Water Acronyms and Definitions

To access the list, select a letter of the alphabet.

0 - 9 A B C D E F G H I K L M N O P Q R S T U V W Z

0 - 9

304(a) Guidance: refers to Section 304(a) of the Clean Water Act (CWA), 33 U.S.C. § 1314(a), which requires the United States Environmental Protection Agency to publish and periodically update ambient water quality criteria which will be protective of human health and the environment
401 Certification: Clean Water Act Section 401 requires state water quality certifications prior to the issuance of federal permits and licenses to ensure that proposed projects will not violate state water quality standards. The decision to issue a Section 401 water quality certification is based on compliance with APC&EC Rule 2, Establishing Water Quality Standards for Surface Waters of the State of Arkansas.
404 Permit: Clean Water Act Section 404 is the permitting program that controls the discharge of dredged or fill material into waters of the U.S. This also includes utility crossings.
7-day Average: also known as “average weekly” means the highest allowable average of “daily discharges” over a calendar week, calculated as the sum of all “daily discharges” measured during a calendar week divided by the number of “daily discharges” measured during that week

Abatement: the reduction in degree or intensity of pollution
Act: the Clean Water Act, Public Law 95-217 (33.U.S.C. 1251 et seq.) as amended
Acute Toxicity: a statistically significant difference (at the 95 percent confidence level) in mortality or immobilization between test organisms and a control measured during a specified period of time which is normally less than 96 hours
ADH: Arkansas Department of Health
Administrator: the Administrator of the U.S. Environmental Protection Agency
ADPC&EC: Arkansas Department of Pollution Control and Ecology Commission
AFIN: DEQ Facility Identification Number; an AFIN is a seven-digit number assigned by Fiscal Services to any new physical facility, i.e. building, set of buildings, plant, farm, landfill etc. The first two digits of the AFIN represent the county number; the last five are assigned according to how many facilities there are currently registered in that county.
AGFC: Arkansas Game and Fish Commission
Agricultural Water Supply Use: this beneficial use designates waters which will be protected for irrigation of crops and/or consumption by livestock
Algae: simple plants without roots, stems, or leaves that contain chlorophyll and are capable of photosynthesis
All Flows: takes into account all flows and data collected throughout the year, including elevated flows due to rainfall events
ANRC: Arkansas Natural Resources Commission
APC&EC: Arkansas Pollution Control and Ecology Commission
Applicable Effluent Standards and Limitations: all State and Federal effluent standards and limitations to which a discharge is subject under the Act, including, but not limited to, effluent limitations, standards of performance, toxic effluent standards and prohibitions, and pretreatment standards
Applicable Water Quality Standards: all water quality standards to which a discharge is subject under the federal Clean Water Act and which has been (a) approved or permitted to remain in effect by the Administrator following submission to the Administrator pursuant to Section 303(a) of the Act, or (b) promulgated by the Director pursuant to Section 303(b) or 303(c) of the Act, and standards promulgated under (APC&EC) Rule 2, as amended
Aquatic Biota: all those life forms which inhabit the aquatic environment
Aquatic Life Use: the designated use of a waterbody determined by the fish community and other associated aquatic biota
AST: Aboveground Storage Tanks
AWAG: Arkansas Watershed Advisory Group, a partnership of government, private, and nonprofit entities, including DEQ; dissolved 2013. DEQ currently collaborates with former AWAG members on various water quality and watershed management projects.
AWAPCA: Arkansas Water and Air Pollution Control Act
AWQMN: Ambient Water Quality Monitoring Network
AWWCC: Arkansas Water Well Construction Commission

Base Flows: that portion of the stream discharge that is derived from natural storage (i.e., outflow from groundwater or swamps), or sources other than recent rainfall that creates surface runoff; also called sustaining, normal, dry weather, ordinary, or groundwater flow
Bioaccumulation: the process by which a compound is taken up by an aquatic organism, both from water and through food
Best Management Practices (BMP): these are activities, practices, maintenance procedures, and other management practices designed to prevent or reduce the pollution of waters of the State. BMPs also include treatment technologies, operating procedures, and practices to control plant site runoff, spillage or leaks, sludge or waste disposal, or drainage from raw sewage. BMPs may include structural devices or nonstructural practices.
BOD5: Biochemical Oxygen Demand (5 day)
Bypass: the intentional diversion of waste streams from any portion of a treatment facility, as defined at 40 CFR 122.41(m)(1)(i)

