Kaʻū Water Systems +
Hydroelectric Energy
Water is a precious resource that was carefully used by ancient Hawaiians to sustain life. The Olson Trust works to maintain respect for water by protecting forests, improving existing systems, and generating clean energy.
Olson Trust Land Manager, John Cross, in the Kaʻū forest inspecting restored water flume system. Photo: Elyse Butler
History of Water in Kaʻū
The district of Kaʻū is larger than the island of Oʻahu, yet has no ever-flowing river or stream. Stream flow is a flash event, due to excessive rain. Springs exist across the district at high-elevation perched sources or at the ocean's edge. The daily recharge rate of the ground water of Kaʻū is estimated in the realm of billions of gallons per day. Kaʻū having the geology of Pāhala ash clay layers, stratified over and between porous lava flows, made for a unique water resource. This was captured by horizontal ash bed tunnels bored by the sugar plantations starting at the turn of the century and progressing through the late 1920s.
The upland springs in the Kaʻū forest provide the water for the agriculture growing below.
Restored Water Systems
Deep into the pristine native forest reserve, above Wood Valley, Kaʻū, parts of a water supply system have lain abandoned since the sugar plantations closed. The origins of the water system dates back to early plantation days in the late 1890s to 1930s. In recent years, crews from the Olson Trust restored several USGS horizontal ash bed tunnels in this area. Carved through solid rock and layers of volcanic ash, these tunnels meander underground for lengths of 2,000 feet (about 609.6 m) and more. Descending from elevations as high as 3,500 feet (about 1.07 km) crossing small ravines and ridges, the open flumes and wooden trestles were difficult to maintain. The system is now restored and maintained to provide water to the farmlands and farmers of Ka’ū, supply the Ka’ū Coffee Mill, and double as a hydroelectric resource. A 12-inch pipeline has replaced old leaking flumes for history to connect with the future and agriculture to continue throughout, while materials have been recycled and reused whenever possible.
Kaʻū Hydroelectric Plant
Completed in 2023, the 3.5 million dollar water systems and hydroelectric project took 12 years to build. The system is now operational, and Ka’ū Coffee Mill grows, mills, roast, and serves coffee using renewable energy. Any extra energy is utilized by other onsite projects such as an ice and refrigeration facility, aquaculture ponds, and a proposed timber sawmill. This provides clean, sustainable energy, without the harmful emissions of fossil fuels.
The tailwater reservoir from Kaʻū hydroelectric plant is used for agriculture, the Kaʻū Coffee Mill, and has been the home to several native waterfowl species.
Native Hawaiian Birds at Kaʻū Reservoir
The tailwater reservoir from the hydroelectric power plant has been the home to several native waterfowl species. Flocks of Nene geese reside and rear their young there. The endangered A’eo (Hawaiian Stilt) have called on the reservoir as their home as well. A breeding pair showed up and raised two chicks to fledge age. These birds were only the second successful breeding pair in all of East Hawaii. The family of four now travel to other estuaries in Kaʻū like Honuʻapo or Nīnole, but they always visit the hydro-reservoir at least once a month.
Our Work
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Agriculture
Sustainable agriculture aims to take care of the land and the land provide local food for our communities.
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Land
With the end of the sugar cane industry in Hawai’i, Edmund C. Olson was able to secure thousands of acres for agriculture and conservation.
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Energy
Olson Trust seeks to invest in and develop clean energy for Hawai’i. Current projects generate hydroelectric and solar energy.