ONEPOTO DOMAIN: WETLAND & SANCTUARY Group One
ONEPOTO DOMAIN: WETLAND & SANCTUARY
DESIGN STATEMENT
The Wetland Design This design proposal responds to the needs of the Domain users as well as to those of the environment, and aims to provide long term benefits to both. It provides for the creation of a natural wetland environment that includes both an ecological sanctuary and an active zone that will encourage users to experience this area in two quite different ways. The sanctuary with its new forest core will offer a site for education, observation and protection. Whilst the active area will provide an opportunity for people to become physically immersed in the wetland experience. The design of the wetland aims to work with the sites natural processes to create a diverse and self-sustaining environment that complements existing areas of native vegetation. The proposed wetland and sanctuary areas will provide both amenity and recreational areas that complement the Domain’s diverse variety of areas and uses. Water is given prime consideration in this design proposal as water quality is a key factor in providing a healthy and sustainable wetland environment. The wetland’s natural processes of filtering and settling storm water will play a significant role in improving the quality of water to other amenities in the Domain and is seen as vital for the health of the Domain ponds.
The concept for the ‘Onepoto Domain Wetland & Sanctuary’ is simple; in essence it is to create an urban ecological patch, which connects to the Green Infrastructure of its surrounding region.
Seven zones; two uses...
This is achieved by establishing a new forest Core (Mesic Zone) supported by a wetland buffer (Aquatic, Emergent, Saturated, Moist & Grassland Meadow Zones) creating a hub, which in turn connects to the already established forest corridor (Dry Zone - existing forest) that sits on the surrounding slopes connecting to the wider context.
The Active side of the wetland design promotes informal paths and gravel walkways which run throughout the Grassland, Saturated and Moist Zones - encouraging the community to connect with their surrounding environment. The aim of this area is to provide an open recreational space for children and adults which allows for the discovery and hands on exploration of how a native wetland ecosystem functions.
Guiding Principles for design - Water Care and Enhancement - Sanctuary - Habitat Creation - Health and Well-being
- Core Creation - Urban Wild - Circulation - Corridor Linkages
Active Use
Passive Use The Sanctuary part of the wetland consists of a boardwalk and gravel promenades which run around the wetland cutting through seven zones, subsequently providing the community with the ability to experience various native habitats as well as the flora and fauna species that dwell within them. The boardwalk and gravel path, which runs across the north east crater tuff rim, separates the Dry Zone (existing indigenous broadleaf forest) from the Mesic Zone (temperate hardwood forest) allowing for best views of both habitats. These two also provide a contrast to the open park areas, which are found throughout the domain. While the second part of the boardwalk leads directly through the center of the Wetland, cutting across the Emergent, Saturated and Moist Zones. This part of the design promotes ecological awareness by supporting interpretive signage alongside the path to educate the community on the wetland ecosystem; how it works; the biodiversity it promotes as well as the benefits and importance of having a healthy wetland ecosystem. It encourages the users to remain on the boardwalk, which will feature counter levered viewing platforms, or forest lookouts with handrails to prevent users from going astray and coming into contact with the protected habitats.
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
MASTERPLANNING
Proposed Site
Existing Site
Design Methodology Topography
Existing Topography and Contours
Proposed changes to Topography and Contours
The Onepoto Domain is located inside a Maar Tuff ring volcano that was once open to the adjacent estuary and subject to tidal flows, so usually filled with seawater. During the construction of the Auckland Harbour bridge in the 1950’s, the superfluous earth cut from Northcoate Point was used to fill the crater which created an entirely new ecological situation in the site.
Existing Slope and Elevation
Proposed changes to Slope and Elevation
From the North-Eastern to the North-Western boundary of the crater, native and exotic vegetation has established forming a urban forest. The slope of this area is very steep and residential housing has been confined to the rim of the crater.
Existing Pedestrian Circulation Pathways
Propsed new Pedestrian Circulation Pathways
Evolved Completed Design Concept
Original Design Concept
Regional Ecological Links Within the North Shore region there a number of large urban forest that form part of a regional corridor that supports the “North-Western Wild life Corridor” which attempts to connect the Wildlife sanctuaries; “Tiritiri Matangi Island off Whangaparoa Peninsula” with “Arc in the Park in the Waitakere Ranges.” The small forest on the slopes of the Onepoto Domain crater acts as a part of this regional corridor connection. Implementation and Rational of Design The concept plan played a major part in the re-grading of the site, and in turn the new contours that were created informed the re-design process. The idea of creating a sanctuary was a fundamental facet of the concept. Expanding upon this, the implementation of the “Meurk and Hall” concept of a new forest Core Zone became a driver for the design in tandem with Wetland creation. The fact that these two systems support each other – the wetlands becoming the Buffer Zone or Hub to the Core made absolute sense, coupled with the fact that the system would sit adjacent to an existing wildlife corridor to also support it, this would in fact establish a large new Patch to add to the existing green infrastructure of the region. On the Master Plan the Mesic Ecological Zone represents the new forest Core.
As a group, the concept plan was discussed and preliminary designs were produced. But the mapping of the site played a major role in the outcome of the final design in terms of: re-contouring and re-grading of the site, ecological zoning, sanctuary area, positioning of habitat creation, internal circulation infrastructure and reshaping of conceptual description.
Layers merged to create the Onepoto Domain Wetland & Sanctuary Master Plan
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Onepoto Domain | Group ONE | July 2014
This design not only creates new and diverse habitats within the Onepoto Domain itself, but becomes a jewel in the necklace of Corridor links, Hubs and Cores throughout the North Shore and wider Auckland region.
ONEPOTO DOMAIN: WETLAND & SANCTUARY
MASTERPLANNING
Legend Ecological Zones
D03
Emergent
Mesic (Newly Created Core) Dry (Existing Forest)
Saturated
Grassland Meadow
Moist
Wildlife Sanctuary
Aquatic
b a
Infrastructure Housing Footprints Storm Water
D01
Roads
a
Overland Water Flows
b
Circulation Existing Aggregate Path
Proposed Boardwalk / Lookout
Aggregate Path
Boardwalk
Concrete Path
Aggregate Path
Boardwalk
Permeable Concrete
Boardwalk
Mown path
(2.5mtrs wide) 1.8mtrs wide)
(2.5mtrs wide) (2.5mtrs wide) 1.8mtrs wide)
D02
(3.5mtrs wide)
(2.5mtrs wide)
c
1.8mtrs wide) 1.2mtrs wide)
1.2mtrs wide)
SCALE 1:500 @ A0
c
ONEPOTO DOMAIN: WETLAND & SANCTUARY
PERSPECTIVE 01
Overall Concept Design
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Onepoto Domain | Group ONE | July 2014
ONEPOTO DOMAIN: WETLAND & SANCTUARY
PERSPECTIVE 02
A surmount feeling overlooking the sanctuary core of the Onepoto design is present with the public viewer as they take a moment of appreciation with the natural landscape. This inner connection is supported through the alloying of contrasted hardwood material and soft treescape and a moment of solitude on this perspective boardwalk, helping affirm that they too are part of the ecology in which they stand.