CAFO: Concentrated Animal Feeding Operation
CAO: Consent Administrative Order
CAP: Corrective Action Plan
CBA: Cost/ Benefit Analysis
CBI: Compliance Biomonitoring Inspection
CBOD5: Carbonaceous Biochemical Oxygen Demand (5 day)
CCC: Criterion Continuous Concentration
CEI: Compliance Evaluation Inspection
CFR: Code of Federal Regulations
CFS: Cubic Feet per Second
Chronic Toxicity: a statistically significant difference (at the 95 percent confidence level) in mortality or immobilization, reduced reproduction or limited growth between test organisms and a control measured during a substantial segment of the life span of the test organism
CMC: Criterion Maximum Concentration
Combined Sewer Overflow (CSO) Inspection: The inspector evaluates compliance with CSO provisions present in the NPDES permit, an enforcement order, a consent decree, or another enforceable document. The inspector verifies that the permittee is preventing CSOs during dry weather, implementing the nine minimum CSO controls, adhering to a schedule for development, submission, and implementation of a Long-Term CSO Control Plan, eliminating or relocating overflows from sensitive areas, adhering to effluent limitations, and implementing a monitoring program.
Commission: The Arkansas Pollution Control and Ecology Commission
Compliance Biomonitoring Inspection (CBI): A CBI reviews a permittee's toxicity bioassay techniques and records maintenance to evaluate compliance with the biomonitoring terms of the NPDES permit and to determine whether the permittee's effluent is toxic. The CBI also includes the collection of effluent samples by the inspector to conduct acute and chronic toxicity testing to evaluate the biological effect of a permittee's effluent discharge(s) on test organisms.
Compliance Evaluation Inspection (CEI): A non-sampling inspection designed to verify permittee compliance with applicable permit self-monitoring requirements, effluent limits, and compliance schedules. Inspectors must review records, make visual observations, and evaluate treatment facilities, laboratories, effluents, and receiving waters. During the CEI, the inspector must examine both chemical and biological self-monitoring, which form the basis for all other inspection types except the Reconnaissance Inspection.
Compliance Sampling Inspection (CSI): During a CSI of an NPDES-permitted or unpermitted facility, inspectors must take representative samples. Inspectors then verify the accuracy of the facility’s self-monitoring program and reports through chemical and bacteriological analysis, determine compliance with discharge limitations, determine the quantity and quality of effluents, develop permits, and provide evidence for enforcement proceedings where appropriate. In addition, the CSI includes the same objectives and tasks as a CEI.
Composite Sample: a mixture of grab samples collected at the same sampling point at different times, formed either by continuous sampling or by mixing a minimum of 4 effluent portions collected at equal time intervals (but not closer than one hour apart) during operational hours, within the 24-hour period, and combined proportional to flow or a sample collected at more frequent intervals proportional to flow over the 24-hour period
Concentrated Animal Feeding Operation (CAFO) Inspection: The objective of this inspection is to evaluate a CAFO’s compliance with permit requirements, permit conditions, applicable regulations, and other requirements. The three types of CAFO inspections are the Status Determination Inspection, the Permit Compliance Inspection, and the Settlement Agreement Inspection. The type of information that the inspector gathers depends on the type of CAFO inspection being conducted.
Consent Administrative Order (CAO): an agreement negotiated between and then signed by DEQ and a facility or entity to resolve violations of a Permit or State or Federal law. CAOs, once signed, are binding and enforceable by DEQ in court.
Conventional Pollutants: pursuant to section 304(a)(4) of the Clean Water Act, 33 U.S.C. § 1314(a)(4), includes biochemical oxygen demand (BOD), total suspended solids (nonfilterable) (TSS), pH, fecal coliform, and oil and grease
Corrective Action Plan (CAP): the most common submittal requested by DEQ in an Order. The CAP typically details proposed remedial action to deal with a pollution event, non-compliance with a permit or violations noted on an inspection report and will usually include a timeline for such action and a reporting schedule.
CPP: Continuing Planning Process
Criterion Continuous Concentration (CCC): an estimate of the highest concentration of a material in ambient water to which an aquatic community can be exposed indefinitely without resulting in an unacceptable adverse effect. This is the chronic criterion.
Criterion Maximum Concentration (CMC): an estimate of the highest concentration of a material in ambient water to which an aquatic community can be exposed briefly without resulting in an unacceptable adverse effect. This is the acute criterion.
Critical Flows: the flow volume used as background dilution flows in calculating concentrations of pollutants from permitted discharges. These flows may be adjusted for mixing zones. The following critical flows are applicable:
- For a seasonal aquatic life - 1 cubic foot per second minus the design flow of any point source discharge (may not be less than zero);
- For human health - harmonic mean flow or long term average flow;
- For minerals - harmonic mean flow, except as follows:
  - Rule 2.511(A) Site Specific Mineral Criteria listed with an asterisk- 4 cubic feet per second
  - Rule 2.511 (C) Domestic Water Supply: Q7-10; and
- For metals and conventional pollutants - Q7-10
Critical Season: that period of the year when water temperatures exceed 22°C. This is normally the hot, dry season and after the majority of the fish spawning activities have ceased. This season occurs during a different time frame in different parts of the state, but normally exists from about mid-May to mid-September.
CSI: Community Structure Index or Compliance Sampling Inspection
CSO: Combined Sewer Overflow
Cumulative: increasing by successive additions
CV: coefficient of variation. The CV is used as a measure of precision among replicates for each treatment concentration of a Whole Effluent Toxicity Test. Coefficient of Variation is a standard statistical measure defined as the standard deviation divided by the mean.
CWA: Clean Water Act
CWS: Community Water System

