corporate world
o a sense of ‘community’ that is no longer easily found in city.
15. A
database of businesses in the WRHA will be created as a result of the
stocktake. This will be able to be sorted by sector, address, and current
contact details. All of this information was obtained from publicly available
sources (such as telephone directories, the internet and signage). The
information in the database will provide a useful baseline to track future
business activity trends in the WRHA. It is intended to share the database
with other Council departments on request.
16. The
Local Board provided feedback on the draft stocktake proposal at meetings held
in March and April 2014. At those meetings, the Local Board members expressed
their interest in supporting small-scale sustainable businesses in the eastern
foothills of the WRHA in accordance with the framework of the Act. The
recommendations made in the stocktake report for future projects are applicable
to the entire WRHA across the various business types that currently exist. The
Local Board has an opportunity to implement economic well-being initiatives to
target all business owners in the WRHA. The Board may also choose to target a
certain business sector (for example, creative industry) or an area (for
example, the eastern foothills). Given that about 70 percent of the businesses
identified by the stocktake are located in the foothills, it is appropriate to
focus economic well-being initiatives on the foothills. The options discussed
below are applicable to all businesses in the WRHA, including those located in
the eastern foothills.
Possible options for future projects
17. Based
on the analysis of findings and recommendations in the stocktake report, five
options for future projects are discussed below. These options suggest
opportunities for the Local Board to support people who work in the WRHA to provide
for their economic well-being in a manner that aligns with the Act. The options
discussed below align with the Local Board’s intention to support sustainable
business activities in the WRHA. Options 1 and 2 could be implemented
relatively quickly at a minimal cost. Options 3, 4 and 5 require further
investigation and budget allocation from the Local Board. A longer list of
potential project options is discussed in detail under section 5 of the
stocktake report given in Attachment A.
18. Option
1: Offer business advice in collaboration with Council departments
Auckland Tourism Events
and Economic Development (ATEED) offers free business
clinics on a regular basis to people seeking business advice and encouragement.
At these clinics, ATEED provides help with various aspects of businesses such
as exploring business opportunities, business strategy and marketing
challenges. Three such clinics have recently been announced for West Auckland
businesses between August and October 2014. The Local Board can explore
possibilities with ATEED to organise additional advice clinics which support
business activities located in the WRHA.
The costs involved to
organise the clinics include personnel hours of ATEED and Local Board officers,
and venue and communication charges. As ATEED is a Council-controlled
organisation, there is flexibility to tailor the content and scope of these
clinics.
19. Option
2: Share information about networking opportunities and support services
The major commercial
banks organise periodic networking events for local businesses. These free
events provide businesses with the opportunity to share experiences and build
networks. Information about such free networking opportunities can be passed on
to the business owners in the WRHA through the contact database created by the
stocktake report. The Local Board may also use existing communication channels
such as the Council website and the regular Local Board newsletter to
disseminate information about these events. This information can also be published
in the local newsletters within the WRHA. The Local Board could explore
opportunities with the commercial banks to organize events which cater for
business owners in the WRHA.
The costs involved to
organise such networking events include the personnel hours of Local Board
officers, and venue and communication charges. There might be, however, limited
flexibility to influence the content and scope of such events.
In addition to the
networking event discussed above, there are a number of web based networking
opportunities and support services that the businesses in the WRHA could access
and potentially benefit from.
The Local Board could
share information about such opportunities through its existing communication
channels or by publishing and distributing a newsletter targeted at businesses
in the WRHA.
20. Option
3: Organise business exposition
The Local Board could
fund an exposition to showcase products created by businesses in the WRHA,
which could also be used to promote the unique work of local artists. This
option needs to be further explored with ATEED prior to implementation.
Following points should be noted prior to considering this option:
· It would require
budget allocation from the Local Board.
· The Local Board
would need to determine the scope and consequently the cost of any proposed
exposition, such as whether to target all businesses in the WRHA, or instead
focus on certain business sectors or geographical areas.
21. Option
4: Publish an online directory of businesses
An online directory of
businesses in the WRHA can be created from the stocktake database. This
directory will provide exposure to those small businesses who cannot afford
their own website or advertising services. The following points should be noted
prior to considering this option:
· It would require
budget allocation from the Local Board. There would be costs involved in
setting-up and maintaining the database. The on-going maintenance of the
directory would require on-going budget.
· Before going live
with the database, Council would need to confirm with businesses that they wish
to be listed in the directory.
· A web location to
host the database would need to be determined. Possible options are the Local
Board web page on the Council website or a dedicated web site.
22. Option
5: Provide work space for businesses
This option involves
providing temporary work space in town centres such as Titirangi or Glen Eden.
This would benefit those business owners who do not have their own space, or
are located remotely and would allow for meetings to be held with clients.
There would also be access to broadband internet which would benefit business
owners located in areas with low speed internet connection. Further details
about this option need to be explored. However, following points are to be
noted:
· It would require
budget allocation from the Local Board.
· There will be cost
involved in setting up, operation and on-going maintenance for a purpose built
facility. An alternative option is to use the existing Council facilities.
23. The
above five options were discussed in two meeting in August 2014 with the Local
Board’s Economic Development portfolio holder. At those meetings, staff from
Council’s Economic Development Unit and ATEED were also present for the
discussion of the options. Those meetings preferred to initially implement
Options 1 and 2 in the financial year 2014/15 and to explore possibility of
organising an event (such as an exposition) in the financial year 2015/16. As
part of implementing Options 1 and 2, the preferred approach was to investigate
the possibility of publishing a newsletter targeted at the businesses in the
WRHA.
24. Organising
business clinics in remote locations in the WRHA identified issues with the
logistics involved with organising such clinics. ATEED, however, is able to
support those businesses in the WRHA that have potential growth aspirations.
Such businesses could attend ATEED organised services such as business clinics
and ‘Starting of right’ program.
25. Recommendations:
i) Progress
dialogue with ATEED around the possible provision of additional business advice
clinics which support business activities located in the WRHA.
ii) Implement
aspects of Option 2: Share information about networking opportunities and
support services:
Publish and distribute a newsletter targeted
at the businesses in the WRHA:
In addition to disseminating relevant news, the
newsletter could also:
· inform businesses
about opportunities to network and services that they could access
· provide an
opportunity for two-way communication between the local board and the business
community in the WRHA.
It is recommended to
publish the first edition of the newsletter in November 2014 and subsequent
editions at six monthly intervals (May and November). Initially, the
newsletter would be distributed by email and the postal system. It is intended
to gradually shift towards email distribution where possible which would reduce
cost of distribution of the subsequent editions.
Consideration
Local
board views and implications
26. Workshops were held with the Local Board to present the preliminary
findings of the stocktake in July and August 2014.
27. This report informs the Local Board about the stocktake and outlines
five possible options for the Local Board to support economic well-being in the
WRHA. One option is recommended to be progressed this financial year. Budget
would be required to implement the option of developing and distributing a
newsletter and it is noted that $3,000 is currently allocated 2014/15 under the
topic ‘small business facilitation’
Maori impact statement
28. Mana
whenua (Te Kawerau a Maki and Ngati Whatua) have not been specifically consulted
as part of the stocktake report and this agenda report. They are part of the
engagement in other projects of the WRHA Implementation Programme such as the
current Local Area Plan for Te Henga (Bethells Beach) and the Waitākere Valley.
29. The
stocktake was a research project. Engagement with mana whenua may be required
when the recommendations made in this report are implemented.
30. Providing
for the well-being of local businesses in the WRHA will benefit local
residents, including Maori.
Implementation
31. The North West Planning Unit worked with an economic development
expert to carry out the stocktake. Budget allocation is
required from the Local Board to undertake further work associated with
economic well-being in the WRHA, including the preferred option recommended in
this report. Such an allocation may be a part of the WRHA Implementation
Programme.
32. The cost of
publishing and distributing the first edition of newsletter discussed in this
report is approximately $1,200. The cost of the newsletter can be covered from
the $3,000 allocated from the Waitakere Ranges Programme for the financial year
2014/15 under the topic ‘small business facilitation’.
33. Networking
with Council’s Economic Development Unit and ATEED, who have the necessary expertise
about economic development, will be required to implement future work
associated with providing for the economic well-being of people in the WRHA.
Coordination with some external agencies may also be required.
Attachments
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No.
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Title
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Page
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aView
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Waitakere Ranges Heritage Area
Business Stocktake (Under Separate Cover)
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Signatories
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Authors
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Raj Maharjan - Planner
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Authorisers
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Penny Pirrit - Regional & Local Planning Manager
Glenn Boyd - Relationship Manager Henderson-Massey,
Waitakere Ranges, Whau
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Waitākere
Ranges Local Board
25 September
2014
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Dune Management at Piha
Review and
Proposed Management Plan
Prepared
for Auckland Council
Prepared
by: J Dahm, Eco Nomos Ltd
September
2013
CONTENTS
1. Introduction.. 3
1.1 Purpose of Review.. 3
1.2 Area Relevant to this Review.. 3
1.3 Work Undertaken. 4
2. Coastal Processes and Shoreline Trends. 5
2.1 Description and Coastal Setting. 5
2.2 Shoreline Trends at Piha Beach over the
last 70-80 Years. 6
2.3 Likely Future Shoreline Trends at Piha. 9
2.4 Implications of Ongoing Shoreline Advance
for Piha Beach. 10
2.5 Can the Shoreline Advance be stopped by
Human Intervention?. 11
2.6 Will the Shoreline Advance eventually cease
Naturally?. 11
2.7 Has Dune Planting cause the Beach to
Advance?. 12
3. Review of Dune Management to Date. 16
3.1 Dunes and Dune Vegetation at Piha. 16
3.2 Historic Dunes Damage and Modification. 17
3.3 Dune Restoration Work to Date. 22
3.4 Review of Work to Date. 23
4. Proposed Dune Management Plan.. 25
4.1 Objectives of Dune Management. 25
4.2 Raising Community Support, Awareness and
Involvement. 26
4.3 Minimising Problems with Windblown Sand and
Wind Erosion. 28
4.4 Maintenance and Enhancement of Public
Access and Amenity Values. 32
4.5 Natural Character and Biodiversity. 38
References. 41
1.1 Purpose
of Review
The study for this
report is the area of Piha along Marine Parade South (south of Lion Rock)
(Figure 1), one of New Zealand’s most iconic beaches and a popular destination
for surfing and swimming.
