The West Arm of Doubtful Sound is also the location of an underground power station that was built in the late 1960s to supply energy for an aluminium smelter (!) near Invercargill. The idea behind the project was to use the 167 meter difference in altitude between Lake Manapouri and Deep Cove near the ocean.
All that was needed for this project was a tunnel dug through the mountain to allow the water drop down these 167 meters to drive turbines. The project was heavily opposed then because the initial plan was to raise the water level of Lake Manapouri by 40 meters. The protest against destroying such a jewel of natural beauty for producing aluminium was so massive that this plan was dropped and a compromise was found.
The power station was indeed built, however without raising the level of the lake. Moreover, most of the “works” are underground. The power plant now has even become a major tourist attraction. Parts of the power station are of course noticeable when you approach West Arm, but it definitely is not disrupting the scenery or a real bang in the eye.
So, this is the living proof that reasonable economic development can be achieved with the utmost concern for the environment!