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Literature Review: Possible Funding Sources for Proper Closure of Abandoned Water Wells on Private Lands in the South Central RegionCONTENTS
INTRODUCTIONThis letter summarizes research the staff at the National Water Management Center has conducted to document possible sources of funding for proper abandonment of water wells on private lands. Included are sections discussing background information on abandoned well hazards, ground-water use, the theory behind proper well plugging, the agencies regulating water well abandonment and their responsibilities, possible sources of assistance for decommissioning abandoned water wells, selected references with a brief description, a listing of State agencies and their addresses, and a glossary of related terminology. BACKGROUNDWithin the four states comprising the South Central Region (Arkansas (AR), Louisiana (LA), Oklahoma (OK), & Texas (TX)) there are hundreds of thousands of abandoned wells. These wells penetrate all principal aquifers within the Region and vary considerably in construction and depth. Improperly plugged abandoned wells are direct conduits to ground water and constitute a serious threat to the Region’s ground-water resources by allowing chemical and biological contaminants direct access to ground water from the surface. Improperly plugged abandoned wells may also allow the intermixing of ground waters from different aquifers, which may vary considerably in quality. Abandoned wells are a physical safety hazard to humans, livestock, wildlife, and machinery which may fall into these wells. Additionally, well owners may be liable if their well is found to be contaminating the ground water, especially if willful negligence is proven. Ground water is one of the Region’s most valuable natural resources. In 1990, ground water provided an estimated 15,000 million gallons per day (Mgal/d), or approximately 34% of the Regions water needs (figure 1). By far the largest user of ground water within the Region is agriculture, using an estimated 11,309 Mgal/d for irrigation and livestock watering or approximately 76 % of the total ground water use (figure 2) (Solley, Pierce, and Perlman, 1993). Because agriculture is the largest user of ground water, it is also, potentially, the most vulnerable to ground water contamination.
Improperly abandoned wells are a serious liability. Once ground water is contaminated, it is difficult, if not impossible, to clean up, and the process is always expensive. The logical course of action is to remove the liability by properly plugging, and sealing, or decommissioning all abandoned wells. Knowledge about how a water well was constructed is helpful in determining procedures for decommissioning. Ideally, these wells should be filled and sealed in a manner that would restore the well bore to original hydrologic conditions. Unfortunately, restoring the well bore to original hydrologic conditions is generally not possible or practical. The 5 basic objectives for decommissioning a well are 1) to eliminate all physical hazards; 2) to eliminate conditions that lead to the degradation of ground water quality; 3) to prevent the commingling of desirable and undesirable ground water; 4) to preserve hydrostatic conditions within the water-bearing zones; and 5) to protect investments in ground water-supply systems or in replacement water wells. AGENCIES AND RESPONSIBILITIESARKANSASWithin the State of Arkansas, the Arkansas Water Well Construction Commission has the primary responsibility for regulating water well construction and abandonment. The Commission's "Rules and Regulations" document provides minimum standards for the construction or repair of water wells, and locations of water wells which are used or intended to be used to locate, acquire, divert or artificially recharge ground water within the boundaries of the State of Arkansas. Specifically, Sections 3.29 and 15, briefly discuses abandoned wells. The Arkansas Soil and Water Conservation Commission is responsible for maintaining the quality and quantity of Arkansas' ground waters. Under the "Arkansas Ground Water Protection and Management Act", ACA §15-22-901, the Commission requires all non-domestic users with wells that can produce more than fifty thousand gallons per day to register their wells, each year, no later than March 1st, reporting withdrawals for the prior water year. The Act also requires that owners that are replacing existing registered wells to abandon the well in the manner prescribed by the Arkansas Water Well Construction Commission under Section 15.2 Arkansas Water Well Construction Code Rules and Regulations. LOUISIANAThe Louisiana Department of Transportation and Development - Public Works and Flood Control Directorate - Water Resources Section is the agency responsible for permitting new well construction and well abandonment for the State of Louisiana. Chapter III, Rules, Regulations and Standards