Appendix C Glossary
Acre-foot —
The volume of water required to cover 1 acre of land to a depth of 1 foot. Equal to 1.23 megaliters (ML) or 1,230 cubic meters (m3).
Advanced wastewater treatment —
Any physical, chemical or biological treatment process used to accomplish a degree of treatment greater than that achieved by secondary treatment.
Aquifer —
A formation, group of formations, or part of a formation that contains sufficient saturated permeable material to yield significant quantifies of water to wells and springs.
Basin —
(1) Hydrology: The area drained by a river and its tributaries. (2) Irrigation: A level plot or field, surrounded by dikes, which may be flood irrigated. (3) Runoff control: A catchment constructed to contain and slow runoff to permit the settling and collection of soil material transported by overland and rill runoff flows.
Benefit-cost ratio —
An economic indicator of the efficiency of a proposed project, computed by dividing benefits by costs; usually, both the benefits and the costs are discounted so that the ratio reflects efficiency in terms of the present value of future benefits and costs.
CFU —
Colony-forming unit.
COD —
Chemical oxygen demand.
Contaminant —
An undesirable substance not normally present or an unusually high concentration of a naturally occurring substance in water or soil.
Detection limit —
A number of different detection limits have been defined: IDL (instrument detection limit), is the constituent concentration that produces a signal greater than five times the signal to noise ratio of the instrument; MDL (method detection limit) is the constituent concentration that, when processed through a complete method, produces a signal with a 99 percent probability that it is different from a blank; PQL (practical quantification limit) is the lowest constituent concentration achievable among laboratories within specified limits during routine laboratory operations, The ratios of these limits are approximately: IDL:MDL:PQL = 1:4:20.
Disinfection by-products —
A range of organic and inorganic products resulting from the reaction of disinfecting oxidants with natural aquatic organic material reductants in water systems. The number and nature of all products are not precisely known at present, and vary with type of disinfectant employed. Some of the chlorination by-products are mutagenic (3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone) in the histidine reversion assay, and some are suspected animal carcinogens (Chloroform, and perhaps the entire family of trihalomethanes). Many disinfection by-products are of little or no toxicological significance, such as the non-halogen containing organic oxidation products and the simple halide ion reduction products.
DOC —
Dissolved organic carbon.
Domestic wastewater —
Sewage derived principally from human sources.
Enteric viruses —
A large group of viruses that are characterized by the fact that they replicate in the intestinal tract and are therefore present in fetal material.
Enteroviruses —
A specific group of enteric viruses that includes polioviruses, echoviruses, coxsackie viruses.
Entries to storm drainage —
Water (relatively clean or polluted) discharged into a stormwater drain from sources such as, but not limited to, direct industrial or sanitary wastewater connections, roof leaders, yard and area drains, cooling water connections, manhole covers, ground water or subterraneous stormwater infiltration, etc.
Flow line —
The general path that a particle of water follows under laminar flow conditions.
Fomites —
inanimate objects that might be contaminated with infectious organisms and thus serve to transmit disease.
Ground water —
That part of the subsurface water that is in the saturated zone.
Ground water mining —
The withdrawal of ground water through wells, resuiting in a lowering of the ground water table at a rate faster than the rate at which the ground water reservoir can be recharged.
Hydraulic conductivity —
A proportionality constant relating hydraulic gradient to specific discharge which for an isotropic medium and homogeneous fluid, equals the volume of water at the existing kinematic viscosity that will move in unit time under a unit hydraulic gradient through a unit area measured at right angles to the direction of flow.
Head —
The pressure of a fluid on a given area, at a given point caused by the height of the fluid surface above the point. Also, water-level elevation in a well, or elevation to which the water of a flowing artesian well will rise in a pipe extended high enough to stop the flow.
Hydraulic loading rate —
In recharge, the average infiltration into a recharge basin expressed over time, including flooded, dry, and cleaning cycles for the basin.
Infiltration rate —
Generally, the rate at which a soil under specified conditions can absorb falling rain or melting snow; in recharge, the rate at which water drains into the ground when a recharge basin is flooded, expressed in depth of water per unit time.
Injection well —
Well used for emplacing fluids into the subsurface.
Irrigation return flow —
The part of applied water that is not consumed by evapotranspiration and that migrates to an aquifer or surface water body.
