Water Quality Exam 2 SG

USEPA defines "Attainable Uses" of a water body as

"The uses that can be achieved when (technology-based) effluent limits are imposed on point source dischargers and when cost-effective and reasonable best management practices are imposed on non-point source dischargers."

Drinking Water Supply

- For human consumption and general household use

Oyster Propagation

- Maintain biological systems that support economically important species of oysters, clams, mussels, or other mollusks so that their productivity is preserved and the health of human consumers of these species is protected

Floating, Suspended, and Settleable Solids (General Criteria)

- No substances present in concentrations sufficient to produce distinctly visible solids or scum, nor shall there be any formation of long-term bottom deposits of slimes or sludge banks attributable to waste discharges from municipal, industrial, or other sources - The administrative authority may exempt certain short-term activities permitted under Sections 402 or 404 and certified under Section 401 of the Clean Water Act, such as maintenance dredging of navigable waterways or other short-term activities determined by the state as necessary to accommodate legitimate uses or emergencies or to protect the public health and welfare.

Toxic Substances Standards (Numerical Criteria)

- Numerical criteria for specific toxic substances are mostly derived from publications of the Environmental Protection Agency, but also from natural background conditions - Based on acute and chronic concentrations in fresh and marine waters are developed primarily for attainment of the fish and wildlife propagation use. - Criteria applied to water bodies designated as drinking water supplies are developed to protect that water supply for human consumption, including protection against taste and odor effects, to protect it for primary and secondary contact recreation, and to prevent contamination of fish and aquatic life consumed by humans. - Criteria for water bodies not designated as drinking water supplies are developed to protect them for primary and secondary contact recreation and to prevent contamination of fish and aquatic life consumed by humans. - Metals criteria are based on dissolved metals concentrations in ambient waters. - For purposes of criteria assessment, the most stringent criteria for each toxic substance will apply.

Chlorides, Sulfates, and Total Dissolved Solids (Numerical Criteria)

- Numerical criteria for these parameters generally represent the arithmetic mean of existing data from the nearest sampling location plus three standard deviations. - For water bodies not specifically listed in the Numerical Criteria and Designated Table, increases over background levels of chlorides, sulfates, and total dissolved solids may be permitted. Such increases will be permitted at the discretion of the department on a case-by-case basis and shall not cause in- stream concentrations to exceed 250, 250, and 500 mg/L for chlorides, sulfates, and total dissolved solids, respectively, except where a use attainability analysis indicates that higher levels will not affect the designated uses. - Under no circumstances shall an allowed increase over background conditions cause any numerical criteria to be exceeded in any listed water body or any other general or numerical criteria to be exceeded in either listed or unlisted water bodies. -NO ROUNDING

Turbidity (General Criteria and Numerical Criteria)

- Other than that of natural origin shall not cause substantial visual contrast with the natural appearance of the waters of the state or impair any designated water use. Turbidity shall not significantly exceed background; background is defined as the natural condition of the water. Determination of background will be on a case-by-case basis. - As a guideline, maximum turbidity levels, expressed as nephelometric turbidity units (NTU), are established and shall apply for the following named water bodies and major aquatic habitat types of the state. - Freshwater lakes, reservoirs, and oxbows = 25 NTU - Designated scenic streams and outstanding natural resource waters not specifically listed = 25 NTU

Designated water bodies under the Louisiana Natural and Scenic Rivers System or designated by the department as ecological significance for:

- Preservation - Protection - Reclamation - Enhancement of wilderness, aesthetic qualities, and ecological regimes

Temperature (Numerical Criteria)

- Represent maximum values obtained from existing data - The criterion consists of two parts, a temperature differential and a maximum temperature. The temperature differential represents the maximum permissible increase above ambient conditions after mixing. - Fresh Water. The following temperature standards apply to fresh water: • maximum of 2.8°C (5°F) rise above ambient for streams and rivers; • maximum of 1.7°C (3°F) rise above ambient for lakes and reservoirs; and • maximum of 32.2°C (90°F), except where otherwise listed in the tables. - Estuarine and Coastal Waters. The following temperature standards apply to estuarine and coastal waters: • maximum of 2.2°C (4°F) rise above ambient from October through May; • maximum of 1.1°C (2°F) rise above ambient from June through September; and • maximum temperature of 35°C (95°F), except when natural conditions elevate temperature above this level. - These temperature criteria shall not apply to privately owned reservoirs or to reservoirs constructed solely for industrial cooling purposes.