for Plugging Abandoned Water Wells and Holes, of the Water Well Rules, Regulations and Standards list the legal responsibilities of the owner and contractor and construction requirements for abandoning a water well. OKLAHOMAFor the State of Oklahoma, the Oklahoma Water Resources Board has the primary responsibility for permitting new well construction and well abandonment. The Oklahoma Water Resources Board regulations, Section 785:35, Subchapter 11, discusses the requirements for plugging and capping groundwater wells. The Oklahoma Water Resources Board defines policy and conducts the State's water business through a nine-member Board appointed by the Governor. TEXASThe Texas Natural Resources Conservation Commission is the agency responsible for permitting, new well construction and abandoned well plugging. Rules and regulations governing abandoned wells may be found in Chapter 32, Section 32.017., Chapter 38, Subchapter C, §238.48. - §238.50, and Chapter 340, Subchapter C, §340.75. of the Texas Water Code. The Texas Natural Resources Conservation Commission is the lead environmental agency to the state. The Office of Water Resource Management helps manage and protect the state's water resources, including the integrity of public drinking water systems in Texas. United States Department of Agriculture (USDA)-Natural Resources Conservation Service (NRCS)The USDA - Natural Resources Conservation Service's Conservation Practice Standards and Specifications, Code 351, provides guidance for the proper decommissioning of abandoned water wells (USDA). Additionally, NRCS has standard engineering drawings for well plugging procedures (Carman, 1996). Both documents are available on the internet. United States Environmental Protection Agency (USEPA)The United States Environmental Protection Agency's "Manual of Water Well Construction Practices" was developed with the National Water Well Association to provide a guide to well construction. Practices and techniques discussed are not EPA recommendations, regulations or standards required under any Federal action, but are furnished for informational and educational purposes only. Article 56, of this manual, entitled "Permanent Well and Test Hole Abandonment", includes a brief discussion on the basic concepts for properly well abandonment, preparation for abandonment, borehole bridging, abandonment of flowing artesian wells, abandonment of other borings and holes, and functions of seals (USEPA, 1975). POSSIBLE SOURCES OF ASSISTANCE FOR DECOMMISSIONING ABANDONED WELLSThe USEPA has a number of grant programs designed to provide financial assistance to community based groups, schools and other organizations wishing to carry out projects to address Environmental Justice. Two of these grant programs which may be applicable to abandoned wells are: 1) the Environmental Justice Small Grants - provides assistance to small community groups and tribal governments to support projects to design, demonstrate or disseminate methods or techniques related to environmental justice, and 2) the Environmental Justice through Pollution Prevention Grants - provides assistance to small community groups and tribal governments for projects that address environmental justice and use pollution prevention activities as the proposed solution (USEPA, 1998). The Omaha Tribe of Nebraska received an EPA Environmental Justice Small Grant in 1995 to protect the surface and groundwater on or surrounding the reservation. The Tribe used the Environmental Justice grant to seek and identify abandoned well locations in and near the well head which serves the Tribal rural water system. Additionally, grant funding was used to fill approximately 44 large diameter, hand-dug wells, and stabilize and install locks on another 65 wells (USEPA, accessed Aug. 1998). The Farm*A*Syst program is another program which may be used to assist private land owners plug abandoned wells. Jointly supported by USDA's Cooperative State Research Education and Extension Service, USDA's Natural Resource Conservation Service, and U.S. Environmental Protection Agency, Farm*A*Syst is a voluntary program partnering government agencies and private business enabling individuals to prevent water pollution on farms, ranches, and homes using free, confidential, environmental risk assessments (Farm*A*Syst / Home*A*Syst, Accessed Aug. 1998). Sevier County, in southwest Arkansas, has adapted the Farm*A*Syst program to fill abandoned wells identified through the program. Supported by the Sevier County administrator, 41 wells have been plugged with the assistance of county highway crews, saving farmers on average $250 per well (Farm*A*Syst, 1996). Several States across the Country; including Iowa, Kansas, and Nebraska, have established water well decommissioning funds to assist private land owners properly plug their abandoned wells. To encourage plugging of abandoned wells Iowa provides cost-sharing money through the Grants to Counties