NTU —
Nephelometric turbidity units.
Pathogen —
A disease-causing microorganism.
Permeability —
The property or capacity of a porous rock, sediment, or soil for transmitting a fluid without impairment of the structure of the medium; a measure of the relative ease of flow under unequal pressure.
PFU —
Plaque-forming unit.
Porosity —
The ratio of void volume to total volume of a porous medium.
Potable reuse, direct —
Occurs when there is a piped connection of water reclaimed from wastewater to a potable water supply distribution system or a water treatment plant.
Potable reuse, planned indirect —
Occurs when wastewater effluent is discharged to a water source with the intent of subsequently reusing the water rather than as a means of disposal.
Potable reuse, unplanned indirect —
Occurs when a water supply is withdrawn for potable purposes from a natural surface or underground water source that is fed in part by the discharge of a wastewater effluent. The wastewater effluent is discharged to the water source as a means of disposal and subsequent reuse of the effluent is a byproduct of the disposal plan.
Potable water —
Water that has been treated to be or is naturally suitable for drinking.
Pretreatment —
As used in this report, any treatment (e.g., the removal of
material such as gross solids, grit, grease, metals, toxicants, etc. or treatment such as aeration, pH adjustment, etc.) to improve the quality of a wastewater prior to recharge. This can also refer to the initial treatment processes of a sewage treatment plant.
Recharge area (ground water) —
An area in which water infiltrates the ground and reaches the zone of saturation.
Recharge capacity —
The ability of the soils and underlying material to allow precipitation and runoff to infiltrate and reach the zone of saturation.
Recharge, incidental —
Water that infiltrates to the water table by seepage from manmade works such as water supply lines, sewage systems, septic tank leach fields, etc. which are unintended sources of ground water recharge.
Recharge, natural —
The replenishment of ground water by downward infiltration of water from rainfall, streams, and other natural sources of water.
Recharge, planned (also called artificial) —
As used in this report refers to any active and artificial means of enhancing natural recharge. It includes spreading basins, recharge pits, injection wells, and other direct means of recharging ground water basins. The purposeful reinjection of low quality water for disposal purposes, such as related to oil and gas recovery, is not intended for future beneficial use and is not included within this definition.
Reclaimed water —
Wastewater made fit for reuse for potable or nonpotable purposes.
SAT —
Soil-aquifer treatment refers to processes that occur in the soil and aquifer that act to remove or reduce chemical and biological constituents of concem.
Saturated zone —
That part of the earth's crust beneath the regional water table in which all voids, large and small, are filled with water under pressure greater than atmospheric.
Secondary porosity —
The porosity developed in a rock formation after its deposition or emplacement, either through natural processes of dissolution or stress distortion, or artificially through acidization or the mechanical injection of coarse sand.
Sheet flow —
Overland flow in a relatively thin sheet of generally uniform thickness.
Site characterization —
A general term applied to the investigation activities at a specific location that examines natural phenomena and human-induced conditions important to the resolution of environmental, safety and water-resource issues.
Stormwater runoff —
Water resulting from precipitation which either infiltrates into the ground, impounds/puddles, or runs freely from the surface, or
is captured by storm drainage, a combined sewer, and to a limited degree, by sanitary sewer facilities.
is captured by storm drainage, a combined sewer, and to a limited degree, by sanitary sewer facilities.
Tertiary treatment —
The treatment of wastewater beyond the secondary or biological. Terms normally implies the removal of nutrients, such as phosphorus and nitrogen, and of a high percentage of suspended solids. Term now being replaced by preferable term, advanced waste treatment.
TDS —
Total dissolved solids.
TOC —
Total organic carbon.
Unsaturated zone —
The zone between the land surface and the regional water table. Generally, water in this zone is under less than atmospheric pressure, and some of the voids may contain air or other gases at atmospheric pressure. Beneath flooded areas or in perched water bodies the water pressure locally may be greater than atmospheric.
Vadose zone —
See unsaturated zone.
Wastewater —
Water that carries wastes from homes, businesses, and industries; a mixture of water and dissolved or suspended solids.
Water quality —
The chemical, physical, and biological condition of water related to a beneficial use.
Water resource —
The supply of ground and surface water in a given area.
Watershed —
A geographic region (area of land) within which precipitation drains into a particular river, drainage system or body of water that has one specific delivery point.