Boardwalk Perspective
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
PERSPECTIVE 03
An affirmed barrier that disconnects the public with the sanctuary core is shown distinctly by the built up wetland and constructed boardwalk, which borders the sanctuary edge. This disconnect affirms a solid consciousness between the natural ecology that is present with the public and their inability to intrude within the space, while the natural ecology engages their imagination creating the opportunity to roam beyond their edge. A gentle epiphany reaffirms the public that they too are part of the ecology in which they stand.
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Onepoto Domain | Group ONE | July 2014
Sanctuary Lookout
ONEPOTO DOMAIN: WETLAND & SANCTUARY
PERSPECTIVE 04
Separate activities enhance a variety of public space and use; observed from the built playground lookout, separate processes couple to form a larger embodied structured organization. This array of various activities encoupled through the notion of viewing at a wider perspective in essence, creates an urban ecological infrastructure that connects to the larger surrounding region and establishes a conscious relationship between the public and natural ecology. A harmonic comparison reaffirms the public conscious that they too are part of the ecology in which they stand.
Playground Lookout
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
CROSS-SECTIONS
Existing dry forest escarpment bordering Onepoto Domain is connected to the wetland regeneration design; and supports bushwalking and recreational use via improved gravel tracks which link to the boardwalks of the wetlands
SPORTS FIELD
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Onepoto Domain | Group ONE | July 2014
The open grassland area creates a sublte break between the manicured sports fields, and the densely planted wetland zones, allowing easy flow of planting and planned visual effects of the overall design. 1.2m mown paths meander through the grassland, providing access to the wetland boardwalks as well as the field
GRASSLAND
Moist zoning areas are occasionally saturated, but allow ideal conditions for larger native tree species which forms a buffer around the periphery of the wetland centre. Taller trees also support a diverse range of bird and insect species, as well as shade for more habitats
MOIST
Soils are generally saturated most part of the year, thus plant species are selected to tolerate both flood and dry periods
Several boardwalks run through the wetland as a public amenity, encouarging active recreational use and awareness of the ecological functions of a native sanctuary
SATURATED
EMERGENT
Permanent open water zone established with tubers, rooted plants or plant fragments which are entirely submerged. Depth of ponding is generally >1m
AQUATIC
The constructed wetland and made-connections to the existing forest escarpment will provide food, refuge and breeding habitat’s for a variety of birds, fish and insects - encouraging an ecological functionality of a modern urban park.
Shallow water supporting partially submerged plant species which provide shade for fauna
EMERGENT
Cantilevered outlook point as part of the boardwalk which sits over the eastern fringe stormwater channel. Allows people a place to stop and rest, while supporting important viewpoints into the wildlife sanctuary for people to appreciate. [Refer to Detail 01]
MESIC
Existing forest escarpent on site
DRY
Sylvan Avenue residential boundary of Onepoto Domain. Stormwater will continue to flow from houses into the Domain in order to feed the wetland & stormwater channels, where all contaminated urban runoff is appropriately filtered and treated by the constructed wetland system
RESIDENTIAL
SECTION ‘aa’ - ONEPOTO WETLAND ZONING SCALE 1:400 9
ONEPOTO DOMAIN: WETLAND & SANCTUARY
CROSS-SECTIONS
Dynamics of the purposefully chosen Dynamicsisof the purposefully planting better seen at scalechosen 1:200 planting is better seen at and scalecreated 1:200 emphasizing the density emphasizing the density and created heights of the native plants and trees, heightsultimately of the native and trees, which formplants a number of which ultimately form a number of the differing habitats for wildlife within differing habitats for wildlife within the sanctuary sanctuary
SATURATED SATURATED
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Onepoto Domain | Group ONE | July 2014
Proposed boardwalk Proposed boardwalk route which cuts through route which cuts through the wetland sanctuary; the wetland sanctuary; allowing a strict access allowing a strict within access path for people path for people within the core passive areas, to the corewildlife passivehabitats areas, to ensure ensure wildlife habitats and envisioned ecological and envisioned ecological functioning remains functioning remains from intact and protected intact and protected from trampling trampling
EMERGENT EMERGENT
The wetland’s natural processes of filtering and settling storm water is low impact urban design which plays an important role in improving contaminated stormwater runoff from the surrounding residential areas. It is vital that all water flowing on site is treated and cleaned effectively before running off into wider water systems and ammenities (Onepoto Ponds and subsequently Shoal Bay).
Deep wetland pooling is accentuated by a steep bank covered in Mesic & Dry forest planting, creating an abundance of shady spots for birds to roost, and also supporting microbial assemblage as this zone is always submerged
AQUATIC
MESIC SECTION ‘bb’ - WILDLIFE SANCTUARY CORE SCALE 1:200 11
ONEPOTO DOMAIN: WETLAND & SANCTUARY
CROSS-SECTIONS
Redistributed stormwater channel running along the western side of the wetland, feeding water into the connected Onepoto Ponds. Channel is buffered with native riparian edges and riprap to slow down water flow and improve its quality before reaching the ponds
MESIC
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Onepoto Domain | Group ONE | July 2014
MOIST
Pathing on the active side of the wetland provides several informal routes to encourage people to become physically immersed in the natural wetland environment, allowing people to jump off track and explore
Existing boardwalk 2.5m wide, which connects to a second boardwalk route deeper within the wetland
Meandering mounded paths of permeable concrete through low-lying Saturated and Moist zones. 1.8m wide. [Refer to Detail 02]
SATURATED SECTION ‘cc’ - ACTIVE WETLAND AREA AS PUBLIC SPACE SCALE 1:100 13
ONEPOTO DOMAIN: WETLAND & SANCTUARY
PLANTING PLAN
ZONING & STRATIFICATION
The two key objectives in determining plant species and positioning are the maximum filtration of stormwater flowing through the site, and the provision of a rich and varied habitat for native wildlife. Planting zones have been created based on typical patterns of wetland ecological niches. Diversity of habitat has been enhanced by varying the intersection of zones, while maintaining appropriate planting gradients and buffers for each ecological zone. The positioning of planting zones varies depending on the relative proximity to the average water level. Species more suited to an aqueous environment or highly saturated soils are planted lower in the water table, while those plants less tolerant of waterlogging are planted in drier positions. A meadow area has been established to further the site’s habitat diversity, providing a seasonal nesting site and a food bank of insects for resident birdlife, as well as adding to informal recreation space.
1. Wetland Zone: Aquatic -1.5m to -1.1m below water level Vegetative zone largely submerged
2. Wetland Zone: Emergent
-1.1m to -0.3m below water level Shallow pond slope with vegetation protruding
3. Wetland Zone: Saturated
-0.3m to 0.0m below water level Soils are saturated almost year-round
4. Wetland Zone: Moist
0.0m to 0.3m above water level Flooded in winter and periods of high rainfall
5. Wetland Zone: Mesic
0.3m to 5.0m above water level Occasionally flooded, but generally dry
6. Existing Dry Forest
5.0m to 25.0m above water level Free-draining upland slopes
7. Open Grassland
0.3m to 0.8m above water level Mixed native/naturalised grassland meadow
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Onepoto Domain | Group ONE | July 2014
ONEPOTO DOMAIN: WETLAND & SANCTUARY
PLANTING PLAN
ZONING DEVELOPMENT
The Aquatic Zone of the wetland is central to the successful passing of water through the site. It is the course of minimum interference, and is the deepest zone of the wetland, its floor being between 1.1 and 1.5m below the water surface. During excess water influx, this area of minimum obstruction allows water to pass through the site without encouraging water to back up and leading to subsequent flooding elsewhere upstream or over the wetland banks. This permanent section of open water area is important also to the the take-off and landing of birds requiring a longer run, such as pukeko and ducks. Vegetation in this area is largely submerged. Some leaves are floating, but the majority of plant life is submerged apart from flowering parts. These plants contribute to water clarity by reducing the movement of sediment through the site. The plants in the Aquatic Zone are not likely to survive in instances where unusual drought periods leave the wetland dry even for short periods. Due to the distinct flora of this habitat, it is a rich source of fish, insects, and other aquatic invertebrate as food for birds of the wetland. Plants in this zone are planted as plugs, sourced in biodegradable pots that break down over time after planting as the plants establish.
