Environmental baseline study for geothermal development in Puna, Hawaii

Abstract

The Hawaii Geothermal Project, a coordinated research effort of the University of Hawaii funded by the County and State of Hawaii, as well as ERDA, was initiated in mid-1973 in order to identify and help develop geothermal energy on the Big Island of Hawaii. To develop a geothermal resource, a number of stages preliminary to production are required: exploration and selection of a site for drilling; exploratory drilling; testing to determine critical characteristics of the well or wells; and -- optionally -- operating a model plant to test output potential. By the spring of 1974 Phase I of the Project had been completed, when a site for an exploratory well was located and permission for drilling was obtained from the private corporation owning the site. After the competitive bidding process was completed, a drilling contract was awarded in November, 1975 and actual drilling began in December of last year. The drilling was completed late in April, 1976, when a depth of approximately 6,400 feet had been penetrated -- approximately 6,000 feet below sea level. A slotted liner for the bottom portion of the well was installed in June, 1976. The well flashed spontaneously on 3 July and was blown to rid it of drilling debris on 22 July 1976, after which testing of its physical properties was begun. From the beginning of the Hawaii Geothermal Project, it has been recognized that the successive steps of geothermal development starting with drilling must be carefully scrutinized to ascertain in a timely way if there would be any adverse effects on the environment and local ecosystems, and, should they occur, that it was necessary to identify and recommend measures to minimize such impacts. For this reason, in the summer of 1975, once the drill site had been selected and long before the drilling began, baseline data were collected on critical aspects of environmental conditions as they existed before any significant disturbance by the Project. These included ground water supply, air, soil and the flora, as well as the archaeology of the area surrounding the drill site. In February, 1976 the area was studied to see if it provided a habitat for birds which are endemic, or otherwise of special interest. Generally, the area examined for environmental impact lies within a circle having a radius of approximately a half mile from the center of the four-acre drill site. However, the testing of ground water included sampling wells and a spring more than a mile from the site. Additional tests of the water and air were conducted at the site in June, 1976, after the drilling was completed but before the well was blown to free it of debris accumulated during drilling. The results of that testing, along with results obtained before the drilling began, are summarized in this assessment statement. The results of the pre-drilling studies were such as to enable the University of Hawaii, under the regulations of the Hawaii Environmental Quality Commission, to issue a negative declaration concerning the exploratory hole -- i.e. that the drilling of the well seemed to pose no significant threat to the environment in the vicinity of the well site in Puna, Hawaii. It is hoped and intended that the environmental data established by this study will serve as baselines from which to measure changes which may be associated with geothermal development, not only in the area immediately neighboring the present drill site, but, with appropriate adjustments, for development which may occur elsewhere in the Puna District. How transferable the baselines may be to other areas, say other districts of the Island of Hawaii or to other islands within this archipelago, is a question which must be examined in context as further geothermal exploration is undertaken.