East Maui Irrigation System

At the time of Haiku Sugar Company's charter in 1858, there were only ten sugar companies in the Kingdom of Hawaiʻi.  Five of these sugar companies were located on the island of Maui:  East Maui Plantation at Kaluanui; Brewer Plantation at Haliʻimalie; LL Torbert and Captain James Makee's plantation at Ulupalakua; Haiku Plantation; and Hana.

In 1871, Samuel T Alexander became manager of the Haiku mill on Maui.  Alexander and his partner, Henry Perrine Baldwin, saw the need for a reliable source of water, and to this end undertook the construction of the Hāmākua ditch in 1876. 

The first part of the work was completed in the summer of 1877; the Pacific Commercial Advertiser, on July 14, 1877, noted:   “The great display of the day was at Haiku, where several hundred Natives and Foreigners assembled to celebrate the completion of the Big Ditch, and to see for themselves, the water from the mountain gushing through great iron pipes, emptying itself into the ditch, and rolling on to the valley, and spreading over the cane fields, making the earth glad with its presence. The motto, “The Grass Grows And Water Runs,” was pointed on canvas and stretched across the principal avenue; flags were flying apparently from every bush,—the Wailuku brass band was in attendance and discoursed screech music. Too much credit cannot be bestowed upon Messers. Alexander and Baldwin for their perseverance and energy in completing so great and valuable an enterprise.”  (Kuykendall)

The completed Old Hāmākua Ditch was 17-miles long and had a capacity of 60-million gallons per day.  A second ditch was added, the Spreckels Ditch; when completed, it was 30-miles long with a capacity of 60-million gallons per day.  Before World War I, the New Hāmākua, Koʻolau, New Haiku and Kauhikoa ditches were built. 

A total of ten ditches were constructed between 1879 and 1923; this system makes up what is known today as East Maui Irrigation (EMI.)

This privately financed, constructed and managed irrigation system was one of the largest in the United States.  It demonstrated the feasibility of transporting water from steep tropical forested watersheds with high rainfall across difficult terrain to fertile and dry plains.

East Maui Irrigation system consists of 388-separate intakes, 24-miles of ditches and 50-miles of tunnels, as well as inverted siphons, numerous small dams, pipes, flumes and 8-reservoirs, spanning 39 drainage basins. 

The aqueducts bring water from the steep, wet eastern slopes of Haleakalā to the fertile semi-arid central Maui plain. They provide half the irrigation water to the sugar growing area of Maui. 

Sugar production dramatically increased with irrigation and improved cultivation practices.  Sugar yields increased from 2-tons per acre to over 13-tons per acre grown with 2-year crop cycles. 

Eventually sugar production from the Islands exceeded 1.2-million tons per year, comprising the major economic sector of Hawaii for 100-years.

Over the years of the development of this system, many engineers gained experience in building irrigation systems. They used what they learned from the East Maui Irrigation System to develop other irrigation systems; EMI System was the forerunner of major aqueducts in the Western United States by the Bureau of Reclamation for irrigation districts and regional domestic supplies.  

In 2003, the East Maui Irrigation System was designated as an ASCE National Historic Civil Engineering Landmark.   It is the third National Historic Civil Engineering Landmark in the State of Hawaiʻi.  The other two landmarks are the Kamehameha V Post Office Building, dedicated in 1987, and the Red Hill Underground Fuel Storage Facility, dedicated in 1994.

Today, the EMI System conveys billions of gallons per year from high rainfall slopes on the Windward side of Haleakalā to the semi-arid region between east and west Maui for sugar cane cultivation.  In addition, some of the water diverted serves 10,000 Upcountry customers.

The issue of stream diversion, at EMI and elsewhere, however, is not simply engineering success and diversion on one part of the island to irrigate crops on another part of the island.  Taking too much from a stream can impact the stream ecosystem.

This relates to Instream Flow Standard which is “a quantity or flow of water or depth of water which is required to be present at a specific location in a stream system at certain specified times of the year to protect fishery, wildlife, recreational, aesthetic, scenic, and other beneficial instream uses.”

The technical language of the law is complicated; I simplify this to say that the instream flow standard simply allows a stream to be a stream.

Because ground and surface waters of the state are held in public trust for the benefit of the citizens of the state, the people of the state are beneficiaries and have a right to have the waters protected.

The object of the public trust is not maximum consumptive use, but rather the most equitable, reasonable and beneficial allocation of state water resources, with full recognition that resource protection and natural processes also constitute “use.”

Adequate provisions must also be made for the protection of traditional and customary Hawaiian rights, the protection and procreation of fish and wildlife, the maintenance of proper ecological balance and scenic beauty, and the preservation and enhancement of water of the state for municipal uses, public recreation, public water supply, agriculture, and navigation.  Such objectives are declared to be in the public interest.

Related to this, EMI and other diversion systems have been the subject of conflict, litigation and contested case hearings before the Department of Land and Natural Resources and the State Commission on Water Resource Management (CWRM.)  In the past few years, CWRM adopted interim instream flow standards for 27 of the EMI streams. The saga continues.

While taking water for appropriate off-stream uses, at issue with diversions are the fundamental principles of letting a stream be a stream (don't divert too much to cause ecological changes in the stream) and protection of downstream user rights (allowing downstream users to also use the water resource - especially for taro cultivation.)

I was fortunate to have served as the Chair and Director of the Department of Land and Natural Resources and the Chair of the Water Commission, working on these and other related issues.

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