The high levels of
use and strong onshore winds have, historically, resulted in significant damage
to critical sand trapping vegetation on the natural dunes backing the beach, leading
to problems with wind erosion damage and windblown sand. Historically, the
dunes and back beach areas have also been altered by various human activities –
including subdivision and development, roads and car parks, and stream training
and reclamation.
Eco Nomos was
engaged by Council to review dune management in this southern area of Piha
Beach to date, identify further work required in the short term to improve the
containment of the dune sand, and to produce a local dune management plan to
guide future management and maintenance of the dunes. This local dune
management plan is non-statutory and for guidance only. It should not be
confused with a Reserve Management Plan which is a statutory document, the
development of which must follow the Reserves Management Act.
1.2 Area Relevant to this Review
The area
of Piha Beach relevant to this review is the area extending from the dunes on
the southern side of Piha lagoon to the south end of Marine Parade (Figure 1). It
includes:
· The dunes fronting
the surf club car park and private properties to the north
· The Moana Stream
entrance area
· The dunes fronting
the southern car park and private properties to the south, as well as the large
dune at the very southern end of the beach seaward of the boat launching access
road. (The large dune at the south end, together with the access road and boat
launching road are part of the Waitakere Ranges Regional Park).
The area
is approximately 550 metres in length.
For this
purposes of this review, this area is referred to as Piha Beach – with the
areas north of Lion Rock referred to as North Piha. The study area is also
sometimes referred to as Piha but that term has been avoided in this report
except where it appears in quotes from other sources.
Important
community infrastructure (including the Surf Club, car parks, road access and
stormwater drainage) and private properties occur directly landward of the
dunes (Figure 1). These assets are located within what was originally the
active dune system and have only a limited width of dune buffer to seaward
(Figure 1). These areas have experienced issues with windblown sand.
Figure
1: Area of Piha Beach relevant to this review
1.3 Work Undertaken
The work undertaken during the review
included:
· Site inspection and assessment of
recent dune management works and present dune condition
· Review of dune condition and changes
over time using historic photography
· Review of available information on
coastal processes and trends – including the previous work by King et al (2006)
and beach profile data held by Auckland Council (including surveys to October
2011)
· Consideration of earlier work -
including the decision by Hearings Commissioner former Justice Arnold Turner
decision in 1992 (often known locally as the Turner Decision), the Piha Coastal
Management Plan completed in 2000 (WCC, 2000), Piha Reserves Management Plan
and outcomes from the two 2009 Community Open Days on Piha Beach and dunes
(WCC, 2009)
· Informal discussions with
representatives and individuals from various stakeholder groups - including
Piha Ratepayers and Residents, Piha Coastcare, Piha Boardriders, Piha Surf Life
Saving Club and a beachfront landowner. These informal meetings discussed
matters related to dune management – including any concerns, activities and
interests that need to be taken into account, and suggestions to ensure future
dune management continues to improve and is widely supported.
· Review of the draft
Management Plan by Council staff.
· Workshop with Local
Board to outline and discuss proposed plan
· Community workshop
held in Piha Saturday 25 August 2012 to discuss plan
· Community
submissions/comments
· Follow up meetings
with representatives of surfers (Sunday 14 October 2012) and Piha Ratepayers
and Residents (Saturday 17 November 2012) to discuss particular concerns of
these groups
· Revised plan
forwarded to Council, Piha Coastcare and Piha Residents and Ratepayers for
comment
· Revision and
finalising of plan.
2. Coastal
Processes and Shoreline Trends
This section
discusses the coastal setting of Piha Beach and the consequent shoreline trends
experienced – which have significant implications for dune and coastal
management at Piha.
2.1 Description and Coastal Setting
Piha
Beach is approximately 2.6-2.7 km long. The embayment in which the beach is
contained (sometimes called Piha Bay) is formed by headlands at either end
which extend approximately 300-500 m seaward from the beach. The beach is
backed by dunes over most of its length, the total width of dunes varying from
20m to in excess of 200 m. The frontal dune system is vegetated in spinifex (Spinifex sericeus -
also
known as kowhangatara or silvery sand grass) and pingao (Ficinia spiralis
- also known as golden sand sedge). These native species play a critical role
in natural sand trapping and dune repair as well as preventing wind erosion. The
dunes are backed by relict sea cliffs cut into the Waitakere Ranges. The isolated
promontory of Lion Rock divides Piha Beach into Piha and North Piha.
The
beach is characterised by high wave energy with a modal wave height somewhere
between 1.5-2.5 m (up to 6.5 m in storms) and mean wave periods of 12 seconds
(King et al., 2006). During storms, breaking waves can extend more than 500 m
offshore. The seaward edge of the active beach system and cross-shore sand
transfer probably extends to water depths of at least 6-8m and possibly
deeper.
Piha
Beach is part of a large scale interconnected sand system that extends from
Taranaki to North Cape. The beach sands along this coast, including those at
Piha, are ultimately derived primarily from erosion of andesitic volcanic
materials in Taranaki – over time undergoing a net northwards movement by
waves. There may also have been significant historic contribution to west coast
sands from the Taupo Volcanic Zone via the Waikato River but this is now
minimal as the river is dammed in upper regions.
The
beach also lies only a short distance north of the large Manukau Harbour
entrance. The harbour entrance disrupts the northwards longshore movement of
sediment – with the sediment tending to accumulate and bypass the entrance in
large “slugs” of sand. This has a significant effect on shoreline trends
observed at Piha – as discussed in more detail below.
2.2 Shoreline
Trends at Piha Beach over the last 70-80 Years
Piha
Beach has been undergoing an overall trend for shoreline advance since at least
the 1930’s (and possibly earlier). While periods of erosion have occurred
within this period, the overall trend has been for net shoreline advance (NIWA,
1999; King et al., 2006).
This
shoreline advance reflects the northward alongshore movements of colossal
volumes of sand bypassed past the Manukau Harbour entrance to Whatipu over the
last 150 years.
The
earliest recorded period of shoreline advance occurred at Whatipu between 1844
and 1910 when the shoreline prograded several hundred metres from the cliffs
behind. This was followed by a period of erosion. A second and even more
significant period of shoreline advance has occurred since the mid 1930’s,
causing the shoreline at Whatipu to advance seaward by up to approximately 1400
m between the 1935 and 1954 (Williams, 1977).
The very
large volumes of sand which have accumulated at Whatipu over this period are
evident in aerial photographs of this area (Figure 2). Prior to this
accumulation the shoreline lay along the rocky cliffs behind.
The large volumes
of sand that have bypassed the Manukau Harbour to Whatipu are being
progressively moved northwards causing shoreline advance at both Karekare and
Piha.
For instance,
several years ago access from Karekare to Whatipu was only possible at low
tide. However, the shoreline has now built out to the point that it is now
possible to walk from Karekare to Whatipu even at high tide.
Photographs
in Sandra Coney’s book “Piha - A History in Images” (Coney, 1997) suggest the
shoreline advance at Piha had commenced by the 1930’s and perhaps even
earlier.
King et
al (2006) investigated shoreline changes at Piha between 1940 and 2000 and
noted considerable net shoreline advance over this period, notwithstanding
periods of erosion. There was also considerable variability noted in average
shoreline accretion rates – both between different areas of the beach and over
time (i.e. spatially and temporally).
Figure
2: Sand accumulation at Whatipu
In the
period from 1940-2000 as a whole, the net shoreline advance was most
significant at the northern end of the beach where the average rate of
shoreline advance over the period varied from 0.8-1.1 m/yr. Central areas of
the beach exhibited considerable variation with net shoreline advance averaging
0.5 m/yr over the 60 years, but including a high average accretion rate (1.2
m/yr) in the period from 1940-60 and erosion of about 8.3 m in the period
1991-93. The southern end of the beach, the focus of the present study,
exhibited the greatest variability – with an average net shoreline advance of
0.5 m/yr over the 60 year period but including periods of erosion from 1960-80
and 1991-93. In other words, over the 60-year period, the southern end of the
beach experienced periods of quite marked shoreline advance as well as periods
of erosion – with an overall trend for net advance.
King et
al (2006) presented data showing the area of net accretion over the entire
length of Piha Beach for the periods 1940-60, 1960-80 and 1980-2000 and this
data is shown plotted in Figure
3.
It can be seen that relatively high rates of net accretion occurred in the
period from 1940-1960 and from 1980-2000, whereas the net rate was lower in the
intervening period from 1960-80. The reasons for the variability in net
shoreline advance over time – within and between different areas of the beach
and over the beach as a whole are not yet known and are likely to be complex.
Given
the very significant implications of the ongoing alongshore sand flux for
future changes at Karekare, Piha, Te Henga (Bethells) and Muriwai beaches it is
critical to have further research investigating the nature of the alongshore
transfers from Whatipu and the various controlling factors. This will help
better predict future changes and may also assist with understanding past
changes. The research required is significant and is more suited to
FoRST-funded work than smaller-scale research (occasional PhD or Master’s
study) otherwise likely to be funded. It is recommended that Auckland Council
should lobby for further investigation in this area. Ideally, the research
would involve a partnership between NIWA, Auckland Council and local research
institutions (particularly Auckland University). There is also a strong case
for a major FoRST-funded research programme for the west coast sandy system
from Taranaki-Cape Reinga given the inter-connected nature of this sand system,
the large temporal and spatial timescales of change on this coast, the poorly
understood nature of these changes and dynamic links and the increasing demands
on the coast. Auckland Council could liaise with Taranaki, Waikato and
Northland regional councils and other relevant parties (including tangata
whenua) with a view to lobbying central government science agencies for this
work.