Taste and Odor (General Criteria)

- Taste- and odor- producing substances in the waters of the state shall be limited to concentrations that will not interfere with the production of potable water by conventional water treatment methods or impart unpalatable flavor to food fish, shellfish, and wildlife, or result in offensive odors arising from the waters, or otherwise interfere with the designated water uses.

Dissolved Oxygen (Numerical Criteria)

- The following dissolved oxygen (DO) values represent minimum criteria for the type of water specified. - Naturally occurring variations below the criterion specified may occur for short periods. However, no waste discharge or human activity shall lower the DO concentration below the specified minimum. - These DO criteria are designed to protect indigenous wildlife and aquatic life species associated with the aquatic environment • Fresh Water. For a diversified population of fresh warmwater biota including sport fish, the DO concentration shall be at or above 5 mg/L. Fresh warmwater biota is defined in LAC 33:IX.1105. • Estuarine Waters. Dissolved oxygen concentrations in estuarine waters shall not be less than 4 mg/L at any time. • Coastal Marine Waters (Including Nearshore Gulf of Mexico). Dissolved oxygen concentrations in coastal waters shall not be less than 5 mg/L, except when upwellings and other natural phenomena cause this value to be lower.

Biological and Aquatic Community Integrity (General Criteria)

- The ideal condition of the aquatic community inhabiting the unimpaired water bodies of a specified habitat and region as measured by community structure and function. - Guided by the fish and wildlife propagation use designated for that particular water body. The condition of these aquatic communities shall be determined from the measures of physical, chemical, and biological characteristics of each surface water body type, according to its designated use. - Reference site conditions will represent naturally attainable conditions, which are least impacted and most representative of water body types • Observed to support the greatest variety and abundance of aquatic life in the region as is expected to be or has been recorded during past surveys in natural settings essentially undisturbed by human impacts, development, or discharges • Determined by consistent sampling and reliable measures of selected, indicative communities of animals and/or plants as established by the department and may be used in conjunction with acceptable chemical, physical, and microbial water quality measurements and records as deemed appropriate for this purpose.

Flow (General Criteria)

- The natural flow of state waters shall not be altered to such an extent that the basic character and water quality of the ecosystem are adversely affected except in situations where alterations are necessary to protect human life or property. - If alterations to the natural flow are deemed necessary, all reasonable steps shall be taken to minimize the adverse impacts of such alterations. Additionally, all reasonable steps shall be taken to mitigate the adverse impacts of unavoidable alterations.

Color (General Criteria)

- Water color shall not be increased to the extent that it will interfere with present usage or projected future use of the state's water bodies - Waters shall be free from significant increase over natural background color levels - A source of drinking water supply shall not exceed 75 color units on the platinum-cobalt scale - No increase in true or apparent color shall reduce the level of light penetration below that required by desirable indigenous species of aquatic life

Aesthetics (General Criteria)

- all waters shall be free from such concentrations of substances attributable to wastewater or other discharges sufficient to: - settle to form objectionable deposits; - float as debris, scum, oil, or other matter to form nuisances or to negatively impact the aesthetics; - result in objectionable color, odor, taste, or turbidity; - injure, be toxic, or produce demonstrated adverse physiological or behavioral responses in humans, animals, fish, shellfish, wildlife, or plants; or - produce undesirable or nuisance aquatic life.