1. Aquatic Zone 2. Emergent Zone
3. Saturated Zone
4. Moist Zone
- - - - - - -
Chara globularis Myrophyllum propinquum Nitella hookerii Nitella pseudoflabellata Potamogeton cheesemanii Potamogeton ochreatus Ruppia polycarpa
5. Mesic Zone
6. Existing Dry Forest
7. Open Grassland 0m
25m
50m
100m
200m
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
PLANTING PLAN
ZONING DEVELOPMENT
The mix of plants contributing to the Emergent Zone are solely sedgeand rush-like species, of which their growth crown is submerged and the majority of leaves reach partially or entirely above water level. The zone’s floor varies between 0.3m and 1.1m below water level, often sloping as it meets its shallower perimeter. This area contains standing water at all times other than in exceptional dry periods. There is high contact between water and vegetation herein, and subsequently maximum biofiltration of the water because of the significant microbial interaction. The emerging stems and leaves form a bridge for insects and small birds to connect to the water. As such, the zone presents an important field for foraging of water insects by birds.
1. Aquatic Zone
2. Emergent Zone 3. Saturated Zone
4. Moist Zone
5. Mesic Zone
6. Existing Dry Forest
7. Open Grassland 0m
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Onepoto Domain | Group ONE | July 2014
25m
50m
100m
200m
- - - -
Baumea articulata Bolboschoenus fluviatilis Elaeocharis sphacelata Schoenoplectus tabernaemontani
ONEPOTO DOMAIN: WETLAND & SANCTUARY
PLANTING PLAN
The Saturated Zone presents the most abundant wildlife density due to its warmer and shallower waters, as well as the shade created by the larger plant species such as harakeke. Fish and insect breeding is prolific here, as with the nesting and foraging of wading birds. Water is generally 0.0m to 0.3m deep in this zone, often sitting as a gently sloping shelf.
ZONING DEVELOPMENT
Soils are saturated year-round, though the margins may dry out during summer periods.
- - - - - - - - - - -
Apodasmia similis Baumea arthrophylla Baumea rubiginosa Bolboschoenus fluviatilis Carex secta Carex virgata Cyperus ustulatus Eleocharis acuta Isolepis prolifer Phormium tenax Schoenoplectus pungens
1. Aquatic Zone
2. Emergent Zone
3. Saturated Zone 4. Moist Zone
5. Mesic Zone
6. Existing Dry Forest
7. Open Grassland 0m
25m
50m
100m
200m
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
PLANTING PLAN
ZONING DEVELOPMENT The Moist Zone sees the emergence of ferns and dicotyledenous plants, and subsequently a greater amount of shade. There is enough oxygen in the soil to support woody plant species here, and as such species such as cabbage tree and kahikatea establish freely. These branching plants also present opportunities for birds that prefer the shelter of higher nesting sites, such as the fantail. Often puggy underfoot, the soil will usually be flooded on a seasonal basis, as well as after heavy rains. Soils sit 0.0m to 0.3m above water level.
1. Aquatic Zone 2. Emergent Zone 3. Saturated Zone
4. Moist Zone 5. Mesic Zone 6. Existing Dry Forest 7. Open Grassland 0m
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Onepoto Domain | Group ONE | July 2014
25m
50m
100m
200m
- - - - - - - - - - - - - - - -
Carex geminata Carex lessoniana Coprosma propinqua Coprosma tenuicaulis Cordyline australis Cortaderia fulvida Dacrycarpus dacrydioides Dicksonia squarrosa Cyperus ustulatus Gahnia xanthocarpa Juncus pallidus Juncus sarophorus Laurelia novae-zelandiae Leptospermum scoparium Phormium tenax Syzygium maire
ONEPOTO DOMAIN: WETLAND & SANCTUARY
PLANTING PLAN
An outer “wall� to the wetland is created by the trees in the Mesic Zone. The enclosure assists in bringing a security to birdlife of the area, as well as shade, and perching and nesting sites. Soft-leaved broadleaf plants and their high rate of evapotranspiration create much absorption from the wetland.
ZONING DEVELOPMENT
This area experiences flooding occasionally, but for only very short periods. It is generally dry, sitting 0.3m to 5.0m above water level. This zone is more typical of lowland Auckland forests, where moisture is in abundance and the site is sheltered from exposure.
1. Aquatic Zone
2. Emergent Zone
3. Saturated Zone
4. Moist Zone
- - - - - - - - - - - - - - - - - -
Alectryon excelsus Carex dipsacea Carex flagellifera Carpodetus serratus Coprosma robusta Cordyline autralis Dacrycarpus dacrydioides Hebe stricta v. stricta Kunzea ericoides Leptospermum scoparium Macropiper excelsum Melicytus ramiflorus Pittosporum tenuifolium Podocarpus totara Prumnopitys taxifolia Schefflera digitata Sophora chathamica Vitex lucens
5. Mesic Zone 6. Existing Dry Forest
7. Open Grassland 0m
25m
50m
100m
200m
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
PLANTING PLAN
ZONING DEVELOPMENT
The Existing Forest is only “dry” in the sense that it is neither part of the wetland nor subject to flooding, particularly given its steeper slopes ranging from 5.0m to 25m above water level. It is free-draining, and forms a band of buffer between the wetland and the residential area surrounding Onepoto Domain. This buffer shelters the site from high winds, as well as reducing human impact on the natural processes of the wetland. This existing bank of mixed native and garden-escape species provides an area of elevated nesting for insects, amphibians and birdlife familiar with a forest habitat. While distinct from this wetland restoration proposal, the surrounding band of established vegetation is also important to the health of the wetland due to its harbouring of pest weed and animal species that will affect the wetland’s prosperity. Significant species such as Tradescantia, Wild Ginger and Monkey Apple are in abundance, displacing weaker native flora. The resurrection of this zone is an important longer-term step in the wetland’s management and success.
1. Aquatic Zone
2. Emergent Zone
3. Saturated Zone
4. Moist Zone
5. Mesic Zone
6. Existing Dry Forest 7. Open Grassland 0m
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Onepoto Domain | Group ONE | July 2014
25m
50m
100m
200m
ONEPOTO DOMAIN: WETLAND & SANCTUARY
PLANTING PLAN
ZONING DEVELOPMENT
The area designated as Open Grassland creates a transition between the manicured sportsfields and the naturalised wilds of the developed wetland. The mix of native and naturalised grasses brings together recreation and biodiversity - a rare recreation meadow opportunity in an urban realm. Ground level runs from 0.3m to 0.8m above water level. This recreation area is buffered from the deeper wetland by the higher planting of the Moist Zone, minimising noise disturbance to the wetland’s birdlife. The array of wild grasses and weeds left to flower attract an abundance of insect life - an important food bank for resident birds. This area will be closed off seasonally for the period when birds proximal to the wetland areas are nesting.
