Proceedings of the National Conference on Irrigation and Drainage Engineering, held in Honolulu, Hawaii, July 22-26, 1991. This collection contains 110 papers focusing on current and future major issues in irrigation and drainage. Topics include: surface-groundwater interactions; water quality; the vadose zone; aquifer recharge and discharge; geochemistry, computer models; canal modeling; agricultural water quality; on-farm irrigation management; hydrology in volcanic regions; and the integration of drainage into irrigation design.