Section 331.2 - DefinitionsGeneral definitions can be found in Chapter 3 of this title (relating to Definitions). The following words and terms, when used in this chapter, have the following meanings.
(1) Abandoned well--A well which has been permanently discontinued from use or a well for which, after appropriate review and evaluation by the commission, there is no reasonable expectation of a return to service.(2) Activity--The construction or operation of any of the following: (A) an injection well for disposal of waste;(B) an injection or production well for the recovery of minerals;(C) a monitor well at a Class III injection well site; or(D) any other class of injection well regulated by the commission.(3) Affected person--Any person who has a personal justiciable interest related to a legal right, duty, privilege, power, or economic interest affected by the proposed injection operation for which a permit is sought.(4) Annulus--The space in the wellbore between the injection tubing and the long string casing and/or liner.(5) Annulus pressure differential--The difference between the annulus pressure and the injection pressure in an injection well.(6) Aquifer--A geological formation, group of formations, or part of a formation that is capable of yielding a significant amount of water to a well or spring.(7) Aquifer recharge project--A project involving the intentional recharge of an aquifer by means of an injection well authorized under this chapter or other means of infiltration, including actions designed to:(A) reduce declines in the water level of the aquifer;(B) supplement the quantity of groundwater available;(C) improve water quality in an aquifer;(D) improve spring flows and other interactions between groundwater and surface water; or(8) Aquifer restoration--The process used to achieve or exceed water quality levels established by the commission for a permit/production area.(9) Aquifer storage and recovery--The injection of water into a geologic formation, group of formations, or part of a formation that is capable of underground storage of water for later retrieval and beneficial use.(10) Aquifer storage and recovery injection well--A Class V injection well used for the injection of water into a geologic formation as part of an aquifer storage and recovery project.(11) Aquifer storage and recovery production well--A well used for the production of water from a geologic formation as part of an aquifer storage and recovery project.(12) Aquifer storage and recovery project--A project involving the injection of water into a geologic formation for the purpose of subsequent recovery and beneficial use by the project operator.(13) Area of review--The area surrounding an injection well described according to the criteria set forth in § 331.42 of this title (relating to Area of Review) or in the case of an area permit, the project area plus a circumscribing area the width of which is either 1/4 mile or a number calculated according to the criteria set forth in § 331.42 of this title.(14) Area permit--A permit that authorizes the construction and operation of two or more similar injection, production, or monitoring wells used in operations associated with Class III well activities within a specified area.(15) Artificial liner--The impermeable lining of a pit, lagoon, pond, reservoir, or other impoundment, that is made of a synthetic material such as butyl rubber, chlorosulfonated polyethylene, elasticized polyolefin, polyvinyl chloride (PVC), other manmade materials, or similar materials.(16) Baseline quality--The parameters and their concentrations that describe the local groundwater quality of an aquifer prior to the beginning of injection operations.(17) Baseline well--A well from which groundwater is analyzed to define baseline quality in the permit area (regional baseline well) or in the production area (production area baseline well).(18) Bedded salt--A geologic formation, group of formations, or part of a formation consisting of non-domal salt that is layered and may be interspersed with non-salt sedimentary materials such as anhydrite, shale, dolomite, and limestone. The salt layers themselves often contain significant impurities.(19) Bedded salt cavern disposal well--A well or group of wells and connecting storage cavities which have been created by solution mining, dissolving or excavation of salt bearing deposits or other geological formations and subsequently developed for the purpose of disposal of nonhazardous drinking water treatment residuals.(20) Blanket material or blanket pad--A fluid placed within a salt cavern that is lighter than the water in the cavern and will not dissolve the salt or any mineral impurities that may be contained within the salt. The function of the blanket is to prevent unwanted leaching of the salt cavern roof, prevent leaching of salt from around the cemented casing, and to protect the cemented casing from internal corrosion. Blanket material typically consists of crude oil, mineral oil, or some fluid possessing similar noncorrosive, nonsoluble, low density properties. The blanket material is placed between the salt cavern's outermost hanging string and innermost cemented casing.