690-230-0020 Definitions (1) “Bottom hole temperature” means the maximum temperature measured in the well or borehole. It is normally attained directly adjacent to the producing zone, commonly at or near the bottom of the borehole, and will in all cases be greater than or equal to the temperature of fluid produced from the borehole. (2) “Low-temperature geothermal effluent” means the outflow, discharge or waste fluid, with its associated dissolved or suspended constituents (being original or introduced), that is produced by a low-temperature geothermal well and its utilization system. (3) “Low-temperature geothermal fluid” means any groundwater used for its thermal characteristics that is encountered in a well with a bottom hole temperature of less than 250 degrees F, or any other fluid that is circulated within a well having a bottom hole temperature of less than 250 degrees F and used for its thermal characteristics. (4) “Low-temperature geothermal injection well” means any well as defined under ORS 537.515(9) that is constructed or used for returning low-temperature geothermal effluent to a groundwater reservoir. (5) “Low-temperature geothermal production well” means any well as defined under ORS 537.515(9) with a bottom hole temperature of less than 250 degrees F that is constructed or used for the thermal characteristics of the fluid contained within. (6) “Nonstandard low-temperature geothermal effluent disposal system” means any low-temperature geothermal effluent disposal system in which one or more of the following conditions are met: (a) Any portion of the effluent is disposed of in a manner considered non-beneficial by the Director. This includes, but is not limited to, disposal via storm sewer, drainage hole or direct discharge to land surface or a surface water body; (b) The effluent contains contaminants, other than heat, that have been added to the low-temperature geothermal fluid; (c) The effluent is injected into a groundwater reservoir that is not considered suitable by the Director. Factors which may render a groundwater reservoir unsuitable include, but are not limited to, chemical or physical incompatibility of the fluids involved or adverse hydraulic characteristics of the receiving reservoir; (d) There are other existing or potential site specific problems or conditions, that require the nonstandard designation of effluent disposal. Examples include, but are not limited to, instability of near-surface earth materials, undue alteration of thermal characteristics of groundwater, unreasonable head changes or leakage of effluent back to the surface. (7) “Secondary use” means the consumption of low-temperature geothermal effluent for beneficial use including, but not limited to, domestic, irrigation, stock watering, commercial and industrial uses. (8) “Standard low-temperature geothermal effluent disposal system” means any low-temperature geothermal effluent disposal system in which one or more of the following conditions are met: (a) No contaminants other than heat, have been added to the low-temperature geothermal fluid and the effluent is put to a secondary use; (b) No contaminants, other than heat, have been added to the low-temperature geothermal fluid and the effluent is returned to the producing groundwater reservoir or other suitable groundwater reservoir as determined by the Director. In addition there are no other existing or potential problems or special conditions as determined by the Director, that include, but are not limited to, those factors, problems and conditions listed in subsections (6)(c) and (d) of this rule. Statutory/Other Authority: ORS 183, 536, 537 & 540 Statutes/Other Implemented: ORS 183, 536, 537 & 540 History: WRD 18-1990, f. & cert. ef. 12-14-90 WRD 7-1988, f. & cert. ef. 6-29-88 WRD 13-1986, f. 10-7-86, ef. 11-1-86, Renumbered from 690-065-0010 WRD 5-1986, f. 5-16-86, ef. 5-19-86 WRD 12-1982, f. & ef. 12-14-82