Program. This program pays up to $200 of plugging costs for eligible participants. To be eligible for the cost-sharing money, the county board of supervisors must submit a short grant proposal to the Iowa Department of Natural Resources and agree to administer the program locally (Glanville, 1992). The Kansas State Conservation Commission, through local conservation districts, can provide cost-share incentives up to 70 percent of all necessary costs incurred by the landowner to plug an abandoned water well. Local district supervisors assign priority to projects which are most effective in controlling erosion or improving water quality based on critical needs identified for their district (Kansas Conservation Commission, Accessed Sept. 1998). The State of Nebraska currently has a Water Well Decommissioning Fund from which they reimburse local conservation districts who meet the rules and regulations governing the fund. The districts may be reimbursed for each water well decommissioned with district cost-share assistance not to exceed the lesser of: (1) 75% of the cost of such decommissioning; (2) $300 for all water wells other than hand-dug wells; or (3) $700 for hand-dug water wells (Nebraska Natural Resources Commission, 1995). CONCLUSIONS / RECOMMENDATIONSBesides being an environmental and safety hazard, almost every state has laws requiring abandoned water wells to be plugged. In most instances, the land owner has 60 to 90 days to plug an abandoned well once it is replaced or discovered. If a well is not plugged and is found to be contaminating the ground water, the land owner may be found libel for clean-up cost, damages, and fines, which easily could run into millions of dollars. At first glance, well plugging may seem to involve little more than dumping something into an open well. But, effective well plugging calls for experience with well construction materials and methods, and a working knowledge of the geology of the well site. Furthermore, most plugging operations require special equipment to remove old pumps and piping, pumps to properly install sealing materials inside the well, and excavating equipment to remove the top few feet of casing and compact soil over the well. Inappropriate plugging materials and methods can lead to settling, sudden collapse, and a continued threat of groundwater contamination. Once a well has been plugged, it is very expensive and possibly impossible, to correct an improper plug installation. For these reasons, it is recommended that most wells be plugged by a registered well contractor who follows your State's laws and regulations concerning proper well abandonment. Several different federal grant programs are available to assist landowners in plugging abandoned wells. Such programs include the Farm*A*Syst program administered by USDA, and the Environmental Justice Small Grant and the Environmental Justice through Pollution Prevention Grant programs administered by the USEPA. These programs are not specifically designed to assist in well abandonment and thus may require substantial work to secure. By far the most effective programs in assisting land owners in plug abandoned wells have been the cost-sharing programs administered by State governments through local conservation districts. If such programs are available in your State, we recommend that you get the word out and take full advantage of the program to help reduce the serious threat abandoned wells pose to our ground water resource. If a cost-sharing program is not available in your state, it is recommended that you begin working with your local conservation districts, appropriate State agencies and State legislators to get a cost-sharing program implemented. Kansas, Iowa, Nebraska, and several other States have excellent cost-sharing programs which may be used as models for your State's program. SELECTED REFERENCESARKANSAS
LOUISIANA
OKLAHOMA
TEXAS
OTHER
AGENCY ADDRESSES AND TELEPHONE NUMBERSARKANSASArkansas Soil and Water Conservation Commission Arkansas Water Well Construction Commission LOUISIANAAll request should be made in writing and mailed to: OKLAHOMAOklahoma Water Resources Board Water Quality Division TEXASTexas Natural Resource Conservation Commission Texas Department of Licensing and Regulations GLOSSARYAbandoned Well: A water well that is no longer in use or any water well, the use of which has been accomplished or permanently discontinued. Acre-foot (acre-ft): The volume of water required to cover 1 acre of land (43,560 square feet) to a depth of 1 foot. Alluvium: A general term for unconsolidated material deposited by a stream or other body of running water. Animal Specialties: Water use associated with the production of fish in captivity except fish hatcheries, fur-bearing animals in captivity, horses, rabbits, and pets. See also livestock water use. Annular Space: The space between the well bore and the outside of the well casing. Aquaculture: Farming of organisms that live in