MAUI ISLAND

Maui, the second largest Hawaiian Island, measures 77 by 42 km at its extreme dimensions and has an area of about 1,886 km2. Puu Kukui, West Maui, emerged in part from the ocean in the Pliocene and early Pleistocene. Haleakala, East Maui, emerged in the early and middle Pleistocene with renewed volcanic activity in the middle to late Pleistocene and in recent times. West Maui, the older part of the island, rises to 1,764 m altitude and is deeply eroded. East Maui attains 3,056 m in altitude and features relatively smooth slopes on its western and northern sides.

Ninety-six perennial streams were recognized on Maui by Timbol and Maciolek (1978). Fifty-eight percent were continuous, the rest interrupted. Seven streams (7 %) were found to have altered channels, four in the Lahaina District and three in the Wailuku District. All seven channelized streams were usually dry at lower elevations because normal flows were diverted and exported from their natural drainages. Discharge to the ocean occurs irregularly, mainly during periods of heavy winter rainfall.

Iao stream, Wailuku District, is the largest of Maui's altered streams on the basis of stream length and watershed area and Kauaula Stream, Lahaina District, is the smallest. A total of 5 km of modified stream channel occurs among the seven altered streams. Modified sections of the altered streams averaged 3 % (range <1 - 11) of total stream length. The estimated percentage of the 5 km total by channel modification type was:

Cleared and realigned - 54 %

Revetment - 34 %

Lined channel - 8 %

Elevated culverts - 4 %

Aside from the 7 % channelized Maui streams, diversions were found on 59 % and road crossings on 96 % of Maui's perennial streams. Only 1 % (1 stream) of Maui streams were found to be physically pristine in the Timbol and Maciolek's study.