Restoring the Waterways within the University of Canterbury - A Partnership Plan: Analysis and Preliminary Proposals May 1998
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Restoring the
Waterways
within the
University of
Canterbury
A Partnership Plan:
Analysis and Preliminary
Proposals
May 1998Restoring the
Waterways
within the
University of
Canterbury
A Partnership Plan:
Analysis and Preliminary
Proposals
Written and compiled by Leanne O’Brien
In association with Rachel Barker, Jeff Weston,
Alan Cutler, Allan Watson, Chris Rance, and
Ken Couling, Christchurch City Council
Plans by Jeff Weston
Published by:
The Waterway & Wetlands Team
Water Services Unit
Christchurch City Council
PO Box 237
CHRISTCHURCH
Tel. 379-1660
Fax. 371-1384
1Contents Page
Summary 3
Administrative/Management Context 4
University of Canterbury 4
Christchurch City Council 4
Canterbury Regional Council 5
Other organisations 5
Background to the waterways of the University 6
Stream flows 6
Human use 7
Vegetation 8
Fish 8
Birds 8
Aquatic invertebrates 11
Other fauna 11
Ecological basis for Waterway Restoration 12
The function of riparian vegetation 12
Key guidelines 12
Improving in-stream values 14
General Issues 15
Water quantity 15
Water quality 15
Bank stabilisation 16
Streambank maintenance 16
Stream bed maintenance 17
Development setback distance 18
Administration of the plan 18
Goals and Objectives 19
Suggested goals and objectives for the waterways 19
Restoration objectives for waterways 20
Restoration Proposals 22
Okeover Stream 22
Avon River 23
Ilam Stream 24
Implementation of restoration proposals 26
Research and academic opportunities 27
Specific educational opportunities for restoration 27
Monitoring 28
Recommendations 29
Appendix: Weeds/plant pests 30
References 31
Cover and Page 1 Illustrations:
2 Ilam c 1920s. (W. A. Taylor Collection, Canterbury Museum)Summary
This document outlines proposals for the restoration, protection and management
of the waterways within the University of Canterbury grounds. This will ideally
be achieved in a partnership between the University of Canterbury, its student
body and the Christchurch City Council.
The waterways within the University of Canterbury campus are the Avon and Ilam
Rivers and Okeover Stream. These waterways are significant landscape features,
however their natural and ecological values have been compromised. The overall
abundance and diversity of species has declined due to past modification of the
waterway system. Commitment to this plan, through the adoption of sustainable
management practices and the realisation of ecological potential, will ensure the
future enhancement of these waterways.
The vision is to sustainably develop, as near as possible, a self-maintaining and
functional waterway system, while maintaining values associated with the cultural
and amenity use of the landscape. Restoration of the waterways will create
habitats and establish wildlife corridors for terrestrial and aquatic life. The vision
can be achieved through adoption of practices assisting native plant regeneration
and the planting of indigenous plant communities.
This plan provides the framework to further develop a partnership for the
management and restoration of the waterways within the University campus. Staff,
student and City Council input is essential for the success of this partnership
plan.
Feedback is welcomed at both the May seminar and through submissions due by
30 June 1998.
The Avon River above Waimairi
Road showing good results
from previous restoration
៊ planting.
3Administrative/
Management
Context
Several organisations have responsibilities over the waterways within the University
of Canterbury campus. The University, its students and the Christchurch City
Council are the key partners responsible for waterway management. Internal
guidelines exist within these organisations which concern the preservation of
waterways.
University of Canterbury
The University has title to most of the stream bed of the Okeover and Ilam
Streams, a substantial section of the Avon River and the surrounding land. It
is therefore essential to include the University in any strategy to restore these
waterways.
The University of Canterbury Charter (1992) states that it should be “actively
concerned about the University’s impact on the environment”, in particular it
states it will be a “responsible and sensitive guardian of land, flora and fauna
under its control and ownership”.
Christchurch City Council
Christchurch City Council is responsible for the management and maintenance of
the surface waters of Christchurch. Through the Christchurch Drainage Act (1953)
and Local Government Act (1974) it has had a long association with land drainage,
flood alleviation and waterway maintenance. Changes have come about as a result
of the Resource Management Act (1991) and the Council has new and important
functions under the recent Proposed City Plan (1995).
The City Plan states the following:
• Ensuringthat the margins of waterways are managed in a manner which retains
amenity, ecological and natural values, both adjacent to and within the
waterway.
• The retention of an unmodified stream bank for reasons of conservation and
the enhancement of the City’s waterways as habitats for fish and other aquatic
species and plants.
• Future management of the City’s waterways will be based on promoting the
natural character of waterways in preference to artificial solutions (such as
retaining walls) and to encourage sustainable solutions such as planting of
4 riparian strips along these waterways.Canterbury Regional Council
The Canterbury Regional Council is responsible for the protection of the water
quality and quantity of surface and groundwater resources. Under the Resource
Management Act (1991) the Canterbury Regional Council reviews, places conditions
and declines or approves any resource consents concerning these issues, including
any works involving the streambed of natural waterways.
Other organisations
Other important organisations concerned with the maintenance of fish populations
are the Ministry of Agriculture and Fisheries, the Department of Conservation,
the North Canterbury Fish and Game Council and Ngai Tahu.
All of the above organisations have overlapping interests and responsibilities for
aspects of the waterways and their riparian environment. This plan attempts to
provide a preliminary framework for co-operative management toward a common
goal. Through this common vision and willingness to develop the partnership,
progress may be made in the ecological restoration of these waterways.