Daily Discharge: the discharge of a pollutant measured during a calendar day or any 24-hour period that reasonably represents the calendar day for purposes of sampling
- Mass Calculations: for pollutants with limitations expressed in terms of mass, the “daily discharge” is calculated as the total mass of pollutant discharged over the sampling day
- Concentration Calculations: for pollutants with limitations expressed in other units of measurement, the “daily discharge” is calculated as the average measurement of the pollutant over the day
Daily Maximum: discharge limitation means the highest allowable “daily discharge” during the calendar month
Default Administrative Order (DAO): an order issued by a circuit court judge against a facility in their absence after they fail to appear for a court hearing
Department: The Division of Environmental Quality or its successor
Degradation: the act or process of causing any decrease in quality
DEQ: Division of Environmental Quality
Design Flow: a facility discharge flow of process wastewater that is authorized in a National Pollutant Discharge Elimination System (NPDES) permit
Designated Uses: those uses specified in the water quality standards for each waterbody or stream segment whether or not they are being attained
Diagnostic Inspection (DI): The DI primarily focuses on publicly owned treatment works (POTWs) that have not achieved permit compliance. POTWs that are having difficulty diagnosing their problems are targeted. The purposes of the DI are to identify the causes of noncompliance, suggest immediate remedies that will help the POTW achieve compliance, and support current or future enforcement action. Once the cause of noncompliance is defined, an administrative order is usually issued that requires the permittee to conduct a detailed analysis and develop a composite correction plan.
Director: the Director of the Division of Environmental Quality
Discharge: a discrete point source of waste or wastewater entering into waters of the state
Dissolved oxygen (DO): a measure of the concentration of oxygen in solution in a liquid
DLG: Digital Line Graph
DMR: Discharge Monitoring Report
Domestic Water Supply Use: this beneficial use designates water which will be protected for use in public and private water supplies. Conditioning or treatment may be necessary prior to use.

Ecologically Sensitive Waterbody (ESW): this beneficial use identifies segments known to provide habitat within the existing range of threatened, endangered or endemic species of aquatic or semi-aquatic life forms
Ecoregion: a large area of landscape with relatively homogenous physical, chemical and biological characteristics
Emergency Order (EO): an enforcement action issued (initially verbally, then in writing) by the Director of DEQ under the authority of the Arkansas Water and Air Pollution Control Act that seeks to halt, as quickly as possible, a pollution event that is directly affecting the environment or human health
Endemic: native to and confined to a specific region
EO: Emergency Order
EPA: Environmental Protection Agency
ER: Emergency Response
EPT: Ephemeroptera/ Plecoptera/ Trichoptera
ERW: Extraordinary Resource Waters
Escherichia coli (E. coli): a rod shaped gram negative bacillus (0.5 – 3-5 microns) abundant in the large intestines of mammals
ESW: Ecologically Sensitive Waterbody
Existing Uses: those uses listed in Section 303(c)(2) of the Clean Water Act, 33 U.S.C. § 1313(c)(2) (i.e., public water supplies, propagation of fish and wildlife, recreational uses, agricultural and industrial water supplies, and navigation), which were actually attained in the waterbody on or after November 28, 1975, whether or not they are included in the water quality standards
Extraordinary Resource Waters (ERW): this beneficial use is a combination of the chemical, physical and biological characteristics of a waterbody and its watershed which is characterized by scenic beauty, aesthetics, scientific values, broad scope recreation potential and intangible social values