- - - -
Anemanthele lessoniana Apodasmia similis Microlaena stipoides Naturalised exotic spp.
1. Aquatic Zone
2. Emergent Zone
3. Saturated Zone
4. Moist Zone
5. Mesic Zone
6. Existing Dry Forest
7. Open Grassland 0m
25m
50m
100m
200m
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
PLANTING PLAN
Alectryon excelsus
Titoki
Carpodetus serratus
Putaputaweta
Coprosma robusta Karamu Coprosma tenuicaulis
Hukihuki / Swamp Coprosma
Cordyline australis
Ti Kouka / Cabbage Tree
Dacrycarpus dacrydioides
Kahikatea
Hebe stricta v. stricta
Koromiko
Juncus pallidus
Wiiwii
Kunzea ericoides
Kanuka
Leptospermum scoparium
Manuka
Macropiper excelsum
Kawakawa
Melicytis ramiflorus
Mahoe / Whiteywood
Phormium tenax
Harakeke / NZ Flax
Pittosporum tenuifolium Kohuhu Podocarpus totara Totara Prumnopitys taxifolia Matai Schefflera digitata
Pate / Seven-finger
Sophora chathamica
Coastal Kowhai
Syzygium maire
Maire Tawake / Swamp Maire
Vitex lucens Puriri Fruit production
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Onepoto Domain | Group ONE | July 2014
Nectar production
be ce m De
Go od for In
r
r be No ve m
r Oc tob e
pte m
be
Coprosma propinqua Mingimingi
Se
st gu Au
J ul y
e J un
Ma y
ril Ap
Ma rch
r ua ry Fe b
Jan
ua ry
r
se c ts
BIODIVERSITY ENHANCING PLANTS
ONEPOTO DOMAIN: WETLAND & SANCTUARY
PLANTING SCHEDULE
AQUATIC PLANTING ZONE
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
PLANTING SCHEDULE
EMERGENT PLANTING ZONE
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Onepoto Domain | Group ONE | July 2014
ONEPOTO DOMAIN: WETLAND & SANCTUARY
PLANTING SCHEDULE
SATURATED PLANTING ZONE
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
PLANTING SCHEDULE
MOIST PLANTING ZONE
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Onepoto Domain | Group ONE | July 2014
ONEPOTO DOMAIN: WETLAND & SANCTUARY
PLANTING SCHEDULE
MESIC PLANTING ZONE
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
PLANTING SCHEDULE
MEADOW PLANTING ZONE
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Onepoto Domain | Group ONE | July 2014
ONEPOTO DOMAIN: WETLAND & SANCTUARY
ECOLOGICAL OUTCOMES
Ecological Functions The wetland restoration will provide valuable ecosystem services such as nutrient cycling, sediment retention, water filtration, habitat diversity, recreational areas and educational opportunities. This design recognizes the site’s many and interconnected ecological systems – topographical, geological, human, biological and hydrological – and the interdependence and reliance each part has on the healthy functioning of other parts in order to contribute to a sustainable and healthy whole. The design aims to improve the ecological functioning of not only the wetland area but of the entire Domain. In particular this relies on the need to address the Domain’s hydrological functioning and water management systems.
Fig. 1: Wetland grasses, flaxes and trees supporting ecological diversity http://www.forestandbird.org.nz/kapiti/john-topliffawarded-old-blue
Fig. 2: Tui Source: Shutterstock
Fig. 3: Skink http://www.stuff.co.nzFunds-for-wet lands-lizard-site Fig. 4: Onepoto Domain Urban Ecology Diagram
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
ECOLOGICAL OUTCOMES
Water Systems
Existing Yacht Pond
The existing wetland area has been cut off from key water supplies resulting in it being relatively dry and struggling to survive over the summer months. When water does accumulate here it quickly becomes stagnant due to the fact that the watercourse out-flow points are blocked with sediment. These blockages cause a build up of contaminants which poison the aquatic habitat and starve it of oxygen. This has become a major concern in regard to the health of the Domain’s waterways and particularly the ponds. A key factor in our design proposal is the provision of a healthy wetland environment that will capture the surrounding stormwater runoff from the escarpment, channelling it into the wetland, where it will be filtered and settled before being directed to the various inlets of the Domain’s freshwater ponds. From the ponds any excess water will flow out to the stream and estuary areas and finally out to sea. The deliberate channeling of water into the wetland will create a sustainable wetland area that restores the water quality to areas that have become almost uninhabitable for aquatic species. The wetland will also provide flood protection to this low lying area.
The Domain’s Yacht pond is Auckland’s main model boat sailing location and as such the restoration and maintenance of this pond is a priority to ensure that it can continue to be used by these groups whilst also remaining a healthy habitat for the local wildlife. The pond’s poor water quality, weed and algae problems, lack of fresh water flow, accumulation of sediment, and stagnation has impacted not only on the ability of the ‘yachties’ to sail their boats here, but also on the ponds aquatic and bird life. Our design aims to restore these ponds to freshwater lakes as per their original design intention. This will be achieved by providing a continuous flow of fresh, filtered water into the Northern end of the pond which will establish a flow of water across the recently dredged pond and prevent a recurrence of the current stagnation and weed problems. This in turn will provide a healthier environment for the aquatic species and birds that inhabit this pond.
Fig. 5: Proposed On-site water Flow from Wetland to Yacht Pond
Fig. 6: Model Yacht Racing at Onepoto Domain Photo: Ray Tomes http://www.flickr.com
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Onepoto Domain | Group ONE | July 2014
ONEPOTO DOMAIN: WETLAND & SANCTUARY
ECOLOGICAL OUTCOMES
Biological Diversity This design focuses on promoting biological and ecological diversity by providing a wide variety of habitats within the wetland area. This is achieved by using a variety of water depths, landforms and plant species to create diverse environmental gradients from the aquatic areas up to the terrestrial areas. This ecological diversity aims to promote the restoration of healthy biological systems, which will support viable populations of native plant, aquatic and animal species. Ecological Sanctuary Zone
The Ecological Sanctuary Zone The Sanctuary part of the design aims to promote an awareness of wetland and forest ecosystems and the species they support. The creation of a large new forest core will link to the existing patches of indigenous broadleaf forest running along the escarpment and provide a contrast to the open park spaces of the domain. This side of the wetland will encourage user’s to stay on the boardwalk and gravel paths - to observe and learn but not disturb. Interpretive signage alongside the boardwalks will explain the importance of the wetland area and its fauna and flora – identifying species and their habitats and explaining how this environment impacts on other areas within the domain.
Fig. 8: Example of the unmown meadow area between the sports field and the wetland. Source: Rottle,N., &Yocom, K. (2010). Ecological Design. Switzerland: AVA Publishing.
Active Zone
The Wetland Active Zone The mounded earth paths to the South side of the wetland provide informal routes that encourage people to connect with and become physically immersed in the natural wetland environment. This area will provide a safe space for children to explore and experience the diverse variety of birds, fish, and insects that this wetland supports. It will be a space that promotes discovery and hand’s-on exploration. To the west of the wetland area an unmown meadow will create an edge to the sports fields. This area will provide another safe space for children to play and meander through the mown pathways.