់ Okeover Stream
5Background to the
waterways of the
University
Stream flows
The Avon River is fed by many tributaries whose water originates from groundwater
springs and surface water runoff. Major changes have occurred along Christchurch
waterways, the most significant being the draining of wetlands and deforestation.
As the city of Christchurch developed, drainage patterns changed due to an
increase in impervious surfaces and modifications to the waterway to control
stormwater and flooding (Lamb 1981).
Water from Okeover Stream:
Air-conditioning water from
the Commerce Building. ៉
One of the consequences of these alterations is a change in the water quality
and flow characteristics in the waterways. Ground water springs have reduced
or disappeared in the Okeover and Ilam streams, while artificial input sources,
such as stormwater drains and building discharges, have become the main source
of water flow.
The change in the source of water has had a significant effect on the waterway
system. Spring water has a uniform flow and is both pure and cool, while
stormwater inputs tend to be warmer, have the potential to contain contaminants
and silt and have highly variable flow rates. This has lead to the siltation,
stagnation and bank instability of University tributary streams. The result has
been the loss of the diverse invertebrate populations that once occurred within
them (Robb 1990).
Restoration of waterways generally involves enhancement of the positive
characteristics and features that still occur along the waterways. These include
areas without retaining walls, the meandering course of the Avon River, natural
spring sources, natural regeneration of indigenous plants and areas with gravel
6 substrate and rocks.Human Use
People have a natural association with waterways. Maori utilized the once bountiful
food and resources of the Avon River, naming it Otakaro “the place of a game”.
Both Maori and Europeans used local waterways for transport. Rowing and fishing
were favourite pastimes along the Avon River.
The original Ilam Homestead
in the 1850s. Modification
of the waterways is already
៊ evident.
In 1850 John Charles Watts-Russell arrived on one of the first four ships and
established a 500 acre farm at Ilam which was taken over in 1882 by the Harper
family. The property changed hands several times and then in 1914 Edgar Stead
took over the estate and rebuilt the burnt homestead. In 1957 the University
started to move to Ilam from the city centre. The campus grew and is still growing
with buildings and car parks progressively replacing green open space.
Many items of cultural interest occur along the waterways. Opposite ់ Ilam Homestead in 1882.
University of Canterbury staff club is a water-wheel. This wheel
was moved from Heathcote and was originally used to
pump water to Ilam Homestead and is still able to
be used to irrigate the Ilam playing fields. Trees
dedicated to peace and women’s suffrage are
also found as well as other memorials.
Attitudes towards the waterways have
changed over the years. In the early years
waterways were modified to remind colo-
nists of “home” as well as for flood
security. Notably in 1941 the Drainage
Board Act viewed the Avon and Heathcote
waterways merely as drains. Management
practices followed which reduced the occur-
rence of floods in the city, but also decreased
the ecological potential and value of the rivers.
Attitudes changed when it became apparent that
human activity was irrevocably altering the quality and
integrity of waterways. 7Currently the goal is to balance human use of the waterways with ecological
necessity in order to develop a sustainable management plan. This plan aims to
satisfy the needs of people by maintaining areas for sitting and enjoying the
waterway landscape. The further needs of students and staff will be incorporated
through further consultation.
Vegetation
The University of Canterbury grounds were once part of a mosaic of wildlife
habitats on the Canterbury plains which included swampland, forest and scrub
communities (Molly 1995). Before the human occupation of New Zealand three
plant communities occurred around the University grounds (Lucas & Meurk 1995).
The waterways would have been fringed with characteristic species of Sedge, Flax
and Rush. Areas of Kahikatea swamp forest associations, such as that still
present in Riccarton Bush, dominated damp areas. In drier areas Totara and
Hohere forest communities existed, with Totara being most common on campus.
These communities were largely lost through natural events, such as the
Waimakariri River flooding, and human activity such as fires and land
clearance.
In 1914 distinguished ornithologist Edgar Stead
took over the estate and developed what is now
the Ilam Gardens. Native trees were planted
between the confluence of the Avon and Ilam
streams to attract native birds. However, Edgar
Stead is best remembered as an enthusiast of
Rhododendrons, which are now a prominent
feature of Ilam gardens. The Ilam Galaxy range
of Rhododendrons were reregistered this year
fifty years after Edgar Stead registered the
Edgar Stead ៉ originals (pers. comm. Peter Cadigan).
Planting development of the University Campus began in earnest in the 1970s
as the University settled into its new grounds. The present vegetation is
dominated by exotic deciduous trees from various countries. With mown grass
as groundcover the river margin has largely been devoid of any waterway vegetation
until mowing along river margins ended, about two years ago. This resulted in the
rapid regeneration of ferns and other waterway plants which had previously been
removed. Thus the waterways have the realistic potential to become a corridor
of native wildlife habitat within a setting of predominantly exotic vegetation and
bank development. Further potential exists to extend this habitat by planting
native species known to be wildlife food sources throughout the campus. Native
habitat has been found to regenerate rapidly where grazing and fire do not occur.
Restoration of native vegetation along the waterways will be dependent upon future
management and maintenance.
Fish
The fish community present in the Avon River system changed significantly as
Christchurch was settled. The general trend has been a reduction in the abundance
8 and diversity of native fish species present. This is believed to be due to thecombined effects of introduced trout and the deterioration of the freshwater
environment and habitat. Preferred fish habitats have been typified by waterways
with varied depth, instream and overhanging vegetation and/or undercut banks,
with areas of gravel or cobble substrate in which to spawn. Both the quantity
and quality of these habitats have been reduced within the University
waterways.