(21) Buffer area--The area between any mine area boundary and the permit area boundary.(22) Caprock--A geologic formation typically overlying the crest and sides of a salt stock. The caprock consists of a complex assemblage of minerals including calcite (CaCO3), anhydrite (CaSO4), and accessory minerals. Caprocks often contain lost circulation zones characterized by rock layers of high porosity and permeability.(23) Captured facility--A manufacturing or production facility that generates an industrial solid waste or hazardous waste that is routinely stored, processed, or disposed of on a shared basis in an integrated waste management unit owned, operated by, and located within a contiguous manufacturing complex.(24) Casing--Material lining used to seal off strata at and below the earth's surface.(25) Cement--A substance generally introduced as a slurry into a wellbore which sets up and hardens between the casing and borehole and/or between casing strings to prevent movement of fluids within or adjacent to a borehole, or a similar substance used in plugging a well.(26) Cementing--The operation whereby cement is introduced into a wellbore and/or forced behind the casing.(27) Cesspool--A drywell that receives untreated sanitary waste containing human excreta, and which sometimes has an open bottom and/or perforated sides.(28) Commercial facility--A Class I permitted facility, where one or more commercial wells are operated.(29) Commercial underground injection control (UIC) Class I well facility--Any waste management facility that accepts, for a charge, hazardous or nonhazardous industrial solid waste for disposal in a UIC Class I injection well, except a captured facility or a facility that accepts waste only from other facilities owned or effectively controlled by the same person.(30) Commercial well--An underground injection control Class I injection well which disposes of hazardous or nonhazardous industrial solid wastes, for a charge, except for a captured facility or a facility that accepts waste only from facilities owned or effectively controlled by the same person.(31) Conductor casing or conductor pipe--A short string of large-diameter casing used to keep the top of the wellbore open during drilling operations.(32) Cone of influence--The potentiometric surface area around the injection well within which increased injection zone pressures caused by injection of wastes would be sufficient to drive fluids into an underground source of drinking water or freshwater aquifer.(33) Confining zone--A part of a formation, a formation, or group of formations between the injection zone and the lowermost underground source of drinking water or freshwater aquifer that acts as a barrier to the movement of fluids out of the injection zone.(34) Contaminant--Any physical, biological, chemical, or radiological substance or matter in water.(35) Control parameter--Any physical parameter or chemical constituent of groundwater monitored on a routine basis used to detect or confirm the presence of mining solutions in a designated monitor well. Monitoring includes measurement with field instrumentation or sample collection and laboratory analysis.(36) Desalination brine--The waste stream produced by a desalination operation containing concentrated salt water, other naturally occurring impurities, and additives used in the operation and maintenance of a desalination operation.(37) Desalination concentrate--Same as desalination brine.(38) Desalination operation--A process which produces water of usable quality by desalination.(39) Disposal well--A well that is used for the disposal of waste into a subsurface stratum.(40) Disturbed salt zone--Zone of salt enveloping a salt dome cavern, typified by increased values of permeability or other induced anomalous conditions relative to undisturbed salt which lies more distant from the salt dome cavern, and is the result of mining activities during salt dome cavern development and which may vary in extent through all phases of a cavern including the post-closure phase.(41) Drilling mud--A heavy suspension used in drilling an injection well, introduced down the drill pipe and through the drill bit.(42) Drinking water treatment residuals--Materials generated, concentrated or produced as a result of treating water for human consumption.(43) Drywell--A well, other than an improved sinkhole or subsurface fluid distribution system, completed above the water table so that its bottom and sides are typically dry except when receiving fluids.(44) Enhanced oil recovery project (EOR)--The use of any process for the displacement of oil from the reservoir other than primary recovery and includes the use of an immiscible, miscible, chemical, thermal, or biological process. This term does not include pressure maintenance or water disposal projects.