Fig. 7: Diagram of Active and Sanctuary Wetland Zones Fig.9: Example of mounded informal paths through wetland edge. Source: Rottle,N., &Yocom, K. (2010). Ecological Design. Switzerland: AVA Publishing.
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
ECOLOGICAL OUTCOMES
Native Flora
Native Fauna
Currently this area of the site is overrun with pampus grass which is preventing the establishment of native species. It is proposed that the pampus be completely removed to prevent ongoing encroachment in the future. The proposed wetland and sanctuary forest core will then be revegetated using native plants of varying densities, understories, tree heights, and distribution to enhance the characteristics of the wetland area.
The presence of wetland birds is reliant on the wetland area maintaining a healthy environment for native aquatic species. To achieve this the wetland edge aims to provide a diverse variety of niches and edge habitats for plants, aquatic macro-invertebrates and animals. Both the open-water and vegetated zones will provide a range of feeding areas to attract a variety of birds. The gentle slopes to the edge of the wetland will provide habitats for larger wading birds and the shallow shelves will provide feeding areas for smaller wading birds. Once new trees have established, they will provide perching sites for birds directly over the water, as well as roosting and nesting areas within the forest core, away from the disturbance of the active zone. The wetland and forest environments will, over time, create a sustainably integrated food web supporting a diverse and resilient aquatic ecosystem.
The wetland and forest plants will provide food, refuge and breeding habitat’s for a variety of birds, fish and insects. The wetland plants will also act as a bio-filter for the storm water runoff that will be directed into the wetland area. This will have the effect of improving the water quality that is subsequently fed through to other areas of the site.
Fig. 10: Conceptualised Food Web that exist in a Healthy Waterway Information Source: http://resources.ccc.govt.nz/files/CityLeisure/parkswalkways/environmentecology/waterwayswetlandsdrainageguide
Pests
The large area of native vegetation that will form the proposed forest sanctuary will connect through to the existing Western Escarpment which contains the sites oldest and most significant native species, and also to the Eastern Escarpment’s area of regenerating native bush. Together these areas will form a large and very valuable area of native vegetation that will become an important asset for the wider environment and its communities.
Invasive exotics and pest species will be removed or managed to allow for the restoration of native vegetation which will in turn provide food and habitat’s for a diverse range of native bird and aquatic species. Pest animals, such as possums, rats, mice, stoats, cats and dogs, can have a huge impact on the biodiversity and survival of native flora and fauna species. The urban location of this site will likely mean these pests and predators will be an ongoing problem requiring long term management.
This considerable area of native vegetation will provide a rich and dynamic contrast to the established area of exotic species that dominate the Southern end of the Domain. This contrast will enable both areas to be more fully appreciated for their unique qualities. Fig. 11: Pukeko and Banded Rail Photos: Rob Suisted
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Onepoto Domain | Group ONE | July 2014
ONEPOTO DOMAIN: WETLAND & SANCTUARY
ECOLOGICAL OUTCOMES
Corridors
Social & Community
The wetland and its forest sanctuary will become part of the wider Auckland green corridor network supporting the ‘North-West Wildlink Corridor’ which provides a route for wildlife to move across the Auckland isthmus from Tiritiri Matangi Island all the way to the Waitakere Ranges. This corridor play a vital role in supporting the health and biodiversity of broader ecological systems throughout the region. At a more local level the wetland’s network of paths and boardwalks will provide both walking and shared-use loops and tracks that wind around and through the wetland environment. These formal and informal pathways through both the sanctuary and active areas will encourage people to explore and appreciate these new areas in a variety of ways. These pathways will also provide connections and linkages through to other areas of the domain and to the wider surrounding suburban environment.
This design promotes opportunities for beneficial human interaction with the natural environment - providing restorative, educational and recreational opportunities. The wetland area will complement the other uses within the domain and become a valuable community amenity that promotes environmental and ecological values. The escarpments around the park and the site’s openness mean there will be plenty of opportunities for passive surveillance of the area from both the surrounding residential properties and other park users. The ‘Onepoto Residents Association’ and local community volunteers will be encouraged to continue with their active participation as stewards of the domain environment. Their valuable contribution to planting and maintaining this environment continues to raise awareness of the ecological systems and diversity found on this site and the important part they play in providing a healthy and sustainable community environment.
Fig. 14: Learn to ride areas, Onepoto Domain Source: http://www.aucklandcouncil.govt.nz/EN/ontrackinonepotodomain.aspx
Fig. 15: Community planting and involvement http://theplan.theaucklandplan.govt.nz/aucklands-response-to-climate-change/
Fig. 13: Onepoto Regatta http://www.electron.co.nz/#/2010-onepoto-regatta/4541103418 Fig. 12: Auckland’s North-West Wild Link Source: http://www.forestandbird.org.nz/what-we-do/projects/northwest-wildlink
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
DETAILED DRAWINGS
1100 WIDE GAPS IN BOARDWALK RAILING.
EXISTING BOARDWALK
1,400
850
1,100
45 25 105 75
900
45
HANDRAIL WHERE HEIGHT ABOVE GROUND IS GREATER THAN 500mm
2,400
WHERE HEIGHT ABOVE GROUND EXCEEDS 1200mm PROVIDE EITHER 100x 75 DIAGONAL BRACING IN EACH DIRECTION. FIX WITH 1-M 16 BOLT PLUS 50x50x3 WASHERS AT EACH END, OR PROVIDE SPECIFIC DESIGN AS CANTILEVER PILE.
C A N T I L E V E R J O I N T. R E F E R T O ENGINEER SPECIFICATIONS
150 S.E.D IN 300 CONC. 20 MPa INTO FIRM CLAY
4,500
4,500
8,000
DETAIL 01
CANTILEVERED BOARDWALK DETAIL
1:50
75
75 x 75 x 900 HANDRAIL. TOP REACHING 1060MM
25
75 x 50 KICK BOARD CHAMFERED TOP EDGES 100 x 25 PACKER 150mm LONG WITH GALV. M10 COACH BOLTS @600 CTRS
100
45
ATTACHMENT OF DECKING TIMBER BY NAIL TO JOIST USING 1-3.75mm¢ x 100 NAIL AT 600mm CENTERS
150 x 45 PLANK DECKING
150
100 x 50 H4 JOIST
2/M16 HOT DIP GALV. BOLTS @ 50mm CTRS
DETAIL 01 CLOSE UP
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150 x 50 H4 TIMBER BEARER 100mm
H5 POST
50 100 50
JOINERY DETAIL
1:10
NOTE 1. ALL TIMBER IS TO BE H4 TREATED OR HIGHER. 2. THE TIMBER THICKNESSES AND DEPTHS SHOWN ARE MINIMUM ONLY AND WHERE SITE CONDITIONS REQUIRE THE DIMENSIONS ARE TO BE INCREASED TO SUIT OR AS DIRECTED BY SITE ENGINEER. 3. ALL STRUCTURAL STEELWORK TO COMPLY WITH NZS 3404 GRADE 250. 4. ALL WELDS TO BE GENERAL PURPOSE &: COMPLY WITH NZS 4701 USING E41XXN ELECTRODES. 5. ALL BOLTS TO BE 4.6/s IN ACCORDANCE WITH AS 1252. 6. ALL STEELWORK, BOLTS, NUTS, WASHERS ETC. TO BE HOT DIPPED IN GALVANIZED AFTER FABRICATION TO 70 MICRON MIN. THICKNESS. ALL WELDING TO TAKE PLACE PRIOR TO GALVANIZING.
