ALLUVIUM--Clay, silt, sand, and gravel, or similar unconsolidated material deposited by a stream or other body of flowing water.
ANTICLINE--An arched fold in which the rock layers dip away from the axis of the fold.
AQUIFER--A formation, group of formations, or part of a formation that contains sufficient saturated permeable material to yield usable quantities of water to wells and springs.
ARTESIAN AQUIFER--Synonymous with confined aquifer.
ARTESIAN WELL--A well derives its water from an artesian or confined aquifer.
AVERAGE DISCHARGE--The arithmetic average of all complete water years of record of discharge whether consecutive or not.
BACTERIA--Microscopic unicellular organisms, typically spherical, rodlike, or spiral and threadlike in shape, often formed into colonies. Some bacteria cause disease, whereas others perform an essential role in nature in the recycling of materials; for example, by decomposing organic matter into a form available for reuse by plants.
BENCHMARK--A permanent marker embedded in a fixed and enduring natural or artificial object, indicating a precisely determined elevation above or below a standard datum (usually sea level) and bearing identifying information, and used as a reference in topographic surveys.
BEDROCK--A general term for the consolidated (solid) rock that underlies soil or other unconsolidated surficial material.
BOSQUE--A Spanish term for the vegetation of the riparian woodland along the Rio Grande.
BOTANY: A plant community extending over a large area and dominated by trees, the crowns of which form an unbroken covering layer or canopy. The bosque along the Rio Grande has evolved significantly since the introduction of exotic species prior to 1900 and the construction of flood-control and bank-stabilization projects. During the last 60 to 70 years, the bosque has developed in an area that was formerly semibarren flood plain.
CLASTIC ROCKS--Composed principally of broken rock fragments that are derived from pre-existing rocks or minerals and have been transported from their place of origin. The most common clastic rocks are sandstone and shale.
COLLUVIAL DEPOSIT--Heterogeneous incoherent soil or rock material that slowly moves (creeps) down slope. Although creep is too slow to be observed, the cumulative results become obvious over a period of years.
COMMERCIAL WATER USE--Water for motels, hotels, restaurants, office buildings, and other commercial facilities, and institutions, both civilian and military. The water may be obtained from a public supply or may be self-supplied.
CONFINED AQUIFER--an aquifer bounded above and below by impermeable beds or by beds of distinctly lower permeability than that of the aquifer itself; an aquifer containing confined ground water.
CONFINED GROUND WATER--Ground-water under pressure substantially greater than atmospheric throughout and whose upper limit is the bottom of a bed having distinctly lower hydraulic conductivity than that of the material in which the confined water occurs.
CONFINING UNIT--A body of impermeable or distinctly less permeable material bounding one or more aquifers and is a general term that replaces aquitard and aquiclude.
CONSUMPTIVE USE--Water withdrawn that evaporates, transpires, is incorporated into products or crops, is consumed by humans or livestock, or otherwise removed from the immediate water environment. This use is also referred to as water consumed and water depletion.
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.
CUBIC FOOT PER SECOND--The rate of discharge representing a volume of 1 cubic foot passing a given point during 1 second and is equivalent to about 7.48 gallons per second, 448 gallons per minute, or 0.02832 cubic meter per second.
DISCHARGE--The volume of water (or generally, the volume of liquid plus suspended material) that passes a given point within a given period.
DISSOLVED--Refers to a substance present in true chemical solution. In practice, however, the term includes all forms of substances that will pass through a 0.45-micrometer membrane filter, and thus may include some colloidal particles.
DIVERSION--A channel designed to divert water from a body of water for purposes such as prevention of flooding, reduction of erosion, irrigation, or promotion of infiltration.
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 and self-supplied water.
DRAINAGE BASIN--The total area drained by a stream and its tributaries. Drainage area, determined planimetrically from topographic maps, is expressed in square miles or square kilometers.
EPHEMERAL STREAM--A stream or reach of a stream that flows briefly only in direct response to precipitation in the immediate locality and whose channel is at all times higher than the water table.
EVAPOTRANSPIRATION--The withdrawal of water from surface water and soil by evaporation and plant transpiration. This water is transmitted to the atmosphere as vapor.
FAULT--A fracture in bedrock along which movement of the bedrock has occurred.
FECAL COLIFORM BACTERIA--Bacteria that are present in the intestine and feces of warm-blooded animals. They are often used as indicators of the sanitary quality of water. There concentrations are expressed as numbers of colonies per 100 mL of sample.
FECAL STREPTOCOCCI BACTERIA--Bacteria that are found in the intestine of warm-blooded animals. Their presence is considered to verify fecal pollution. Their concentrations are listed as number of colonies per 100 mL of sample.
FORMATION--A body of rock identified by unique physical characteristics and relative position.
FREE WATER SURFACE--The surface of a body of water at which the pressure is atmospheric and below which the pressure is greater than atmospheric; the surface of any pond, reservoir, lake, or stream that is open to the atmosphere, or a water table (Syn: free water level).