water, such as fish, shellfish, and algae. Aquiclude: A body of relatively impermeable soil or rock materials that is capable of absorbing water but will not transmit it fast enough to supply a well. Aquifer: A geological formation, group of formations, or part of a formation that contains sufficient saturated permeable material to yield significant quantities of water to wells and springs. Artesian Well: A well in an aquifer where the groundwater is confined under pressure and the water level stands above the top of the confined aquifer. Augered Well: A well that is constructed by using an auger to bore the hole and extract materials. Bedrock: A general term for the consolidated (solid) rock that underlies soils or other unconsolidated surficial materials. Bentonite: A processed clay material composed principally of the mineral montmorillonite. It has a great affinity for fresh water and when hydrated will increase its volume more than seven times. Water/bentonite suspensions are essentially impermeable. Bentonite Grout: Bentonite grout consists of powered sodium bentonite clay and clean water in the proportion of less than 1 pound of powdered bentonite to 1 gallon of water. Bentonite grout may be used in all geologic formations. Bentonite pellets and granular bentonite may also be used as a seal material without forming a slurry. Bored Well: Synonymous with an augered well or a well dug with a bucket-drill. Capillarity: The rise of water level because of adhesion of water to solid particles. Capillary Fringe: The zone above the water table in which water is held by surface tension. Water in the capillary fringe is under lower-than-atmospheric pressure. Casing: A tubular retaining structure installed in the excavated hole to maintain the well opening. Clay: A fine-grained inorganic material (grains less than 0.005 mm in diameter) that has a very low permeability and is plastic (malleable). Commercial Water Use: Water for motels, hotels, restaurants, office buildings, other commercial facilities, and institutions. The water may be obtained from a public supply or may be self supplied. See also public supplied water. Concrete Grout: A mixture of one sack (94 pounds) of Portland cement, an equal amount by volume of sand and gravel or crushed stone, and not more than 7 gallons of clean water. Cone of Depression: The depression of hydraulic heads around a well caused by the withdrawal of water. Confined Aquifer: An aquifer saturated with water and bounded above and below by beds having a distinctly lower hydraulic conductivity than the aquifer itself. Confining Layer: A body of impermeable or distinctly less permeable material that lies above and/or below one or more water-bearing zones. Consumptive Use: That part of water withdrawn that is evaporated, transpired, incorporated into products or crops, consumed by humans or livestock, or otherwise removed from the immediate water environment. Also referred to as water consumed. Contaminant Plume: An elongated and mobile column or band of a pollutant moving through the subsurface. Contamination: The degradation of natural water quality as a result of man's activities. There is no implication of any specific limits, since the degree of permissible contamination depends upon the intended end use, or uses, of the water. Conveyance Loss: Water that is lost in transit from a pipe, canal, conduit, or ditch by leakage or evaporation. Generally, the water is not available for further use; however, leakage from an irrigation ditch, for example, may percolate to a ground-water source and be available for further use. Cooling Water: Water used for cooling purposes, such as of condensers and nuclear reactors. Curing Time: Minimum time required for particular types of cementing or grouting materials to harden. Decommissioned Wells: When used in relation to a water well shall mean the act of filling, sealing, and plugging a water well in accordance with the rules and regulations of the appropriate State agency. Delivery/Release: The amount of water delivered to the point of use and the amount released after use; the difference between these amounts is usually the same as the consumptive use. See also consumptive use. Discharge Area: An area in which water is lost from the zone of saturation. Domestic Water Use: Water for household purposes, such as drinking, food preparation, bathing, washing clothes and dishes, flushing toilets, and watering lawns and gardens. Also called residential water use. The water may be obtained from a public supply of may be self supplied. See also public supply and self-supplied water. Drawdown: The decline in ground water level at a point caused by the withdrawal of water from an aquifer. Drilled Well: A well that is constructed with a rotary drilling machine that incorporates the use of circulating drilling fluid or compressed air to remove drill cuttings from the well hole. Dug Well: A hand-dug well sometimes lined with brick or stone but in