Water bodies that have, but are not limited to:

- highly diverse or unique instream and/or riparian habitat - high species diversity - balanced trophic structure - unique species

Agriculture

-For crop spraying, irrigation, livestock watering, poultry operations, and other farm purposes not related to human consumption

Grouping Guidlines

-States are not required to designate each of these use categories to all waters. However, states must demonstrate that use attainment for categories that are excluded is not possible or unreasonable, and cannot be obtained in the future. -States may also remove specific uses already assigned to waters if the specific use is demonstrated to be unattainable currently or in the future.

Variances from Water Quality Standards

-Variance procedures involve the same substantive and procedural requirements as removing the designated use, but unlike use removal, variances are both discharger and pollutant specific, are time- limited, and do not forego the currently designate use. -A variant should be used instead of removal of a use where the State believes the standard can ultimately be attained. With a variance, NPDES permits may be written such that reasonable progress is made toward attaining the standards without violating section 402(a)(1) of the Act, which requires the NPDES permits must meet the applicable water quality standards. ➢ Variance is included as part of the water quality standard, and granted for a specific period of time and for specific constituents, ➢ State should demonstrate that meeting the standard is attainable, ➢ Justification for variance, Public notice ➢ Other requirements

Read 090207

090207 Where: Water Quality Management Basin Number Segment Number Subsegment Number

Generally, designated uses can be grouped:

1) Agricultural and industrial water supply, 2) recreation, 3) public water supply, and 4) aquatic life.

LOUISIANA'S DESIGNATED USES

1) Primary Contact Recreation (PCR) 2) Secondary Contact Recreation (SCR) 3) Fish & Wildlife Propagation (FWP) 4) Drinking Water Supply (DWS) 5) Shellfish Propagation (SFP) 6) Agriculture (AGR) 7) Outstanding Natural Resource (ONR) 8) Limited Aquatic/Wildlife Use (LAW)

Three General Approaches to Nutrient Criteria Development

1. The use of frequency distributions of nutrient concentrations from selected reference streams or available data, 2. The use of predictive relations between nutrients and selected response variables (e.g. chlorophyll-a, dissolved oxygen, aquatic life community structure), and 3. The modification of established nutrient and algal thresholds as defined in the literature (e.g., nuisance periphytic biomass defined as chlorophyll-a ranging from 100 to 150 mg/m2.

Nepal

60% waterborne diseases

AGR

Agriculture

Bacteria (Numerical Criteria)

Dependent on the strictest designated use of a water body.

DWS

Drinking Water Supply

FWP

Fish & Wildlife Propagation

Foaming or Frothing Materials (General Criteria)

Foaming or frothing materials of a persistent nature are not permitted.

Oil and Grease (General Criteria)

Free or floating oil or grease shall not be present in quantities large enough to interfere with the designated water uses, nor shall emulsified oils be present in quantities large enough to interfere with the designated uses

Designated Uses are a

LDEQ system

LAW

Limited Aquatic/Wildlife Use

Selenium

Neurodisruptor in fish, once fish are eaten they become a neurodisruptor for humans

Toxic Substances (General Criteria)

No substances shall be present in the waters of the state or the sediments underlying said waters in quantities that alone or in combination will be toxic to human, plant, or animal life or significantly increase health risks due to exposure to the substances or consumption of contaminated fish or other aquatic life. The numerical criteria (LAC 33:IX.1113.C.6) specify allowable concentrations in water for several individual toxic substances to protect from the toxic effects of these substances.

