TOTAL MAXIMUM DAILY LOADS: TMDL 101 Robyn Saunders, Senior Project Manager
October 3, 2012
ROBYN SAUNDERS • 15+ years Stormwater Expertise • Senior Project Manager • Regulatory Specialist with Engineering
Skills and Willingness to Communicate
Founded in 1964 25 offices throughout Northeast
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The Stick: An Overview of TMDLs and Implications for Municipalities, State Agencies and Landowners. TMDLS have become a common mechanism to require municipalities, state agencies and land owners to address impaired waters. Given the increasing and rapidly evolving applications of TMDLs, it is important for all municipalities to understand what TMDLs are, how the obligations apply, and when to take action to maintain compliance with the Clean Water Act and permit regulations.
•Introduced in the Senate as S. 2770 by Edmund Muskie (D–ME) on October 28, 1971 •Committee consideration by: Senate Public Works Committee •Passed the Senate on November 2, 1971 (86-0) •Passed the House on March 29, 1972 (passed) •Reported by the joint conference committee on October 4, 1972; agreed to by the House on October 4, 1972 (366-11) and by the Senate on October 4, 1972 (74-0) •Vetoed by President Richard Nixon on October 17, 1972 •Overridden by the Senate on October 17, 1972 (52-12) •Overridden by the House and became law on October 18, 1972 (247-23)
What happens if a waterbody doesn’t attain WQ Standards?
• Bad Report Card
• “…get written up in a report…”
Comments due by January 10, 2014
Hint: TMDL
What happens if a waterbody doesn’t attain WQ Standards?
• Bad Report Card
• “…get written up in a report…”
So, what exactly is a TMDL?
• “Pollution budget” for receiving waters to still meet WQ standards
Pollutant Contributions
Point SourcesNon-point SourcesMargin of SafetyBackground
Σ WLA Σ LA + MOS + Background
TMDL
Presenter
Presentation Notes
Background info: Under section 303(d) of the Clean Water Act, states, territories, and authorized tribes are required to develop lists of impaired waters. These are waters that are too polluted or otherwise degraded to meet the water quality standards set by states, territories, or authorized tribes. The law requires that these jurisdictions establish priority rankings for waters on the lists and develop TMDLs for these waters. A Total Maximum Daily Load, or TMDL, is a calculation of the maximum amount of a pollutant that a waterbody can receive and still safely meet water quality standards.
What is a TMDL?
• Total Maximum Daily Load for impaired waters • Requirement of the Clean Water Act Section 303(d)
– WQ standards – Pollutant specific – Calculations
As of June 2012: 41,173 Impaired Waters in U.S.
47,022 TMDLs since 1995
Presenter
Presentation Notes
Background info: Under section 303(d) of the Clean Water Act, states, territories, and authorized tribes are required to develop lists of impaired waters. These are waters that are too polluted or otherwise degraded to meet the water quality standards set by states, territories, or authorized tribes. The law requires that these jurisdictions establish priority rankings for waters on the lists and develop TMDLs for these waters. A Total Maximum Daily Load, or TMDL, is a calculation of the maximum amount of a pollutant that a waterbody can receive and still safely meet water quality standards. Regulations governing the TMDL program (40 CFR 130.2 and 130.70) define the TMDL as “the sum of the individual wasteload allocations (WLAs) for point sources and load allocations (LAs) for nonpoint sources.” Storm water discharges that are regulated under Phase I or Phase II of the NPDES storm water program are point sources that must be included in the WLA portion of a TMDL. Where a TMDL has been approved, NPDES permits must contain effluent limits and conditions consistent with the requirements and assumptions of the wasteload allocations in the TMDL. Effluent limitations to control the discharge of pollutants generally are expressed in numerical form.
What is a TMDL?
Impaired Waters in U.S. • 2012: 41,173 • 2013: 41,509
TMDLs in US since 1995 • 2012: 47,022 • 2013: 51,107
– Source:
www.EPA.gov
Presenter
Presentation Notes
Background info: Under section 303(d) of the Clean Water Act, states, territories, and authorized tribes are required to develop lists of impaired waters. These are waters that are too polluted or otherwise degraded to meet the water quality standards set by states, territories, or authorized tribes. The law requires that these jurisdictions establish priority rankings for waters on the lists and develop TMDLs for these waters. A Total Maximum Daily Load, or TMDL, is a calculation of the maximum amount of a pollutant that a waterbody can receive and still safely meet water quality standards. Regulations governing the TMDL program (40 CFR 130.2 and 130.70) define the TMDL as “the sum of the individual wasteload allocations (WLAs) for point sources and load allocations (LAs) for nonpoint sources.” Storm water discharges that are regulated under Phase I or Phase II of the NPDES storm water program are point sources that must be included in the WLA portion of a TMDL. Where a TMDL has been approved, NPDES permits must contain effluent limits and conditions consistent with the requirements and assumptions of the wasteload allocations in the TMDL. Effluent limitations to control the discharge of pollutants generally are expressed in numerical form.