HEAD--The height above a standard datum of the surface of a column of water (or other liquid) that can be supported by the static pressure at a given point.
HYDRAULIC CONDUCTIVITY--The volume of water will move in a porous medium in unit time under a unit hydraulic gradient through a unit area measured at right angles to the direction of flow. In contrast to permeability, it is a function of the properties of the liquid as well as of the porous medium.
HYDRAULIC GRADE LINE--In a closed channel, a line joining the elevations that water would attain in atmospheric pressure; in an open channel, the free water surface.
HYDRAULIC GRADIENT--In an aquifer, the rate of change of total head per unit of distance of flow at a given point and in a given direction. In a stream, the slope of the hydraulic grade line.
HYDRAULIC HEAD--(a) The height of the free surface of a body of water above a given subsurface point. (b) The water level at a point upstream from a given point downstream.
HYDROELECTRIC POWER WATER USE--Water used in the generation of electricity at plants where the turbine generators are driven by falling water. Hydroelectric water use is classified as an instream use.
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 obtained from a public supply or may be self-supplied.
INFILTRATION--The flow of water into soil at land surface, as contrasted with percolation, which is movement of water through layers of soil or other surficial material.
INSTREAM WATER USE--Water that is used, but not withdrawn from a ground- or surface-water source for purposes such as hydroelectric power generation, navigation, water-quality improvement, fish propagation, and recreation. Sometimes called non withdrawal use or in-channel use.
INTERMITTENT STREAM--A stream that ceases to flow occasionally or seasonally because evaporation and leakage to ground water exceed the available water supply.
IRRIGATION RETURN-FLOW--The part of artificially applied water that is not consumed by evapotranspiration and that migrates to an aquifer or surface-water body.
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.
LIMESTONE--A dense rock formed by chemical precipitation of calcium carbonate from solution in water.
LIVESTOCK WATER USE--Water for stock watering, feed lots, dairy operations, fish farming, and other on-farm needs.
MAXIMUM CONTAMINANT LEVEL (MCL)--Primary drinking water standard for public water supplies established by the U.S. Environmental Protection Agency (2001). MCLs are health related and legally enforceable.
MEDIAN--The middle number in a given sequence, or the average of the two middle numbers when the sequence has an even number of numbers. Median is not the average of the numbers.
MICROGRAMS PER LITER--A unit expressing the concentration of chemical constituents in solution as mass (micrograms) of solute per unit volume (liter) of water. One thousand micrograms per liter is equivalent to 1 milligram per liter.
MIDDLE RIO GRANDE BASIN (VALLEY)--The Middle Rio Grande Basin covers approximately 3,060 square miles in central New Mexico, encompassing parts of Santa Fe, Sandoval, Bernalillo, Valencia, Socorro, Torrance, and Cibola Counties. Commonly refers to the geologic basin from about Cochiti Dam to about San Acacia.
MILLIGRAMS PER LITER--A unit expressing the concentration chemical constituents in solution as mass (milligrams) of solute per unit volume (liter) of water. Concentration of suspended sediment also is expressed in milligrams per liter and is based on the mass (dry weight) of sediment per liter of water-sediment mixture.
MINING USE--Water used 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, and flotation), and other preparations customarily done at the mine site or as part of a mining activity.
NON-IDEAL COLONY COUNT (K)--A remark code used in reporting bacteria densities when plate counts fall outside of the ideal range. The lower limit of 20 colonies is set as the number below which statistically valid results become increasingly questionable. The upper limit, which differs according to type of bacteria, represents numbers above which interference from colony crowding, deposition of extraneous material, and other factors appear to result in increasingly questionable results.
OFFSTREAM USE--Water withdrawn or 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 use.
PEAK DISCHARGE--(peak flow, flood peak) the maximum instantaneous discharge during a specified time interval. The series of annual peak discharges at a gaging station is used to determine the recurrence interval (frequency) and exceedance probability of floods.
PEDIMENT--A broad, gently sloping erosion surface developed at the base of a mountain range in a dry region and is usually covered with a thin layer of gravel.
PERCENTILE--One of the values of a variable that divides the distribution of the variable into 100 groups having equal frequencies. In this report, the 25th and 75th percentile are used. Median also is used and is equivalent to the 50th percentile.
PERENNIAL STREAM--A stream that flows continuously.
pH--pH is defined as the negative logarithm of the hydrogen ion concentration. This parameter is dimensionless and has a range from 0.0 to 14.0, with a pH of 7.0 representing pure water. A pH of greater than 7.0 indicates the water is basic whereas a pH of less than 7.0 indicates acidic water.
PERMEABILITY--A measure of the ability of a porous medium to transmit fluids under a hydraulic gradient.
PIEZOMETER--A device used to measure ground-water pressure head at a point in the subsurface.
POROSITY--The volume percentage of the total bulk not occupied by solid particles.
POTENTIOMETRIC SURFACE--An imaginary surface representing the static head of ground water and defined by the level to which water will rise in a tightly cased well.
