Technical Memorandum Report No. 2
Hydrogeologic Aspects of Underground Effluent Disposal at Waimanalo
Doak C. Cox
February 18, 1966
ABSTRACT
It has been proposed that underground discharge of effluent from a sewage treatment plant planned at Waimanalo be substituted for discharge through a long and expensive ocean outfall. As a contribution to the determination of feasibility of underground discharge of treatment plant effluent at Waimanalo, and in accordance with an agreement reached at a meeting at the Division of Water and Land Development on 16 December, the Water Resources Research Center arranged a conference on the hydrogeologic aspects involved. The conference was held Thursday afternoon 10 February, 1966, at the University of Hawaii. In attendance were the following: Agatin T. Abbott, U.H.; Dan A. Davis, USGS; W. M. Adams, U.H.; Augustine S. Furumoto, U.H.; Stephen Bowles, BWS; Dan Lum, DOWALD; Mel Caskey, U.H.; Gordon A. Macdonald, U.H.; D. C. Cox, U.H.; Akio Ogata, USGS; Robert Dale, USGS; Leonard A. Palmer, U.H.
This memorandum report is based mainly but not entirely on the discussion at the conference. A draft was distributed among attendees for criticism, but responsibility for opinions expressed here remains with the writer, not with other attendees or the organizations they represent. In summary this memorandum includes discussions of the geology of the Waimanalo area and of the hydrology of the area. It is concluded herein that the proposal for underground effluent disposal seems reasonable and if successful would be much cheaper than the designed ocean disposal. A sequence of hydrogeologic exploration, pilot testing and ultimate development is recommended. In consideration of the magnitude and difficulty of the investigations required and the present commitment of manpower, the employment of at least one additional full-time professional hydrogeologist is recommended.