Beach
profile monitoring at the southern end of Piha Beach by Auckland Council indicate
that this shoreline is continuing to advance seaward in front of the surf club
(Figure
4)
and the landward end of the southern car park. The shoreline in front of the
surf club has in fact grown seaward at an average rate of about 1 m/yr over the
period of the beach profile record (Figure 4) – similar to the
high rates observed in some periods in central and northern areas of the beach
by King et al (2006).
Figure
3: Rate of increase in shoreline area at Piha Beach (over the
entire beach) between 1940 and 2000. (Data from King et al., 2006 - Table 3, p
1365).
Overall,
despite considerable temporal and spatial variability, net shoreline advance
has been experienced along the entire length of the beach since at least 1940. King et al (2006)
estimated that the total area of foredunes increased by just over 121,000
square metres between 1940 and 2000.
The volumes of sand
required to effect shoreline advance of this scale along Piha Beach are huge -
as the seaward edge of the beach system lies over 500 m offshore and the entire
beach width has to build. King et al (2006) estimated the additional volume of
sand stored above mean sea level alone (i.e. about mid tide) between 1940 and
2000 at about 700,000 cubic metres. Given that the seaward edge of the beach
system at Piha extends over 500 m seaward to depths of at least 6 m below mean
sea level (probably deeper), the total volumes of sand causing the observed
shoreline change were even larger. For instance, assuming the seaward edge of
the beach system is as shallow as only 6m, formulae used to calculate beach
nourishment volumes suggest that at least 1.2 million cubic metres of sand were
required to cause the increase in shoreline area noted between 1940 and 2000
alone (i.e. the volume of sand accumulating at Piha averaged about 20,000 cubic
metres per year). If the seaward edge of the beach system is deeper than 6m
(quite possible), then the calculated volumes would be even larger.
2.3 Likely Future Shoreline Trends at Piha
It is
difficult to reliably estimate how much longer the Piha Beach shoreline will
continue to prograde. However, there are still very large volumes of sand
stored at Whatipu (Figure
2)
and it is possible that, ultimately, most of the sand stored here will move
northwards. Accordingly, it seems likely that Piha Beach will continue to
experience an overall trend for net seaward advance (albeit with occasional
periods of erosion) for some time, probably several decades and possibly even
longer.
It is
also difficult on the basis of existing information to estimate how much
further seaward Piha Beach will ultimately advance and the rates of this
advance. However, based on the historic rates noted above, it is possible that
the beach will continue to grow seaward at an average rate of 0.5-1 m/yr when
averaged over long periods of time. However, as in the past, there is likely to
be considerable spatial and temporal variability in the rate of net shoreline
advance. As discussed in King et al (2006) there is finite sand storage space
in the Piha littoral cell, and the current phase of accretion will not continue
forever i.e. it must slow or reach capacity at some stage in the future.
Figure
4: Selected surveys conducted at Auckland Council beach profile
site Piha 2 (top) showing progressive shoreline advance over time since surveys
commenced in 1993. The most landward profiles are from 1993 and 1994; the mid
profiles from 2002 and the most seaward profiles date from May and October
2011. The beach profile monitoring site is located near the surf club as shown
in the location map (bottom) – where it is labelled “Profile 2”.
2.4 Implications
of Ongoing Shoreline Advance for Piha Beach
The
ongoing shoreline advance has significant implications for Piha Beach.
Many of
the surfing and swimming values of Piha Beach in particular relate to the
embayed nature of this area and to the partial sheltering from (and refraction
of) the prevailing southwesterly swell around the southern headland. These
values have already been adversely impacted by natural shoreline advance and
further changes are likely to be experienced with continuation of these natural
trends in the future.
For
instance, a long-standing Piha surfer advises that shoreline advance to date
has already eliminated a very popular surf break that used to exist between
Pakiti
and the shore (Mr Barry Davis, pers. comm.), a break variously known as the
“reform” or the “ditch”. Mr Davis notes there was a strong current that ran
through this area, landward and southwards around Pakiti and then out to sea -
creating a deep gully and providing a useful surf break as well as an important
fishing area. With the very large volumes of sand that have moved into this
area from Whatipu in recent decades, the beach has now built out and it is no
longer possible to surf this area. The rip is now seaward of Pakiti.
Long term residents
also advise that the “blue pool” which used to form in the area landward of the
Gap no longer occurs at low tide due to infilling of the area with sand. The
Piha Ratepayers and Residents, in anecdotal evidence provided with their
submission and in a subsequent meeting, noted that while the pool historically
used to fill in to less than 1 m depth, the sand would later be discharged and
pool depths increase to as much as 2 m. In the last 20 years, the infilling due
to natural coastal processes has persisted and a valued natural feature has
been lost.
Lifeguards advise
that the shallowing of the beach has made the situation around the rocks at the
south end more dangerous because the areas have become more accessible. They
also note that it has been much easier to walk around some seaward areas of
Lion Rock in recent years.
As the southern end
of Piha Beach continues to advance seaward over time, surfing and swimming
values are likely to continue to alter and may be adversely affected. The
seaward advance will also result in the width of the dunes increasing over
time, which will improve the natural protection these features provide to
adjacent infrastructure and assets. .
2.5 Can the Shoreline Advance be stopped by Human
Intervention?
In a word, no. The
sand volumes being moved alongshore into Piha are simply huge and the scale of
these natural changes is beyond reasonable human control.
2.6 Will the Shoreline Advance cease Naturally?
Yes -
eventually. While the Piha shoreline seems likely to continue to advance
seaward for the foreseeable future for the reasons noted above, a point will
eventually be reached when the volumes of sand moving northwards alongshore out
of Piha exceed the volumes arriving. The shoreline will then cease advancing.
Piha is
not the final destination of the large ‘slug’ of sand gradually being moved
alongshore from Whatipu. This slug of sand will eventually move past Piha. As
it does so, the shoreline at Piha will eventually experience a sustained period
of shoreline erosion. In the longer term, there is also potential
for projected sea level rise to cause coastal erosion.
The work
by King et al (2006) suggests that this future period of retreat may well
remove most or even all of the sand that has accumulated over the last 80 years
or more. Accordingly, as emphasized in the Piha Coastal Management Plan, it is
not appropriate to assume the dunes will also be there. . It is important to
realize that the dunes provide important protection to these public and private
assets. In the long term, serious erosion may necessitate private development
and infrastructure in these areas to be retreated landward.
It is
very difficult to usefully predict when this sustained period of erosion will
commence – but it does not seem likely within the next few decades, given the
large volumes of sand still stored at Whatipu.
2.7 Has Dune Planting
caused the Beach to Advance?
In discussions and
submissions it was noted over and again that there is a strongly held view by
some parties that past dune work has contributed to the beach changes that
resulted in loss of important amenity values such as the Pakiti surf break and
the infilling of the “blue pool”. This has resulted in controversy and division
over Coastcare and dune restoration at Piha.
In general, these
concerns relate to the fact that early dune works broadly coincided in time
with more rapid advance of the shoreline at the southern end of the beach.
The rate of shoreline
advance has varied significantly in space and time along Piha Beach (King et
al. (2006) as discussed in section 2.2). While the reasons for this would
require detailed research, they do not relate to dune planting and restoration.
Any coincidence in timing between beach advance and dune management is only
that - as it is simply not possible to cause beach advance by planting dunes.
Significant net
shoreline advance as observed at Piha requires the input of very large volumes
of sand to the beach system. Net shoreline advance occurs when the volume of
sand input to the beach system exceeds that removed. Dunes form when sand
already in the beach system is blown landward and trapped by natural
vegetation. No matter how much sand is trapped in the dunes by natural
vegetation, this will not contribute at all to beach advance.
The situation is in
fact the exact reverse – beach advance causes dune advance, not the other way
round. If the beach advances seaward over time (as is occurring at Piha due to
longshore inputs from Whatipu) then the dune will also advance. Conversely, if
the beach retreats or is severely eroded by a storm, then the dune will also
erode. Dunes follow beaches, not the other way round. Dunes can only be formed
where there is sufficient width of high tide beach to permit this.
Natural vegetated
dunes at Piha Beach are evident in the earliest photos of this area (see
Section 3) and these dunes have played no role whatsoever in the changes to the
surf break. Dunes are natural features and occur simply because sand blown
landward from the beach is trapped by vegetation.
The concern with
the loss of the surf breaks and other values is entirely understandable.
However, the link drawn between the dunes and the loss of these values is
incorrect. The beach advance and consequent impact on surfing breaks and other
values relate to the natural longshore input of very large volumes of sediment
from Whatipu. That natural process is likely to continue in the foreseeable
future for the reasons discussed above.
However, this is
not to deny that some early works (e.g. those in the Moana Stream entrance
discussed below) were unnecessary. Many people with concerns noted that they
were not against dune restoration per se but simply against unnecessary works.
The recommended restoration plan (Section 4) attempts to provide improved
guidance in this respect.
What about
the “Artificial Dunes” across Moana Stream entrance?
There are some long
term Piha residents and visitors who argue that the beach advance and loss of
the surfing breaks was wholly or partly caused by the training of Moana Stream
in the 1980’s (Figure 5), the later construction of dunes across the originally
flared stream estuary (Figure 6), and the decrease in stream flows since
stormwater from Rayner Road was diverted into Piha Stream rather than into
Moana Stream. They note that the stream lowered the beach to seaward and the
original flared stream entrance (e.g. see Figures 7 and 12 later in this
report) allowed large volumes of wave run-up and surge to wash into the area
during storms. They argue that the outflows reinforced the rip formed at the
south end of the beach, helping to prevent sediment accumulating in the
embayment between Lion Rock and the southern end of Piha Beach. It is their
view that training of the stream and decreased stream flows was largely
responsible for beach advance.
The training of the
Moana Stream and associated work was unnecessary as made clear in the 1992
Turner decision. There is also no question that the works significantly altered
the natural and human use values of the area. It is unlikely however that the
infilling and reclamation of the former flared stream entrance played a
significant role in the beach advance. Breaking waves transport large volumes
of water into the Piha Beach embayment every day and it is the return of this
water to the sea that generates the very strong longshore currents and rips.
