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Total Maximum Daily Loads (TMDLs)
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Yvonne Baker
Water Permits Division
LDEQ
TMDL Defined• TMDL = WLA + LA + MOS
WLA = Waste Load Allocation for point source loads LA =Load Allocation for nonpoint source load MOS = Margin Of Safety (account for
uncertainty/growth)
• TMDLs establish the maximum amount of loading that a waterbody can assimilate while maintaining the established water quality criteria.
TMDL DefinedTMDLs:• Can be developed for any parameter that can be
expressed as a load• Set limitations on waterbodies based on
established target values (standards or criteria) • Can be expressed as various statistical functions
at various frequencies• Can be expressed in terms of load reductions
through Best Management Practices (BMPs) when appropriate
TMDL Regulations• TMDLs requirements were established in Section 303(d) of
the Clean Water Act; additional clarification is provided in the Code of Federal Regulations (40 CFR 130.7)
• States must: identify impaired waters establish priority ranking establish TMDLs for those pollutants suspected to cause
the impairments• TMDLs must be completed for all waterbody/parameter
combinations, but a higher priority is given to impaired waterbodies.
• If states do not develop TMDLs for impaired waters, EPA will.
Primary Steps in TMDL Development
• Waterbodies are defined as regulatory subsegments by Louisiana’s Environmental Regulatory Code (ERC 33:IX.1123).
• Waterbodies defined as subsegments are assessed as part of the 305(b) report
• Waterbodies that fail their assessments are placed on the 303(d) list and scheduled for TMDL development
Primary Steps in TMDL Development
• Collect and analyze all needed data. Gather all available hydrologic data, water quality data,
and stream characterization information. Conduct field surveys - particularly for dissolved oxygen
TMDLs.• Calculate TMDLs, WLAs, LAs, and load reductions. For
dissolved oxygen and possibly fecal coliform, this involves the development of computer models.
• Write the draft report• Public review• Address comments and finalize the TMDL• EPA approval (only for impaired waterbodies)
Kimberly CortsLDEQ/Water Permits Division
MS4s in Louisiana
How is Storm Water Regulated Under the LPDES Program?Phased approach to regulation consistent with federal
regulations:– Phase I: Regulated discharges from large and
medium MS4s, large construction projects, and industrial activity - §402(p)(2)
– Phase II: Regulated discharges from small MS4s and small construction projects - §402(p)(6)
List of LA MS4 Permittees• Large and Medium MS4s (Individual Permit
Coverage):– 4 large MS4s are permitted– New Orleans, Baton Rouge, Shreveport, and
Jefferson Parish• Small MS4s:
– Covered under the general permit, LAR040000– 44 MS4s have obtained coverage
2010 Census• Currently, permitted MS4s were required to obtain coverage
based on the 2000 census• Based on the 2010 census several communities have been
identified as needing permit coverage and will be required to develop a Storm Water Management Plan and many currently permitted areas have expanded.
• The urbanized area maps are used as the basis for MS4 requirements, although LDEQ may designate MS4s using other population information
MS4 GIS Layer
Permitting Challenges• TMDLs have recently been developed/approved in heavily
impacted areas – East Baton Rouge, Livingston, Ascension Parishes and along the north shore of Lake Pontchartrain that include allocations for MS4s
• EPA intends on proposing a new rule in 2013, which could change the requirements for small MS4s – who is considered “regulated”, new construction/redevelopment requirements, etc
Upcoming TMDL Changes
Urban Pollutants Associated with MS4s
• Sediment from Construction Sites• Oil and Grease From Parking Lots and Streets• Nutrients and Pesticides from Lawns and Golf Courses• Storm water runoff from all existing and new development
(residential and commercial)• Metals such as dissolved lead caused by atmospheric
deposition
EPA’s 2002 Guidance Memorandum Regarding Wasteload Allocations for
Stormwater Sources• “National Pollutant Discharge Elimination System (NPDES)-regulated
stormwater discharges must be addressed by the wasteload allocation (WLA) component of a TMDL.”
• “NPDES-regulated stormwater discharges may not be addressed by the load allocation (LA) component of a TMDL.”
• “Stormwater discharges from sources not currently subject to NPDES regulation may be addressed by the load allocation component of a TMDL.”