FEA: Formal Enforcement Action
Fecal Coliform Bacteria (FCB): gram-negative nonspore-forming rods that ferment lactose in 24 ± 2 hours at 44.5 ± 0.2°C with the production of gas in a multiple-tube procedure or produce acidity with blue colonies in a membrane filter procedure. For the purpose of this regulation, the genus Klebsiella is not included in this definition.
Fishable/ Swimmable: refers to one of the national goals stated in Section 101(a)(2) of the Clean Water Act, 33 U.S.C. § 1251(a)(2) ,“...provides for the protection and propagation of fish, shellfish and wildlife and provides for recreation in and on the water”
FK: Fish Kill
Follow-up Inspection: The follow-up inspection is a resource intensive inspection conducted when an enforcement problem is identified as a result of a routine inspection or a complaint. For a follow-up inspection, the appropriate resources are assembled to deal effectively with a specific enforcement problem.
Formal Enforcement Action: a Consent Administrative Order (CAO), Default Administrative Order (DAO), or Emergency Order (EO) is considered as a Formal Enforcement Action

Grab Sample: an individual sample collected in less than 15 minutes in conjunction with an instantaneous flow measurement
Groundwater: water below the land surface in a zone of saturation

Hardness: a measure of the sum of multivalent metallic cations expressed as calcium carbonate (CaCO₃)
Harmonic Mean Flow: the reciprocal of the mean of the reciprocals of daily flow measurements
HBI: Hilsenhoff Biotic Index
Headwater: the upper watershed area where streams generally begin; typically consists of 1st- and 2nd-order streams
Heavy Metals: a general name given to the ions of metallic elements heavier than iron, such as cadmium, lead, mercury, copper, zinc and chromium
HUC: Hydrologic Unit Code
Human Health Criteria: levels of toxicants in ambient water which will not manifest adverse health effects in humans
Hypolimnion: that portion of a thermally stratified lake or reservoir below the zone in which the rate of temperature change is greatest; an area of minimal circulation and mixing

ICIS: Integrated Compliance Information System
IGP: Industrial Stormwater General Permit
Impairment: exceedences of the water quality standards by a frequency and/or magnitude which results in any designated use of a waterbody to fail to be met as a result of physical, chemical or biological conditions
Indicator Species: species of fish which may not be dominant within a species group and may not be limited to one area of the state, but which, because of their presence, are readily associated with a specific ecoregion. All indicator species need not be present to establish a normal or representative fishery.
Indigenous: produced, growing or living naturally in a particular region or environment
Industrial User: a nondomestic discharger, as identified in 40 CFR Part 403, introducing pollutants to a publically owned treatment work (POTW)
Industrial Water Supply Use: this beneficial use designates water which will be protected for use as process or cooling water. Quality criteria may vary with the specific type of process involved and the water supply may require prior treatment or conditioning.
Instantaneous Flow Measurement: the flow measured during the minimum time required for the flow-measuring device or method to produce a result in that instance. To the extent practical, instantaneous flow measurements coincide with the collection of any grab samples required for the same sampling period so that together the samples and flow are representative of the discharge during that sampling period.
Instantaneous Maximum: when limited in the permit as an instantaneous maximum value, shall mean that no value measured during the reporting period may fall above the stated value
Instantaneous Minimum: an instantaneous minimum value, shall mean that no value measured during the reporting period may fall below the stated value
Integrated Compliance Information System (ICIS): a database maintained by the EPA of all National Pollutant Discharge Elimination System (NPDES) permits (including requirements under the permits such as effluent limits or scheduled reports) and formal enforcement actions
Interstate: of, connecting, or existing between two or more states
Intrastate: existing or occurring within a state
Ionizing Radiation: gamma rays and x-rays; alpha and beta particles, high speed electrons, neutrons, protons and other nuclear particles; but not sound or radio waves, or visible, infrared or ultraviolet light
IWC: Instream Waste Concentration

Key Species: fish which are normally the dominant species (except for some ubiquitous species) within the important groups such as fish families or trophic feeding levels. All specified key species need not be present to establish a normal or representative fishery.

