Waterways

Parks

Restorations

Okeover Stream

University of Canterbury, Christchurch

Background

In the 1970's the University of Canterbury established its Ilam campus. The extensive campus encompasses three waterways, the Avon and Ilam rivers, and Okeover Stream. The university gardens have become internationally renowned but the campus waterways have slowly degraded.

The Okeover Stream, identified as having high restoration potential, has also experienced the greatest pressure from university activities. Hydrological changes have included the reduction of ground water springs and an increase in artifical inputs, such as carpark runoff and air conditioning output. Extensive siltation and low in stream heterogeneity due to adjacent development (for example installation of large stream side buildings) and the use of traditional maintenance methods has lead to a decline in the richness of macroinvertebrate species.

An exciting new restoration project was initiated in 1997. Ecological landscape treatments and the manipulation of velocity have increased habitat. Riparian vegetation was restored and aquatic plants allowed to regenerate, while natural processes of sediment and debris accumulation were encouraged. The result has been immediately visible and has transformed an overlooked landscape feature into a natural environment enjoyed by the community. Annual monitoring is conducted to document the response of waterway species as habitat improves.

Partnerships

The work was acheived in partnership with the following teams:

Christchurch City Council: Rachel Barker, Jeff Weston, Howard Simpson, Brian Keown and Hunter Morton.

University of Canterbury student groups: Leanne O'Brien, Kakariki and FERG.

University staff: Daryl Cone and Facilities Management.

Project details

Project started:	1997
Area/size:	800 m Clyde to Ilam Roads
Costs:	Christchurch City Council.- planting, design and restoration costs (construction and plant supply). University - shared construction costs (Engeneering Pond) and plant supply. Kakariki - planting and plant supply.
Plants:	Many species of ecosourced wetland, kahikatea swamp forest and dry terrace plants have been located and established in natural associations.
Maintenance and monitoring:	University and Karariki - plant establishment. University - grass mowing and routine stream maintenance. Christchurch City Council - aquatic vegetation and litter control. Freshwater Ecology Research Group (FERG) - monitoring.
Stream flows:	Spring fed, storm water and air conditioning discharge. Summer low flow is maintained by air conditioning discharge.
Construction:	Basalt rock, gravel, geotextile and wetland margin planting have been used to control bank erosion and slumping. Boulders, sunken kahikatea and totara logs, gravel islands and beaches have been used to improve low in-stream heterogeneity and habitat diversity by manipulating channel width, water level and flow velocity. A 600mm deep rock lined sediment trap has been excavated on the upper stream-bed to assist in protecting the restored reaches from further sedimentation.

Results

Ecology:	Habitat heterogenity increased, riparian vegetation restored and aquatic plants now starting to thrive.
Heritage:	Natural heritage of the stream restored.
Culture:	Harvesting of water-cress is occuring, while cultural harvesting of harakeke (flax) is encouraged and provided for, adjacent to the Maori Department.
Landscape:	Enhanced landscape quality. Natural process expressed. Recognition of Okeover Stream as an important element to the campus landscape character and identity.
Recreation:	Enriched stream experience enjoyed by campus community.
Drainage:	Drainage values improved.