ONR

Outstanding Natural Resource

PCR

Primary Contact Recreation

Radioactive Materials (General Criteria)

Radioactive materials in the surface waters of the state designated for drinking water supply use shall not exceed levels established pursuant to the Federal Safe Drinking Water Act (P.L. 93-523 et seq.). -All phosphorous fertilizers are radioactive

Secondary Contact Recreation

Recreation or contact with water that involves body contact with the water where there is a probability of incidental or accidental ingesting a minimal amount of water occurs - Fishing - Wading - Boating

Primary Contact Recreation

Recreation or contact with water that involves prolonged or regular full- body contact with the water where there is a probability of ingesting a considerable amount of water occurs - Swimming - Skiing - Diving

SCR

Secondary Contact Recreation

SFP

Shellfish Propagation

Nutrients (General Criteria &Numerical Criteria)

The naturally occurring range of nitrogen-phosphorous ratios shall be maintained. This range shall not apply to designated intermittent streams. To establish the appropriate range of ratios and compensate for natural seasonal fluctuations, the administrative authority will use site- specific studies to establish limits for nutrients. Nutrient concentrations that produce aquatic growth to the extent that it creates a public nuisance or interferes with designated water uses shall not be added to any surface waters.

pH (Numerical Criteria)

The pH shall fall within the range of 6.0 to 9.0 unless natural conditions exceed this range or where otherwise specified in the table (LAC 33:IX.1123). No discharge of wastes shall cause the pH of a water body to vary by more than one pH unit within the specified pH range for the subsegment where the discharge occurs.

Fish and Wildlife Propagation

Use of water for any indigenous wildlife and aquatic life species associated with the aquatic environment - Aquatic habitat - Food - Resting - Reproduction - Cover - Travel corridors • Level of water quality that prevents damage to the above and contamination of aquatic biota that is consumed by humans

Background Condition

a concentration of a substance in a particular environment that is indicative of minimal influence by human (anthropogenic) sources.

Hydraulic Unit Code (HUC)

a hierarchical land area classification system created by the United States Geological Survey (USGS) that is based on surface hydrologic features in a standard, uniform geographical framework. Louisiana is mostly in 8. (Not correlated w/ Designated Uses)

Harmonic Mean Flow

a statistical value used to calculate permit limits where 7Q10 flow is not appropriate. This calculation is intended for positive numbers and non-zero values, thereby, precluding the use of negative flow values. The formula is as follows:

Excepted Use

a water body classification reflecting natural conditions and/or physical limitations that preclude the water body from meeting its designated use(s)

Acute Toxicity

adverse effects that take place in <96 hours

Chronic Toxicity

adverse effects that take place in >96 hours

Waters of the State (or State Waters)

all surface and underground waters and watercourses within the state of Louisiana, whether natural or man-made, including but not limited to, all rivers, streams, lakes, wetlands, and groundwaters, within the confines of the state, and all bordering waters extending three miles into the Gulf of Mexico.

Effluent Limitation

any applicable state or federal qualitative or quantitative limitation that imposes any restriction or prohibition on quantities, discharge rates, and concentrations of pollutants discharged into the waters of the state.

Cypress-Tupelo Swamps

areas inundated or saturated by surface water or groundwater of negligible to very low salinity at a frequency and duration sufficient to support, and that under normal circumstances do support, cypress-tupelo vegetation.

Bottomland Hardwood Swamps

areas inundated or saturated by surface water or groundwater of negligible to very low salinity at a frequency and duration sufficient to support, and that under normal conditions do support, bottomland hardwood vegetation.

All bodies of water must support

fish and life

Process Heat

heat derived from unnatural sources such as power plants and other industrial cooling processes.

Artificial Heat

heat derived from unnatural sources, such as power plants and other industrial cooling processes.

In establishing Water Quality Standards, states are first required to

identify and describe how surface waters are used and what traits (i.e., water quality parameters) should be managed to protect the use or uses.

White water

limestone naturally brings white water

Nuclear fallout in the Himalayas

may be contaminating water

Antidegradation

no further degregation or no start of degregation

Intermittent Streams

streams that provide water flow continuously during some seasons of the year but little or no flow during the drier times of the year.

Administrative Authority

the Secretary of the Department of Environmental Quality, or his designee or the appropriate assistant secretary or his designee.

Ambient Toxicity

the effect measured by a toxicity test on a sample collected from a water body.

7Q10 Flow

the minimum average stream flow for seven consecutive days with a recurrence interval of once every 10 years.