Long Term Average Flow: an average annual stream flow based on a period of record which reflects the typical annual variability

MC: Methylene Chloride
MCL: Maximum Contaminant Level
mg/l: Milligrams per Liter or Parts per Million (ppm)
MGD: Million Gallons per Day
Milligrams per Liter (mg/L): the concentration at which one milligram is contained in a volume of one liter; one milligram per liter is equivalent to one part per million (ppm) at unit density
MIT: Mechanical Integrity Testing
Mixing Zone: an area where an effluent discharge undergoes mixing with the receiving waterbody. For toxic discharges a zone of initial dilution may be allowed within the mixing zone.
Monthly Average: the highest allowable average of “daily discharges” over a calendar month, calculated as the sum of all “daily discharges” measured during a calendar month divided by the number of “daily discharges” measured during that month. For Fecal Coliform Bacteria (FCB) or E-Coli, report the Monthly Average as the geometric mean of all “daily discharges” within a calendar month.
Monitoring and Reporting: when a permit becomes effective, monitoring requirements are of the immediate period of the permit effective date. Where the monitoring requirement for an effluent characteristic is monthly or more frequently, the Discharge Monitoring Report (DMR) shall be submitted by the 25th of the month following the sampling. Where the monitoring requirement for an effluent characteristic is Quarterly, Semi-Annual, Annual, or Yearly, the DMR shall be submitted by the 25th of the month following the monitoring period end date.
- Monthly: defined as a calendar month or any portion of a calendar month for monitoring requirement frequency of once/month or more frequently
- Bi-monthly: defined as two (2) calendar months or any portion of 2 calendar months for monitoring requirement frequency of once/ 2 months or more frequently
- Quarterly:
  1. is defined as a fixed calendar quarter or any part of the fixed calendar quarter for a non-seasonal effluent characteristic with a measurement frequency of once/quarter. Fixed calendar quarters are: January through March, April through June, July through September, and October through December; or
  2. is defined as a fixed three month period (or any part of the fixed three month period) of or dependent upon the seasons specified in the permit for a seasonal effluent characteristic with a monitoring requirement frequency of once/quarter that does not coincide with the fixed calendar quarter. Seasonal calendar quarters are: May through July, August through October, November through January, and February through April.
- Semi-annual: defined as the fixed time periods January through June, and July through December (or any portion thereof) for an effluent characteristic with a measurement frequency of once/6 months or twice/year
- Annual or Yearly: defined as a fixed calendar year or any portion of the fixed calendar year for an effluent characteristic or parameter with a measurement frequency of once/year. A calendar year is January through December, or any portion thereof.
Mouth: the point of confluence where a stream enters a larger body of water
MS4: Municipal Separate Storm Sewer System

National Pollutant Discharge Elimination System (NPDES): the national program for issuing, modifying, revoking and reissuing, terminating, monitoring and enforcing permits, and imposing and enforcing pretreatment requirements under Sections 307, 402, 318, and 405 of the Clean Water Act.
Natural and Scenic Waterways (NSW): this beneficial use identifies segments which have been legislatively adopted into a state or federal system.
Natural Background: ambient conditions or concentrations of a parameter due to non-anthropogenic sources; natural background does not typically interfere with support of designated uses nor the level of aquatic biota expected to occur naturally at the site.
Naturally Occurring Excursions: temporary deviation from natural background due to natural events such as severe storm events, drought, temperature extremes, etc.
Nephelometric Turbidity Unit (NTU): a measure of turbidity based upon a comparison of the intensity of light scattered by a sample of water under defined conditions with the intensity of light scattered by a standard reference suspension; NTU are considered comparable to the previously reported Jackson Turbidity Units (JTU). May also be reported as Formazin Turbidity Units (FTU) in equivalent units.
NFH: National Fish Hatchery
NH3-N: Ammonia Nitrogen
NHD: National Hydrography Dataset
NOEC: No Observed Effect Concentration
Nonpoint Source: a contributing factor to water pollution that is not confined to an end-of-the-pipe discharge, i.e., stormwater runoff not regulated under Clean Water Act § 402(p)(1), 33 U.S.C. § 1342(p), agricultural or silvicultural runoff, irrigation return flows, etc
Notice of Violation (NOV): an NOV, although similar in format to a Consent Administrative Order (CAO), is exactly what it claims to be, a notice. An NOV is signed only by DEQ’s Director and requires the Respondent to retain an attorney and file a request for hearing if they want to dispute the allegations stated therein or negotiate the corrective action set out by DEQ. Typically, NOVs do not proceed to hearing but are settled instead by a CAO after the facility contacts DEQ requesting negotiations.
NPDES: National Pollutant Discharge Elimination System
NPS: Non-Point Source
NRCS: Natural Resources Conservation Service
NRSA: National Rivers and Streams Assessment
NSW: Natural and Scenic Waterways
NTU: Nephelometric Turbidity Unit
Nuisance Species: those organisms capable of interfering with the beneficial use of water
Nutrient: any substance assimilated by an organism which promotes growth and replacement of cellular constituents. The usual nutrient components of water pollution are nitrogen, phosphorus and carbon.