Trout were first introduced in 1868 and have since seriously affected the
abundance of native freshwater fish due to direct predation and competition for
food. To understand what the Avon River could have contained, comparisons can
be made with Pigeon Bay Stream on Banks Peninsula, in which no trout are found.
Far left: Longfinned Eel.
៊ Left: Whitebait
Thirteen species of native fish are present in Pigeon Bay Stream. The community is
dominated by lampreys, longfinned and shortfinned eels and three species of bully;
common, bluegilled and upland. With the exception of the upland bully these species
are migratory. This community structure was also found in NIWA’s survey of 100
New Zealand rivers. Nine native species of fish are still present in the Avon system
while only three are currently found in the campus waterways (longfinned eel,
shortfinned eel, upland bully).
The potential exists for the recolonisation of common bully, bluegilled bully and
lamprey (pers. comm. Angus McIntosh). These species are present at Mona Vale
Avon River, University of
៊ Canterbury grounds 1976
9which is only 2.5km downstream from the University. Different water velocities
provide habitat for different species. In the pools and slow runs of Pigeon Bay
Stream, inanga, common, upland and red-finned bullies can be found. Eels inhabit
a range of water habitats while larval lampreys live burrowed in shallow, slack
water areas with silty deposits. Restoration of fish populations will be dependent
upon the successful restoration of aquatic invertebrate prey species, migratory
access to the sea and the nature of restored waterway habitat as well as the
presence or absence of trout.
Birds
A drastic decline in the diversity of native bush birds has occurred in the
Christchurch area in the last hundred years. The causes of decline are attributed
to habitat reduction, isolation of forest fragments, predation of ground dwelling
and hole nesting species and shooting pressure. The patches of lowland forest
that were present, in what was to become Christchurch, provided “stepping stones”
for the movement of birds between extensive forest blocks on Banks Peninsula
and the Canterbury foothills. This movement was important for maintaining
populations (Molly, 1995). Recreating similar patches of forest in today’s
Christchurch will assist in increasing bird numbers in the city and Canterbury.
Many native species of birds will never occur in Canterbury again, yet the species
that have remained are abundant and some populations are even growing in
response to increases in habitat.
Emphasis in this proposal is placed on encouraging the establishment and
abundance of New Zealand species. Currently there are more introduced bird
species on campus than there are native. Native birds that are known to occur
regularly on campus are the grey duck, silvereye, grey warbler, fantail, welcome
swallow, little shag and the spur-winged plover. Kereru (native pigeon) have been
seen in the Ilam Gardens and there are vagrant bellbirds in Riccarton Bush which is
only 500m from the University.
Scaup. ៉
10Native birds that could be established on University grounds within the next ten
years include scaup, kereru and the shining cuckoo (pers. comm. Andrew Crossland).
Scaup numbers are increasing significantly and are now present at Mona Vale.
Scaup can be encouraged into the Ilam Stream by planting Carex secta which is
its preferred species for nesting. Kereru make extensive feeding forays and will
become resident in Ilam Gardens if there are sufficient food resources. The shining
cuckoo is a migratory bird which parasitises the nests of the grey warbler and
will occur anywhere the grey warbler is common. Increases in insect and fish
numbers will encourage visits by kingfishers. Inadequate quantity or quality of
habitat and inadequate food resources are likely to limit future re-establishment of
these species.
Aquatic Invertebrates
In 1973 a study of the University waterways found that the aquatic invertebrate
community was dominated by worms, snails and amphipoda (Marshall 1973). These
common groups still dominate today, however, several other changes have occurred
in response to changes in the waterway system, particularly increases in silt and
Typical stream invertebrates
decreases in water flow. The abundance of invertebrates such as mayflies, beetles
៌Deleatidium sp
and caddisflies, which prefer gravel substrates, have reduced, while molluscs,
prefering silt, have increased. These changes are seen in Drainage Board
invertebrate surveys which indicate that about 60% of the species present at
the sampling sites within the University grounds in 1980 were absent in 1990
(Robb 1990).
Recolonisation of aquatic invertebrates is possible as many have adult flying stages
which can travel considerable distances. Ducks are also thought to facilitate
movement of aquatic wildlife (pers. comm. Mike Winterbourn). Increasing the range
of habitat types present will also increase the aquatic fauna present. Low flow
rates, however, are a limiting factor for a species which prefers fast moving water. ៌Amphipod
Some potential exists to manipulate existing flow and velocity by rock and gravel
placement and stream narrowing. Overall, restoration of aquatic invertebrate
populations will depend on water velocity, substrate type, extent of riparian
vegetation and the occurrence of aquatic plants.
Other fauna
It is also likely that terrestrial invertebrate numbers will increase due to habitat
creation. It is not known whether the common gecko which is resident in Riccarton
Bush occurs on campus. The establishment of a wildlife corridor between the
University and Riccarton Bush is likely to increase the chance of its occurrence
on campus.
៊ Gecko.
11Ecological basis
for Waterway
Restoration
The function of riparian
vegetation
Riparian vegetation is that vegetation which occurs along the edge of a waterway.
This vegetation has the potential to function as a wildlife corridor linking remnant
areas of ecological value throughout Christchurch. It also allows the increased
movement of fauna and decreases the adverse effects of urban fragmentation.
Strong links exist and need to be maintained between terrestrial and aquatic
environments, especially in narrow waterways such as within the University
grounds. Terrestrial vegetation is an important wildlife refuge that stabilises,
interacts with, and enhances the aquatic system.