The big swells surging in and out of Moana Stream, while undoubtedly
impressive, were only occasional events and would only ever have been a small
component of the wave generated circulation in the embayment south of Lion
Rock. The works in the Moana Stream entrance are therefore not likely to have
significantly affected the volumes of water circulating through the embayment.
It is agreed that any impact on this aspect would certainly have been negative
(i.e. reduced flows) rather than positive but the effect on the total volumes
of water circulating through the embayment would have been very small. The human-
built dune shown in Figure 6 would also not have survived if the beach had not
already advanced seaward because of the large volumes of sand being moved into
Piha Beach from areas further south. In fact, it is probable that a natural
dune would have developed over part of the area in response to the beach
advance – though a flared stream entrance would have remained in the absence of
the stream training works.
Figure
5: Moana Stream in 31 March 1991 subsequent to training (concrete
lining) of stream (1984-5) which eliminated the earlier flared entrance to
create a larger grassed amenity area. This photo was taken prior to
construction of the along dunes along seaward margin and it can be clearly seen
that beach views from the reserve were then quite expansive (Photo supplied by
Mr Barry Davis).
Figure
6: Photograph a few months later (31 May 1991) shortly after
human construction of dune across the seaward margin of Moana Stream. This dune
diminished views of the beach reserve and may also have impacted on sea views
from the adjacent road and some private properties. The dune has however also
enhanced amenity by providing a sheltered area that folk can picnic in during
the common periods of winds from westerly directions. (Photo supplied by Mr
Barry Davis).
It would be
possible to restore a flared entrance to the Moana Stream entrance if the
community as a whole wished to pursue this – as discussed later (see discussion
in Section 4.5). However, this work would not restore the surf break that once
existed and is also unlikely to have any measurable effect on future shoreline
advance. Nonetheless, the work could be desirable because it would restore some
of the natural character and landscape values that have been modified,
contribute to restoring stream function and natural values. The work could
probably also be designed to enhance public use and amenity values in this area
(see Section 4 for further comment).
Implications
of Shoreline Advance
The ongoing trend
for natural beach advance will continue to alter the offshore beach profile and
waves at the southern end of the beach as discussed above. This has
implications for surfing values in this area (as discussed above) but will also
have implications for the dunes, including:
· Increased width of
dunes:
Existing dunes will widen further seaward over time, even though they may be
periodically cut back by storm events.
· Reduced issues with
windblown sand:
The increasing dune width will progressively reduce issues with windblown sand
as the width of sand trapping vegetation increases.
· Create backdune
space for amenity:
Wider dunes will eventually create sufficient space behind the critically
important sand trapping vegetation that can be used for amenity (e.g. see
Section 4.4).
· Impacts on sea
views.
Ongoing seaward advance will help limit dune height - a stationary dune would
grow higher over time because more sand is added to the dune face and crest.
However, in the longer term, the increased width of the dunes may impact on sea
views – as has occurred in central and northern areas of the beach where the
shoreline was originally just across the road shortly after original
subdivision.
· Erosion: In general, the beach advance
will lessen erosion risk to adjacent roads and car parks. However, the dunes on
the immediate northern side of the Moana Stream entrance (often referred to
locally as “artificial dunes” as they were man-made and occupy an area that was
previously part of the stream entrance) may tend to push the stream entrance
into the dunes fronting the southern car park. This may cause some erosion of
these narrow dunes (particularly towards the eastern end of the car park).
However, as discussed later in the report, there are means of addressing this
and potential to return the stream entrance to a more natural state.
3. Review
of Dune Management to Date
3.1 Dunes and Dune Vegetation at Piha
Dunes and dune vegetation are natural
features on this coast, evident at the southern end of Piha Beach since the
earliest photographs in the late 1800’s and early 1900’s.
Early historic photographs indicate two separate areas
of natural vegetated dunes within this area of Piha (Figure 7):
· The area between Piha lagoon and the
former embayed Moana Stream entrance
· The area between the southern side of
the Moana Stream entrance and the south end of the beach
The photos indicate a relatively extensive cover of
spinifex over the dune areas and patches of darker vegetation further landward,
with little to no evidence of human damage (Figure 7).
Figure
7: Photograph of Piha Beach dating from the early 1930’s showing
areas of natural dunes (arrowed) – also evident in earlier photos. (Photograph
from Alexander Turnbull Library).
The dunes at Piha Beach are often referred to as
“artificial dunes”, even within parts of the Piha Coastal Management Plan.
However, it is clear from this historic photography that vegetated dunes are
natural to this area of Piha – except in the immediate vicinity of the Moana
Stream entrance where dune building would have been naturally restricted by
stream flow discharging across the upper beach with alongshore migration of the
stream channel. The latter are the only artificial (i.e. man-made) dunes.
Long-time residents/visitors to Piha recount that the large dune at the extreme
south end of the beach (adjacent to the boat launching area) was first
constructed by humans – but a dune would have developed in this area naturally
as the beach advanced creating an increased width of high tide beach.
In their
natural state, the most seaward or frontal dune was dominated by native sand
trapping vegetation – particularly spinifex with a lesser component of pingao
(Esler, 1975). This vegetation is of sufficient height to slow the wind in
areas close to the ground where the highest concentrations of windblown sand
occur. This decreases sand transport capacity of the wind, causing sand to be
deposited.
This
sand trapping vegetation plays a number of critically important roles in
natural dune function and character, including:
· The sand trapping
process is critical to natural dune building and repair. For instance, after
storm erosion, spinifex grows down the seaward face of the eroded dune -
trapping windblown sand and naturally repairing the erosion.
· Significant
reduction in problems with windblown sand further landward
· Prevention of wind
erosion damage to dunes
· Ecological values –
pingao, one of the key sand trapping species, was almost eliminated from New
Zealand dunes by historic human and animal damage and is still relatively rare
on this coast
The
native sand trapping vegetation on the seaward dune is however vulnerable to
damage from human trampling. Once the vegetation is damaged or destroyed,
windblown sand simply passes straight up and over the dune and is deposited
further landward – causing issues with windblown sand. In addition, damage to
the native sand trapping vegetation causes bare areas of sand to appear and
opens the dune to wind erosion damage.
Low
vegetation such as exotic perennial grasses (e.g. kikuyu) and iceplant are
often more resistant to human trampling. However, these are too low to be
effective sand trapping species. They are far less effective than the native
species at reducing windblown sand and in natural repair of dunes. Exotic
perennial grasses (e.g. kikuyu twitch) also compete with spinifex and invasion
of spinifex areas by this vegetation needs to be managed.
Inland
of the frontal dune, spinifex and pingao gradually gives way to other plant
communities of increasing diversity and height. Immediately inland of the
spinifex zone, common native vegetation can include pohuehue and knobby club
rush. Further inland, trees and shrubs start to appear – such as the karo
dominated shrubland evident at North Piha.
3.2 Historic Dunes Damage and Modification
Human damage to
dune vegetation and resultant problems with wind erosion and windblown sand
have been significant issues at Piha, especially adjacent to the high use car
park areas that are located within the active dune system. There has also been
significant human modification of the natural dunes over time.
Early dune
condition
Early photography suggests the natural vegetated dunes
of Piha remained in a relatively undamaged state up until at least the early
1930’s (Figure 7).
Dune
damage and modification
However, following subdivision in the 1930’s there is
evidence of increasing damage to the natural dunes and stabilising dune
vegetation, leading to consequent problems with wind erosion and windblown
sand.
For instance, in the vicinity of the surf club, early
subdivision extended seaward over the natural dunelands reducing the width of
natural dunes further seaward. Photographs from the 1940’s show poorly managed
human use, with intense human pressure on the critical sand trapping vegetation
on the seaward dune face (Figure 8 )
Figure
8: Photograph of area in front of the former surf club. Note
people sitting all over the seaward face of the frontal dune, damaging the
sensitive native sand trapping vegetation. (Photograph from Alexander Turnbull
Library).
By the 1950’s, photos indicate that human disturbance
of vegetation and consequent wind erosion was common with widespread use of
brush wind break fences to minimise wind erosion and windblown sand (Figure 9).
In the mid 1950’s, levelling of dunes in front of the
surf club to create car parking commenced and this area was progressively
extended into the 1960’s (Figure 10). Long term residents advise that clay fill
was also placed extensively over this area at the time (Helen Pearce, pers.
comm.). The car parks also encroached seaward, significantly further reducing
the width of natural dunes seaward of the car park. The poor management of beach
access resulted in the dune face seaward of the car park being largely devoid
of vegetation at this time (Figure 10)
Historic
photographs show a similar sequence of events at the southern end of the beach.
By the early-mid 1950’s, subdivision, roading and car park areas had encroached
over the former natural dunelands – extending right to the top landward edge of
the seaward dune face.
Parking occurred
along the full length during high use periods and access to and from the beach
was unmanaged – resulting in extensive disturbance of sand trapping vegetation
on the seaward dune face by the early 1960’s (Figure 11).
Figure
9: Photograph of Piha taken in January 1951 to the immediate
north of the surf club showing brush fences (examples arrowed) erected to
control wind erosion. (Whites Aviation photo – from Alexander Turnbull
Library).
In the mid 1980’s,
the Moana Stream entrance was also significantly modified – including training
the stream with a concrete-lined channel (Figure 12), reclamation of the former
embayed stream entrance and construction of dunes across the head of the former
embayment (these dunes often referred to locally as the “artificial dunes”).
The modification of the Moana Stream entrance was controversial and was
subsequently deemed unnecessary by the Turner decision.
Figure
10: Photograph from 1963 showing area of Piha fronting surf club
and areas to the north. Note that dunes fronting the surf club have now been
levelled to create a car park and the dune face seaward of this car park is now
largely devoid of vegetation. (Whites Aviation photo – from Alexander Turnbull
Library).
Figure
11: Photograph of southern car park area dating from January 1963.
There were some
ongoing attempts at improved dune management at Piha in the 1980’s and the
early 1990’s – including attempts at access management and planting. In the
early 1990’s, this work included significant and successful revegetation of the
dunes fronting the southern car park – largely using pingao (at that time, spinifex
could not be obtained from nurseries). While this useful planting work was
endorsed by the Turner decision, it encountered various problems and opposition
and did not persist.