many locations unlined. Evaporation: Process by which water is changed from a liquid into a vapor. See also evapotranspiration and transpiration. Evapotranspiration: A collective term than includes water discharged to the atmosphere as a result of evaporation from the soil and surface-water bodies and as a result of plant transpiration. See also evaporation and transpiration. Filling Materials: Well-plugging materials that are used to take up space in a well. Freshwater: Water that contains less than 1.000 milligrams per liter (mg/L) of dissolved solids; generally, more than 500 mg/L of dissolved solids is undesirable for drinking and many industrial uses. Gaining Stream: A stream or reach of stream that receives water from the zone of saturation. Glacial Drift: A general term for material transported by glaciers and deposited directly on land or in the sea. Granular Bentonite: A naturally occurring clay that is crushed and sized for pouring and easy handling. Like processed bentonite, it swells when hydrated by fresh water and will form a plastic, essentially impermeable mass. Gravel-packed Well: A well in which filter material is placed in the annular space to increase the effective diameter of the well and to prevent fine-grained materials from entering the well. Groundwater: Generally all subsurface water as distinct from surface water; specifically, that part of the subsurface water in the saturated zone (a zone in which all voids are filled with water) where the water is under pressure greater than atmospheric. Ground Water Divide: A ridge in the water table or potentiometric surface from which ground water moves away at right angles in both directions. The line of highest hydraulic head in the water table or potentiometric surface. Grout: A fluid mixture of cement and water (neat cement), cement and sand (sand cement), and cement, sand and coarse aggregate (concrete), bentonite seal or other material that is substantially equivalent, to form a permanent impervious, watertight bond in the annular space or between tow or more strings of casing. Hydroelectric Power Water Use: The use of water in the generation of electricity at plants where the turbine generators are driven by falling water. Hydroelectric water use is generally classified as an instream use. Hydraulic Conductivity: The capacity of a rock to transmit water; expressed as the volume of water that will move in unit time under a unit hydraulic gradient through a unit area measured at right angles to the direction of flow. Hydraulic Gradient: The slope of the water table or potentiometric surface; that is, the change in water level per unit of distance along the direction of maximum head decrease. Determined by measuring the water level in several wells. Hydraulic Head: In ground water, the height above a datum plane (such as sea level) of a column of water. In a ground water system, it is composed of elevation head and pressure head. Hydrologic Cycle: The exchange of water between the Earth and the atmosphere through evaporation and precipitation. Hydrologic Properties: The properties of rocks or soil that control the entrance of water and the capacity to transmit water. Igneous Rock: A rock that solidified from molten or partly molten material. In-channel use: See instream use. Inactive Status: A water well which is in a good state of repair, which the owner has properly maintained, and which meets the following standards: does not impair the water quality of the groundwater encountered by the well; has a water-tight cover constructed to prevent unauthorized access of removal; is visibly marked and identified as a water well and the area around the well kept clean and clear of wastes and debris. Industrial Water Use: Water used for industrial purposes such as fabrication, processing, washing, and cooling, and includes such industries as steel, chemical and allied products, paper and allied products, mining, and petroleum refining. The water may be self supplied. See also public supply and self-supplied water. Instream Use: Water that is used, but not withdrawn, from a ground- or surface-water source for such purposes as hydroelectric power generation, navigation, water-quality improvement, fish propagation, and recreation. Sometimes called nonwithdrawal use or in channel use. Irrigation District: A cooperative, self-governing public corporation set up as a subdivision of the State government, with definite geographic boundaries, organized and having taxing power to obtain and distribute water for irrigation of lands within the district; created under the authority of a State legislature with a consent of a designated fraction of the landowners or citizens. Irrigation Water Use: Artificial application of water on lands to assist in the growing of crops and pastures or to maintain vegetative growth in recreational lands such as parks and golf courses. Karst: A landscape or region characterized by rock dissolution. Kilowatt-hour: A unit