Highest Attainable Use

the modified aquatic life, wildlife, or recreation use that is both closest to the uses specified in section 101(a)(2) of the Clean Water Act and attainable, based on the evaluation of the factor(s) in LAC 33:IX.1109.B.3 that preclude(s) attainment of the use and any other information or analyses that were used to evaluate attainability. There is no required highest attainable use where the state demonstrates the relevant use specified in section 101(a)(2) of the Clean Water Act and subcategories of such a use are not attainable.

LC50

the numeric limit or concentration of a test material that is lethal to 50 percent of the exposed aquatic organisms within a specified period of time.

Whole Effluent Toxicity

the total toxic effect of an effluent measured directly with a toxicity test.

Receiving Waters

the waters of the state into which an effluent is, or may be, discharged.

Existing Use

those uses actually attained in the water body on or after November 28, 1975. They may or may not be designated uses.

1500

water bodies are not meeting designated uses

Numerical Criteria

• Apply to the specified water bodies, and to their tributaries, distributaries, and interconnected streams and water bodies contained in the water management subsegment if they are not specifically named therein, unless unique chemical, physical, and/or biological conditions preclude the attainment of the criteria. - In those cases, natural background levels of these conditions may be used to establish site-specific water quality criteria. • Those water bodies officially approved and designated by the state and EPA as intermittent streams, man-made water bodies, or naturally dystrophic waters may be excluded from some or all numerical criteria as stated in LAC 33:IX.1109. • Although naturally occurring variations in water quality may exceed criteria, water quality conditions attributed to human activities must not exceed criteria when flows are greater than or at critical conditions (as defined in LAC 33:IX.1115.C). -water bodies and designated land use

Policy Statements

• Concerned with the protection and enhancement of water quality in the state • In the state of Louisiana, there are policy statements provided on: - Antidegradation - Water use - Water body exception categories - Compliance schedules and variances - Short-term activity authorization - Errors - Severability - Revisions to standards - Sample collection and analytical procedures

Secondary Contact Recreation-Bacteria (Numerical Criteria)

• No more than 25 percent of the total samples collected on a monthly or near monthly basis shall exceed a fecal coliform density of 2,000/100 mL. This secondary contact recreation criterion shall apply year round.

Primary Contact Recreation-Bacteria (Numerical Criteria)

• No more than 25 percent of the total samples collected on a monthly or near monthly basis shall exceed a fecal coliform density of 400/100 mL. This primary contact recreation criterion shall apply only during the defined recreational period of May 1 through October 31. During the nonrecreational period of November 1 through April 30, the criteria for secondary contact recreation shall apply.

Drinking Water Supply-Bacteria (Numerical Criteria)

• No more than 30 percent of the total samples collected on a monthly or near-monthly basis shall exceed a fecal coliform density of 2,000/100 mL.

Limited Aquatic Life and Wildlife Use

• Subcategory of Fish and Wildlife Propagation • Recognizes "the natural variability of aquatic habitats, community requirements, and local environmental conditions" • Water bodies with habitats for regionally expected aquatic species that are absent or low in species diversity and richness, and a severely imbalanced trophic structure • Includes aquatic species that are tolerant of severe or variable environmental conditions • Qualifying water bodies include: - Intermittent streams - Man-made water bodies

Oyster Propagation-Bacteria (Numerical Criteria)

• The fecal coliform median most probable number (MPN) shall not exceed 14 fecal coliforms per 100 mL, and not more than 10 percent of the samples shall exceed an MPN of 43 per 100 mL for a fivetube decimal dilution test in those portions of the area most probably exposed to fecal contamination during the most unfavorable hydrographic and pollution conditions. -all warmblooded animals have fecal coliform in their intestines