PUBLIC WATER SUPPLY USE--Water withdrawn by public and private water suppliers and delivered to users Public suppliers provide water for a variety of uses, such as domestic commercial, thermoelectric power, industrial, and public water use.
RAIN SHADOW--A dry region on the lee side of a mountain or mountain range. A rain shadow occurs because much of the moisture in an air mass is removed in the form of precipitation on the windward side of the mountain, as the air mass moves up and over the mountain. Because the air is then drier, precipitation on the lee side is noticeably less. Albuquerque is on the lee side of the Sandia Mountains.
RECHARGE--The process by which water is absorbed and added to the saturated zone (aquifer), either directly into a body of rock or indirectly by way of an adjacent body of rock. Also, it is the quantity of water that is added to the saturated zone.
REPORTING LIMIT--Minimum concentration of an analyte that can be reliably measured and reported by the laboratory using a particular analytical method.
SANDSTONE--The consolidated equivalent of sand. (See particle-size classification).
SANTA FE AQUIFER SYSTEM--This aquifer system supplies the ground-water resources for the Albuquerque metropolitan area and surrounding communities within the Middle Rio Grande Basin, and is composed chiefly of sand and silt with lesser amounts of gravel and clay. The system is divided into three parts: the upper (from less than 1,000 to 1,500 ft. thick), middle (from 250 to 9,000 ft. thick), and lower (from less than 1,000 to 3,500 ft. thick). Only about 2,000 ft of the aquifer is typically used for ground-water withdrawal. Ground water from this system is currently the sole source of water for municipal supply, domestic, commercial, and industrial use in the Middle Rio Grande Basin.
SATURATED ZONE--The subsurface zone in which all openings are full of water and are under hydrostatic pressure equal to or greater than atmospheric pressure.
SCREEN--A length of pipe of various lengths set at established depths in a well. It consists of small, regularly spaced, uniform perforations that allow water to pass into a well but not the sediment. The "screened interval" in a well is surrounded above, around, and below the screen by fine-grained sand.
SECONDARY MAXIMUM CONTAMINANT LEVEL (SMCL)--Secondary drinking-water standard for public water supplies established by the U.S. Environmental Protection Agency (2001). SMCLs primarily address aesthetic qualities of drinking water, and are not legally enforceable.
SECONDARY PERMEABILITY--The porosity developed in a rock after its deposition or emplacement, through such processes as solution or fracturing.
SEDIMENT--Unconsolidated solid material that originates mostly from disintegrated rocks and is transported by water or air. Also, it may include chemical and biochemical precipitates or decomposed organic material, such as humus.
SELF-SUPPLIED DOMESTIC WATER USE--Water withdrawn from a water source by a user rather than a public supplier.
SHALE--The consolidated equivalent of clay. (See particle-size classification).
SILTSTONE--The consolidated equivalent of silt.
SODIUM-ADSORPTION RATIO (SAR)--A measure of irrigation water sodium hazard. It is the ratio of sodium to calcium plus magnesium adjusted for valence. The SAR value of water is considered along with specific conductance in determining suitability for irrigation.
SPECIFIC CAPACITY--The rate of discharge of water from the well divided by the drawdown of the water level within the well.
SPECIFIC CONDUCTANCE--A measure of water's ability to conduct an electrical current. Specific conductance is expressed in microsiemens per centimeter (mS/cm) at 25 degrees Celsius (25oC). For water containing between 100 and 5,000 mg/L of dissolved solids, specific conductance in mS/cm (at 25oC) multiplied by a factor between 0.55 and 0.71 will approximate the dissolved-solids concentration in mg/L. For most water, reasonable estimates can be obtained multiplying by 0.64.
STAGE--The height of a water surface above an established datum plane.
STREAMFLOW--The discharge in a natural channel. Although the term "discharge" can be applied to a flow of a canal, the word "streamflow" is used only to describe the discharge in a surface-stream course. The term "streamflow" is more general than "runoff", since streamflow may be applied to discharge whether or not it is affected by diversion or regulation.
STREAMFLOW-GAGING STATION--A particular site on a stream, canal, lake, or reservoir where systematic observations of hydrologic data are collected.
TERRACE--A step-like landform above a stream and its floodplain representing a former, abandoned floodplain of a stream.
UNCONFINED AQUIFER--An aquifer that has a water table.
UNCONFINED GROUND WATER--Water in an aquifer that has a water table.
UNCONSOLIDATED--Refers to grains of sediment that are loose, separate, and (or) unattached to one another.
VOLCANICLASTIC--A clastic rock containing volcanic material
WATER TABLE--The water table is that surface in an unconfined water body at which the pressure is atmospheric. It is defined by the levels at which water stands in wells that penetrate the water body just far enough to hold standing water. In wells penetrating to greater depths, the water level will stand above or below the water table if an upward or downward component of ground-water flow exists.
WELL--A bored, drilled or driven shaft, or a dug hole, whose depth is greater than the largest surface dimension.