In pre-Captain Cook times, kalo (taro) played a vital role in Hawaiian culture. It was not only the Hawaiians’ staple food but the cultivation of kalo was at the very core of Hawaiian culture and identity.
Taro can be cultivated by two very different methods. Upland, or dryland, taro is planted in non-flooded areas that are fed by rainfall. Lowland, or wetland, taro is grown in water-saturated fields.
The early Hawaiians probably planted kalo in marshes near the mouths of rivers. Over years of progressive expansion of kalo lo‘i (flooded taro patches) up slopes and along rivers, kalo cultivation in Hawai‘i reached a unique level of engineering and sustainable sophistication.
Kalo lo‘i systems are typically a set of adjoining terraces that are typically reinforced with stone walls and soil berms. Wetland taro thrives on flooded conditions, and cool, circulating water is optimal for taro growth, thus a system may include one or more ʻauwai (irrigation ditches) to divert water into and out of the planting area. (McElroy)
Most important in the system of distribution of water for application to the soil were the main ditches diverting the water from natural streams. Each of these large ʻauwai was authorized and planned by the King or by one or more chiefs or konohiki whose lands were to be watered thereby, the work of excavation being under the direction of the chief providing the largest number of men. (Perry, Hawaiʻi Supreme Court)
The ʻauwai construction and maintenance formed foundations around which an entire economy, class system, and culture functioned. The ʻauwai, lo‘i and the taro plant’s mythical and spiritual connections in Hawaiian society influenced individual and social activity within the ahupua‘a. (Handy, HART)
Taro cultivation affected many aspects of Hawaiian life: the labor required to build and maintain the ʻauwai; the shared water rights; and tributes to the Mō‘ī and to the chiefs (Ali‘i.) (Handy, HART)
All ʻauwai had a proper name, and were generally called after either the land, or the chief of the land that had furnished the most men, or had mainly been instrumental in the inception, planning and carrying out of the required work. All ʻauwai tapping the main stream were done under the authority of a konohiki of an ahupuaʻa. (Nakuina, Thrum)
ʻAuwai were generally dug from makai – seaward or below – upwards. The konohiki who had the supervision of the work having previously marked out where it would probably enter the stream, the diggers worked up to that point.
The different representatives in the ahupuaʻa taking part in the work furnished men according to the number of kalo growers on each land. (The quantity of water awarded to irrigate the loʻi was according to the number of workers and the amount of work put into the building of the ʻauwai.)
Dams that diverted water from the stream were a low loose wall of stones with a few clods here and there, high enough only to raise water sufficiently to flow into the ʻauwai, which should enter it at almost a level. No ʻauwai was permitted to take more water than continued to flow in the stream below the dam (i.e. no more than half.)
Use of the water was regulated by time increments, which varied from a few hours each day for a small kalo patch to two or three days for a kalo plantation. By rotation with others on the ʻauwai, a grower would divert water from the ʻauwai into his kalo. The next, in turn, would draw off water for his allotted period of time. (KSBE)
The ʻauwai primarily existed to support taro cultivation. Other crops, such as sweet potatoes, bananas or sugar cane, were regarded as dry land crops dependent on rainfall. Sugar cane and bananas were almost always planted on loʻi banks (kuauna) to receive moisture seeping through. (Nakuina, Thrum)
ʻAuwai varied in size and structure depending on the number and size of lo‘i they irrigated. In smaller lo‘i, water could be directed from one terrace into the next below it. However, larger lo‘i required individual ʻauwai capable of carrying more water. In more complex systems, these might be branches from another ʻauwai, often connected to the same source. (HART)
An early description of ʻauwai is from explorer Nathaniel Portlock, noting the Kauaʻi ʻauwai in 1787, “This excursion gave me a fresh opportunity of admiring the amazing ingenuity and industry of the natives in laying out the taro and sugar-cane grounds; the greatest part of which are made up on the banks of the river, with exceeding good causeways made with stones and earth, leading up the valleys to each plantation; the taro beds are in general a quarter of a mile over, dammed in, and they have a place on one part of the bank, that serves as a gateway.”
“When the rains commence, which is in the winter season, the river swells with the torrents from the mountains, and overflowed their taro-beds; and when the rains are over, and the rivers decrease, the dams are stopped up, and the water kept in to nourish the taro and sugar-cane during the dry season; the water in the beds is generally about one foot and a half, or two feet, over a muddy bottom … the taro also grows frequently as large as a man’s head.”
Another early description of ʻauwai and loʻi is from Otto von Kotzebue, a Russian naval officer who was in the Islands in 1816, “The artificial taro fields, which may justly be called taro lakes, excited my attention. … I have seen whole mountains covered with such fields, through which water gradually flowed; each sluice formed a small cascade which ran … into the next pond, and afforded an extremely picturesque prospect.”
The burden of maintaining the ditches fell upon those whose lands were watered; failure to contribute their due share of service rendering the delinquent hoaʻāina (tenant) subject to temporary suspension or to entire deprivation of their water rights or even to total dispossession of their lands. (YaleLawJournal)
In some ʻauwai, not all of the water was used; after irrigating a few patches the ditch returned the remainder of the water to the stream. (YaleLawJournal)
One notable ʻauwai, with water still flowing through it (however, the loʻi kalo is long gone) is in Nuʻuanu. After damage to the ʻauwai system during the battle of Nuʻuanu, Kamehameha moved to quickly restore the valley’s agriculture production, summoning Kuhoʻoheiheipahu Paki to rebuild the irrigation system.
“(I)n three days, (Paki) rallied several hundred men to construct the tremendous Nuʻuanu irrigation system which supplies the numerous pondfields (from Luakaha, near Kaniakapūpū to around what is now Judd Street) …this irrigation system is known even today as the Paki ʻauwai.” (Hawaiʻi Legislature)
Among other loʻi along its course, Paki ʻAuwai served the loʻi kalo of Queen Emma at Hānaiakamālama (the Queen’s Summer Palace.)
The image shows a portion of the rock-lined Paki ʻAuwai in Nuʻuanu (just below Kaniakapūpū (you take the same trail to see each.)) In addition, I have added other related images in a folder of like name in the Photos section on my Facebook and Google+ pages.