Restoring the Waterways within the University of Canterbury - A Partnership Plan: Analysis and Preliminary Proposals May 1998

 
Restoring the
 Waterways
 within the
University of
 Canterbury

  A Partnership Plan:
Analysis and Preliminary
       Proposals

      May 1998
Restoring 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

                                                  1
Contents                                                     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.

                                                                                                               3
Administrative/
    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

                                                                                                        5
Background 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.                                                                                       7
Currently 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 the
combined 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

                                                                                                               9
which 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. ៉

10
Native 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.
                                                                                                          11
Ecological 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. ៉

12
Stagnant 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.

14
General 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.                                                                                   15
Bank 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 stream
bed, 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 maintenance
Method: 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.                                                                           21
Restoration
                              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.                                                                                             23
University 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.

                                                                                                   25
Implementation
     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/reports
Research 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.

28
Recommendations
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.

                                                                                       29
APPENDIX: 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

30
References
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     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
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Eldon, G. A., Kelly, G. R. 1992. Fisheries survey of the Avon river, 1991–1992,
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Fowles, C. 1969. A study of substrate fauna relationships in the Ilam Stream.
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Robb, J. A.. 1980. A Biological Survey of Rivers in the Metropolitan Christchurch
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