of energy equivalent to one thousand watt-hours. Livestock Water Use: Water for livestock watering, feed lots, dairy operations, fish farming, and other on-farm needs. Livestock as used here includes cattle, sheep, goats, hogs, and poultry. Also included are animal specialties. See also rural water use and animal specialties water use. Losing Stream: A stream or reach of a stream that contributes water to the zone of saturation. Metamorphic Rock: A rock formed when preexisting rocks undergo mineralogical, chemical, and structural changes caused by high temperature, pressure, and other factors. Million Gallons per Day (Mgal/d): A rate of flow of water. Mineralized Water: Water containing dissolved minerals in concentrations large enough to affect the use of the water for some purposes. A concentration of 1,000 mg/L of dissolved solids is used commonly as the lower limit for mineralized water. Mining Water Use: Water use for the extraction of minerals occurring naturally including solids, such as coal and ores; Liquids, such as crude petroleum; and gases, such as natural gas. Also includes uses associated with quarrying, well operations (dewatering), milling (crushing, screening, washing, flotation, and so forth), and other preparations customarily done at the mine site or as part of a mining activity. Does not include water used in processing, such as smelting, refining petroleum, or slurry pipeline operations. These uses are included in industrial water use. Neat-cement Grout: A mixture of one 94-pound sack of Portland cement to not more than 7 gallons of clean water. Bentonite up to 2 percent by weight may be added to reduce shrinkage. Offstream Use: Water withdrawn of diverted from a ground- or surface-water source for public-water supply, industry, irrigation, livestock, thermoelectric power generation, and other uses. Sometimes called off-channel use or withdrawal. Per Capita Use: The average amount of water used per person during a standard time period, generally per day. Permeable: Having a texture that permits water to move through it perceptibly under the head differences ordinarily found in subsurface water. Permeability: A measure of the relative ease with which a porous medium can transmit a liquid. pH: A number used by chemists to express the acidity of solutions, including water. A pH value lower than 7 indicates and acidic solution, a value of 7 is neutral, and a value higher than 7 indicates an alkaline solution. Most ground waters in the United States have pH values ranging form about 6.0 to 8.5. Porosity: The volume of openings in a rock. When expressed as a fraction, porosity is the ratio of the volume of openings in the rock to the total volume of the rock. Potentiometric Surface: An imaginary surface representing the level to which water will rose in a well. Public Supply: Water withdrawn by public and private water suppliers and delivered to users. Public suppliers provide water for a variety of users, such as domestic, commercial, thermoelectric power, industrial, and public use. See also commercial water use, domestic water use, thermoelectric power water use, industrial water use, and public water use. Public-Supply Deliveries: Water provided to users through a public-supply distribution system. Public Water Use: Water supplied from a public-water supply and used for such purposes as firefighting, street washing, and municipal parks and swimming pools. See also public supply. Recharge Area: The area in which water reaches the saturated zone by surface infiltration. Reclaimed Wastewater: Wastewater treatment plant effluent that has been diverted to beneficial use before it reaches a natural waterway or aquifer. Recycled Water: Water that is used more than one time before it passes back into the natural hydrologic system. Residential Water Use: See domestic water use. Return Flow: The water that reaches a ground- or surface-water source after release from the point of use and thus becomes available for further use. Reuse: See recycled water. Rural Water Use: Term used in previous water-use circulars to describe water used in suburban or farm areas for domestic and livestock needs. The water generally is self supplied, and includes domestic use, drinking water for livestock, and other uses, such a dairy sanitation, evaporation from stick water ponds, and cleaning and waste disposal. See also domestic water use, livestock water use, and self-supplied water. Saline Water: Water that contains more than 1,000 milligrams per liter of dissolved solids. Sand-cement Grout: A mixture of one 94-pound sack of Portland cement, an equal amount by volume of clean masonry, sand, and not more than 7 gallons of clean water. Sandpoint Well: A well constructed by driving or jetting a pointed well screen connected to a small-diameter pope into water-bearing sand or gravel. Saturated Zone: The subsurface zone in which all openings are full of water. Sealing Materials: Well-plugging materials that