total maximum daily load tmdl n.
Skip this Video
Loading SlideShow in 5 Seconds..
Total Maximum Daily LOAD (TMDL) PowerPoint Presentation
Download Presentation
Total Maximum Daily LOAD (TMDL)

Total Maximum Daily LOAD (TMDL)

104 Vues Download Presentation
Télécharger la présentation

Total Maximum Daily LOAD (TMDL)

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Total Maximum Daily LOAD (TMDL) Teresa Marks Director

  2. Laws and Regulations • The Clean Water Act of 1972 requires states to establish water quality standards (WQS) for all waterbodies within the state • Arkansas’s WQS are established in Regulation No. 2 by the Arkansas Pollution Control and Ecology Commission (APC&EC) • WQS include: • Designated uses • Water Quality Criteria

  3. Water Quality Standards • “Designated uses” specify how the water body can be used, such as warm water fishery or primary contact recreation or domestic water supply. States must assign one or more uses to each of their waters. • Water quality criteria are the in-stream parameters designed to protect the designated uses. Water quality criteria can be numeric or narrative.

  4. Water Quality Standards • "Numeric Criteria" are quantitative criteria specifying precise, measurable levels of particular chemicals or conditions allowable in a water body such as Turbidity (in lakes at base flows is 25 NTUs), pH (is 6 to 9), and Dissolved Oxygen (in Ozark Highland streams is 6 mg/L). • "Narrative Criteria" are used when pollutants cannot be precisely measured, and are used to express a parameter in a qualitative form such as for Oil and Grease (“shall not be present…to the extent they produce globules or other visible, colored film on the surface….”)

  5. Laws and Regulations • Section 303(d) of the CWA requires states to develop a list of impaired waterbodies • This list is known as the 303(d) list • Any waterbody that does not meet WQSs for one or more criteria or fails to support one of its designated uses is considered impaired • The CWA requires states to update their 303(d) list every two years

  6. ADEQ’s Responsibilities under the Clean Water Act • ADEQ is responsible for: • Assessing surface waters to determine if they meet water quality standards [CWA §305(b) report] • ~150 Ambient monitoring stations sampled every month • Five years of data constitutes the period of record • 3 currently active stations on Crooked Creek • Identifying those waters that do not meet standards [CWA §303(d) List of Impaired Waters]

  7. Total Maximum Daily Loads Section 303(d) of the CWA requires states to develop a list of impaired waterbodies and, once listed, “[e]ach state shall establish…the total maximum daily load…” for each pollutant in each impaired waterbody

  8. What is a Total Maximum Daily Load (TMDL)? • A federally mandated planning tool to help an impaired waterbody attain water quality standards • Calculates the amount of a contaminant, from all natural and man-made sources, that a waterbody can receive and still meet all water quality standards • Must be written within 13 years of being listed • TMDLs become the basis for effluent limitations and discharge permit limits

  9. Why Are TMDLs Needed? • TMDLs are intended to reduce loadings of pollutants to bring a waterbody back into compliance with water quality standards • A new source or discharge into an impaired waterbody cannot be permitted unless the owner/operator first demonstrates: • Sufficient pollution load allocation remains to allow the new discharge • Existing dischargers are subject to compliance schedules designed to bring the waterbody into compliance with standards [40 CFR § 122.4(i)(2)]

  10. How is a TMDL created? • A TMDL is a scientific analysis ranging from simple mass balance calculations to complex computer simulation modeling that: • Is based on actual water quality monitoring data and the best available river flow data from: • ADEQ • Private labs that follow approved guidelines • State and federal agencies that follow approved guidelines

  11. Components of a TMDL • Sum of loads allowed to enter a waterbody that still enables that waterbody to meet water quality standards • Wasteload allocations (WLA) from point sources • Load allocations (LA) from nonpoint sources and natural background • Margin of safety (MOS)

  12. Summary • Assess the quality of the state’s water every 2 years • Determine if water quality standards are attained • List impaired waterbodies (303(d) List) • Develop a TMDL for each pollutant for each listed waterbody • EPA approves or disapproves TMDL • Take into consideration total maximum daily loads in subsequent regulatory actions, where appropriate