Criteria

• Water quality elements that set limits, both general and numerical, on the substance amount or other characteristics of state waters that are allowed to sufficiently support a specific designated use • General and numerical criteria are established to promote restoration, maintenance, and protection of state waters which may be modified to take into account site-specific, local conditions • In Louisiana, the criteria is based on their present and potential uses and the existing water quality indicated by data accumulated through monitoring programs of the department and other state and federal agencies as well as universities and private sources • If the available water quality and flow data are not adequate to establish criteria, they are established based on the best information available from water bodies which are similar in hydrology, water quality, and physical configuration • General criteria specifically apply to human activities and numerical criteria applies to naturally occurring conditions -if there is no discharge there probably isn't any criteria -numerical water bodies are to specific waterbodies

Antidegradation Policy

➢ All state waters whose existing quality exceeds the specifications of the approved water quality standards or otherwise supports an unusual abundance and diversity of fish and wildlife resources will be maintained at their existing high quality. No lowering of water quality. ➢ Water quality cannot be lowered in waters where the designated water use standards are not being attained ➢ No wastewater discharge or activity will be permitted if it would impair water quality or use ➢ No degradation is allowed in water that are high-quality with ecological significance. ➢ Protecting existing use such as swimming, fishing or other uses.

Contact Recreation

➢ All states have adopted water quality criteria to protect the health of humans coming into contact with waters during recreational activities. ➢ Primary contact recreation is defined as any activity that involves the potential ingestion of or complete immersion in water, e.g. swimming, water-skiing, diving, and surfing. ➢ Secondary contact recreation is defined as activities that result in incomplete immersion, such as wading and boating. ➢ States may conduct UAA to demonstrate that specific waters cannot naturally support contact recreation criteria. ➢ Water quality criteria generally include fecal coliforms, total coliforms, and E. coli.

Antidegradation pt.2

➢ Antidegradation implementation is an integral component of a comprehensive approach to protecting and enhancing water quality. ➢ The 1987 amendment codifed in section 303(d) (4)(B) requires satisfaction of antidegradation requirements before making certain changes in NPDES permits. ➢ Applies to Outstanding National Resource Waters (ONRW), where the ordinary use classifications and supporting criteria may not be sufficient or appropriate. ➢ States may allow some limited activities which result in temporary and short-term changes in water quality, but such changes in water quality should not impact existing uses or alter the essential character os special use that makes the water an ONRW.

Antidegradation Pt.3

➢ Antidegradation policy ensures that high quality waters where there are existing point and nonpoint source control compliance problems, proposed new or expanded point sources are not allowed to contribute additional pollutants that could result in degradation. ➢ Where such problems exist, it would be inconsistent with the philosophy of the antidegradation policy to authorize the discharge of additional pollutants in the absence of adequate assurance that any existing compliance problems will be resolved. ➢ Antidegradation policy should be interpreted on a pollutant-by-pollutant and waterbody-by-waterbody basis. For example, proposed new BOD source that degrade high quality water should not be allowed prior to the implementation of required BMPs.

Aquatic Life Use

➢ Aquatic life use is intended to protect the propagation of fish and wildlife and aquatic biodiversity. ➢ Aquatic life use designation is highly subjective and requires that states assess the attainability of uses by individual water bodies. This is most often done for "classified segments" that are usually divided into individual lakes, reservoirs and wetlands, and stream or river reaches confined to a given geographic area. ➢ Toxic compounds including organics, metals, and other inorganics usually have specific numeric criteria developed by acute and chronic toxicity tests using model organisms (i.e. zooplankton). ➢ Other water quality parameters have numeric criteria necessary to support various degree of aquatic life use that may be regionally or system specific. Some of these variables include water temperature, pH, dissolved oxygen, and turbidity.