By the early
2000’s, the high use area in front of the surf club was still seriously damaged
with exposed clay fill and very little native sand trapping vegetation (Figure 13).
The Piha Coastal
Management Plan also reported that storms periodically uncovered rubble and
waratahs and other sharp material, and there were issues with weeds (including
cape ivy and boneseed). Serious problems with windblown sand continued to be
experienced on both the surf club and southern car parks.
Figure
12: View of surf club car park and Moana Stream entrance area in
1985. Note the concrete stream training works in the Moana Stream and the
placement of sand trapping fences (arrowed) to create dunes on the immediate
northern side of the former embayment.
Figure
13: Area in front of surf club (undated but circa 2003) - before
commencement of Coastcare dune restoration works. (Photo supplied by Chris
Ferkins, Auckland Council).
3.3 Dune Restoration
Work to Date
Piha
Coastcare was formed in 2002 to address the various dune management issues and
for the general enhancement and protection of the natural environment at Piha.
It was initially set up under the auspices of the Piha Ratepayers and Residents
but is now a separate trust.
The
serious dune damage and windblown sand problems has necessitated an initial
focus on restoration of a good cover of native sand trapping vegetation over
the frontal dune and management of human use to provide for beach access while
preventing damage to this restored vegetation.
The work
to date has primarily involved:
· Some dune
reconstruction using machinery to rebuild dunes in badly wind damaged areas
prior to planting and to remove or bury historic clay fill from the car park
· Review and
realignment of several stormwater outfall pipes that discharged through the dune
and caused blow outs (Jo Morris, Auckland Council, pers. comm.).
· Restoration of
native sand trapping vegetation (particularly spinifex) over the frontal dune
· Installation of
defined accessways and guiding fencing (bollards and ropes) to provide beach
access while protecting the sensitive sand binding vegetation – together with
signage.
· Weed control –
eliminating the problem species noted in the Piha Coastal Management Plan and
ongoing management to stop exotic perennial grasses invading the native sand
binders.
More
recently, a retaining wall has also been installed along the back of the dunes
to:
· Provide a collection area for
windblown sand that gets past the frontal dune and thereby reduce the volumes
directly going onto the road and car park
· Provide for pedestrian accessway along
the back of the dune but separated from the car park area for improved safety.
The minimum width
of the accessway has been set to allow a machine to come in from time to time
to remove sand as it builds up. In general, this removed sand is perfectly
suitable for return to the beach provided it does not contain glass or other
significant contaminants.
3.4 Review of Work to
Date
The works conducted
to date are generally of a high standard and despite setbacks have been very
successful in addressing the serious dune damage and restoring a good cover of
critical native sand trapping vegetation.
This is
particularly evident in the area between the Moana Stream entrance and Piha
Lagoon, including the area fronting the surf club car park. There is now an
extensive cover of native sand- trapping vegetation in this area, contrasting
markedly with the state prior to the formation of Coastcare. While there are
still some localised areas of dune damage which need to be addressed, the
improvements to date are impressive.
The most recent
works fronting the southern car park were only completed in mid-2011 and so the
plants are not yet well established. This area has also suffered from some
ongoing vandalism since the plantings, including deliberate pulling of
significant areas of the planting. However, the approach undertaken in this
area is sound and with ongoing establishment and maintenance of the plantings
will significantly reduce the serious windblown sand issues historically
experienced. There is a minor issue with exotic perennial grasses recovering
among the spinifex plantings. Problems of this nature can be minimised in
future by spraying such grassed areas and allowing time for die-off before
earthworks. These exotic grasses can be readily sprayed out on a calm day –
though some spinifex may also be affected and require replanting. The spraying
of the grassed areas should occur before any further plantings of spinifex are
undertaken.
A difficulty is the
limited width of natural dune in front of the car parking areas, reflecting the
historic encroachment of development and infrastructure seaward over the former
natural dunes. An ideal minimum width of sand trapping vegetation for
Piha is probably in the order of 30m – but existing dunes are generally less
than this, particularly along the front of the southern car park (typically
<20 m width). The
limited width means that ongoing problems with windblown sand will continue to
be experienced for some time and these areas will require particular attention.
However, over time, ongoing seaward advance will increase dune width in some
places – particularly the area between Piha Lagoon and the eastern end of the
southern car park. Available data suggests less certainty of dune advance in
central and western areas fronting the southern car park.
With the presently
advancing shoreline, the issues with windblown sand in the car parks will
decrease over time as long as effective dune restoration work is continued.
However, in the longer term future, when serious erosion may occur the car park
may eventually need to be relocated. Long term planning should address
opportunities for future retreat of this and the surf club car park.
There appears to be
widespread support for the work undertaken to date. Coastcare report a good
turn-out to working bees and note considerable positive response to the gains
achieved so far. Field inspections during this review also indicate that the
vast majority of beach users use the defined accessways rather than cutting
across the dunes. In addition, surf club personnel spoken to advise that they
now train their volunteers from nipper stage in terms of accessing the beach
using defined accessways rather than trampling the sensitive dune vegetation.
Some tensions were
however identified in relation to matters such as:
· Consultation and communication
· Misunderstanding in relation to causes
of beach advance and consequent impacts on surfing breaks and the “blue pool”
(see Section 2.7)
· Concerns with the impact of dune
management structures (e.g. fences, retaining walls) on natural character
· Dune height blocking views from
properties and car parks to landward, with concerns having been raised in the
past from property owners behind the surf club and southern car parks, as well
as the extreme southern end of the beach. Community feedback indicates that
views from certain areas of the surf club car park (i.e. adjacent to the surf
club vehicle access) are particularly important for disabled people.
· Lack of elevated grassed areas for
viewing and amenity.
Dune management is an incremental process and the focus
to date has necessarily been on repair of the seriously damaged dune and
reduction of issues with windblown sand. These wider matters can be increasingly
addressed in the future as seriously damaged dune is restored and various
recommendations in regard to these matters have been included in the proposed
Management Plan.
A particular
concern is the persistence of misunderstanding on the role of the dunes in the
natural shoreline advance, despite this matter having been traversed in detail
by the earlier NIWA report (NIWA, 1999). This misunderstanding has no basis in
fact (see discussion in section 2.7) but has resulted in considerable
antagonism towards dune management and appears to have played a significant
role in the vandalism experienced to date. The issues arising from this
misunderstanding (including abuse, vandalism of plantings, etc) are proving
difficult and exhausting for Coastcare volunteers to deal with.
Coastcare
volunteers emphasized the need for more support from Council with consultation
and communication - as the work is very demanding and time-consuming on top of
the practical works required. This was also supported by others spoken to in
the community who believe that there is a need for improved consultation on
proposed dune works and is discussed later in the proposed management plan.
Overall, it is my
opinion that the achievements to date are outstanding given the seriously degraded
dune state at the start and the range of considerable difficulties faced. The
planting, access management and earthworks have generally been undertaken very
well and progress to date is notable despite the recent vandalism. It is
important that these gains are maintained and built upon with future work and
this has been given focus in the proposed Management Plan discussed in the next
section.
4. Proposed
Dune Management Plan
4.1 Objectives of Dune Management
A key element in
dune restoration and management is knowing what work is necessary and what is
not – so clear objectives are critical.
The
primary purpose of dune restoration and management is to maintain and restore
natural dune processes by preventing and repairing human damage. In addition, at
popular beaches such as Piha, dune management must provide for human use and
enjoyment as well as the protection of natural values. In contrast,
controlling nature is almost never the purpose of dune restoration and
management. Intervention with natural processes is generally only necessary
when major assets (e.g. roads) are directly threatened. And even then, there
may be better options (e.g. move the threatened asset).
Dune
restoration and management is also an incremental rather than an overnight process.
The damage and modification of the dune system over the past 70-80 years (see
Section 3.2) will take some time to restore. It also takes time to develop a
good understanding and community agreement on relevant matters at any beach –
let alone this site, one of New Zealand’s most iconic and intensively used
beaches with a wide range of stakeholders and values.
The
progress to date with restoration of natural dune vegetation and processes and
the repair and control of human damage is generally excellent and a
considerable achievement by all those involved, particularly considering the
damaged state of the dunes when the work commenced (see discussion in Sections
3.2 and 3.3). A key aim of the Dune Management Plan is to also provide an
agreed basis to maintain and build upon these achievements and to address
remaining matters of concern.
The key
objectives suggested for dune restoration and management in this area of Piha
are:
· Continuing to raise
community support, awareness and involvement
· Minimising problems
with windblown sand (particularly on roads and car parks) and wind erosion
· Maintenance and
enhancement of public access and amenity values
· Protection and
restoration of natural character
These
objectives overlap, as do the actions recommended to achieve them.
It is
important that any dune management plan is not overly prescriptive as a degree
of flexibility is required to accommodate coastal change and various management
issues as they arise.
4.2 Raising Community Support, Awareness
and Involvement
4.2.1 Discussion
The
raising of community support and awareness is an important objective for any
dune management work and is particularly important at Piha Beach as:
· Piha Beach is one
of New Zealand’s most iconic and popular beaches with a wide range of
stakeholders, with various interests and values. The support of beach users and
the local community is critical to the long term success and sustainability of
dune management. This requires good communication and consultation and a
balancing of interests – it is not an easy task.
· An informed and
supportive beach user community provides the most effective protection for
coastal dune values – while also minimising maintenance requirements and the
need for control and structures. Natural dunes not subject to human pressure
require little to no management. Most dune management is focused simply on
repairing natural dunes that have been damaged by human action and/or action
designed to protect critical dune vegetation from human disturbance.
· The physical
setting of Piha results in significant shoreline movements over long periods of
time due to natural forces and changes that are beyond reasonable human control
(as discussed in Section 2). A good understanding of these natural shoreline
changes allows proactive planning and avoids the kinds of misunderstanding
which have often complicated dune management at Piha to date and impacted on
community support. Awareness of ongoing trends is also important. For
instance, management issues at Piha will change radically when the beach system
eventually moves from its present long term trend for advance to a long term
trend for shoreline retreat. While the timeframe for this change is uncertain
and may be several decades away, it is important to work through and plan for
the implications of future retreat. For instance, at Piha, it may prove
extremely unwise to allow any further subdivision and intensification of use on
former sand dunes - as appropriate protection of these areas may not be
possible in the event of serious retreat.