ONEPOTO DOMAIN: WETLAND & SANCTUARY
DETAILED DRAWINGS
450 HEAD OF PEG TO FINISH 25MM BELOW GROUND 30 X 30 X 225 MIN PEGS OR BATTONS. NAILED FROM EACH SIDE (MIN. 2NAILS PER PEG) WITH 50MM GALVANIZED FLATHEAD NAILS.
2,300 1,200
30 X 145 MIN. H4 ROUGH SAWN TIMBER EDGING BOARD.
30
30
585
355
MOUNDED PERMEABLE CONCRETE P AT H A C R O S S A L O W LY I N G WETLAND. REFER TO MASTER PLAN. RECOVERED SITE TOP SOIL. FREE OF LARGE CLODS, ROCKS, RUBBLE AND RUBBISH.
3% GRADIENT
DRIVEN 30 X 30 MIN. H4 STAKES MIN. 225MM LONG AT 500MM CTRS MIN.
20% FALL
COMPACTED GAP 7 FREE DRAINING SCORIA
20% FALL
110 mm N O VA F L O COIL
3,200 MOUNDED PERMEABLE PATH
1:20
145mm PERMEABLE COLOURED CONCRETE
145
DETAIL 02 VIEW 01
230
COMPACTED GAP 7 225mm min.
112
170
SLOTTED NOVAFLO COIL 110mm. CONNECTED TO STORM WATER SYSTEMS. REFER TO ENGINEER SPECIFICATIONS.
COMPACTED GAP 40 HARDFILL
DETAIL 02 VIEW 02
MOUNDED PATH LONG SECTION
1:20 NOTE 1. ALL TIMBER IS TO BE H4 TREATED OR HIGHER. 2. THE TIMBER THICKNESSES AND DEPTHS SHOWN ARE MINIMUM ONLY AND WHERE SITE CONDITIONS REQUIRE THE DIMENSIONS ARE TO BE INCREASED TO SUIT OR AS DIRECTED BY SITE ENGINEER. 3. ALL EXCAVATED SOILS WILL BE DISTRIBUTED ON SITE IN ALLOCATED AREAS. REFER TO MATER PLAN.
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
DETAILED DRAWINGS
3000
1,050
C O M PA C T E D S O I L B A C K F I L L RECOVERED FROM EARTHWORKS. FREE OF CLODS, ROCKS, RUBBLE AND RUBBISH.
RIPARIAN BANK PLANTING. PLANTS GROW WITHIN AND AROUND THE TUBE SOCK GEOTEXTILE BONTERRA FIBER SOCKS.
2000
60 ANGLE RETAINED BANK. REFER TO ENGINEER SPECIFICATIONS. 1000
250
0m
THE WATER LEVELS ACCOMMODATE FOR EXTENSIVE RAINFALL AND FLOODING.
HIGH WATER MARK
LOW WATER MARK
1,000
100 X 100 WIRE MESH FRAMED GABION. STACKED WITH LARGE ROCKS WITH LARGE GAPS. REFER TO ECOLOGICAL STATEMENT.
TUBE SOCKS ARE A NON-PERISHABLE MATERIAL.
-1000
1,000 2,700
DETAIL 03
ECOLOGICAL RETAINING WALL DETAIL
1:50
ORGANIC FIBER GEOTEXTILE BONTERRA CF7 or CF9 COIR FIBER 50
WOODEN PEGS 250mm. H4 TREATED TIMBER.
270
INNER LINER OF BONTERRA C2 or HP90
50
TUBE SOCKS WILL BE PACKED HARD AGAINST THE EXCAVATED BANK AS PER ENGINEER SPECIFICATIONS.
NOT RECOMMENDED FOR CLIMBING OR ANY FORM OR HUMAN ACTIVITY.
WHEN FILL AND COMPACT THE TUBE SOCKS WILL HOLD TOGETHER. FORMING A FIRM RETAINING WALL.
1,100
DETAIL 03 CLOSEUP
TUBE SOCK DETAIL
75
1:20 NOTE 1. ALL CONSTRUCTION MUST BE TO THE AUCKLAND COUNCIL CODE OF PRACTICE STANDARDS. 2. TUBE SOCK RETAINING STRUCTURE MUST REACH RECOMMENDED ECOLOGICAL STANDARDS. REFER TO ECOLOGICAL SPECIALIST.
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
CONTOURS & GRADING
In order to allow a more comfortable circulation of the site as well as better view shafts for people using the Domain, we propose changing the existing terrain of the domain by creating a retention pond and using the cut earth from the excavation to form mounded hills. As a result, the new grading of this site within Onepoto Domain effectively handles topography and hydrology, supporting the wetland & sanctuary vision and creating a site with both ecological and ammenity value. The red arrows on the adjoining grading plan shows how water flow from around the Domain and through the wetland will work.
A little hill here
hp
Legend
New Contours at 1m intervals New Contours at 0.5m intervals
2
Flow of Water across the Site Exisiting Contours A pool here, which the water can drain to
Stormwater Channels Boardwalks
2
Paths Cut Area 01 Fill Area 01 (soil from Cut Area 01 will be used to fill this area and creae mounds. Cut Area 02 Fill Area 02 (soil from Cut Area 02 will be used to fill this area and flatten it out).
SCALE 1:500 @ A0 37
ONEPOTO DOMAIN: WETLAND & SANCTUARY
WEED MANAGEMENT
Weeds at Onepoto Weed control is part of the overall site management and restoration program. It focuses on the species and communities wanted in place of the weed species, rather than on simply eliminating weeds. It will implement preventative programs to keep the site free of species that are not yet established at the Domain, but which are known to be apparent elsewhere in the region. It will set priorities for the control or elimination of weeds that have already established on the site, according to their actual and potential impacts on native species and communities, particularly on conservation targets. It will take action only when careful consideration indicates leaving the weed unchecked will result in more damage than controlling it with available methods. The current footpath through the native bush along the eastern side of the reserve will be upgraded. The weed management plan will cover the wetland and bush area on north eastern Onepoto Domain. Principles and objectives found within the Weed Management Plan are derived from the Green Network vision. For objectives to be accomplished, sound theory must be followed. This includes ensuring Best Practice Guidelines are utilised during all weed control operations. Site Description Native plants such as NZ cabbage tree, juncas and flax are distributed throughout the wetland with a juncas patch located in the centre of the wetland. The bush land on site is mainly native broadleaf forest. The proposed boardwalk is connected along the current storm water drainage route.
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Onepoto Domain | Group ONE | July 2014
Current map of Onepoto Domain outlining site for wetland development
The formal and informal mowing paths are designed for pedestrian walkways and weed management purposes. The aquatic and wetland areas are native and exotic species and will be densely planted.
Site purpose Onepoto Domain attracts residents throughout Auckland and is a recreational reserve with unique and natural environmental benefits. With the new proposed boardwalk design in place local pedestrians and cyclists are able to bike through the wetland area allowing them to explore, enjoy and learn about the natural environment.