Drinking Water Supply Standards Pt.2

➢ Disinfectant compounds such as chlorine, chlorine dioxide, and chloramines are harmful for human consumption. They can cause eye/nose and stomach irritation and even anemia and nervous system disorders in children and young adults. ➢ These disinfectant compounds can undergo chemical reactions with organic matter in water to form various disinfectants by-products such as chlorite, haloacetic acids, and trihalomethanes. These compounds cause liver, kidney and nervous system disorders, and increased risk of various cancers. Therefore, disinfectants and disinfectant by-products in drinking water are monitored. -Different river segments have different criteria

Drinking Water Supply Standards

➢ Drinking water quality standards fall under federal jurisdiction. ➢ Under Safe Drinking Water Act (SDWA) 1974 USEPA -federal established national primary drinking water standards for microbiological contaminants, inorganic and organic chemical contaminants, and disinfectants and disinfection by-products. ➢ Drinking water standards are most often expressed in the form of a Maximum Contaminant Level (MCL). ➢ Contaminants can cause a variety of adverse effects in humans, including kidney, liver, and nervous system disorders and increased risk of various cancers. -states drop more water when it's allowed

Industrial and Agricultural Water

➢ Few states list specific water quality criteria for industrial and agricultural uses. This is most likely because most waters used in industrial and agricultural practices also have other uses such as aquatic life uses with more sensitive water quality criteria. However, some criteria listed include sulfate, chloride and total dissolved solids for agricultural water use. ➢ Many environmental concerns outside of water quality, such as aquifer depletion and minimum stream flows, drive environmental regulations on industrial water and agricultural water.

Frequency Distributions and Gradients

➢ Frequency distribution on Median Data from waterbodies across large spatial scales such as states, eco-regions, or large basins are used in developing nutrient criteria. ➢ Using Median Value of a waterbody in frequency distribution ensures the same influence of each waterbody in nutrient criteria determination across the region. ➢ Median Data values ensures less likely influence of extreme values or outliers.

NUTRIENT CRITERIA DEVELOPMENT

➢ Historically, narrative criteria for nutrients have been used by any states to protect designated uses. For example, Arkansas' Regulation 2 states that "Materials stimulating algal growth shall not be present in concentrations sufficient to cause objectionable algal densities or other nuisance aquatic vegetation or otherwise impair any designated use of the water body." ➢ States often assess variable that indicate impairments due to nutrient enrichment. For example, turbidity for water clarity, chlophyll-a for periphyton and or phytoplankto production, dissolved oxygen, pH fluctuations, aquatic life communities for fish and macroinvertebrate community structure, and other biological metrics based on aquatic life. ➢ Turbidity, dissolved oxygen, and pH are often used to indirectly assess designated use attainability related nutrients because these variables change response to nutrient availability.

Mixing Zones

➢ It is not always necessary to meet all water quality criteria within the discharge pipe to protect the integrity of the water body as a whole. Sometimes it is appropriate to allow for ambient concentrations above the criteria in small areas near outfalls. These areas are called mixing zones. ➢ Whether to establish a mixing zone policy is a matter of State discretion, but any State policy allowing for mixing zones must be consistent with the CWA and is subject to approval of the Regional Administrator. Allowing mixing zone characteristics should be established to ensure that: ➢ Mixing zones do not impair the integrity of the water body as a whole, ➢ There is no lethality to organisms passing through the mixing zone, ➢ There are no significant health risks, considering likely pathways of exposure.

Mixing Zones Pt.2

➢ Mixing zone characteristics should be defined on a case-by-case basis after it has been determined that the assimilative capacity of the receiving system can safely accommodate the discharge. ➢ This assessment should take into consideration of the physical, chemical, and biological characteristics of the discharge and the receiving system; the life history and behavior of the organisms in the receiving system; and the desired uses of the waters. ➢ Mixing zones should not be permitted where they may endanger critical areas, e.g., drinking water supplies, recreational areas, breeding grounds, areas with sensitive biota. -Mixing zones have higher pollutants than natural waters -the bigger the mixing zone the more companies can dump

Relations Between Nutrients and Biological Response Variables

➢ Nutrient Criteria developed based on Algae, Macroinvertebrate, Fish, Macrophyte, and Watershed Responses. ➢ Nutrient enrichment influences not only autotrophic response (e.g., periphyton biomass, chlorophyll-a) but also heterotrophic biomass and production, including heterotrophic microbes, macroinvertebrates and fish. ➢ Various statistical techniques used include correlation analyses, simple linear regression, nonlinear regression, locally weighted scatterplot smoothing, change point, and classification analysis.