Sustainable
protection of natural dunelands at Piha ultimately requires informed beach
users who understand the critical role played by natural dune vegetation and
who conduct their beach use activities in a manner which do not disturb this
vegetation – particularly the native sand trapping vegetation (spinifex and
pingao) on the most seaward dune exposed to strong onshore winds.
Piha
Coastcare has already built a good level of community support and awareness –
with good support for working bees (for instance, 60-100 people turning out in
mid 2011 to assist with restoration of the dunes fronting the southern car
park) and a large network
and Email list
of supporters. Coastcare also maintains a web site which endeavours to keep the
community informed on current activities and plans – as well as providing an
opportunity for interested community members to sign up to the Coastcare Email
list to be kept informed of activities. The web site and Email contact list are
good initiatives and awareness of these should continue to be promoted to
assist in expanding the level of community involvement.
Feedback
during consultation suggested that Auckland Council consider producing and
widely circulating a pamphlet outlining the reasons why shoreline advance is
natural at Piha (i.e. not a consequence of dune restoration) and the importance
of protecting and restoring natural dune vegetation.
However,
there are also issues that need to be addressed going forward to continue to
build community understanding, awareness and support.
Various parties
spoken to raised the need for more openness and active community consultation
prior to major works (e.g. significant reshaping of dunes, etc) so everybody
can understand what is being planned and why, and there is opportunity for
input. Some expressed the view that there had been less opportunity for
community participation and dialogue in decision-making in recent times.
However,
the wide range of demands in respect to community consultation and communication
are very difficult for Coastcare volunteers to meet at a popular and iconic
beach such as Piha. The key volunteers note that the workload is presently very
high and too demanding, with more support from Council required. Council and
Coastcare need to work together to provide appropriate consultation and
communication.
Prior to
Coastcare, many attempts at dune management failed at this site due to the
extreme difficulties. Strong Council (and community) support is critical to
ongoing success. Many councils involved in dune management employ or contract
dedicated coordinators to support and assist Coastcare volunteers – though the
most appropriate model for Auckland Council needs to be assessed. Subsequent to
formation of Auckland Council, a key Council staff member has been appointed
and this has improved the situation – though the staff member covers the whole
western area. A Memorandum of Understanding (MOU) with Auckland Council/Local
and Sports Parks West approved by the Waitakere Ranges Local Board has also
been suggested as a useful way forward to ensure clear roles, expectations and
boundaries.
4.2.2 Recommendations:
Community Support and Information
It is
recommended that:
a. A specific
MOU be developed between Piha Coastcare and Auckland Council
b. Auckland
Council give consideration to how best they can improve the level of support
provided to Piha Coastcare, particularly to assist with improving consultation
and communication in relation to dune management - including:
i. building
community awareness and support for dune management
ii. improving
communication and relationships with those stakeholder groups who have ongoing
reservations and concerns regarding dune management
iii. addressing
existing misunderstandings of coastal processes at Piha (e.g. with information
pamphlet)
iv. resolving
stakeholder concerns as they arise
v. provision of
an independent web site that is kept up to date with Coastcare activities and
plans (upcoming working bees; meetings)
vi. providing
opportunities for increased participation in dune management at Piha
4.3 Minimising Problems with Windblown
Sand and Wind Erosion
4.3.1 Discussion
This is
a critical element of dune management at high use public beaches such as Piha.
Windblown sand is a natural part of dune formation. Historic management issues
with windblown sand arise from human damage to natural sand stabilising
vegetation and from seaward encroachment of human activities into dynamic dune
areas (see discussion in Section 3). The main requirements to minimise
windblown sand are:
· Restoration and
maintenance of a good cover of native sand trapping vegetation (spinifex with a
component of pingao) over the most seaward dune and particularly the seaward
face to the crest
· Managing beach
access and human use on the frontal dune to avoid trampling and disturbance of
this critically important vegetation
· Building community
and beach user understanding and acceptance that the beach and dune is a mobile
system (see Section 4.2 above)
Earthworks
are also occasionally necessary (subject to attaining necessary resource
consents) to repair serious human damage to natural dunes (e.g. remove clay and
rubble fill from historic car park/roading projects, reshape dune to natural
topography following serious wind erosion damage, address areas of serious weed
infestation).
As noted
in the review (Section 3.4), Coastcare has significantly improved management of
this aspect. There is now generally a good cover of native sand trapping
species and beach users generally use the defined accessways rather than
disturb vegetated areas. These gains need to be maintained and built upon.
The
dunes fronting high use car parking areas will require particular ongoing
attention as, because of historic encroachment, they remain too narrow to
completely avoid windblown sand issues. Any problems in this area with
disturbance of vegetation cover and poor management of human use will be
reflected in aggravation of windblown sand issues. At this stage, it appears
that ongoing beach advance will eventually increase dune widths to adequate
dimensions and therefore the immediate focus should be on restoration and
maintenance of appropriate native sand trapping vegetation. However, if
shoreline advance does not continue, reconfiguration of the car parks may be
required to create extra dune width. In the event of future shoreline retreat,
the car parks may ultimately have to be retreated to alternative locations.
The
following recommendations are suggested to reinforce existing sound practice
and ensure ongoing improvement in the management of windblown sand:
4.3.2 Recommendations:
Planting and Weed Control:
a. Planting and
weed control are primarily required to restore natural sand trapping vegetation
damaged and modified by historic and ongoing human activities.
b. Restore and
maintain a good cover of appropriate native sand trapping vegetation over the
frontal dune, with particular emphasis on narrow dune areas seaward of the car
parks. This will maximise the sand trapping potential of the dunes and minimise
erosion.
c. Plantings on
the seaward face and crest should continue to emphasize spinifex with a
subcomponent of pingao. These are the most appropriate species for the control
of windblown sand at Piha and are also part of the original natural character
of Piha dunes.
d. Plantings in
more landward areas of the frontal dune and/or on the interface with grassed
reserves should emphasize knobby club rush interplanted with species such as Muehlenbeckia
complexa, sand coprosma and the native spinach.
e. Use of
regionally critical threatened dune species (e.g. sand coprosma) should be
incorporated in planting where appropriate to aid regional restoration. This
work should however be conducted carefully with appropriate planning (e.g.
specific “Threatened Pant Translocation Plan” for the species and site – using
the template developed by the Auckland Council Biodiversity Team) and
monitoring.
f. Wave erosion
is a natural process and it is not necessary or desirable to plant eroded dune
scarps formed by such erosion if there is already a good cover of native sand
trapping vegetation to landward. The spinifex and pingao in the more landward
areas will grow seaward down the dune face and naturally repair the erosion as
natural processes permit. Any planting would be at risk of loss in the event of
further storm erosion and dune repair is best left to natural processes. It is
important that wave erosion is a natural and expected process and does not
require any intervention unless significant assets (e.g. roads) are likely to be
threatened.
g. It is not
necessary to plant along the seaward edge of a well-vegetated dune system to
encourage seaward expansion – provided a good coherent cover of spinifex and
pingao is maintained on the seaward face of the dune. This vegetation will
naturally extend seaward. In general, any seaward expansion of dunes should be
left to natural processes unless there are compelling reasons for
intervention.
h. Plants should
be appropriately eco-sourced, ideally from the nearest population or within the
Waitakere Ecological District. It is acceptable however if the nearest
population is in an adjacent ecological district. If the only available seed
source is further afield, thought should be given to most genetically
appropriate source. With some species (e.g. spinifex) alongshore dispersal
i. Eradicate
exotic perennial grasses within spinifex areas (even if some area of spinifex
are damaged and need to be replanted) and ensure exotic perennial grasses do
not invade from grassed areas to landward. Spraying is best undertaken during
active growth periods in autumn and/or spring using a grass-specific herbicide
with an appropriate wetting agent. Spraying among spinifex should only be
undertaken on very calm days using a nozzle that gives strong control over
direction – to minimise damage to adjacent spinifex.
j. Where dunes
are reworked by machinery to prepare for planting, ensure that any exotic
perennial grasses are appropriately sprayed and die-off prior to the earthworks
to minimise reinvasion. Otherwise, stolons broken up by the earthworks may lead
to serious re-invasion of the exotic grasses.
k. Remove any
incursion by common garden plants (e.g. gazanias, arctotis and agapanthus) as
these species can spread rapidly and impact native vegetation.
l. The knobby
club rush community recommended along the landward margin of the spinifex zone
will assist in managing invasion by the exotic grasses (allowing grass specific
herbicides to be used without damaging spinifex), while also enhancing natural
character of the dunes. It will also assist with access management and
protection of natural character (see Section 4.5).
m. When dunes
have to be reworked (subject to attaining any required resource consent) to
bare sand prior to planting, ensure planting is undertaken as soon as
practical and dense planting (e.g. spacing 0.3-0.5 m) is desirable to assist in
rapid restoration of a good vegetation cover.
n. The Coastcare
annual plan should incorporate an inspection of the spinifex areas
(particularly seaward of the car parks) in autumn – so that any significant
bare areas that have developed (e.g. as a consequence of human damage over
summer) can be planted that growing season.
4.3.3 Recommendations:
Accessways:
a. Defined
accessways are required and critical to prevent human damage to natural sand
trapping vegetation. It is also important in terms of natural character and
visual amenity to keep the number of these accessways to the minimum required.
b. The present
number of accessways is largely adequate but an additional defined pedestrian
accessway should be established at the southern end of the surf club car park
(as arrowed below in Figure
14)
where an informal accessway presently exists.
c. The existing
practice of aligning accessways so the seaward end is not aligned into
prevailing southwest winds is sound and should be retained.
d. Over time,
where reasonably practicable, accessway alignments can be adjusted as required
to include curvature - located so that any sand blowing into the seaward end lands
on spinifex, rather than travelling through to the landward end of the
accessway. Straight accessways are less desirable as they tend to act as a
“conveyor belt” for sand movement into landward areas.
e. The state of
the accessways should be monitored to ensure they stay well maintained,
including allowance for sand removal when required (e.g. the alongshore
accessways landward of the dunes and seaward of the car parks). Observing where
particularly significant windblown sand accumulations occur in these areas will
also provide useful clues on the issues that need to be addressed in the dune
areas to seaward.
f. Recognise
the need to maintain the natural character of Piha Beach and to minimise and
avoid structures to the extent reasonably practical (see Section 4.5 below).
