Revisiting Manapouri - 50 years on

By Alan Petrie

It’s 50 years since New Zealanders launched the “Save Manapouri” environmental campaign, preventing the raising of the levels of lakes Manapouri and Te Anau as part of the construction of the Manapouri Power Project.

“Save Manapouri” became the catchcry of a generation, which culminated in a massive petition signed by 264,907 people in 1972 -  that’s about one in ten New Zealanders at that time.

The campaign was arguably the genesis of our country’s modern environmental movement, prompting the formation of activist groups like Ecology Action. More recent members of the New Zealand Institute of Landscape Architects may not be aware that several of our members - Robin Gay, George Malcolm, Jan Woodhouse and myself - were directly associated with the Manapouri Hydro Power scheme, with our skills utilised in the restoration of disturbed natural areas within the Fiordland National Park and surrounding district. 

Alan Petrie standing in front of restoration plantings at the Lake Te Anau control structure. The trees are silver beech and cabbage trees.

After graduating from Lincoln (Dip LA) in 1972 I was approached by Robin Gay, who was with the Department of Lands and Survey, to see if I would help the Fiordland National Park Board, with advice on how to reinstate areas that had been affected by the Manapouri Hydro Power scheme. I was initially hesitant - I knew how controversial the scheme was, particularly in Southland where I grew up - but eventually agreed.

It became evident that the scheme wasn’t just confined to Lake Manapouri, but was defined by geographical boundaries that spanned from Deep Cove in Doubtful Sound, West and South Arms of Lake Manapouri, both the Waiau and Mararoa Rivers, and to the south end of Lake Te Anau. It encompassed three ecological districts. 

I came to the conclusion that decisions were made quickly in relation to the scheme, with little public consultation, thanks to the all-empowering Manapouri-Te Anau Development Act 1967. In some cases field sketches and notes were literally handed to a digger operator on how the side slopes of a permanent road should be finished off, or what plant communities were intolerant to compaction from heavy machinery.

Aerial view in 1975 of the natural-looking landform that overtopped the core dam of the Lake Te Anau Control Structure.

The urgency in the completion of the project was primarily threefold: the political timetable; avoiding downtime for contractors’ expensive machinery; and a number of key MWD engineering staff were starting to relocate to Cromwell to commence investigatory work for the Upper Clutha Power Scheme.

It became clear to me that my landscape architectural skills could really only be applied on the last major construction component of the power scheme, this being the Lake Te Anau Control Structure. The power planners had already designed a geometric earth dam similar to Benmore,  to stretch between the control structure and the edge of the national park. 

A report was prepared for the Fiordland National Park board on how this area in the future would become a major gateway into the park for the public, and due to the large volume of surplus soil from the tailrace channel this could be laid over the core dam to create a natural landform that replicated the low ridgelines that descended towards the margins of the lake. It should be noted that a decade later this entrance point to the national park became the start/finish to the Kepler Track, one of New Zealand’s great walks.

The concept was endorsed by the park board, the Nature Conservation Council and the Guardians of the Lakes, and eventually accepted by the Commissioner of Works in Wellington.

In May 1973 the project engineer, Robin Gay, George Malcolm (who was working for the MWD’s Christchurch office) recruited Jan Woodhouse to help me draw up a more comprehensive set of plans.

Pulverised granite from the second Manapouri Tailrace Tunnel before being reshaped to replicate a natural debris slip.

About the same time, horticulturalist Terry Meadows was employed to establish a temporary native plant nursery (Home Creek Nursery) on the outskirts of Manapouri township to assist with the revegeation of the newly formed earth dam and additionally to help with the restoration of other areas affected by the power scheme. The species grown were confined to mainly fast growing colonisers such as manuka and tree tutu along with a small selection of hardy shrubs like Coprosma propinqua. The nursery also carried out extensive field trials on direct seeding of several woody native species.

Because of the short planned life of the nursery it was decided that a different technique wold be used for canopy species such as silver beech. During the winter of 1973 members of the Southland Branch of Ecology Action voluntarily root pruned beech saplings along the edges of Borland Pass Road. After two years the tagged saplings were wrenched and planted over the newly formed earth dam at Lake Te Anau with an almost 100 % survival rate - an instant landscape was created.