(45) Excursion--The movement of mining solutions, as determined by analysis for control parameters, into a designated monitor well.(46) Existing injection well--A Class I well which was authorized by an approved state or United States Environmental Protection Agency-administered program before August 25, 1988, or a well which has become a Class I well as a result of a change in the definition of the injected waste which would render the waste hazardous under § 335.1 of this title (relating to Definitions).(47) Fluid--Material or substance which flows or moves whether in a semisolid, liquid, sludge, gas, or any other form or state.(48) Formation--A body of rock characterized by a degree of lithologic homogeneity which is prevailingly, but not necessarily, tabular and is mappable on the earth's surface or traceable in the subsurface.(49) Formation fluid--Fluid present in a formation under natural conditions.(50) Fresh water--Water having bacteriological, physical, and chemical properties which make it suitable and feasible for beneficial use for any lawful purpose. (A) For the purposes of this chapter, it will be presumed that water is suitable and feasible for beneficial use for any lawful purpose only if:(i) it is used as drinking water for human consumption; or(ii) the groundwater contains fewer than 10,000 milligrams per liter (mg/L) total dissolved solids; and(iii) it is not an exempted aquifer.(B) This presumption may be rebutted upon a showing by the executive director or an affected person that water containing greater than or equal to 10,000 mg/L total dissolved solids can be put to a beneficial use.(51) General permit--A permit issued under the provisions of this chapter authorizing the disposal of nonhazardous desalination concentrate and nonhazardous drinking water treatment residuals as provided by Texas Water Code, § 27.025.(52) Groundwater--Water below the land surface in a zone of saturation.(53) Groundwater protection area--A geographic area (delineated by the state under federal Safe Drinking Water Act, 42 United States Code, § 300j-13 ) near and/or surrounding community and non-transient, non-community water systems that use groundwater as a source of drinking water.(54) Hazardous waste--Hazardous waste as defined in § 335.1 of this title (relating to Definitions).(55) Improved sinkhole--A naturally occurring karst depression or other natural crevice found in carbonate rocks, volcanic terrain, and other geologic settings which has been modified by man for the purpose of directing and emplacing fluids into the subsurface.(56) Individual permit--A permit, as defined in the Texas Water Code (TWC), §27.011 and §27.021, issued by the commission or the executive director to a specific person or persons in accordance with the procedures prescribed in the TWC, Chapter 27 (other than TWC, §27.025).(57) Injection interval--That part of the injection zone in which the well is authorized to be screened, perforated, or in which the waste is otherwise authorized to be directly emplaced.(58) Injection operations--The subsurface emplacement of fluids occurring in connection with an injection well or wells, other than that occurring solely for construction or initial testing.(59) Injection well--A well into which fluids are being injected. Components of an injection well annulus monitoring system are considered to be a part of the injection well.(60) Injection zone--A formation, a group of formations, or part of a formation that receives fluid through a well.(61) In service--The operational status when an authorized injection well is capable of injecting fluids, including times when the well is shut-in and on standby status.(62) Intermediate casing--A string of casing with diameter intermediate between that of the surface casing and that of the smaller long-string or production casing, and which is set and cemented in a well after installation of the surface casing and prior to installation of the long-string or production casing.(63) Large capacity cesspool--A cesspool that is designed for a flow of greater than 5,000 gallons per day.(64) Large capacity septic system--A septic system that is designed for a flow of greater than 5,000 gallons per day.(65) Licensed professional geoscientist--A geoscientist who maintains a current license through the Texas Board of Professional Geoscientists in accordance with its requirements for professional practice.(66) Liner--An additional casing string typically set and cemented inside the long string casing and occasionally used to extend from base of the long string casing to or through the injection zone.(67) Long string casing or production casing--A string of casing that is set inside the surface casing and that usually extends to or through the injection zone.