The Cobb Valley in the Kahurangi National Park was formed by a large glacier that left behind a steep-sided valley. The Cobb Power Station has the highest hydraulic head of any hydro station in New Zealand: the dam is nearly 600 metres higher up than the power station. The Cobb River runs through the Tasman Mountains to the dam, filling the Cobb Reservoir. It then flows through a 4-kilometre-long tunnel system to the power station, which sits at the point where the Cobb River flows into the Takaka River. The high hydraulic head means that a lot of power can be generated using only a little water. The Cobb Power Station’s output is 192 GWh each year, only a small fraction of New Zealand’s total hydroelectric power generation, but every little bit counts.