Objectionable Algal Densities: numbers of total algae which would interfere with a beneficial use
OSG: Office of the State Geologist

Performance Audit Inspection (PAI): The inspector conducts a PAI to evaluate the permittee's self-monitoring program. As with a compliance evaluation inspection (CEI), the PAI verifies the permittee's reported data and compliance through a records check. However, the PAI provides a more resource-intensive review of the permittee's self-monitoring program and evaluates the permittee's procedures for sample collection, flow measurement, chain-of-custody, laboratory analyses, data compilation, reporting, and other areas related to the self-monitoring program. In a CEI, the inspector makes a cursory visual observation of the treatment facility, laboratory, effluents, and receiving waters. In a PAI, the inspector observes the permittee performing the self-monitoring process from sample collection and flow measurement through laboratory analyses, data workup, and reporting. The PAI does not include the collection of samples by the inspector. However, the inspector may require the permittee to analyze performance samples for laboratory evaluation purposes.
Permit Data System (PDS): DEQ’s in-house software for tracking permit information such as facility mailing address, applicable use codes and invoicing information. Also provides links to lists of inspections, complaints and enforcement actions.
Persistent: degraded only slowly by the environment
pH: the negative logarithm of the effective hydrogen-ion concentration in gram equivalents per liter
Picocurie: One trillionth (10 ^-13) of a curie which is a unit of quantity of any radioactive nuclide in which 3.7 X 10¹⁰ disintegrations occur per second
PMSD: percent minimum significant difference. In chronic whole effluent toxicity tests, the PMSD is used for evaluating within-test variability. The PMSD is the smallest percentage decrease in growth or reproduction from the control that could be determined as statistically significant in the test.
Point Source: a discharge from a discrete point
POTW: Publically Owned Treatment Works
ppm: Parts per Million
Pretreatment Compliance Inspection (PCI): The PCI evaluates the POTW's implementation of its approved pretreatment program. It includes a review of the publicly owned treatment work’s (POTW's) records on monitoring, inspections, and enforcement activities for its industrial users (IUs). The PCI may be supplemented with IU inspections. An IU inspection is an inspection of any significant IU that discharges to the POTW. The inspection can include sampling or not, depending on the reason for the inspection. If feasible, inspectors should conduct the PCI concurrently with another NPDES inspection of the POTW.
Primary Contact Recreation: this beneficial use designates waters where full body contact is involved. Any streams with watersheds of greater than 10 mi² are designated for full body contact. All streams with watersheds less than 10 mi² may be designated for primary contact recreation after site verification.
Primary Season: that period of the year when water temperatures are 22°C or below. This includes the major part of the year from fall through spring, including the spawning season of most fishes. It normally occurs from about mid-September to mid-May.
PWS: Public Water Suppliers
PWSSP: Public Water Supply Supervision Program
Publicly Owned Treatment Works (POTW): a treatment works which is owned by a state or municipality

Q7-10: a flow volume equal to or less than the lowest mean discharge during 7 consecutive days of a year which, on the average, occurs once every 10 years
QA/ QC: Quality Assurance / Quality Control

Regulated-Flow Stream: Those streams restricted by structures which have the ability to control stream flow
Reconnaissance Inspection (RI): The RI is used to obtain a preliminary overview of a permittee's compliance program. The inspector performs a brief visual inspection of the permittee's treatment facility, effluents, and receiving waters. The RI uses the inspector's experience and judgement to summarize quickly any potential compliance problems. The objective of the RI is to expand inspection coverage without increasing inspection resources. The RI is the briefest and least resource- intensive of all NPDES inspections.
River Reach File 3 (RF3): The U.S. Environmental Protection Agency's River Reach File is a hydrographic database and GIS layer of the surface waters of the continental U.S. and Hawaii. The structure and content of the Reach File database were created expressly to establish hydrologic ordering, to perform hydrologic navigation for modeling applications, and to provide a unique identifier for each surface water feature. Development of Reach File 3 began in 1989. RF3 contains over 3,100,000 individual hydrographic features (reaches) and over 93,000,000 coordinate points. The RF3 file is no longer the primary GIS layer used. USGS Medium or High Resolution National Hydrography Dataset (NHD) data is most commonly used now.
RST: Regulated Storage Tanks
RWQMN: Roving Water Quality Monitoring Network