ONEPOTO DOMAIN: WETLAND & SANCTUARY
WEED MANAGEMENT
Existing Weed Issues Weeds are a major threat to New Zealand’s unique native species, ecosystems and conservation lands. New Zealand weeds are almost always plant species that humans have introduced to the country. Sometimes, however, even a native species can be considered to be a weed in a particular site if it affects an important natural value on that site. Auckland’s climate is suitable for the growth of a wide range of plants. Current Weed Issues at Onepoto Domain There are a number of weed issues in Onepoto Domain, with weed growth being a prime problem. The yacht clubs have experienced difficulties over the past 2 years with excessive weed growth fouling the keels and rudders of their boats. This has made racing and organised events difficult. The club members themselves have undertaken flushing of the lakes with estuarine water which kills the weed. However, floating dead weed has proven another problem.
Another former weed issue is pampas grass grown in wetland area. The main pampus grass has recently been removed from the wetland area in the Domain. Pampus grass is often a serious threat to New Zealand’s habitats and ecosystems causing fire risks and replacement of native flora or vegetation, and providing a home to native pests such as rats, possums and rabbits. Near the entrance of Sylvan Ave there are exposed pampus plants and gaps where the bush and other plants don’t cover weeds such as wandering jew and dollar weed that scatter madly and form to make a floor. Other weeds like Convolvulus and wild ginger raid this area causing serious problems for cabbage trees and young native seedlings. Native bush areas are relatively weed free and well maintained due to the densely spread native broadleaf bush.
Dock weeds by the new boardwalk
Noxious weeds such as thistle, woolly nightshade and gorse scatter and grow on the posts of the boardwalk areas these weed however are not a threat to the wetland area.
The pond goes through a cycle of intense weed and algal growth during warmer weather accelerated by the high sediment deposits. The pond is then flushed with estuarine water by opening the flood gates to kill the weed growth and maintain the pond for sailing. This is followed by rapid decomposition of the dead weed resulting in low oxygen levels with hydrogen sulphide being emitted.
Mixture of gorse and pampus
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
WEED MANAGEMENT
Statutory Requirements Auckland Council The Auckland Council Weed Management Policy states that, “A weed is defined as any plant growing where it is not wanted and which has an adverse effect as defined within the policy.” Auckland Council is responsible for the development and implementation of the weed management policy. The policy applies to all land owned or administered by Auckland Council and its CCOs. All council and CCOs staff and contractors will be required to adhere to the policy. Weed management on private land and other public land not owned or managed by Auckland Council or its CCOs is outside of the scope of the weed management policy. The policy will influence and allow others to take action on their land to avoid the creation of weeds, to effectively manage their control and to stop them scattering to other areas. Ensuring the integrated use of current best practice methodologies in the prevention and management of weeds is critical to the success of the weed management policy. Best practice weed control involves constant research to keep up to date with evolving weed management techniques, both locally and internationally, and continual innovation to achieve effective, efficient and sustainable outcomes. Auckland Council and its CCOs will set a best practice example for weed management on the land they own or administer. This includes managing the environment to reduce or eliminate habitat for weed establishment and selecting appropriate control techniques that minimise resource use and adverse environmental effects. The council will also ensure it is a good neighbour by managing weeds on land it owns or administers in a way that prevents adverse effects on adjacent land. Auckland Council is responsible for the development and implementation of the weed management policy. Weed spread occurs at the landscape scale, so weed management must also happen at that scale. To achieve this, we must foster a coordinated and cooperative approach to weed management. The objectives of the weed management policy are as follows: 1.
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Take an integrated approach to weed management and vegetation
Onepoto Domain | Group ONE | July 2014
control 2. Ensure best practice in weed management and vegetation control 3. Minimise agrichemical use 4. Minimise non-target effects of agrichemical use 5. Ensure public health and safety 6. Protect and enhance the environment 7. Empower the community to manage weeds in accordance with the policy. 8. Deliver weed management and vegetation control which is value for money.
Department of Conservation Department of Conservation states that: “The Department is prominent in mainland island restoration and largescale pest control programmes and has expertise that would be of value to Onepoto Domainsproject. The Department also has a statutory role in approving wildlife translocation applications under the Wildlife Act 1953.”
ONEPOTO DOMAIN: WETLAND & SANCTUARY
WEED MANAGEMENT
Proposed Weed Management
Objective 1: Support and facilitate community understanding and participation in the management of weed effects.
Objective 3: Care for high value areas from the impact of weeds.
Weed Management goal
•Discover the actions and attitudes of the general community that assist the spread of environmental weeds.
•Evaluate whether weed control at the site is effectively reaching ecological restoration every 2 or so years and include within the annual report.
“Protection of the quality, biodiversity and ecological integrity of Onepoto Domain’s natural habitat from the effects of environmental and invasive weeds”.
•Maintain community motivation, involvement and education project funding.
•Evaluate and analyse Management Plans every 5 years to confirm progress along the restoration phase timeline.
•Develop relationships whereby community groups and their projects are associated with properly qualified staff and/or contractors to assisting the control of weeds (i.e when infestations become too vast of a job for volunteers contractors can assist e.g green network- community planting in parks).
•Organize Weed Management Plans with a useful/operational focus for important sites.
The goal of ecological restoration is to restore an ecosystem to a state where it is self-sustaining, biodiversity is maintained or enhanced and ecosystem services are retained. One main component of such ecological restoration is the control of environmental weeds. Environmental weeds alter the structure, successional and ecological processes, and organisms present in ecological communities. Failure to successfully manage significant weed threats, particularly at ecologically respected sites, will lead to a loss of biodiversity, the progressive deterioration of native ecological communities, and the loss of self-sustaining native bush.
•Encourage community groups where restoration has already been created, and management is ongoing to aid the achievement of volunteers.
It is vital to ensure the methodologies used to manage invasive weed are the most proficient and effective use of resources possible, and are the most successful and environmentally sensitive methodologies available. The following objectives outline the Plans approach to succeeding with this goal. A series of targets are specified for each objective.
•Identify a list of priority sites for site-led weed control programmes, including recent areas of little to zero weed density and analysis every five years. •Monitor and check the development and success of plan implementation and create an annual report describing the control results reached for each site-led weed programme. Reports should contain details of sites controlled, frequency of control visits mapped, methodologies used and the outcome of monitoring, distributions of latest weed control aims.
Objective 2: Remove or contain specific weed species wherever they arise, where this is practical and affordable. •Control programmes should follow the RPMS guidelines and a proven effective method of weed management acceptable for a gradual decrease of infestations over time for containment species. This may require the preparation of plans covering species-specific methodologies. •Ensure all sightings of entire control pest plants are stated to Auckland Council for their records. •Quantitatively map the distributions of any weed species selected for a weed-led programme over the long term. Mapping will be used for communicating the distribution of weeds, self-auditing and measuring progress and achievement.
