The crystal clear waters of Waianu Stream, a tributary of Waiahole Stream, are decorated by pink impatiens, yellow kukui leaves, and green swordtail and hoio ferns. Photo from HawaiianForest.com

Local greens on the menu need water from Oahu’s streams

HONOLULU—The Waiahole Ditch water system was completed in 1916, and diverted nearly 30 million gallons of fresh water from the Koolau Mountains and Windward Oahu watersheds to the Ewa Plain for irrigation purposes. It is a 25-mile system of collection tunnels and ditches that stretch from the mountains of Kahana to central Oahu. Built by the Oahu Sugar Company, the tunnel effectively deprived many Windward farmers of access to water they enjoyed for generations.

Surprisingly, all that is needed to divert water from the Windward Oahu to the Ewa plain is a seven-foot by seven-foot wooden gate.

Due to the characteristics of Leeward Oahu, the sugar industry built the Waiahole Irrigation System, in order to provide water to their crops. Over time, smaller farms and ranches, focusing on diversified agriculture, emerged utilizing the same irrigation system that the sugar plantations constructed and employed.

Although the Oahu Sugar Company shut down in 1995, water from the Waiahole Ditch remains a vital part of agribusiness in both Windward, Central, and Leeward Oahu.

Following contentious legal battles over the allocation of water, about half of the water from the Waiahole Ditch has been returned to Windward Oahu, fostering a resurgence of farming in places like Waikane, Waiahole, and Kahana.

East vs. West


One cause of continuing conflict on Oahu is that parties from the Windward side want to see water diverted through the Waiahole Ditch returned to streams in Windward Oahu, while Leeward Oahu farmers require the water to sustain their crops. The Water Commission tried to resolve the dispute through a contested case hearing, but their decisions have resulted in appeals and cross appeals to the State of Hawaii Supreme Court. 

The case arose from the efforts of small family farmers and Native Hawaiians, led by citizen groups Hakipuu Ohana, Ka Lahui Hawaii, Kahaluu Neighborhood Board, Makawai Stream Restoration Alliance and a coalition of supporters (collectively the “Windward Parties”), to restore streams originally diverted by Central Oahu sugar plantations. The Windward Parties sought to return diverted flows to the streams to restore native stream life, such as `o`opu, `öpae and hïhïwai; protect traditional and customary Native Hawaiian practices; support the productivity of the Kaneohe Bay estuary; and preserve traditional small family farming, including taro cultivation.

Large scale agricultural and development interests, including Campbell Estate, Robinson Estate, Kamehameha Schools, Dole/Castle and Cooke, and others, joined by the State, pushed to continue the flow of Windward water to Leeward lands to subsidize golf course irrigation, short-term corporate agriculture, and housing development.

After seven months of administrative hearings, the Water Commission issued its first decision in 1997, which both the Windward and Leeward parties appealed to the Hawaii Supreme Court.  The Windward Parties argued that not enough water had been restored to the streams, while Leeward interests complained that too much water had been returned. In August 2000, the Hawaii Supreme Court issued a landmark decision in the first appeal. Although the Court acknowledged the Commission’s efforts at stream restoration, it vacated the Commission’s decision and sent the case back to the Commission.

In October 2010, the State appeals court rejected two of three claims by Windward Oahu interests to restore more water to Windward streams, upholding most of a 2006 decision by the Commission on Water Resource Management regarding the allocation of Waiahole water, which provided roughly equal amounts to Windward and Central Oahu.

The price of water


Another issue surrounding the use of Waiahole water involves the cost of water use. In 1999, the Agricultural Development Corporation (ADC) purchased the Waiahole Irrigation System.

ADC’s mission is to acquire, and manage in partnership with farmers, ranchers, and aquaculture groups, selected high-value lands, water systems, and infrastructure for commercial agricultural use. The corporation also directs research into areas that will lead to the development of new crops, markets, and lower production costs.

ADC charges a user fee for water from Waiahole, which is used to pay off their debt from the acquisition of the irrigation system. In comparison with State run and privately run irrigation systems, water from State run systems is cheaper than water from Waiahole by approximately $0.10 per 1,000 gallons. However, water from private irrigation systems can run anywhere from five to eight times as much as water from State run systems, and four to five times as much as water from Waiahole. Add in service and meter charges and the cost rises substantially, which can have a negative impact on businesses.

To read the State’s “Economic Impact of the Waiahole Irrigation System,” click here

In Central Oahu, thousands of jobs are attributed to water from the Waiahole Ditch.

Thirty percent of land on Oahu is classified as agricultural, 22 percent of which is in Central Oahu. The number of jobs generated by businesses that utilize Waiahole water exceeds 2,000. In a 2002 report, the State Department of Agriculture estimated the amount of revenue generated by those businesses at $95 million.

Of the over 12 million gallons of water that flow from the Waiahole Ditch to Central Oahu, the Monsanto Company, the world leader in genetically engineered seed and bovine growth hormone production, receives 2.63 million gallons per day for its 2,052 acres. Robinson Kunia Land receives 2.39 million gallons per day for 995 acres. Dole/Castle & Cooke/Robinson receive 2.13 million gallons for 1,459 acres. Five other permits are issued to smaller entities that use the water for diversified agriculture and irrigation purposes.

Some of the water is permitted for research purposes, as with the Hawaii Agricultural Research Center. Non-agricultural permits are used by others, including the Mililani Golf Course, Mililani Memorial Park, and the Waiawa Correctional Facility.

Future of water on Oahu


While farmers and lawmakers recognize the agricultural potential of areas such as Oahu’s North Shore, the kinds of fruits vegetables that can be grown are limited due to water quality.

In an interview with North Shore Rep. Gil Riviere (R) on Olelo, Susan Matsushima, chief executive of Alluvion farm, talked about finding a way to tap into the Wahiawa Reservoir/Lake Wilson to irrigate farms on the North Shore.

Currently, water that reaches the North Shore through plantation era irrigation is of R-2, a lower grade than required for low-lying vegetables. Hawaii uses three categories of recycled water: R-1, R-2, and R-3. Water from R-2 recycled water has a slightly lower quality relative to R-1 recycled water and must be oxidized and disinfected to meet Hawaii’s requirements for various uses. R-2 recycled water can only be used under restricted circumstances where human contact is minimized.

While Matsushima and legislators are looking at new ways to recycle water and get water to Oahu’s farmers, Riviere said there must first be a commitment established to the farmers themselves.

In order for farmers on Oahu to be able to develop a successful business model, Riviere explained, there needs to be consistent support for getting sufficient water there that will produce crops that are safety certified.

“There seems to be so many moving parts here,” Riviere said. “If we can get the fresh water, get more farmers on the land, get more fresh crops, then there needs to be a committment ... to deliver and to deliver consistently. And then they’ll have a business that could be promoted and worked with [by local chefs].”

Local restaurants are enthusiastic about using locally grown fruits and vegetables. However, safety certification (which protects our public health from contaminated food) on Oahu is hard to come by for many local farmers. And without the right water, in quality or quantity, no amount of enthusiasm is going to make our local farms into sustainable businesses.

Stay tuned to The Hawaii Independent for coverage on Hawaii’s new farmers and the next generation of restauanteurs.

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