Key guidelines to consider in
the ecological restoration
of waterways
Naturally occurring indigenous plant communities are the most appropriate
vegetation to establish along waterways. They are not only adapted to local
conditions but they also maintain the integrity of the restoration project,
particularly in its use as a teaching resource. Planting eco-typical plants that
are locally sourced means planting genetically and species appropriate plants for
the area. These species are predominantly evergreen and as such provide a year
round canopy for waterways. This is important because an indigenous tree canopy
contributes the following:
• Moderation of water temperature; shading water from the sun and retaining
warmth in the winter, thus maintaining favorable water temperature for aquatic
life.
Kakariki restoration planting
August 1992 along the Avon
River by the UCSA Building. ៉
12Stagnant water and debris in
៊ Ilam Stream.
• Creationof a sheltered environment; this prevents ferns from being sun scorched
and also protects frost and wind prone plants.
• Reduction in filamentous algae and aquatic weed growth. Deciduous trees allow
algae to bloom during spring before their canopy develops. Algal blooms smother
the stream bed degrading the habitat for invertebrates and fish spawning while
reducing aesthetic appeal. Algae can lead to increased diurnal fluctuations in
pH and dissolved oxygen which can stress or eliminate sensitive species. 13• Provision of food and habitat for native birds; thus indigenous species are a
valuable restoration tool.
• Leaf and branch fall into the waterway; this process is very important in aquatic
ecosystems, as it provides habitat and is the basis of food webs. However large
inputs of leaves, such as from deciduous trees, into slow moving streams may
lower water quality as the leaves decay. It is therefore preferable that existing
deciduous trees be progressively replaced by native species.
Vegetation provides cover and habitat for both terrestrial and aquatic fauna.
However, the quality of this habitat depends on establishing an appropriate
structure by combining margin plants with shrubs and canopy trees. Vegetation
with a substantial root system helps to stabilise bank soils and slows run-off
thereby further reducing erosion. The choice of tree species for this purpose is
important. Willow, which have traditionally been planted along Christchurch
waterways, have aggressive root systems, deposit large quantities of debris and
require annual maintenance work which is expensive and difficult. Kahikatea on
the other hand require minimal work.
Improving In-Stream Values
A waterway is a one-way system, thus what happens upstream will affect what
happens downstream. The University waterways are part of the Avon River system
which is a strong focal point in the city centre and elsewhere. Thus restoration
is important to Christchurch as a whole.
Stream channel diversity is important in aquatic ecosystems because substrate
type and habitat quality control the distribution and abundance of invertebrates
and fish. Sequences of pools and riffles are a natural part of a waterway’s
structure and their creation is an effective restoration tool. These natural features
oxygenate the water and can be used to maintain minimum water levels.
Maintenance of significant areas of aquatic vegetation is essential as aquatic
plants provide important habitat especially for eels and invertebrate species.
Removal of aquatic vegetation results in a decrease in aquatic invertebrates.
Coarse woody debris is another important component of stream habitat as it
helps retain leaves and other food reserves in the stream and increase structural
diversity. Removing snags and debris may, in some situations, improve appearances
and flow but also allows organic matter to be quickly flushed out of the river.
Snags in the river also provide refuge for insects from predation by fish. Aquatic
insects use wood snags as places for ovipositor, pupation, emergence and as a
direct food source.
14General Issues
Water Quantity
One of the greatest threats to the waterways on campus is also the hardest
to control or rectify. The drying of urban springs and the shrinking of waterways is
considered to be and is accepted as an unavoidable consequence of urbanisation.
This process has reduced the Ilam and Okeover streams to relying on pipe-fed
water rather than springs. Thus the major water inputs are from stormwater
drains during winter and air conditioning discharge and de-watering during the
summer. These changes in water quantity affect and threaten the quality of the
water within the streams. Changes in water velocity produce changes in the
invertebrate community due to changes in stream bed characteristics. Although
it is unlikely that water can be easily and sustainably restored to these waterways
future protection of the Avon system will inevitably need to be considered. The
Canterbury Regional Council’s Christchurch-West Melton Groundwater Report 1997
identified the maintenance of spring-fed stream minimum flows as an issue
requiring further investigation.
Water Quality
General water quality in the Avon system is considered to be good and does not
exert any undue pressure on aquatic plant and animal life. However more research
needs to be conducted to fully understand the specific risk human inputs pose
for this restoration project. For instance it has been noted that the Avon River
periodically turns a milky colour.
Stormwater is prone to contamination from human activities. A Canterbury
Regional Council report indicated that zinc is the greatest heavy metal stormwater
contaminant in the Avon. This zinc originates from galvanized roofs and car
tyres.
Algal growth near the
The quality of water entering a waterway via stormwater drains is variable and
់ Staff Club.
is dependent on many factors including:
• frequency of street cleaning
• condition of road surfaces
• traffic density
• construction activity
• deciduous vegetation
• and the activities of residents
Air conditioning discharges into the waterway system can increase water
temperature and poses a risk to invertebrates and fish through temperature
stress. This needs to be monitored as water temperature may limit the
recolonisation by fauna. Also it may be helpful to inform upstream residents of
the restoration work occurring on campus with information on how to protect
water quality. 15Bank stabilisation
The undercutting of banks is a natural process and provides an important habitat,
especially for fish. However where adequate plant root systems are not present
slumping and erosion is likely to occur. This increases the amount of silt in the
river destroying habitat for many invertebrates. It is important that future bank
management depends on the prevention of bank erosion through riparian planting.