(68) Lost circulation zone--A term applicable to rotary drilling of wells to indicate a subsurface zone which is penetrated by a wellbore, and which is characterized by rock of high porosity and permeability, into which drilling fluids flow from the wellbore to the degree that the circulation of drilling fluids from the bit back to ground surface is disrupted or "lost."(69) Mine area--The area defined by a line through the ring of designated monitor wells installed to monitor the production zone.(70) Mine plan--A plan for operations at a mine, consisting of:(A) a map of the permit area identifying the location and extent of existing and proposed production areas; and(B) an estimated schedule indicating the sequence and timetable for mining and any required aquifer restoration.(71) Monitor well--Any well used for the sampling or measurement with field instrumentation of any chemical or physical property of subsurface strata or their contained fluids. The term "monitor well" shall have the same meaning as the term "monitoring well" as defined in Texas Water Code, § 27.002. (A) Designated monitor wells are those listed in the production area authorization for which routine water quality sampling or measurement with field instrumentation is required.(B) Secondary monitor wells are those wells in addition to designated monitor wells, used to delineate the horizontal and vertical extent of mining solutions.(C) Pond monitor wells are wells used in the subsurface surveillance system near ponds or other pre-injection units.(72) Motor vehicle waste disposal well--A well used for the disposal of fluids from vehicular repair or maintenance activities including, but not limited to, repair and maintenance facilities for cars, trucks, motorcycles, boats, railroad locomotives, and airplanes.(73) Native groundwater--Groundwater naturally occurring in a geologic formation.(74) New injection well--Any well, or group of wells, not an existing injection well.(75) New waste stream--A waste stream not permitted.(76) Non-commercial facility--A Class I permitted facility which operates only non-commercial wells.(77) Non-commercial underground injection control (UIC) Class I well facility--A UIC Class I permitted facility where only non-commercial wells are operated.(78) Non-commercial well--An underground injection control Class I injection well which disposes of wastes that are generated on-site, at a captured facility or from other facilities owned or effectively controlled by the same person.(79) Notice of change (NOC)--A written submittal to the executive director from a permittee authorized under a general permit providing changes to information previously provided to the agency, or any changes with respect to the nature or operations of the facility, or the characteristics of the waste to be injected.(80) Notice of intent (NOI)--A written submittal to the executive director requesting coverage under the terms of a general permit.(81) Off-site--Property which cannot be characterized as on-site.(82) On-site--The same or geographically contiguous property which may be divided by public or private rights-of-way, provided the entrance and exit between the properties is at a cross-roads intersection, and access is by crossing, as opposed to going along, the right-of-way. Noncontiguous properties owned by the same person but connected by a right-of-way which the owner controls and to which the public does not have access, is also considered on-site property.(83) Out of service--The operational status when a well is not authorized to inject fluids, or the well itself is incapable of injecting fluids for mechanical reasons, maintenance operations, or well workovers or when injection is prohibited due to the well's inability to comply with the in-service operating standards of this chapter.(84) Permit area--The area owned or under lease by the permittee which may include buffer areas, mine areas, and production areas.(85) Plugging--The act or process of stopping the flow of water, oil, or gas into or out of a formation through a borehole or well penetrating that formation.(86) Point of injection--For a Class V well, the last accessible sampling point prior to fluids being released into the subsurface environment.(87) Pollution--The contamination of water or the alteration of the physical, chemical, or biological quality of water: (A) that makes it harmful, detrimental, or injurious:(i) to humans, animal life, vegetation, or property; or(ii) to public health, safety, or welfare; or(B) that impairs the usefulness or the public enjoyment of the water for any lawful and reasonable purpose.(88) Pre-injection units--The on-site above-ground appurtenances, structures, equipment, and other fixtures including the injection pumps, filters, tanks, surface impoundments, and piping for wastewater transmission between any such facilities and the well that are or will be used for storage or processing of waste to be injected, or in conjunction with an injection operation.