EPA’s 2002 Guidance Memorandum Regarding Wasteload Allocations for
Stormwater Sources
• “It may be reasonable to express allocations for multiple point sources as a single categorical wasteload allocation when data and information are insufficient to assign each source or outfall individual WLAs.”
• The WLAs and LAs are to be expressed in numeric form.
• Most effluent limits for MS4 permittees and small construction stormwater discharges will be in the form of BMPs; numeric limits used only in rare instances.
2010 Update to the 2002 EPA Memorandum
• Numeric WQBELs can clarify permit requirement and improve accountability and enforceability, based on the discretion of the permitting authority.
• WLAs for stormwater sources should be disaggregated in order to establish clear, effective, and enforceable NPDES permit limitations.
• Stormwater limitations may be established through the use of surrogate parameters-ex. turbidity vs. TSS.
• Permitting authorities should consider designating stormwater sources not currently regulated by NPDES permits as candidates for regulation.
ACWA Response to EPA’s 2010 Update to the 2002 Memorandum
• ACWA (Association of Clean Water Administrators) was formerly known as ASIWPCA (Association of State and Interstate Water Pollution Control Administrators)
• Implementation of 2010 memo will be difficult for many states.• Treating stormwater like point source effluent will “fail in achieving
significant environmental benefits”. • “Cost effective, environmentally sound, and sustainable stormwater
management is possible when the realities and uncertainties of stormwater science are acknowledged, and the “point source” NPDES regulatory framework is reworked to include this science.”
ACWA Response to EPA’s 2010 Update to the 2002 Memorandum
• Incorporating numeric limits into stormwater permits will be challenging – not all states have the resources (technology and funding) to do so.
• “States should be afforded significant flexibility to establish numeric effluent limitations in stormwater permits as part of this memorandum.”
• ACWA encouraged “EPA to consider the significant benefits that exist in regulating precipitation-driven discharges in a fundamentally different way than traditional, end of pipe, process waste point source discharges.”
Court Decision Regarding the Accotink TMDL
• Impairment was for sediment.• EPA established a TMDL in 2011.• TMDL used flow as a surrogate parameter for sediment.• On January 3, 2013, the United States District Court for the Eastern
District of Virginia issued its decision, vacating the TMDL.• The Court held that EPA lacked the authority under Section 303(d) of the
Clean Water Act to establish the Accotink TMDL using the Creek’s one- year, 24- hour storm flow rate, a non-pollutant measure, as a surrogate for the pollutant sediment.
• EPA has decided not to appeal, based largely on the fact that the State of Virginia has indicated it will develop a replacement TMDL.
LDEQ Interim Solution• Dissolved oxygen TMDLs: the critical low flow is 7Q10, stormwater is not present at
that time. Include statements indicating that the allocation for all
stormwater loading from point sources is 0.0 lb/day under critical flow conditions.
Allocate a portion of the nonpoint load to the MS4 based on drainage area ratios.
Include statement that the load is not to be interpreted as a permit limit
LDEQ Interim Solution
• LDEQ realizes that this will not be adequate for all cases.
• Future TMDLs may include dynamic modeling to account for
storm events. may be developed for high flow conditions.
• Reevaluate and revise criteria where appropriate
In Summary• EPA guidance and recommendations have indicated a desire
for numeric limitations for MS4s.• This may be very costly for MS4 permittees due to the
increase in monitoring sites and frequency.• TMDLs may require the development of dynamic/spatial
models which are very complex and resource intensive. • EPA is revising stormwater regulations; intends to propose
revisions by June, 2013.
Complying with the TMDL Requirements
Recent DO TMDLs (Bayou Manchac, Gray’s Creek, Bayou Lacombe, Tchefuncte River, etc.) specify that BMPs are the most appropriate method of addressing the TMDL to reduce the nonpoint source loading as well as eliminate illicit discharges.
LAR04 Requires…
Documentation is the key….
Permittees must document in their SWMP how the BMPs and other controls implemented in the SWMP will control the discharge of any pollutant(s) of concern (POCs) for discharges into a receiving water which has been listed on the Clean Water Act 303(d) list of impaired waters.