Where required gravel or rock and gravel ‘toe’ support is the preferred method
of controlling slumping, rather than construction of retaining walls. Retaining walls
compromise the potential for habitat unless they are sensitively designed and
planted with margin and overhanging plants.
Avon River by Clyde Road
showing bank slumping. ៉
Stream Bank Maintenance
Stream bank maintenance is the responsibility of Canterbury University grounds
staff. It is proposed that the intensity of maintenance will vary along the
waterways according to ecological objectives and use of particular reaches. It is
hoped that by all parties working together, practical maintenance guidelines can
be established which promote restoration and continued recreational use.
Some problems have occurred in the restoration area opposite the Student Union
building, where a substantial number of plants have been damaged by weed-eaters.
In order to protect planted and regenerating native species it is suggested that
stream bank maintenance staff observe the following procedure:
• inspect area for native vegetation before commencing work
• releaseany native plants present by hand so that they are easily noticed when
trimming banks and plant beds
• wherever possible stake or mark native seedlings to increase their visibility
during establishment
• minimise use of herbicide
In areas where it is believed that the riverbank must be trimmed with a weed
16 eater, the operators should preferably do this from the bank, not the streambed, as this helps protect vegetation on the bank face/margin which is of primary
importance. The lower branches of trees are frequently removed to promote a
standard tree form. It is proposed that where possible these lower branches are
retained to promote the natural structure of the vegetation.
Plant pests will affect the potential for sustainability and self maintenance of
the restoration project. By actively reducing the presence of these plants on
campus, the level of short and long-term maintenance required will decrease. Plants
such as aluminum plant and ivy form dense patches of vegetation that suppress or
smother other plants. Sycamore trees reproduce vigorously and require constant
removal. Yellow flag iris, umbrella sedge, purple loosestrife, grey and crack willow
can choke waterways if left unchecked. Refer to the Appendix for a list of plant
pests.
Stream bed maintenance
In-stream maintenance is the responsibility of the Christchurch City Council. It
is of particular importance to this restoration proposal as it directly affects the
ecological potential of the waterway. It is envisaged that by all parties working
together practical maintenance guidelines can be established which promote
restoration. The maintenance programme adopted should be at a scale which is
responsive to local stream conditions rather than part of a broad policy applied
universally and resulting in widespread disturbance and loss of stream
diversity.
It is proposed that a developed policy plan, with input from all parties involved,
will consider the following maintenance issues:
• frequency and timing of maintenance
• removal of willow root
• extent of aquatic plant removal
• removal of weir plugs for maintenance
• removal of snags, leaves, and debris dams
• litter removal and bank works
A more “natural” looking
៊ section of Okeover Stream.
17• plant pest removal
• silt removal
It is recommended that in-stream maintenance within the
University of Canterbury waterways be special and specific. It
is envisaged that a separate “maintenance work” document
be produced to detail waterway maintenance requirements.
Overall it is hoped that instream vegetation clearance or
disturbance will be minimised whereever possible, as aquatic
plant removal is effectively the removal of habitat.
The most noticeable consequence of in-stream maintenance
policy has been the eradication of native aquatic plants such
as water milfoil from university waterways. This has been
without any sustainable management of introduced plants
such as watercress. Water milfoil was described as abundant
in Okeover Stream in 1986, and could occur on campus again
(Carrol & Robb 1986).
Development
setback distance
Note close proximity of ៌ The Proposed City Plan 1995 has specified development
building and storage of “setbacks” of 15m for the Avon River and 12m for both the
building materials by Ilam and Okeover Streams. Setback distances are required to protect drainage
Okeover Stream, 1998. patterns, reduce erosion potential and disturbance to ecosystems. They also
protect the natural character and amenity of a waterway. Resource consent is
required for any filling, excavation or building within these setback distances.
Due to past development, many buildings presently encroach upon the waterways
and there are few areas within the campus proper which do not have buildings
within these setback distances. Building construction practices have also
exacerbated the deterioration of campus waterways especially silt levels and litter
in the Okeover Stream. Observance of setback distance is also crucial in the
maintenance of open space. This is important for present and future generations
and is being eroded and lost throughout the city. Future development on campus
should take this into account.
Administration of the plan
It is important that the implementation of any proposal has a clear administrative
structure. It is proposed that one location at which information concerning all
aspects of Campus waterways and restoration progress be kept. The MacMillan
Brown Library would be suitable for this purpose and is willing to maintain an
accessible archive.