  13. What makes up a TMDL Document? • Elements of a typical TMDL document: • Applicable WQS & Numeric Water Quality Target • Loading Capacity • Load Allocations and Waste Load Allocations • Margin of Safety • Consideration of Seasonal Variation • Monitoring Plan to Track TMDL Effectiveness • Implementation Plan • Public Participation

  14. Public Participation • Public participation is encouraged by: • Reviewing and commenting on the 303(d) list • Reviewing and commenting on draft TMDLs

  15. TMDLs in Arkansas • The Arkansas Department of Environmental Quality (ADEQ) is responsible for TMDL development and submission to EPA. Should ADEQ fail to produce TMDLs, then EPA will • Approximately 250 TMDLs have been completed in Arkansas • In no case has a landowner had to relinquish any rights in order to fulfill TMDL requirements

  16. Current TMDL Program • EPA published guidelines in 1992 to govern TMDL procedures • Consent decrees or settlement agreements guide TMDL schedule and priorities in many instances

  17. TMDL Litigation • The Sierra Club brought a lawsuit against the EPA for failure to disapprove Arkansas’s 1998 303(d) list • In 2000, EPA entered a Consent Decree and agreed to timely review Arkansas’ next 303(d) list (2002), which was to include: • Approximately 150 additional stream segments and 30 lakes • Or provide a waterbody specific justification as to why the stream segments were not listed • The Consent Decree established a schedule for the completion of 180 TMDLs during 2001-2010

  18. Nationwide/Arkansas TMDL’s • Impaired Waters: • Nationwide - 41,416 • Arkansas - 224 • TMDL’s approved since 1995: • Nationwide – 46,705 • Arkansas – 250 • TMDL’s nationwide for TDS, chlorides and sulfates - 1445 Data from:

  19. Crooked Creek Watershed • Originates in the Ozark Mnts. near Harrison, & flows eastward to the White River • The drainage area is ~ 462 sq. mi. • Ozark Highlands ecoregion • 94% of the watershed is forest or grass • 3 continuous point source discharges • City of Yellville • City of Harrison • DM Petroleum Cleanup • 33 regulated stormwater discharges

  20. Crooked Creek Impairment • Reach 048 (downstream reach) & reach 049 (upstream reach) • Pollutants causing the impairments were listed as total dissolved solids (TDS) for reach 048 and chloride, sulfate, & TDS for reach 049 (added in 2004 and reviewed in subsequent reports). • The suspected pollutant sources were listed as “resource extraction” & “unknown”.

  21. Use Attainability Analysis • What is a UAA • “structured scientific assessment of the factors affecting the attainment of the use” 40CFR131.3(g) • A UAA must be conducted to justify: • Removing a fishable/swimmable designated use, which is not an existing use, from a waterbody • To identify a subcategory of a fishable/swimmable use which requires less stringent criteria

  22. UAA’s cont. • Reg. 2.303 - The UAA must demonstrate that the designated use is not attainable because: • A Naturally occurring pollutant prevents the attainment of the use; or • Natural water levels prevent the attainment of the use unless effluent discharge enables the use to be met; or • Human caused pollution prevents attainment of the use & cannot be remedied or would cause more environmental damage to correct than leave in place; or • Hydrologic modifications preclude the attainment of the use • Natural physical features of a waterbody unrelated to water quality preclude attainment of aquatic life protection uses; or • Controls more stringent than those required by §301(b) & 306 of the Act would result in substantial & widespread economic & social impact.

  23. UAA Process • Workplan submission and approval • Conduct UAA • Water quality sampling, biological assessments • Demonstrate that existing uses will be maintained • Follow CPP and Reg. 2 Requirements (Reg. 2.303 and 2.306) • Submit petition to APC&EC to initiate rulemaking to change Regulation 2 • Public participation • Legislative Review • Commission – Adoption/Denial • EPA – Approval/Denial/No Action

  24. Questions?