Figure
14: Location of informal accessway (arrowed) at the southern end
of the surf club car park. It is recommended that this accessway be formalised
and defined.
g. The
double-entry on the landward side of the accessways fronting the southern car
park is a useful design innovation. However, with the present narrow dunes in
this area, the double-entries tend to provide more opportunity for windblown
sand to penetrate to landward areas. The dune “islands” formed between the landward
entrances are also difficult to manage. This is not a pressing issue but, over
time, these accessways could be reduced to a single landward entry if required
to minimise issues with windblown sand. The dune “islands” presently formed
between these double entrances can be merged with the adjacent vegetated dune
areas as this work is undertaken.
h. The present
practice of generally avoiding surfacing on accessways (e.g. board and chain
structures; boardwalks) is supported. These structures tend to get buried with
sand on west coast beaches such as Piha and are difficult to maintain. In most
places at Piha, a sand surface is adequate and preferable.
i. The surf
club concrete accessway is an important feature for access to and from the
beach and as practical should be cleared as requested by the Surf Club or
several times a year (e.g. each time machinery is taken to Piha to clear sand
from the roads or pedestrian access track). This particularly important over
summer. The sand removed from this area is perfectly suitable for placement on
the beach unless obviously contaminated by broken glass.
j. If the
present boat ramp ultimately has to be replaced because of excessive
maintenance accompanying beach advance, it should be removed at the time of
replacement rather than allowed to be buried. The new ramp should maintain the
existing northwest orientation to minimise problems with windblown sand.
k. The retaining
wall to minimise sand blow onto the road and the associated pedestrian access
and sand trap along the back of the dune is a useful innovation. It is likely
to remain necessary for some time because of the narrow width of the natural
dunes to seaward. The present design to allow seating on top was commented on
favourably by various parties and is well used according to surf club members
spoken to. Concerns were however raised by some parties in relation to impact
of fences on natural character and so reliance on these structures should be
reduced over time as practical (see recommendations in the discussion of
natural character further below).
Note:
The accessway on the northern side of Piha Lagoon and creeks (outside the study
area) should be widened to improve it for use by the surf life saving club –
who occasionally have to use this accessway in an emergency. The SLSC find this
accessway difficult to use on those rare occasions.
4.3.4 Recommendations:
Dune Reshaping and Earthworks
a. Appropriately
designed earthworks are occasionally necessary to restore seriously damaged
dunes.
b. Where clay fill
or rubble occurs on dunes, any earthworks should remove this to the extent
reasonably practicable.
c. Earthworks
addressing serious grass or weed infestation should be preceded by appropriate
spraying of the relevant weed species, allowing time for die-off before the
works. Deep (>0.75 m) burial of the surficial sand that contained the weed
materials can also be helpful when the earthworks are implemented. These
actions help minimise weed re-establishment.
d. The
earthworks should be conducted as close to the planting date as practicable to
reduce the risk of windblown sand before planting. Earthworks should not be
conducted outside of the best spinifex planting period and ideally within the
period from April to October inclusive.
4.4 Maintenance
and Enhancement of Public Access and Amenity Values
On a
popular public beach like Piha, dune management needs to give attention to
ensuring human use and enjoyment is provided for. This was a common theme in
the feedback received during discussions with representatives of various
stakeholders.
Two
particular areas that were drawn attention to were:
· The general issue
of views – including the maintenance of views from car-parks and properties
landward of the dunes.
· The need to provide
grassed areas (ideally with shade) in elevated locations where people could sit
and view the sea. These areas would also be valuable during the frequent
surfing, surf lifesaving and other competitions held at Piha.
4.4.1 Views
and Dune Height
The
issue of views from behind the dune is a difficult one to exercise much control
over - as dune height is governed by natural processes. Fortunately, any
changes in dune height over time are relatively slow. Nonetheless, it is
important to maintain an empathetic approach to the issue as views from
landward properties and areas are important to those affected. Most properties
in the study area were developed when the dunes to seaward were degraded by
wind erosion due to poor management of human use (see discussion in Section 3.2
of this report). At this time, dunes were probably lower due to wind erosion
and deflation. The natural seaward advance of the shoreline has also likely
impacted views by increasing dune width to seaward.
Auckland
Council conducts regular beach profile surveys (usually 1-2 times per year) and
this provides a means by which dune height can be monitored.
The
options for intervention with natural dune characteristics and processes are
limited. For instance, periodic earthworks to lower the dunes would require
ongoing intervention as well as disruption of native dune vegetation and
natural character and this is not likely to be an appropriate approach. In
addition, obtaining resource consent is likely to be very difficult given the
recognised importance of dune environments in the New Zealand Coastal Policy
Statement and the Auckland Council Regional Plan: Coastal.
There
are however measures that can be taken to minimise the potential for issues.
For instance:
· Encouraging an
extensive cover of natural sand trapping vegetation on the seaward dune face
down to the seaward toe can greatly assist in limiting dune height. An
extensive cover of sand trapping vegetation in this area helps reduce the
volumes of sand reaching the crest where it can lead to increases in height. As
noted earlier, it is not necessary to plant the dune toe area if a good cover
of spinifex already exists on the seaward face – as this vegetation will
natural extend seaward.
· Managing access to
prevent damage to dune vegetation. Human damage of dune vegetation at the toe
and on the seaward dune face can result in more windblown sand reaching the
crest and (typically localised) increases in dune height. Therefore, providing
defined accessways as at present and encouraging use of these helps.
The
present general trend for the shoreline to advance in many areas will also help
minimise increases in dune height (e.g. Figure 4) – advancing dunes
tend to build less height than static dunes in the same environment.
4.4.2 Elevated
Grassed Viewing Areas
In
regard to the provision of elevated grassed and viewing areas, community and
beach user feedback suggest there is widespread support for this. For
instance, the submission from Piha Ratepayers and Residents suggested inclusion
of a specific objective to maximise the opportunity to view the surf from the
dunes.
The
provision of these areas will also require appropriate design and consultation
and detailed recommendations on this matter are beyond the terms of reference
and scope of the present report. However, a discussion of potential options is
included below to help guide any future action.
With the
present narrow dunes, there is no useful opportunity to introduce (or extend existing)
grassed areas seaward of the car parks – as maintaining the full dune width in
spinifex and pingao is required to minimise windblown sand to landward.
Ideally, a width of at least 30-40 m of sand trapping vegetation should be
maintained to minimise windblown sand at this site due to the strong onshore
winds. In the longer term, continuation of existing seaward beach advance may
eventually create sufficient dune width in these areas for new grassed areas to
also be established (Figure
4).
However it must be noted that it is possible that this dune buffer could be
eroded again at some stage in the future.
Shade
trees are also unlikely to be practical in any grassed area eventually able to
be established seaward of the surf club - as views from the surf club must be
maintained for beach safety. Surf club personnel advise that the existing small
pohutukawa currently presents no issues but may need to be managed as it grows
– or possibly relocated.
In terms
of more immediate action, the existing grassed area at the western end of the
southern car park (arrowed in Figure 15) is already extensively used and
could be enhanced for use in the near future. For instance, ground levels are
presently irregular and could be leveled to improve the area for recreational
use. There are also existing small pohutukawa here that will in time provide
useful shade – though they may need to be managed (e.g. periodically opened up
with careful pruning) to maintain views from landward. This is an important
issue to address as otherwise landowners in other nearshore areas will tend to
oppose shade trees because of fears of impacts on views. It is important to
build trust on this issue as this beach (like many) presently lacks shade trees
for beach visitors.
There
are also other local areas, one of which could be appropriate to develop as a
raised grassed viewing area given the high human use in this area of Piha. For
instance, there are elevated backdune areas to the immediate north of the surf
club car park part of which could be used to establish an elevated grassed
areas, while still maintaining a wide spinifex zone (at least 30-35 m) to
seaward (Figure
16).
An advantage of this area is that it is not only immediately adjacent to the
surf club car park but also borders the beach access from the Domain
Figure
15: Grassed area behind spinifex zone at western end of the
southern car park. This area provides an important grassed elevated viewing
area and could readily be levelled to improve suitability for use.
Figure 16: dashed line outlines backdune area to
the immediate north of the surf club car park within which a grassed viewing
area could potentially be established – subject to appropriate design and
consultation.
Another
potential option relates to the dunes on the northern side of the Moana Stream,
which have been a bone of contention among some parties since they were
established. As noted earlier, these dunes are to some extent artificial as
their existence depends totally on the existing Moana Stream training works.
The Turner decision suggested some restoration of natural character be
undertaken in this area. Detailed comment on this is beyond the terms of
reference and scope of this report, but in my opinion there are likely to be
practical options in this regard – with appropriate design and consultation
(see discussion under natural character below). If such work proceeds, the
design could probably also incorporate elevated or improved beach viewing
areas.
In
discussion of the draft plan, the large dune at the extreme south end of the
beach (adjacent to boat launching area) was noted as another alternative where
a new raised grassed viewing area might be considered. This dune is
controversial with some and often referred to as an “artificial dune” as the
initial dune was apparently formed by human intervention. However, a dune would
have formed naturally in this area given the beach advance that has occurred in
recent decades (see discussion in Section 3). An adjacent landowner also
expressed concerned about the impact of this feature on views. However, a
feasibility investigation including appropriate consultation would be necessary
to address the suitability of a grassed area over part of this dune given the
earthworks likely to be required (and any necessary resource consents). This
dune also lies within the Waitakere Ranges Regional Park and is therefore under
different governance – unlike the other dune areas at the south end of Piha
Beach the Local Board does not have jurisdiction Natural values are a priority
within the park. Accordingly, while this area could be investigated there would
be significant complications.
