RESTORATION DESIGN AND MONITORING

AVON RIVER PRECINCT, NORTH FRAME AND EAST FRAME ANCHOR PROJECTS
Helping rebuild Christchurch's CBD

EOS Ecology is responsible for the ecology components of the Te Papa Ōtākaro/Avon River Precinct (ARP) (a 3.2 km stretch of urban river promenade running through Christchurch’s CBD area), and the North/East Frame anchor projects (a 12 ha mixed-use development area bordering the east and north side of the CBD), which form a key part of Christchurch’s CBD rebuild following the 2011 earthquakes. As part of the successful Opus-led design consortium, we commenced the concept design phase in January 2013 and completed the detailed design work in November 2014.

We were tasked with ensuring ecology was a cornerstone of the design process. Our aim: to improve the health of the Avon River corridor, and by doing so bring back life to the CBD. Our philosophy: healthy river = healthy people.

Through our in-depth understanding of ecological principles and how they can integrate with urban and landscape design, along with our knowledge of the past and present ecology of the river and Christchurch landscape, we were able to provide key ecological design criteria needed to improve aquatic and terrestrial health, all the while enabling the creation of an outdoor multi-use space, so essential to a modern city.

IN-RIVER WORKS PACKAGE

A separate in-river works package was created following the concept design phase of the ARP, with a specific focus on improving health and mahinga kai values of the Avon River through the CBD. We were tasked with leading the programme, undertaking the developed and detailed design phases and overseeing construction.

Requiring an inherent understanding of waterway ecology and hydrology, our designs focused on not only improving habitat but also restoring essential river processes to ensure greater ecosystem functionality and reduced long-term management costs.

Our presence in the river during the construction phases ensures that the ecological designs developed on paper are realised on the ground. Developing methods for gravel cleaning, on-site training and education of construction personnel, and continual oversight of the in-river construction are all part of our daily job.

The in-river works package started with Watermark (the first 225 m of river revitalisation that was officially opened on the 29 August 2013), followed by Phase 1 (completed May 2014) and Phase 2 & 3 (started in October 2014).

HALSWELL RIVER RIFFLE HABITATS
Service Areas: Restoration Design and Monitoring, Ecosystem Health Assessment

Longfin eel/tuna are a culturally significant fishery of the Te Waihora/Lake Ellesmere but juvenile rearing habitat is in short supply. Creation of habitat suitable for the juvenile stage of this at risk species is a key focus area for Whakaroa Te Waihora, particularly in one of the major tributaries, the Halswell River. Our design and construction oversight of two riffle habitat sections in the Halswell River will primarily provide key habitat for juvenile longfin eels, but also enhance aquatic values for other biota and improve river processes and riparian functioning.

Our design programme, driven first and foremost by ecology, requires a firm grounding in waterway design and restoration, and an understanding of the hydrologic and ecological state of the system – the key reasons why EOS was tasked with this project.

AVON RIVER PRECINCT LONG-TERM MONITORING
Service Areas: Restoration Design and Monitoring, Ecosystem Health Assessment, Aquatic Sample Processing, Urban Ecology

There is growing concern in the global restoration community about the lack of good monitoring of waterway enhancement programmes. Given the importance of Te Papa Ōtākaro/Avon River Precinct to Christchurch and its size (one of the largest urban river enhancement programmes currently being undertaken in New Zealand), EOS Ecology committed their own time and resources to develop and implement a robust and scientific monitoring programme, covering four key aspects of river ecology: habitat, fish communities, invertebrates, and trout spawning and egg survival.

The monitoring programme is designed to fully elucidate what interventions do and don’t work in terms of habitat and key species improvements. We plan to publish our findings designed to contribute to the global knowledge-base on restoration ecology.

NO. 2 DRAIN RESTORATION
Service Areas: Restoration Design and Monitoring, Ecosystem Health Assessment, Aquatic Sample Processing, Resource Consent Monitoring

EOS Ecology was engaged to investigate the restoration potential of a boxed drain running through one of Christchurch’s northern suburbs.

Aware of an isolated population of bluegill bullies rarely found in Christchurch, scientists at EOS worked closely with the client’s landscape architects and engineers to design a channel that would enhance the bluegill’s habitat. Balancing these habitat requirements with the need to provide for inline stormwater treatment, future urbanisation in the upper catchment, and the riparian vegetation restrictions in the adjacent golf course were also key considerations for the design. The EOS team are currently involved in post restoration surveys to determine the success of this restoration; early indications are promising.

MCCORMACKS BAY HEALTH ASSESSMENT
Service Areas: Restoration Design and Monitoring, Ecosystem Health Assessment, Aquatic Sample Processing, Urban Ecology

With plans in place to modify the three culverts that drain McCormacks Bay, there are hopes that these modifications may restore a more natural tidal cycle to the Bay and thereby reduce excessive sea lettuce growth. Commissioned by the Christchurch City Council, EOS Ecology has designed a monitoring programme for the Bay that will examine any changes in the benthic fauna, sediment, and macroalgae as a result of changes to the culverts and tidal flushing cycles.

Building on previous work the EOS team has undertaken in the Bay, the findings from this programme will form the ‘before’ data against which to monitor changes that may occur as a result of the improvements to the culverts. The EOS team carried out the field survey in June 2010 and upon completion of the laboratory work will produce a report on this baseline data for the Council and community.