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
WEED MANAGEMENT
Management Techniques & Approaches for Different Zones
ZONE A:
Considerations in Wetland and Aquatic Areas Control of invasive plants in or around wetlands or bodies of water requires a unique set of considerations. Removal projects in wetland zones can be legal and effective if handled appropriately. In many cases, herbicides may be the least disruptive tools with which to remove invasive plants. Invasive plant control in wetland areas should be approached with caution for a number of reasons: 1)
Proximity to water makes chemical contamination of surface and ground water much harder to avoid or impossible to control. 2) Wetland areas are critical habitat areas for a large number of wildlife species. Invasive plant control can disturb or destroy habitat. 3) Mechanical removal of invasive plant can lead to erosion and resulting siltation of the waterway. These considerations should influence the choice of method. The presence of water in or near control area creates a far greater risk for spreading herbicides beyond the target plant. In riparian or wetland sites ground water is typically closer to the surface. Any active herbicide residue or components from herbicide breakdown have a shorter distance to travel as runoff before reaching water. When invasive plants have invaded wetland areas the habitat value of the area may be reduced: however, the area may still provide nesting sites for many animals. Wildlife present in the area may be disturbed by efforts to mechanically or chemically remove invasive plants.
MAP NOT TO SCALE
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Onepoto Domain | Group ONE | July 2014
A: Wetland B: Weed Fields C: Grassland D: Native Bush
Mechanical removal of invasive plants can loosen the soil and potentially cause erosion. If timed correctly to prevent seed development, the removal of most annual plants does not require the removal of root systems that hold the soil in place. However, effective mechanical removal of many biannual and perennials will require the removal of the root system or additional cutting to weaken the plant and prevent resprout. Disturbed soil not only creates the potential for erosion but it can also be an avenue of entry for other invasive plant species. Several techniques can minimize the risk for erosion and they include: leaving vegetative strips that will slow and filter run-off, using erosion control materials, and mowing or cutting the invasive followed by hand applied herbicides.
ONEPOTO DOMAIN: WETLAND & SANCTUARY
WEED MANAGEMENT
Plants to Monitor Invasive plant control requires significant resources of time and effort, if not money; perhaps the most important element in invasive plant control is to anticipate the need to monitor for regrowth after the initial control effort is complete. Many invasive plants are prolific seeders whose seed bank may remain viable for a number of years. Regeneration of plant through plant parts missed during removal can and will occur as well. A natural area disturbed by removal of one invasive species may also become invaded by another invasive species. If regrowth is not controlled early, a group’s initial control efforts will need to be repeated, wasting valuable resources. Process - Initial & Ongoing - Hand pulling - Cutting - Pulling with tools - Mowing- pampas, gorse and other noxious weed - Grazing - Covering - Brush hogging or bulldozing- pampas, gorse and other noxious weed - Mulching 100mm after soil is wet and better do it in Autumn. • Observation to sense new weed problems at valuable sites before they become uncontrollable. • Remove all noxious weeds and pampus for assembly of the new wetland design • Support and assist community understanding and connection in the management of weed effects. • The weed removal must not cause harmful affect to the health of local natural communities and habitat. • The removal development must not cause pollution to the natural resource such as water and soil.
ZONE B:
Considerations for Weed Fields It is important that in this restoration technique all areas which are planted are also mulched. Due to the large amount of Pampus in the area that has recently been removed, the ground has become a bare earth situation. A effective process will need to be carried out such as chemical and hand eradication in order to control re-growth and promote desirable growth. As a result of the bare-earth situation, revegetation techniques will require covering with biodegradable erosion and weed control matting. Biodegradable products are recommended so the collection of leaf litter and subsequent natural regeneration and seeding of bush is not inhibited. It is recommended that the following product be utilised due to its water absorption capabilities, erosion control benefits, its supply of plant nutrients, visual integration and insulation properties. This product takes 18 months to 2 years to degrade completely. Any large woody debris like logs and branches from exotic weeds in these areas should be left on site to rot, providing habitats for insects, nutrients to soil and protection from seedlings. Another technique will be the establishment of a nurse crop - as an initial planting process nurse crops reduce the incidence of weeds, prevent erosion, and prevent excessive sunlight from reaching tender seedlings. Species utilised for the nurse crop will include native primary colonisers. The lack of canopy cover can increase weed growth and evapotranspiration, mulching will aid in decreasing these effects. Process - Initial & Ongoing - - - - - - -
Understorey planting Mulching Nurse crop planting Chemical control Hand eradication Initial weed removal Laying of weed and erosion control matting
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
WEED MANAGEMENT
ZONE C:
ZONE D:
Where soil fertility is low this reduces the competitive advantage which thistles, docks and also nettles exploit so successfully. Therefore an important prerequisite for discouraging pernicious weeds and also encouraging species diversity, is to reinstate or continue with traditional low-intensity management without the use of fertilisers. Overgrazing and excessive trampling or poaching should be avoided as this encourages germination of thistles, docks and ragwort. Feeding weed infested hay should also be avoided. It is important therefore, that any action to control the problem weed is made in conjunction with the necessary changes to the management regime.
At present, an established native canopy cover in this restoration area means that the establishment of a nurse crop is not required. A part of the canopy cover in these areas are exotic species which in the long-term are unwanted.
Considerations for Grassland Areas
This area requires canopy cover. This can be achieved through nurse crop planting of enrichment species. It is important to retain the grass on site and to create areas for planting using a spot chemical control technique. Maintenance of planted areas will involve hand held chemical control on grass and around the plants. It will be of benefit to regularly mow the grass also, this will help prevent the establishment of weed species within the grass which will turn the area into a weed field. Mulching of the plants will also help with successful establishments in the long term. Weed control of thistles, docks, ragwort and nettles via mechanical methods such as topping, hand pulling etc. can be sufficient to contain or reduce these weeds and prevent seeding. Complete eradication is not usually necessary or easy to achieve (even using herbicides), and indeed all these weeds are utilised by a number of insects and birds. Process - Initial & Ongoing - - - - -
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Mulching Mowing Chemical control of grass in preparation for planting Hand held/chemical control Plant nurse crop species
Onepoto Domain | Group ONE | July 2014
Considerations for Native Bush
The approach for this area includes the direct eradication of all exotic ground cover, small trees and shrubs, leaving the taller exotic trees as canopy cover in the interim. Subsequent planting will happen under the canopy. Subsequent planting will include enrichment with species appropriate to the site. As the planted native species form, the exotic canopy species can be selectively killed off, with the intention of eliminating all of them once a dependable native canopy is established. In areas where there is very little exotic canopy cover and the native understorey is well established it is considered that the native species will provide enough canopy for effective establishment of enrichment species and therefore, all exotic weeds and canopy species are to be removed. It is vital that the native species are not damaged. In some circumstances the weed species will be ring barked or even chopped but left in situ to rot naturally over time rather than cause harm to necessary species present. Such rotting material also provides a desired food source and nutrients for fauna and flora. The task in this zone is the control of weed seedlings establishing as a result of the presence of seed source in the exotic canopy trees left in the area for the short-term. Maintenance will involve regular removal of these seedlings. Process - Initial & Ongoing - - - -
Regular removal of weed species Planting of native species Remove smaller exotic weed trees, shrubs and ground cover Selective eradication of exotic canopy species.
ONEPOTO DOMAIN: WETLAND & SANCTUARY
WEED MANAGEMENT
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
WEED MANAGEMENT
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Onepoto Domain | Group ONE | July 2014
ONEPOTO DOMAIN: WETLAND & SANCTUARY
WEED MANAGEMENT
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ONEPOTO DOMAIN: WETLAND & SANCTUARY
WEED MANAGEMENT
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Onepoto Domain | Group ONE | July 2014
ONEPOTO DOMAIN: WETLAND & SANCTUARY
WEED MANAGEMENT
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