The
potential for future development of an elevated grassed viewing area in one of
these alternative locations would require investigation and consultation to
confirm which (if any) was the most appropriate area - prior to detailed design
and any required consenting.
Ideally,
any provision of grassed viewing areas should also incorporate shade trees
where practical as they are otherwise less likely to be used, particularly in
summer. Shade trees can create concerns with views from residents to landward
but with active intervention and pruning to open the trees up these concerns
are usually able to be managed. This is particularly so with pohutukawa where
appropriate pruning can maintain shade without significant impacts on views.
Nonetheless, the reflex action of beachfront owners is to oppose tree plantings
and so any such works will need to be undertaken and designed with appropriate
consultation. Where tree planting is able to be undertaken, any agreements
reached in regard to ongoing safeguarding of views through appropriate pruning
must be honoured – as high levels of trust are required to get agreement on
shade trees.
4.4.3 Recommendations:
Dune Height and Views from Landward:
a. Trends in
dune height can be regularly reviewed (say every 1-3 years) following resurvey
of the Auckland Council beach profile sites. If there is evidence of a that
significant (say >0.5-1 m) change in average height over time, options to
manage this could be reviewed though these are likely to be limited.
b. Any
disturbance or significant gaps in sand trapping vegetation should be repaired
to avoid isolated raising the dune crest.
c. Allowing
spinifex runners to extend as far down the dune toe as practical to maximise
sand trapping seaward of the dune crest (though planting this area is not
required if there is already a good spinifex cover to landward)
4.4.4 Recommendations
Increased provision of raised grassed viewing areas:
a. Given the
community/beach user desire for increased provision of grassed viewing areas,
review and consult on possible opportunities to provide an additional grassed
viewing area, including the:
i. backdunes
immediate north of the surf club car park,
ii. dune and
grassed reserve area north of the Moana Stream entrance
iii. large dune
at the extreme south end of the beach (though note that this is within the
regional park and the Local Board does not have jurisdiction).
b. The existing
grassed area seaward of the southern car park (see arrowed area in Figure 15) should
also be improved to enhance use, including leveling. Soil should also be built
up to natural ground level where the roots of pohutukawa tree have been exposed
by wind erosion. Over time, modification of accessways (discussed in 4.2 above)
can also ensure access paths are moved away from the pohutukawa to the extent
practical – to enable these potential shade trees to be used to enhance reserve
amenity. As the pohutukawa increase in size, Council will probably need to
maintain a reasonable pruning regime (designed and undertaken by trained
arborists) to minimise impacts on landowner views while maintaining shade and
amenity. This aspect was reinforced in discussions with and submissions from
adjacent landowners. Building landowner trust in areas of existing trees such
as these is the key to any expansion of shade trees on future grassed viewing
areas.
c. In the much
longer term, a raised grassed area may also be practical seaward of the Surf
Club car park as this shoreline advances, or if the carpark was reduced in
width – though only when the dune is of sufficient width to retain a minimum 30
m width of native sand trapping vegetation seaward of any grassed area. It will
need to be accepted that if such an area was to be developed, it may be
necessary to revegetate with sand binding dune species to provide additional
sand trapping if windblown sand becomes a management issue, and that the area
may also be lost in the future if the dune buffer is eroded in the event of
future shoreline retreat.
d. Opportunities
to provide shade trees in grassed viewing areas could also be investigated in
future work - with appropriate consultation. Any shade trees will need to be
carefully managed to avoid significantly impacting views. This work could
include negotiations with adjacent beachfront owners and the development of
agreements in regard to views that provide reasonable certainty for owners.
While the beach and reserves are public space and there is no right of veto on
the basis of views, a balanced approach that respects all interests is
preferred. The pohutukawa around the perimeter of the camp ground have been
pruned to maintain views and provide an indication of what can be achieved.
4.5 Natural Character and
Biodiversity
4.5.1 Discussion
Piha
Beach is an iconic New Zealand beach with significant natural character and
landscape values, notwithstanding the extensive human development and
modification of the area. These values need to be protected and, where
practical, restored – as outlined in the Piha Design Guidelines (ARC, 2010.
The work
to date by Coastcare has significantly restored natural dune character,
including natural dune vegetation and function. There is opportunity to build
on these gains over time by:
· Minimising the use
of human built structures as much as practical
· Addressing historic
modification around the Moana Stream entrance, and carparks built in dune
system
· Integrating
backdune biodiversity into planting and amenity provision
In regard to human-built structures, fences
and other access management structures are presently essential to protect
restored dunes from a repeat of the serious human damage which historically
characterised these dunes. The need for these measures was acknowledged in the
Turner decision and is also evidenced in the degraded dune condition that
resulted over the preceding 60-70 years (since mid-late 30’s) when access
management was generally poor (see Section 3.2). The wooden retaining walls
separating pedestrian use along the back of the dune from car parking area are
also important for safe use and access, and to act as a sand trap to minimise
windblown sand issues on the car parking areas.
Nonetheless, as the level of beach user
awareness and support for dune management improves, it may be possible to
reduce the structures required and place greater emphasis on the use of natural
dune vegetation for access management.
In the immediate future it would be
possible to soften fencing in some areas by appropriate plantings. For
instance, planting of dense knobby club rush and associated species (e.g. Muehlenbeckia
complexa, sand coprosma and native spinach) could be undertaken along the
landward margin of the naturally vegetated dunes and the landward margins of
accessways.
Initially, any such planting should be
additional to the existing fences. However, as this vegetation establishes and
as support for dune management increases, it may be practical to eventually
remove the fences in such areas and rely on the natural vegetation for access
management. This would be best approached by small trial fence removal once a
dense knobby club rush vegetation community is well established.
The use of vegetation for access management
where this is practical has obvious natural character advantages over
human-built fences. Other advantages include the fact that natural vegetation
is not buried over time as can happen with fences.
Plantings of this nature would also enhance
native dune biodiversity and simplify the control of exotic grasses invading
the spinifex zone from landward.
Knobby club rush and associated backdune
species will not be able to be used to guide access in more seaward dune areas
where these species are not appropriate and are also unlikely to survive.
However, in such areas pingao may be able to be used to provide subtle visual
cues as to the location of accessways and trial of this approach would be
worthwhile. Use of vegetation for this purpose should ensure plantings maintain
the natural character of Piha Beach and avoid artificial appearance. For
instance, planting strips of pingao along the seaward margins of accessways is
likely to appear unnatural - but more subtle planting schemes that provide a
visual cue may be practical.
The training of the
Moana Stream in the mid 1980’s has significantly modified the natural character
in that area and is an ongoing concern to many (particularly longer term)
members of the Piha community. The Turner decision concluded that these works
were unnecessary and proposed that a degree of restoration of natural character
would be desirable – in particular flaring of the stream entrance. During this
review, concerns were expressed that to date there has been little attempt to
undertake such work – though accumulations of concrete and rubble have now been
removed from the seaward end of the trained stream channel.
Design of such work
is outside the scope and terms of reference of this report but I concur with
the Turner decision on the desirability of such work. The consultation also
indicated community and beach users support for work in this area – though
concerns were also raised that changes to stream flows may present issues,
emphasizing the need for careful design. Further work and appropriate
consultation would be required to scope and design the best option; but in my
opinion there would be practical options to significantly restore the natural
character of this area. This reflects the fact that the natural seaward advance
of Piha Beach in recent decades has increased the potential to restore natural
character through flaring of the stream entrance and realignment of the
(man-made) dunes to the immediate northern side of the stream. With appropriate
design, this work could also enhance the existing grassed reserve by the stream
(a useful picnic area according to feedback received) and achieve a variety of
amenity gains in this area (e.g. in regard to reserve use, beach access and
beach views). There is also potential for this restoration to reduce (but not
eliminate) stream erosion at the eastern end of the narrow dune fronting the
southern car park.
Native backdune
communities are very rare on the remaining areas of natural dunelands in the
study area and, while backdune amenity would be given preference in this high
use area, there would be opportunities to integrate natural vegetation with
access management and enhancement of amenity.
4.5.2 Recommendations
a. Incorporation
of native backdune planting is desirable where practical to enhance natural
values. The key opportunities are the areas to the north of the surf club car
park and on the rear of the large dune at the extreme southern end of the
beach.
b. It is
recommended use of native dune vegetation be adopted to assist in access
management as part of a longer term effort to reduce reliance on human-built
structures, including:
i. Planting of
knobby club rush planted densely (spacing of 0.4-0.5 m) along the landward
margin of the naturally vegetated dunes – ideally over a width of at least 2-3
m. Muehlenbeckia
complexa, sand
coprosma and/or native spinach should be inter-planted among the knobby club rush or
introduced later.
ii. Experimentation
with use of pingao as a visual cue for accessway location on the seaward dune
face – while ensuring plantings maintain a natural pattern and appearance (i.e.
simply defining the margins of the accessways with pingao may not be
appropriate)
c. This work
should be additional to existing fencing. However, once dense vegetation is
established, removal of existing fences could be trialled in limited areas with
close monitoring.
d. Restoration
of natural character and enhancement of amenity values in the vicinity of the
Moana Stream can probably be achieved with appropriate design and consultation
and further investigation and design is recommended.
e. The design of
amenity areas (including grassed areas) should usefully incorporate native
backdune species where appropriate, in preference to exotic vegetation.
ARC
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Coney,
S. 1997: Piha: A history in images. Keyhole Press, Auckland.
Esler,
A.E. 1975: Vegetation of the sand country bordering the Waitakere Range,
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1999: Piha Beach: Coastal Physical Processes, effects of human activities and
future management. Report prepared for Waitakere City Council.
King,
D., Nichol, S and Hume T. 2006: Rapid onshore sand flux in a high energy
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2000: Piha Coastal Management Plan: Final management plan June 2000.
WCC
2009: Piha Beach and Dunes: Summary and discussion of results from October 18
2009 community open day. Parks and Open Space Information, 18p.
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