SA: State Agriculture
Sampling and Analysis Plan (SAP): usually required as part of a CAO resolving a pollution event, a SAP will compel the Respondent to submit a technical plan to DEQ detailing their proposal for soil or water sampling with the goal of determining the extent of pollution or the success of a cleanup
Sanitary Sewer Overflow (SSO) Inspection: During an SSO inspection, the inspector evaluates compliance with SSO provisions present in the NPDES permit, an enforcement order, a consent decree, or another enforceable document. The inspector collects information to verify that the permittee is complying with the NPDES standard permit conditions (duty to mitigate and proper operation and maintenance) and the required notification procedures. The inspector also determines whether there have been any unpermitted discharges, or discharges from a location other than the discharge point specified in the permit, to waters of the United States.
SDWA: Safe Drinking Water Act
Seasonal Aquatic Life: the designated aquatic life use that occurs in some waterbodies only during the period when stream flows increase substantially and water temperatures are cooler. This is normally during the months of December through May.
Secondary Contact Recreation: this beneficial use designates waters where secondary activities like boating, fishing or wading are involved
SEP: Supplementary Environmental Project
Severe Property Damage: substantial physical damage to property, damage to the treatment facilities which causes them to become inoperable, or substantial and permanent loss of natural resources which can reasonably be expected to occur in the absence of a bypass. Severe property damage does not mean economic loss caused by delays in products.
Sewage Sludge: the solids, residues, and precipitate separated from or created in sewage by the unit processes at a POTW. Sewage as used in this definition means any wastes, including wastes from humans, households, commercial establishments, industries, and stormwater runoff that are discharged to or otherwise enter a Publicly Owned Treatment Work (POTW).
Sewage Sludge Inspection: The objectives of a sewage sludge inspection are to determine compliance with Federal 503 sludge regulations for any facility engaged in a regulated sludge or disposal practice and to evaluate the permittee’s compliance with sludge monitoring, recordkeeping and reporting, treatment operations, and sampling and laboratory quality assurance. The PCI, CEI, and PAI are the most likely vehicles for evaluating compliance with sludge requirements.
Short Term Activity Authorization: the Director may authorize, with whatever conditions deemed necessary and without public notice, short term activities which might cause a violation of the Arkansas Water Quality Standards. This authorization is subject to the provisions that such activity is essential to the protection or promotion of the public interest and that no permanent or long-term impairment of beneficial uses is likely to result from such activity. Nothing herein shall be intended to supersede existing state and federal permitting processes or requirements. The Director shall specify the degree of variance from the standards, the time limit of activity and restoration procedures where applicable. Such authorization shall not be granted for activities which result in the adverse impact on any federally threatened or endangered species or on critical habitat of such species.
SI: State Industrial
SIC: Standard Industrial Code
SL: State Land Application
SMCL: Secondary Maximum Contaminant Level
SOP: Standard Operating Procedure
SS: State Sanitary
STAA: Short Term Activity Authorization
State of Arkansas Continuing Planning Process: a document setting forth the principal procedures of the State’s water quality management programs, developed pursuant to Section 303(e) of the Clean Water Act, 33 U.S.C. 1313(e), and 40 C.F.R. § 130.5. The CPP is not a regulation.
Storm Water Inspection: Storm water inspections are designed to ensure that regulated facilities have a NPDES permit for storm water discharge and a Storm Water Pollution Prevention Plan (SWPPP) and are following the specifications in each. During the inspection, the inspector reviews the permit and the SWPPP and determines whether the SWPPP meets the requirements set forth in the permit. The inspector also reviews records, such as self-inspection reports, to verify that the facility is complying with its permit and the SWPPP and walks the site to verify that the SWPPP is accurate and BMPs are in place and functioning properly.
s.u.: Standard Units
Supplementary Environmental Project (SEP): a facility under a CAO may, during negotiations, elect to direct up to 35% of their penalty towards a SEP. SEPs are intended to more directly benefit the environment or local community than simply paying a cash penalty to DEQ.
Surface Water: that water contained on the exterior or upper portion of the earth's surface as opposed to groundwater
SVOC: Semi-Volatile Organic Compounds
SWAP: Source Water Protection Program
SWMP: Storm Water Management Plan
SWP: Source Water Program
SWPPP: Stormwater Pollution Prevention Plan
Synergism: cooperative action of discrete agents such that the total effect is greater than the sum of the effects taken independently