If a TMDL has been approved for a waterbody, the permittee will be required to include any TMDL requirements in the SWMP that are applicable to MS4 discharges.
LAR04 Requires…If a TMDL allocation has been assigned for specific pollutants, which are identified as impairments attributed to discharges from regulated MS4s, then the permittee must modify the storm water management program to implement the TMDL within six months of the TMDL’s approval or as otherwise specified in the TMDL. This requirement includes TMDLs that are developed during the term of this general permit.
In addition to any MS4-specific requirements of the TMDL, the permittee must also: 1) implement storm water controls that specifically target the pollutant(s) of
concern 2) identify a measurable goal for the pollutant(s) of concern and 3) implement a monitoring program to assess whether or not the storm water
controls are adequate to meet the WLA.
Part IV.H Impaired Waterbodies with an Approved
TMDL
If a Waste Load Allocation (WLA) has been assigned to discharges of a particular pollutant from your MS4 to a particular basin subsegment:
1. You must include specific and measurable goals in your SWMP targeting the pollutant(s) of concern. Include details, such as identifying areas of focused effort or implementing additional control measures or BMPs that will reduce the pollutant(s) of concern. A schedule for implementing each targeted control shall be included in the SWMP.
Part IV.H Impaired Waterbodies with an Approved
TMDL
2. The permittees shall adopt any assigned Waste Load Allocations (WLAs) as a benchmark goal in the SWMP. The benchmark goal is not a permit limit, but shall be used to measure the progress towards achieving pollutant reductions from the MS4. If the benchmark goal is met, the permittee shall maintain the control measures, BMPs, or other pollutant reduction programs necessary to ensure the goal will continue to be met.
3. If applicable, the permittee must comply with monitoring or compliance schedules established in the TMDL.
Part IV.H Impaired Waterbodies with an Approved
TMDL
4. The permittees shall select one or more of the following recommended controls, or develop other controls that may best achieve the pollutant reduction goals. The following storm water control measures address nutrient, dissolved oxygen, sediment, and/or bacteria impairments.
a. Prioritize the detection and elimination of illicit discharges contributing the pollutant(s) of concern to the MS4.
b. Implement public education measures to reduce the discharge of bacteria and nutrients contributed by pets, livestock, and zoos.
Part IV.H Impaired Waterbodies with an Approved
TMDL
c. Implement a public education program to reduce the discharge of nutrients from the over application of residential and commercial fertilizers. d. Implement programs to reduce the pollutant contributions to the MS4 from failing on-site sewage treatment systems, such as septic tanks and small package plants. Such a program could include requiring the replacement of old septic tanks, regionalization of heavily populated areas without a centralized waste treatment facility, and/or extension of existing sewage treatment lines.
Part IV.H Impaired Waterbodies with an Approved
TMDL
e. Implement programs to enhance the MS4’s sanitary sewer systems. Such a program should address inadequate collection systems, malfunctioning lift stations, or violations of the sewage treatment plant’s water discharge permit. f. For construction activities, require a minimum buffer zone adjacent to surface waters to reduce erosion and sediment runoff.
Part IV.H Impaired Waterbodies with an Approved
TMDL
5.You must implement a monitoring program to determine whether the storm water controls that you have selected are adequate to meet the WLA. Each permitted MS4 must develop a monitoring program that is specific to the selected BMPs and will be an effective tool to determine if measurable goals are being met. Document in your SWMP the reason and justification for the parameters and frequencies selected and how the monitoring program will effectively evaluate storm water controls. Monitoring programs may include, but are not limited to, the following elements:
Part IV.H Impaired Waterbodies with an Approved
TMDL
a. Regular visual inspections of outfalls during wet and dry weather;
b. Regular inspections of receiving water bodies with the purpose of noting erosion or sedimentation problems;
c. Regular inspections of storm drains, major canals, or junctions;
d. Visual inspections of effluent samples for color, clarity, and the presence of foam, oil, debris, or noxious odors;
Part IV.H Impaired Waterbodies with an Approved
TMDL
e. Instantaneous (in situ) water quality measurements of the receiving
water body, such as dissolved oxygen, temperature, pH, etc.; and
f. Sampling and analysis of storm water discharges for pollutants of concern.