(89) Production area--The area defined by a line generally through the outer perimeter of injection and recovery wells used for mining.(90) Production area authorization--An authorization, issued under the terms of a Class III injection well area permit, approving the initiation of mining activities in a specified production area within a permit area, and setting specific conditions for production and restoration in each production area within an area permit.(91) Production well--A well used to recover uranium through in situ solution recovery, including an injection well used to recover uranium. The term does not include a well used to inject waste.(92) Production zone--The stratigraphic interval extending vertically from the shallowest to the deepest stratum into which mining solutions are authorized to be introduced.(93) Project operator--A person holding an authorization by rule, individual permit, or general permit to undertake an aquifer storage and recovery project or an aquifer recharge project.(94) Public water system--A system for the provision to the public of water for human consumption through pipes or other constructed conveyances as defined in § 290.38 of this title (relating to Definitions).(95) Radioactive waste--Any waste which contains radioactive material in concentrations which exceed those listed in 10 Code of Federal Regulations Part 20, Appendix B, Table II, Column 2, and as amended.(96) Recharge injection well--A Class V injection well used for the injection of water into a geologic formation for an aquifer recharge project, including an improved sinkhole or cave connected to an aquifer.(97) Registered Well--A well registered in accordance with the requirements of § 331.221 of this title (relating to Registration of Wells).(98) Restoration demonstration--A test or tests conducted by a permittee to simulate production and restoration conditions and verify or modify the fluid handling values submitted in the permit application.(99) Restored aquifer--An aquifer whose local groundwater quality, within a production area, has, by natural or artificial processes, returned to the restoration table values established in accordance with the requirements of § 331.107 of this title (relating to Restoration).(100) Salt cavern--A hollowed-out void space that has been purposefully constructed within a salt formation, typically by means of solution mining by circulation of water from a well or wells connected to the surface.(101) Salt cavern disposal well--For the purposes of this chapter, regulations of the commission, and not to underground injection control (UIC) Class II or UIC Class III wells in salt caverns regulated by the Railroad Commission of Texas, a salt cavern disposal well is a type of UIC Class I injection well used: (A) to solution mine a waste storage or disposal cavern in naturally occurring salt; and/or(B) to inject nonhazardous, industrial, or municipal waste into a salt cavern for the purpose of storage or disposal of the waste.(102) Salt dome--A geologic structure that includes the caprock, salt stock, and deformed strata surrounding the salt stock.(103) Salt dome cavern confining zone--A zone between the salt dome cavern injection zone and all underground sources of drinking water and freshwater aquifers, that acts as a barrier to movement of waste out of a salt dome cavern injection zone, and consists of the entirety of the salt stock excluding any portion of the salt stock designated as an underground injection control (UIC) Class I salt dome cavern injection zone or any portion of the salt stock occupied by a UIC Class II or Class III salt dome cavern or its disturbed salt zone.(104) Salt dome cavern injection interval--That part of a salt dome cavern injection zone consisting of the void space of the salt dome cavern into which waste is stored or disposed of, or which is capable of receiving waste for storage or disposal.(105) Salt dome cavern injection zone--The void space of a salt dome cavern that receives waste through a well, plus that portion of the salt stock enveloping the salt dome cavern, and extending from the boundaries of the cavern void outward a sufficient thickness to contain the disturbed salt zone, and an additional thickness of undisturbed salt sufficient to ensure that adequate separation exists between the outer limits of the injection zone and any other activities in the domal area.(106) Salt stock--A geologic formation consisting of a relatively homogeneous mixture of evaporite minerals dominated by halite (NaCl) that has migrated from originally tabular beds into a vertical orientation.(107) Sanitary waste--Liquid or solid waste originating solely from humans and human activities, such as wastes collected from toilets, showers, wash basins, sinks used for cleaning domestic areas, sinks used for food preparation, clothes washing operations, and sinks or washing machines where food and beverage serving dishes, glasses, and utensils are cleaned.