Water Milfoil once abundant, ៌ In addition, the appointment of a waterways officer by the University of Canterbury
has now disappeared, possibly who would be responsible for the day-to-day administration of restoration projects
due to in-stream maintenance and with involvement in all activities at all levels regarding the waterways is
practices. desirable. This appointment would allow continuous “hands on” stewardship by
a person able to develop and apply their detailed ecological knowledge of the
18 waterways.Goals and Objectives Suggested Goals and Objectives for the waterways within the University Grounds The original waterway system present in the area changed as land was drained and waterways were realigned. Although it is impractical and unrealistic to recreate the original system, the density and diversity of wildlife can be increased through the creation and sustainable management of diverse habitats. Specific, attainable and evolving goals should be set and questions asked so that the progress of the restoration project can be evaluated. The first objectives outlined below are broad because very little specific data is available. It is expected that these objectives will continue to evolve, becoming more specific as more information is learned about the waterway. Wherever possible re-establishment of indigenous species should be the key objective so that their specific requirements are included in restoration plans. The main restoration tools in this proposal include encouraging natural regeneration, the planting of indigenous plants to create habitat and provide food resources; the use of gravel and rock to improve stream characteristics; the adoption of practices which lead to habitat improvement and sustainable management and education. Different stream reaches need to be identified within the University on the basis of both importance for recreational use and ecological value. These areas can be managed and maintained according to these values allowing different objectives to be met over the whole waterway. For example reaches important for recreational use require more maintenance than areas with greater ecological value which should be left undisturbed wherever possible. Waterway characteristics and features that are valued need to be identified and protected. These include the surrounding water table which is important in maintaining flow from springs. This can be assisted through the general conservation of water, responsible irrigation practices and a greater knowledge of local groundwater. The riparian zone also requires protection from building development by respecting set back distances. Specifically, the waterway should be protected from: • pollution,by educating neighbours about storm water drains and regular monitoring • erosion, by planting prone banks with trees and shrubs • animal pests, by adopting a programme to trap opossums and educate neighbours on responsible cat ownership • plant pests, through removal of all undesirable plants and seed sources 19
• vandalism, by educating students and gaining their involvement
• siltation, by improving building construction practices
• litter,
by providing rubbish bins in frequently used areas and community
responsibly through education
Restoration Objectives for
waterways
Deleatidium sp. ៌ Aquatic Invertebrates
Objective: Increase aquatic invertebrate abundance and diversity
Method: Plant stream banks to increase shade and reduce erosion
In stream planting and reduced in-stream maintenance to increase
habitat
Use rock/gravel to increase stream-bed diversity and habitat
opportunities
Fish
Longfinned eel. ៌
Objective: Increase native fish diversity. Tentatively target common bully, lamprey,
blue-gilled bully and inanga.
Increase abundance of existing fish populations
Method: Maintain Okeover Stream as a trout free stream. (Needs
research)
Plant margin and stream bank to increase shade, habitat and reduce
erosion
The use of rock/gravel to increase areas of spawning substrate
Birds
Objective: Increase the abundance of Silvereye, Welcome Swallow, Fantail and Grey
Kereru (wood pigeon). ៌ Warbler resident on campus
Increase the occurrence of Kereru (wood pigeon) and little shag. Attract
kingfishers, shinning cuckoo, scaup and bellbird
Method: Plant native plant species to directly provide food and indirectly provide
habitat for invertebrates
Native plants
Objective: Increase the amount of vegetation overhanging waterways
Stabilise stream banks, increase waterway shade
Create representative plant communities
Flax. ៌
20 Sustainability and self maintenanceMethod: Plant eco-typical, locally sourced plants
Protect regeneration
Try to ensure both sexes of dioecious species are present
Plant a diversity of plants as species diversity is a measure of
ecosystem health
Pukio or tussock sedge. An
excellent margin plant
៊ providing fish habitat.
Waterway values
Maintain minimum water levels in Okeover Stream using rock/gravel.
Prevent stagnation of Ilam Stream by regular monitoring in summer.
Maintain water temperature below at least 18°C through tree planting and
monitoring discharge temperatures.
Monitor water quality. 21Restoration
Proposals
Okeover Stream
Site of proposed forestry
project, Okeover Stream. ៉
• Installationof large rocks (preferably greywacke) in the waterway is proposed.
These should be placed so as to maintain minimum water levels during summer,
while improving aeration and diversification of the streambed.
• The Forestry Society are intending to manage a restoration project along part of
the Okeover Stream. Their objectives are the restoration of the waterway, the
planting of native New Zealand forest trees and enhancement of the area for
recreational use.
• No trout appear to currently inhabit the stream which allows the existing native
aquatic fauna to thrive. It is hoped that this stream can remain trout-free
as an example of a native fish community. The stream’s currently shallow nature
seems to be a limiting factor on the trout population, however trout do have
access to the stream and have been present in the past. Consideration could
be given to excluding trout in the future.
Okeover Stream near
Chemistry Building. ៉
22• Where the stream bed is dry it is proposed that instream planting be carried
out to enhance appearance and ecological value during summer.
• It is proposed that the north (left) bank be planted with native shrubs and
trees from Ilam Road to Forestry Road.
Suggested Priorities
1. Remove plant pests.
2. Plant areas directly adjacent to and within stream to provide immediate habitat
for aquatic life.
3. Start monitoring programme.
4. Confirm and order tree species to ensure that large grades are available in
the future as required.
5. Address minimum water levels prior to summer 1998/99
Avon River Water wheel and weir on the
Avon River near the Staff
Ilam Gardens ់ Club.
• The method of restoration in this area will predominantly be to assist
regeneration as most of this area is regenerating naturally. Both direct margin
and shrub/tree planting is proposed to increase plant diversity.
• Specificplanting is required to assist control of erosion in areas where slumping
is occurring.
• The removal of various plant pests is a priority along this reach of the
river. 23University campus
Avon River by Student Union
building. ៉
• This reach requires direct planting of the river banks as regeneration is
patchy.
• As this section is also frequently used by people, it is proposed that planting
priority be given to those steeper sections of riverbank where either access
or maintenance of the grass ground cover is difficult.
• Planting of the river bank will reinforce the bank and assist control of bank
erosion as well as increase habitat.
• Both sides of the river to be planted with a variety of native margin
plants.
• Trout can be commonly seen in this reach of the river. Although not a native
species, restoration in the Avon is aimed at increasing their numbers partly
for aesthetic and traditional reasons, as well as Resource Management Act
reasons.
Suggested priorities
1. Remove plant pests.
2. Start monitoring programme.
3. Implement management policy to assist regeneration.
4. Direct plant the river margin especially in lower Avon.
5. Installation of rock or gravel ‘toe’ as appropriate and plant to stabilise eroding
bank at Clyde Road end.