will cause a tight seal in a well because of their characteristic impermeability. Sedimentary Rock: A layered rock formed at or near the Earth's surface (1) from fragments of older rocks, (2) by precipitation from solution, or (3) from the remains of living organisms. Self-Supplied Water: Water withdrawn from a surface- or ground-water source by a user rather than being obtained from a public supply. Slurry: A fluid mixture of cement or bentonite or other solids and water; may be synonymous with grout. Specific Capacity: The rate of discharge of water from a well per unit of drawdown of the water level. Specific Retention: The amount of water that soils or rocks will retain against the pull of gravity to the rock/soil volume. Specific Yield: The amount of water an aquifer will release from storage. Standard Industrial Classification (SIC) Codes: Four- digit codes establish by the Office of Management and Budget and used in the classification of establishments by type of activity in which there are engaged. Standing Water: Water that is displaced in a well due to the addition of sealing or filling materials; water displaced above the normal static water level. Static Water Level: The elevation of the water surface in a well when no water is being pumped. Surface Water: An open body of water, such as a stream or a lake. Thermoelectric Power Water Use: Water used in the process of the generation of thermoelectric power. The water may be obtained from a public supply or may be self supplied. See also public supply and self-supplied water. Till: An unsorted and unsatratified mixture of clay, silt, sand, gravel, and boulders deposited directly by glaciers. Time of Travel: The amount of time it takes for water to reach a well from a certain distance. Total Head: The height (usually above sea level) of a column of water; includes elevation head and pressure head. Ground water flows in the direction of decreasing total head. Transmissivity: The capacity of an aquifer to transmit water; equal to the hydraulic conductivity times the aquifer thickness. Transpiration: Process by which water that is absorbed by plants, usually through the roots, is evaporated into the atmosphere from the plant surface. See also evaporation and evapotranspiration. Tremie Pipe or Line: A device, usually a small-diameter pope of hose that carries grouting materials to the bottom of the hole and allows pressure grouting from the bottom up without introduction of appreciable air pockets. Unconfined Aquifer: An aquifer that contains both an unsaturated and saturated zone (i.e. an aquifer that is not full of water). Unsaturated Zone: The subsurface zone, usually starting at the land surface, that contains both water and air. Wastewater: Water that carries waste from homes, businesses, and industries. Wastewater Treatment: The processing of wastewater for the removal or deduction of contained solids or other undesirable constituents. Wastewater-Treatment Return Flow: Water returned to the hydrologic system by wastewater-treatment facilities. Water-Resources Region: Designated natural drainage basin of hydrologic area that contains either the drainage area of major rivers; of 21 regions, 18 are in the conterminous United States, and one each are in Alaska, Hawaii, and the Caribbean. Water Table: The level in the saturated zone at which the water is under a pressure equal to the atmospheric pressure, another words, the level at which water stands in wells that penetrate an confined aquifer. Water Transfer: Artificial conveyance of water from one area to another. Water Use: 1) In a restrictive sense, the term refers to water that is actually used for a specific purpose, such as for domestic use, irrigation, or industrial processing. 2) More broadly, water use pertains to human's interaction with and influence on the hydrologic cycle, and includes elements such as water withdrawal, delivery, consumptive sue, wastewater release, reclaimed wastewater, return flow, and instream use. See also offstream use and instream use. Well Screen: The intake section of a well that allows water to flow freely into the well from water-saturated materials and serves as a structural retainer to support the bore hole in unconsolidated material. Numerous types of materials are available, and their application depends upon the specific hydrogeologic conditions present. Watt-hour (Wh): An electrical energy unit of measure equal to one watt of power supplied to, or taken from, an electrical circuit steadily for one hour. Withdrawal: Water removed from the ground or diverted from a surface-water source for use. See also offstream use and self-supplied water. Water Well: Any excavation that is drilled, redrilled, cored, board, washed, driven, dug, jetted, or otherwise artificially constructed for the purpose of locating, acquiring, diverting, or artificially recharging ground water; to include heat pump wells. |
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