Pacific Islands Water Science Center
KALO WATER USE
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Water Use of Wetland Kalo Cultivation in West Maui, Hawai'i, 2010
In recent years, competition in Hawai'i over limited surface-water resources has led to contested-case hearings and other proceedings to resolve disputes over the availability of water. Wetland kalo, or taro (Colocasia esculenta (L.) Schott), is a vital part of the cultural and agricultural traditions of Native Hawaiians. Thus, quantifying water use for kalo cultivation is a critical component for establishing instream flow standards and resolving legal disputes over water in Hawai'i. Closely associated with water use for kalo cultivation is water temperature. A temperature of 27°C is cited as the threshold temperature above which wetland kalo is more susceptible to fungi such as Pythium root and corm rot (fig. 1) and other diseases (Gingerich and others, 2007; Ooka, 1994).
This study complements information collected from other sites in Hawai'i by (1) documenting current water use for selected kalo lo'i (shallow, watery terraces and pondfields), and (2) monitoring the variation in inflow and outflow water temperatures of selected kalo lo'i. Three kalo cultivation areas in west Maui, Hawai'i were selected for this study: Kaua'ula, Honokōhau, and Olowalu (fig. 2; table 1).
This study was conducted in cooperation with the County of Maui Office of Economic Development. Access to the lo'i, and information about the irrigation systems and farming practices were graciously provided by Charlie Palakiko of Kaua'ula, Kekai Keahi and Willy Wood of Honokōhau, and John Duey of the Olowalu Cultural Reserve.
Figure 1. The effects of pythium root and corm rot in kalo are stunted growth and rotted corms. Shown in the middle is a healthy kalo plant and on the two sides are examples of rotted kalo plants, Kaua'ula lo'i complex. Photograph courtesy of Kekai Keahi.
Figure 2. Location of study sites, west Maui, Hawai'i.
Table 1. Measurement stations in west Maui, Hawai'i.