Ilam Stream
• Currentlya proposal is being considered for this stream which includes the
supplementation of water flow from both groundwater and the Avon River during
24 summer.Ilam Stream showing extent of
៊ widened stream-bed.
• Emphasis will be placed on margin planting to stabilise the widening banks and
protect the natural regeneration which is occurring.
• Species such as the Canterbury Mudfish could be introduced and/or the area
could be enhanced to attract Scaup. As no substantial aquatic fauna is
currently present, time must be given for this to re-establish.
• The stream bed is currently “over widened” in many areas. It will be necessary
to assess whether this current width is required for flood capacity. If not
proposals to plant the edges of the stream bed to naturally narrow the
waterway can be developed.
Suggested priorities
1. Establish monitoring procedures in order to avoid stagnation
2. Commence river margin planting including ‘instream’ planting to narrow
waterway.
3. Remove Yellow Flag Iris.
Ilam Stream by College
House—note potential to
replace or screen the timber
wall with margin plants, such
៊ as rushes, sedges and flax.
25Implementation
of restoration
proposals
The following summary provides suggestions for the division of work between
organisations. If the partnership is to develop fully, this summary will provide the
basis for each partner taking responsibility for implementation. It should be
remembered that the summary is a starting point only, and could be updated
on an annual basis to help clarify roles.
Summary of Stream work
required
Work required Allocation
Plan Preparation Plan preparation ccc
Consultancy costs ccc
Site work Bank regrading ccc
Rock weir ccc
Rock/gravel placement ccc
“toe” protection ccc
rock walls ccc/uni
Planting preparation Removal of vegetation uni/students
Preparation of ground uni/students
Planting Plants uni
Coordination students
work time students
Maintenance uni
Planting equipment uni
In-stream maintenance Rubbish collection ccc/uni
Exotic weed removal ccc/uni
willow root removal ccc
Bank maintenance Rubbish collection uni/ccc
Plant releasing / watering uni
Exotic plant removal uni/ccc
Facilities Paths/seating, litter bins uni
Bridges uni
Education University course work uni/students
Talks and walk abouts students
Advertising of events students
Information collection students
Research Research uni/student/ccc
Monitoring uni/students
Storage of Central repository for MacMillan Brown Library
26 information data/reportsResearch and Academic opportunities The University waterways have the potential to provide a valuable, immediate educational tool for University departments and students. A few of the areas that could be investigated include restoration ecology, plant identification, eco- physiological experiments, plant dispersal and succession, freshwater restoration ecology, hydrology, fish pass design and construction, urban forestry, analytical chemistry and the cultural use of urban landscapes. These issues will interest various departments including: • Plant and Microbial Sciences • Zoology • Maori • Geography • Forestry School • Chemistry • Civil Engineering • Fine Arts Specific educational opportunities for restoration • Baseline data of all relevant aspects of the restoration objectives to be collected. • Establish consistent sampling techniques to ensure meaningful work in the future. • Hydrological studies such as the mapping of spring and groundwater relationships on campus could be carried out. Investigation of the hydrology of the area is a potential Masters project, though the Civil Engineering department. •A Macroinvertebrate Community Index calculated on the basis of species commonly found in a silt substrate communities could be developed. This would be a more useful method of evaluating the health of urban streams than existing methods. • Investigate ways in which trout could continue to be excluded from the Okeover Stream. • Investigate options on how best to manage silt problems, especially in Ilam Stream. 27
• Assess the sustainability of water supplementation into the Ilam Stream.
• Assess University of Canterbury waterway flood hazard in relation to restoration
proposals.
Monitoring
Monitoring is proposed to assess how the restoration project is proceeding.
Understanding needs to be obtained about how the waterway vegetation and
consequent habitat is developing. In particular, what fauna are being positively
affected. It is hoped that monitoring can be incorporated into undergraduate
University courses.
Waterway components that should be included in an annual monitoring programme
are:
• extent of bank instability
• qualitative surveys of birds present
• semi-quantitative surveys of aquatic macro-invertebrates using kick nets
• target set areas with riffles and those areas sampled in Christchurch City
Council surveys
• use Macroinvertebrate Community Index and species richness
• note dominant invertebrates
• qualitative survey of riparian vegetation regeneration
• include species dispersal mode and distance to possible parent
• qualitative survey of native fish using electric fishing techniques
• qualitative survey of terrestrial insects
The Macroinvertebrate Community Index (Stark 1985) is a descriptive statistic
which allows community compositions to be evaluated. Taxa present are evaluated
on the basis of their proposed pollution tolerance and given a scored from one
to ten (10 being pollution intolerant species). This index is based on gravel
substrate and is affected by sedimentation.
In addition specific monitoring needs to be undertaken regarding the Ilam stream
proposals. Oxygen levels in the Ilam Stream will need to be monitored regularly
during summer. This is essential to ensure that the supplementation of flow is
enough to maintain life in the stream. This will be difficult to achieve without using
an oxygen probe. Waiting until the stream looks stagnant will not be sufficient
monitoring.
28Recommendations
The following recommendations are made for the consideration of all partners
involved in this preliminary plan, including the University staff, its student body,
and Christchurch City Council staff.
Partnership Plan
1. A meeting is held in May 1998 between the University of Canterbury staff,
students and Christchurch City Council to discuss the Partnership Plan,
particularly its issues, proposals and recommendations.
2. Submissions are called on the Plan by 30 June 1998, to be incorporated by
the author. Post submissions to Waterways and Wetlands Team, Christchurch
City Council, PO Box 237, Christchurch.
