WRRCTR No. 43 Artificial Recharge Practices in Hawaii

Abstract

In July of 1969 the Water Resources Research Center began an investigation of artificial recharge practices in Hawaii. The objectives of this study were: (i) to compile all sites in the State where artificial recharge has been practiced, (ii) to provide quantitative information, on the amounts of water recharged, and (iii) to evaluate, where possible, the effectiveness of the various methods of artificial recharge that have been used in Hawaii. Artificial recharge practices in Hawaii include all of the following: (i) stream-water recharge through wells and shafts, (ii) storm drainage disposal through wells and pits, (iii) induced leakage from ditches and reservoirs and deliberate spreading of excess irrigation water, (iv) incidental ditch and reservoir Leakage and other nondeliberate recharge of irrigation water, and (v) cesspool seepage. The most significant source of artificial recharge to groundwater bodies in Hawaii is probably recharge incidental to irrigation. The volume of water recharged in this manner can be calculated from hydrologic budget considerations, but such calculations are limited in their reliability by a general absence of comprehensive data. Seepage from cesspools has probably contributed significant amounts of recharge to ground-water bodies in Hawaii and these amounts can also be determined by hydrologic budget considerations. Deliberate artificial recharge to ground-water bodies in Hawaii consists of wells recharging stream water at Hanapepe, Kauai and Puukapu, Hawaii, welts and pits which dispose of storm drainage at Wailuku and Kahului, Maui and Hilo, Hawaii, and excess irrigation water by induced Leakage from ditches and reservoirs and water spreading over fields and in gulches at Hawaiian Commercial and Sugar Company on the East Maui isthmus. In addition, the Department of Land and Natural Resources of the State of Hawaii will begin disposal of treated sewage through three deep wells at Waimanalo, Oahu as soon as sewerage is completed.