The permittee must also conduct any monitoring, including specific
frequencies, required by applicable TMDLs.
Part IV.H Impaired Waterbodies with an Approved
TMDL
6. The permittees must evaluate the effectiveness of the storm water management program and document progress towards the benchmark goal(s). The MS4 operator may utilize third party data, such as that collected by LDEQ, USGS, EPA, and volunteer organizations in the evaluation process. However, the evaluation shall not be limited to only third party data. If subsequent evaluations show that additional or modified controls are necessary to meet the WLA for a particular pollutant then you must describe the additional or modified controls that will be implemented and include a schedule for implementation. You must continue to evaluate the adequacy of the BMPs that you have implemented to meet the WLA for a particular pollutant. Make modifications to the SWMP as necessary until monitoring for a full permit cycle shows that the WLAs are being met or that the MS4 is no longer contributing to the water quality impairment.
Monitoring
• Monitoring does not necessarily refer to laboratory-analyzed samples only
• Regular visual inspections of outfalls are acceptable!• Some storm water samples may be taken to establish overall
load coming from the MS4 (BOD, COD, TSS, possibly nutrients)• Frequencies and types of monitoring are established by the MS4
permittee
What is an outfall?
An outfall is the point at which any conveyance of a storm sewer system discharges to surface waters of the state – does not include pipes, tunnels, or ditches that connect two storm sewers.
DOTD outfalls are a little different and may include bridges that cross water bodies.
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Bayou Manchac and other Lake
Pontchartrain Basin TMDLs• New Dischargers:Submit an environmental impact assessmentUpon evaluation of the factors associated with the
environmental impact assessment:o Permits with 5 BOD5/ 2 NH3/ 5 DO; or limits not to
exceed 10 BOD5 /2 NH3-No No discharge scenarios (flow elimination, effluent
reduction, hydrographic release, reuse)
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Bayou Manchac and other Lake
Pontchartrain Basin TMDLs• Existing Dischargers:Up to 3 year compliance scheduleMore stringent limitationsoFacilities currently with limitations of 30
BOD5 will receive limitations of 10 BOD5
oFacilities currently with limitations of 10 BOD5 will receive limitations of 5 BOD5
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Bayou Manchac and other Lake Pontchartrain Basin TMDLs
• MS4 regulated areas expected to use BMPs to address documented impairments
and TMDLs BMPs may include:
oPublic educationoProjects to reduce impervious surfacesoRetention pondsoStorm drain trapsoLocation/elimination of unpermitted dischargers
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Options for Affected Parties
• Regionalization• Local Ordinances• Wetland Assimilation• Innovative Technologies for no discharge scenarios
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Regionalization
• More affordable treatment option Cost per gallon of wastewater decreases as
treatment capacity increases• Fewer treatment facilities to operate and maintain• Potentially fewer waterbodies impacted• Moves discharges out of neighborhood ditches
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Local Ordinances• Require approval from DEQ prior to issuing building
permit Request for Preliminary Determinations Receive Final Permit Before Construction
• Do NOT allow developers to utilize individual home treatment units when developing subdivisions.
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Wetland Assimilation• Benefits of a Wetlands Assimilation Project for the Environment
– Removes direct discharges of treated wastewater into state waterbodies
– Can help prevent saltwater intrusion into the wetland – Add an abundance of needed nutrients into the wetland to stimulate
plant growth – Carbon sequestration
• Benefits for a Permittee– Less operations and maintenance costs – Secondary Limitations – A “green” approach to wastewater treatment
• Link to Wetlands Assimilation Webpage: http://www.deq.louisiana.gov/portal/tabid/2960/Default.aspx
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Innovative Technologies
• No Discharge ScenariosRecycle Reuse
• Hydrographic Release
Websites
Access to Louisiana TMDLs or notifications can be obtained at:
http://www.deq.louisiana.gov/portal/default.aspx?tabid=1563
http://www.epa.gov/region6/water/npdes/tmdl/index.htm
http://louisiana.gov/Services/Email_Notifications_DEQ_TMDL/
Contact Information
Yvonne Baker Environmental Scientist Senior
TMDL contact– Chuck Berger,
DCL Senior 225.219.3366
Questions
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