3. The Partnership Plan is endorsed by 31 July 1998 by the three key partners,
University Staff, students and Christchurch City Council.
Roles, Responsibilities
and Budgets
4. Roles and responsibilities for the waterways are clarified between the key
partners, by 31 July 1998.
5. Budgets are allocated by each partner in response to implementing the Plan by
31 July 1998. (Note student budget is likely to be given “in kind”.)
Key Issues
Key issues that require attention are:
6. Immediate need for all partners to target the removal of plant pests within
the grounds.
7. Native regeneration should be protected and restoration projects should
continue on campus.
8. Aim to reinforce wildlife corridor between Riccarton Bush and university
waterways to Waimairi Road.
Future Plans/data
Collection
9. The Preliminary Partnership Plan is developed further into a more detailed
ten-year management plan between the University of Canterbury, its students
and the Christchurch City Council by July 1999.
10. Data collection, technical reports, and a plan for maintenance of the waterways
are developed by the University of Canterbury, held at the McMillan Brown
Library, starting immediately.
29APPENDIX: Weeds/Plant Pests
Plant pests known to be present in Canterbury as at April 1, 1996. Contact Canterbury Regional Council
for more information. Common Name Scientific Name
Common Name Scientific Name Privet—Chinese Ligustrum sinense
All Stipa (except natives) Stipa spp. Privet—Tree Ligustrum lucidum
Banana Passionfruit Passiflora mollissima Sagittaria Sagittaria graminea ssp. platyphilla
Passiflora mixta Senegal Tea Gymnocoronis spilanthoides
Barberry Berberis glaucocarpa Sheeps Bur Acaena agnipila
Bathurst Bur Xanthium spinosum Smilax Asparagus asparagoides
Blackberry (wild aggregates) Rubus fruticosus agg Spanish Heath Erica lusitanica (excluding double flowered
Blue Morning Glory Ipomoea indica cultivars)
Blue Passion Flower Passiflora caerulea Spartina Spartina spp.
Boneseed Chrysanthemoides monilifera St Johns Wort Hypericum perforatum
Boxthorn Lycium ferocissimum Sweet Briar Rosa rubiginosa
Buddleia Buddleja davidii (excluding hybrids) Sweet Pea Shrub Polygala myrtifolia (excluding cultivar
Burdock Arctium minus “Grandiflora”)
Cape Honey Flower Melianthus major Tuber Ladder Fern Nephrolepsis cordifolia
Cape Ivy Senecio angulatus Tutsan Hypericum androsaemum
Cathedral Bells Cobaea scandens Variegated Thistle Silybum marianum
Cotoneaster Cotoneaster glaucophyllus Velvet Groundsel Senecio petasitis
Cotoneaster franchetii Wild Ginger Hedychium gardnerianum
Elaeagnus Elaeagnus x reflexa Hedychium flavescens
German Ivy Senecio mikanioides Yellow Archangel or Galeobdolon luteum
Goats Rue Galega officinalis Artillery Plant
Hawthorn Crataegus monogyna or Aluminium Plant
Heather Calluna vulgaris (excluding double Yellow Flag Iris pseudacorus
flowered cultivars)
Hemlock Conium maculatum
Himalayan Honeysuckle Leycesteria formosa
Horsetail Equisetum arvense
Italian Buckthorn Rhamnus alaternus
Japanese Honeysuckle Lonicera japonica (including cultivars
but not hybrids)
Scientific Name
Japanese Spindle Tree Euonymus japonicus
Oxygen Weed Lagarosiphon major
Lantana Lantana camara var. aculeata
(Yellow-Pink and Yellow-Red varieties)
Lodgepole Pine Pinus contorta Above and below:
Madeira Vine or Anredera cordifolia Yellow flag iris—it may be pretty, but it’s
Mignonette Vine spreading and smothering stream margins.
Mexican Daisy or Erigeron karvinskianus
Seaside Daisy
Moth Plant Araujia sericifera
Nardoo Marsilea mutica
Pampas Grass Cortaderia selloana
Cortaderia jubata
Perennial Nettle Urtica dioica
Phragmites Phragmites australis
Plectranthus Plectranthus ecklonii
Plectranthus ciliatus
Plectranthus grandis
Plumeless Thistle Carduus acanthoides
30References
Canterbury Regional Council, Christchurch City Council, Department of Conservation.
1992. Avon and Heathcote Catchment, Rivers and Estuary: Issues and
Options for managing these resources. Report R92/32.
Regional Council. Investigating Officers Report: Application to discharge air
conditioning cooling water into Okeover Stream, at a mean daily rate of 3.7
lit/sec and up to a maximum daily rate of 30 lit/sec, at or about map
reference M35:763–427. Consent Number: CRC961874.
Carroll, K. D. Robb, J. A. 1986. A Botanical survey of rivers in the metropolitan
Christchurch area and outlying districts: The Avon, Heathcote and Styx rivers
and their tributaries. Christchurch Drainage Board.
Eldon, G. A., Kelly, G. R. 1992. Fisheries survey of the Avon river, 1991–1992,
New Zealand Freshwater fisheries miscellaneous report no.118.
Fowles, C. 1969. A study of substrate fauna relationships in the Ilam Stream.
Unpublished M.Sc. project, University of Canterbury, New Zealand
Lamb, Robert, C. 1981 From the Banks of the Avon: The story of a river. Reed.
Wellington..
Lucas, D., & Meurk, C. 1995. Indigenous Ecosystems of Otautahi Christchurch.
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Canterbury Regional Council.
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