What is required by a TMDL? All NPDES-Permitted Discharges must:
• Comply with TMDL • Not cause or contribute to WQ violation
Pollutant Contributions
Point SourcesNon-point SourcesMargin of SafetyBackground
Σ WLA Σ LA + MOS + Background
TMDL
Presenter
Presentation Notes
Regulations governing the TMDL program (40 CFR 130.2 and 130.70) define the TMDL as “the sum of the individual wasteload allocations (WLAs) for point sources and load allocations (LAs) for nonpoint sources.” Storm water discharges that are regulated under Phase I or Phase II of the NPDES storm water program are point sources that must be included in the WLA portion of a TMDL. Where a TMDL has been approved, NPDES permits must contain effluent limits and conditions consistent with the requirements and assumptions of the wasteload allocations in the TMDL. Effluent limitations to control the discharge of pollutants generally are expressed in numerical form.
What is required by a TMDL? • Municipal Separate Storm
Sewer System (MS4) – Pipes – Ditches – Connections
• Construction • Industrial Discharges
– Paper and lumber mills – Manufacturing – Auto salvage yards – Marinas – …and more…
• Post-construction Discharges in Long Creek Watershed
NPDES = Umbrella Permit
Presenter
Presentation Notes
Where a TMDL has been approved, NPDES permits must contain effluent limits and conditions consistent with the requirements and assumptions of the wasteload allocations in the TMDL. Effluent limitations to control the discharge of pollutants generally are expressed in numerical form.
What is required by a TMDL? NPDES = Umbrella Permit
Presenter
Presentation Notes
Cease and desist
RS
What else should we know about TMDLs? NEW APPROACH! Non-Specific TMDLs • Source: Urban runoff, unknown, unspecified • Surrogate: Impervious Cover (IC), hydrology • Area: Watershed, Statewide
Existing Non-Specific TMDLs: • Connecticut • Maine • Vermont TMDL Amount of pollutant a waterbody can tolerate while still meeting water quality standards “Permittees should demonstrate measurable
progress” to avoid enforcement , potential legal action, etc.
However, in light of 33 U.S.C. §1342(p)(3)(B)(iii), EPA recommends that for NPDES-regulated municipal and small construction storm water discharges effluent limits should be expressed as best management practices (BMPs) or other similar requirements, rather than as numeric effluent limits. The Interim Permitting Approach Policy recognizes the need for an iterative approach to control pollutants in storm water discharges. Specifically, the policy anticipates that a suite of BMPs will be used in the initial rounds of permits and that these BMPs will be tailored in subsequent rounds. EPA’s policy recognizes that because storm water discharges are due to storm events that are highly variable in frequency and duration and are not easily characterized, only in rare cases will it be feasible or appropriate to establish numeric limits for municipal and small construction storm water discharges. The variability in the system and minimal data generally available make it difficult to determine with precision or certainty actual and projected loadings for individual dischargers or groups of dischargers. Therefore, EPA believes that in these situations, permit limits typically can be expressed as BMPs, and that numeric limits will be used only in rare instances. Where the NPDES permitting authority allows for a choice of BMPs, a discussion of the BMP selection and assumptions needs to be included in the permit’s administrative record, including the fact sheet when one is required. 40 C.F.R.§§ 124.8, 124.9 & 124.18. For general permits, this may be included in the storm water pollution prevention plan required by the permit. See 40 C.F.R. § 122.28. Permitting authorities may require the permittee to provide supporting information, such as how the permittee designed its management plan to address the WLA(s). See 40 C.F.R. § 122.28. The NPDES permit must require the monitoring necessary to assure compliance with permit limitations, although the permitting authority has the discretion under EPA’s regulations to decide the frequency of such monitoring. See 40 CFR § 122.44(i). EPA recommends that such permits require collecting data on the actual performance of the BMPs. These additional data may provide a basis for revised management measures. The monitoring data are likely to have other uses as well. For example, the monitoring data might indicate if it is necessary to adjust the BMPs. Any monitoring for storm water required as part of the permit should be consistent with the state’s overall assessment and monitoring strategy.
Impervious Cover Model (ICM) revised • Range of IC% • Restoration feasible? • ROI • Measurable Progress • MS4 Applicability
Presenter
Presentation Notes
EPA’s policy recognizes that because storm water discharges are due to storm events that are highly variable in frequency and duration and are not easily characterized, only in rare cases will it be feasible or appropriate to establish numeric limits for municipal and small construction storm water discharges. The variability in the system and minimal data generally available make it difficult to determine with precision or certainty actual and projected loadings for individual dischargers or groups of dischargers. Therefore, EPA believes that in these situations, permit limits typically can be expressed as BMPs, and that numeric limits will be used only in rare instances. Where the NPDES permitting authority allows for a choice of BMPs, a discussion of the BMP selection and assumptions needs to be included in the permit’s administrative record, including the fact sheet when one is required. 40 C.F.R.§§ 124.8, 124.9 & 124.18. For general permits, this may be included in the storm water pollution prevention plan required by the permit. See 40 C.F.R. § 122.28. Permitting authorities may require the permittee to provide supporting information, such as how the permittee designed its management plan to address the WLA(s). See 40 C.F.R. § 122.28. The NPDES permit must require the monitoring necessary to assure compliance with permit limitations, although the permitting authority has the discretion under EPA’s regulations to decide the frequency of such monitoring. See 40 CFR § 122.44(i). EPA recommends that such permits require collecting data on the actual performance of the BMPs. These additional data may provide a basis for revised management measures. The monitoring data are likely to have other uses as well. For example, the monitoring data might indicate if it is necessary to adjust the BMPs. Any monitoring for storm water required as part of the permit should be consistent with the state’s overall assessment and monitoring strategy.