(108) Septic system--A well that is used to emplace sanitary waste below the surface, and is typically composed of a septic tank and subsurface fluid distribution system or disposal system.(109) Stratum--A sedimentary bed or layer, regardless of thickness, that consists of generally the same kind of rock or material.(110) Subsurface fluid distribution system--An assemblage of perforated pipes, drain tiles, or other similar mechanisms intended to distribute fluids below the surface of the ground. This definition includes subsurface area drip dispersal systems as defined in § 222.5 of this title (relating to Definitions).(111) Surface casing--The first string of casing (after the conductor casing, if any) that is set in a well.(112) Temporary injection point--A method of Class V injection that uses push point technology (injection probes pushed into the ground) for the one-time injection of fluids into or above an underground source of drinking water.(113) Total dissolved solids--The total dissolved (filterable) solids as determined by use of the method specified in 40 Code of Federal Regulations Part 136, as amended.(114) Transmissive fault or fracture--A fault or fracture that has sufficient permeability and vertical extent to allow fluids to move between formations.(115) Underground injection--The subsurface emplacement of fluids through a well.(116) Underground injection control--The program under the federal Safe Drinking Water Act, 42 United States Code, Part C, including the approved Texas state program.(117) Underground source of drinking water--An "aquifer" or its portions:(A) which supplies drinking water for human consumption; or(B) in which the groundwater contains fewer than 10,000 milligrams per liter total dissolved solids; and(C) which is not an exempted aquifer.(118) Upper limit--A parameter value established by the commission in a permit/production area authorization which when exceeded indicates mining solutions may be present in designated monitor wells.(119) Verifying analysis--A second sampling and analysis or measurement with instrumentation of control parameters for the purpose of confirming a routine sample analysis or measurement which indicated an increase in any control parameter to a level exceeding the upper limit. Mining solutions are assumed to be present in a designated monitor well if a verifying analysis confirms that any control parameter in a designated monitor well is present in concentration equal to or greater than the upper limit value.(120) Well--A bored, drilled, or driven shaft whose depth is greater than the largest surface dimension, a dug hole whose depth is greater than the largest surface dimension, an improved sinkhole, or a subsurface fluid distribution system but does not include any surface pit, surface excavation, or natural depression.(121) Well injection--The subsurface emplacement of fluids through a well.(122) Well monitoring--The measurement by on-site instruments or laboratory methods of any chemical, physical, radiological, or biological property of the subsurface strata or their contained fluids penetrated by the wellbore.(123) Well stimulation--Several processes used to clean the well bore, enlarge channels, and increase pore space in the injection interval, thus making it possible for fluid to move more readily into the formation including, but not limited to, surging, jetting, and acidizing.(124) Workover--An operation in which a down-hole component of a well is repaired, the engineering design of the well is changed, or the mechanical integrity of the well is compromised. Workovers include operations such as sidetracking, the addition of perforations within the permitted injection interval, and the addition of liners or patches. For the purposes of this chapter, workovers do not include well stimulation operations.30 Tex. Admin. Code § 331.2
The provisions of this §331.2 adopted to be effective May 13, 1986, 11 TexReg 1980; amended to be effective July 5, 1989, 14 TexReg 3047; amended to be effective June 22, 1992, 17 TexReg 4097; amended to be effective January 2, 1995, 19 TexReg 10099; amended to be effective June 28, 1996, 21 TexReg 5443; amended to be effective April 28, 1997, 22 TexReg 3526; amended to be effective November 23, 2000, 25 TexReg 11433; amended to be effective July 12, 2001, 26 TexReg 5019; amended to be effective January 9, 2003, 28 TexReg 340; amended to be effective October 2, 2003, 28 TexReg 8367; amended to be effective September 16, 2004, 29 TexReg 8824;amended to be effective July 5, 2006, 31 TexReg 5339; amended to be effective July 10, 2008, 33 TexReg 5342; amended to be effective March 12, 2009, 34 TexReg 1638; amended to be effective August 16, 2012, 37 TexReg 6078; Amended by Texas Register, Volume 41, Number 20, May 13, 2016, TexReg 3522, eff. 5/19/2016; Amended by Texas Register, Volume 45, Number 21, May 22, 2020, TexReg 3461, eff. 5/28/2020; Amended by Texas Register, Volume 46, Number 01, January 1, 2021, TexReg 0193, eff. 1/7/2021