TDS: Total Dissolved Solids
TMDL: Total Maximum Daily Load
Total Dissolved Solids (TDS): the total soluble organic and inorganic material contained in water; includes those materials, both liquid and solid, in solution and otherwise, which pass through a standard glass fiber filter disk and are not volatilized during drying at 180°C.
Total Maximum Daily Load (TMDL): a TMDL is a pollution budget and includes a calculation of the maximum amount of a pollutant that can occur in a waterbody and allocates the necessary reductions to one or more pollutant sources.
Toxics Sampling Inspection (XSI): The XSI has the same objectives as a conventional CSI. However, it places increased emphasis on toxic substances regulated by the NPDES permit. The XSI covers priority pollutants other than heavy metals, phenols, and cyanide, which are typically included in a CSI (if regulated by the NPDES permit). An XSI uses more resources than a CSI because sophisticated techniques are required to sample and analyze toxic pollutants. An XSI may also evaluate raw materials, process operations, and treatment facilities to identify toxic substances requiring controls.
TRE: Toxicity Reduction Evaluation
Treatment Works: any devices and systems used in storage, treatment, recycling, and reclamation of municipal sewage and industrial wastes, of a liquid nature to implement section 201 of the Act, or necessary to recycle reuse water at the most economic cost over the estimated life of the works, including intercepting sewers, sewage collection systems, pumping, power and other equipment, and alterations thereof; elements essential to provide a reliable recycled supply such as standby treatment units and clear well facilities, and any works, including site acquisition of the land that will be an integral part of the treatment process or is used for ultimate disposal of residues resulting from such treatment.
Trout Fishery: water which is suitable for the growth and survival of trout, usually characterized as high quality water having a maximum summer temperature of 68°F or less
TSS: Total Suspended Solids

UIC: Underground Injection Control
Units of Measure:
- µg/l: Micrograms per Liter or Parts per Billion (ppb)
- cfs: Cubic Feet per Second
- mg/l: Milligrams per Liter or Parts per Million (ppm)
- MGD: Million Gallons per Day
- ppm: Parts per Million
- s.u.: Standard Units
Upset: an exceptional incident in which there is unintentional and temporary noncompliance with technology-based permit effluent limitations because of factors beyond the reasonable control of the permittee. Any upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, lack of preventive maintenance, or careless of improper operations.
USDW: Underground Sources of Drinking Water
Use Attainability Analysis (UAA): a structured scientific assessment of the factors affecting the attainment of the fishable/swimmable use which may include physical, chemical, biological and economic factors
USFWS: United States Fish and Wildlife Service
USGS: United States Geological Survey
UST: Underground Storage Tank

VOC: Volatile Organic Compounds
Visible Sheen: the presence of a film or sheen upon or a discoloration of the surface of the discharge. A sheen can also be from a thin glistening layer of oil on the surface of the discharge.

W/A: Watershed to Lake Area Ratio
Water Effects Ratio (WER): a specific pollutant’s acute or chronic value measured from a specific site ambient water, divided by the respective acute or chronic toxicity of the same pollutant in laboratory water
Waterbodies, Waterways, Waters: in this document, refers to surface waters of the State as described in Act 472
Weekday: Monday – Friday
WET, Project: Water Education for Teachers
Whole Effluent Toxicity (WET) Testing: refers to the aggregate toxic effect to aquatic organisms from all pollutants contained in a facility's wastewater (effluent). It is one way we implement the Clean Water Act's prohibition of the discharge of toxic pollutants in toxic amounts. WET tests measure wastewater's effects on specific test organisms' ability to survive, grow and reproduce.
WHPA: Wellhead Protection Area
WHPP: Wellhead Protection Program
WQAR: Water Quality Analysis Reporter
WQMP: Water Quality Management Plan
WWTP: Waste Water Treatment Plant

Zone of Initial Dilution (ZID): an area within the mixing zone where a toxic effluent discharge initiates mixing in the receiving waterbody. This is an area where acute water quality criteria may be exceeded, but acute toxicity may not occur.