WATER QUALITY CRITERIA

➢ Once the designated uses of a water body has been established, quantitative water quality criteria are established to protect those uses. ➢ In cases where multiple uses require different levels of the same parameter, the most sensitive value is used as the standard. ➢ USEPA has provided federal guidance to states on water quality criteria for specific pollutants and toxic substances.

REVIEW AND REVISION OF STANDARDS

➢ Section 303(c) (1) of the Clean Water Act requires that a State shall, from time to time, but at least once every three years, hold public hearings to review applicable water quality standards and, as appropriate, to modify adopt standards. ➢ States identify additions or revisions necessary to existing standards based on their 305(b) reports, other available water quality monitoring data, previous water quality standards reviews, or requests from industry, environmental groups, or the public. ➢ Water quality standards reviews and revisions may take any forms, including additions to and modifications in uses, in criteria, in the antidegradation policy, in the antidegradation implementation procedures, or on other general policies.

GENERAL POLICIES

➢ States may adopt certain policies in their standards affecting the application and implementation of standards. ➢ For example, policies concerning mixing zones, water quality standards variances, and critical flows for water quality-based permit limits may be adopted. ➢ These are the areas of State's discretion.

USE ATTAINABILITY ASSESSMENTS (UAAs)

➢ UAA is done potentially for attainment of all designated uses, but most often it is done for Aquatic Life Use. ➢ UAAs involve two phases: 1) a water body survey and assessment (comprehensive assessment of physical, chemical and biological characteristics of a water body that influence the ability of water body to support aquatic life use), and 2) a socio-economic assessment (the cost of improving point source treatment technology and implementing nonpoint source best management practices). ➢ Determination of whether to proceed with improvement, or eliminate or lower the aquatic life use designation.

Sources of Impairment

➢ Unknown sources (largely metals, chlorides, and sulfates). ➢ Natural sources (largely related to low DO, chlorides and sulfates). ➢ Municipal sewage treatment, septic tanks and other fecal coliform sources. ➢ Agriculture.

What are Water Quality Standards? Pt.2

➢ Water Quality Standards (Designated Uses and Associated Numeric Criteria) ➢ Water Quality Standards are dynamic rather than static and require periodic updates that consider changes to designated uses and new technologies that could improve water quality. ➢ States are required to review and update their water quality standards every three years.

Critical Low-Flows

➢ Water quality standards should protect water quality for designated uses in critical low-flow situations. In establishing water quality standards, States may designate a critical low-low flow below which numerical criteria do not apply. ➢ At all times, waters shall be free from substances that settle to form objectionable deposits; float as debris, scum, oil, or other matter; produce objectionable color, odor, taste, or turbidity; cause acutely toxic conditions; or produce undesirable or nuisance aquatic life. ➢ To do steady-state waste load allocation analyses, these low-flow values become design flows for sizing treatment plants, developing waste load allocations, developing water quality-based effluent limits. ➢ Historically, these so-called "design" flows were selected for the purposes of waste load allocation analyses that focused instream dissolved oxygen concentrations and protection of aquatic life. ➢ Now, hydrologically and biologically based analyses are done for the protection of aquatic life and human health. Most States adopt specific low-flow requirements for "design".

What are Water Quality Standards?

➢Water Quality Standards are numeric values or narrative descriptions of water quality parameters that are meant to sustain the designated uses of a water body. ➢ Water Quality Standards involve not only the actual criteria associated with water quality parameters, but how certain levels of those parameters negatively affect the use of that water for human and/or ecological purpose. ➢ CWA requires that states develop numeric criteria for pollutants if the presence of the pollutant was likely to affect the water body's use.